Sunday, June 30, 2019

Case Studies and Examples - Productivity Engineering - Process Industrial Engineering - Methods Industrial Engineering


Case Studies,  Examples and Developments - Productivity Engineering - Process Industrial Engineering - Methods Industrial Engineering - Method Study

Process Industrial Engineering - Methods and Techniques


Identifying, Analyzing and Installing High Productivity Equipment and Machines
Identifying, Analyzing and Utilizing High Productivity Special Processes
Developing special purpose machines
Installing accessories for productivity improvement
Using Jigs and Fixtures
Using more productive tools
Using new lubricants
Using new cutting fluids
Cutting parameters optimization
Process parameters optimization
SMED
Poka Yoke
Machine Work Study
Operation Analysis
Process Analysis
Electric power consumption analysis and reduction
Predictive maintenance
Preventive maintenance
OEE improvement
Manufacturing Cost Policy Deployment (MCPD)

Objectives - Productivity Engineering - Process Industrial Engineering


Zero Waste, Zero Defects, Zero Breakdowns, Zero Stocks, Zero Resources (Investment)

Source: Improving Operations Performance with World Class Manufacturing Technique: A Case in Automotive Industry

Industrial Engineering Redesign of Products and Processes in Different Technologies
https://nraoiekc.blogspot.com/2019/04/industrial-engineering-redesign-of.html

3D Printing - Additive Manufacturing Industrial Engineering
https://nraoiekc.blogspot.com/2017/08/3d-printing-additive-manufacturing.html

Industrial Engineering of Welding Processes
https://nraoiekc.blogspot.com/2019/04/industrial-engineering-of-welding.html

Machine Work Study 


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2019


July 2019

Design Development and Performance Improvement of Heavy Duty Vertical Turning Lathe Machine Tool
International Journal of Innovative Technology and Exploring Engineering (IJITEE), Volume-8 Issue-8S, June 2019
https://www.ijitee.org/wp-content/uploads/papers/v8i8s/H11240688S19.pdf

Using IBM Blueworks Live For Lean Six Sigma and Process Improvement
https://mediacenter.ibm.com/media/t/1_gh6trn2m


Line productivity audits
https://www.sidel.com/en/line-improvement/line-audits-sv1-8

Carolyn Dewar
Delivers large-scale performance-improvement programs that foster culture change and counsels senior executives making leadership transitions
June 10, 2019
In McKinsey  Organizational Health Index (OHI) of almost 2,000 companies, 62 percent were pursuing continuous improvement as a means of moving from good to great.
https://www.mckinsey.com/business-functions/organization/our-insights/the-organization-blog/continuous-improvement-the-realities-of-making-the-shift

Whitlock Consulting Group  Process Review and Improvement

In this effort WCG consultants will assess all business systems and specify current insufficiencies – both in technology and process.
The first step of this assessment will be to collectively create an exhaustive list of processes needing analysis and all systems in use, then conduct on-site meetings with the power users to fully understand the organization’s daily processes and observe the systems in real-time operation. WCG will then take this information to build a process-by-process analysis that will list out specific process and system insufficiencies.

The above insufficiencies will then be paired with possible improvement opportunities given the solutions that exist in the market today. WCG will help identify whether these improvements can come from updating current configuration, streamlining internal processes, whether a system upgrade would address the issue, whether a system replacement would be needed, or finally, if another peripheral technology upgrade could deliver the desired improvement.

Manufacturing
Smart Industrial Solutions
WCG can help your company navigate the many IoT and other advanced technology options and identify the best solutions for your production environment & processes.

Smart manufacturing is about creating an environment where all available information—from within the plant floor and from along the supply chain—is captured in real-time, made visible and turned into actionable insights. Smart manufacturing comprises all aspects of business, blurring the boundaries among plant operations, supply chain, product design and demand management. Enabling virtual tracking of capital assets, processes, resources and products, smart manufacturing gives enterprises full visibility which in turn supports streamlining business processes and optimizing supply and demand.
WCG’s process engineering and product costing expertise spawns from vast experience with some of the world’s leading manufacturing and engineering firms. Let WCG leverage this insight into valuable process optimizations and system solutions for your company.

WCG services for providing Smart Industrial Solutions include:

Needs Assessment & Gap Analyses
Assess gaps in processes, identify process redundancies, communication silos, inefficiencies/risk
Introduce advanced technology options
Software & Technology Selection
Build technical requirements, interface plan, and SOW
Business Application System Implementations
Process mapping with new technology
Testing & Training
Project Management / Vendor & Deliverable oversight
IoT Integration
Scenario Planning
Mobile Work Management Integration
Standard Cost Development
Executive Dashboards
Project Calculations for expansion & new ventures
Budgeting & Projections
Various Cost / Profit Analyses
Application of Industry 4.0

Law of diminishing returns in regards to cost cutting and efficiency improvements
You can effectively cut the first 10% w incremental changes (ie scale, standardization) but the next 10% is much more difficult
You must apply different principles and approaches to achieve that next level and to become a market leader
I4.0 is not simply a one-stop, plug and play product
It is a piece-mealed solution that requires the proper infrastructure, updated processes, resources, and data management
Connectivity can tie machine performance to KPIs to enable machine-as-a-service purchasing agreements (subscription method where payments are tied to KPIs)

https://www.wcg-consulting.com/process-improvement/

June 2019

Work System Design Dr. Inderdeep Singh Department of ... - NPTEL
textofvideo.nptel.ac.in/112107249/lec15.pdf

Increasing the Productivity by using Work Study in a Manufacturing Industry - Literature Review
https://www.researchgate.net/publication/323885075_Increasing_the_Productivity_by_using_Work_Study_in_a_Manufacturing_Industry_-_Literature_Review

Fitwel
Stand Up to Work Study
Stand Up to Work!: Recently published real-world research reinforces the benefits of sit-stand desks in the workplace
https://centerforactivedesign.org/standuptoworkstudy

Analysis on Production Efficiency of Lean Implemented Sewing Line: A Case Study
https://www.omicsonline.org/open-access/analysis-on-production-efficiency-of-lean-implemented-sewing-line-a-case-study-2165-8064-1000386-106569.html

Productivity Improvement in Automotive Industry by Using Method Study: A Review
ijrtsm.com/wp-content/uploads/2018/06/Shikha.pdf

Productivity improvement in chassis assembly line
www.ijesrt.com/issues%20pdf%20file/Archive-2018/June-2018/53.pdf


A Process Study of Lactic Acid Production from Phragmites australis Straw by a Thermophilic Bacillus coagulans Strain under Non-Sterilized Conditions

Phragmites australis straw (PAS) is an abundant and renewable wetland lignocellulose. Bacillus coagulans IPE22 is a robust thermophilic strain with pentose-utilizing capability and excellent resistance to growth inhibitors. This work is focused on the process study of lactic acid (LA) production from P. australis lignocellulose which has not been attempted previously.

Using the integrated process, 41.06 g LA was produced from 100 g dry PAS. The established integrated process results in great savings in terms of time and labor, and the fermentation process under non-sterilized conditions is easy to scale up for economical production of lactic acid from PAS.
https://www.mdpi.com/2227-9717/6/10/175


 Today, Morris is committed to Continuous Improvement (CI), a philosophy of which lean manufacturing is usually a positive byproduct. Jeet Jheetey, Manager of Corporate Systems and Continuous Improvement, explained how this philosophy has been implemented at Morris – and how it helped bring the Quantum to life.

Q. What does CI mean to Morris?

A. For Morris, CI is an ongoing effort to consistently strive to improve products, services, systems and processes. We do this by utilizing technological advancement in the most efficient way to make products of the highest standard.
https://www.morris-industries.com/blog/quantum-leap-how-continuous-improvement-shaped-morris-newest-drill/


AM Machine and Process Control Methods for Additive Manufacturing
Part quality in additive manufacturing (AM) is highly dependent on the process control, but there is a lack of adequate AM control
https://www.nist.gov/programs-projects/am-machine-and-process-control-methods-additive-manufacturing

Railway wheel manufacturing process improvement
The work summarises the results of research on railway wheel manufacturing process focused on reduction of the metal consumption index, material and energy savings, and better wheel performance reproducibility and durability. "EVRAZ NTMK" Open Joint Stock Company has completed a comprehensive and ambitious initiative to find and apply new technical solutions for improved converter treatment and secondary metallurgy, continuous casting processes, new process flow charts of wheel deformation processing by forging, rolling, dishing, restriking, and preforming.
https://www.researchgate.net/publication/299653398_Railway_wheel_manufacturing_process_improvement

John Barry & Associates
Engineering Excellence since 1954
Process Improvement
JBA’s background is heavy in industrial engineering and process improvement. JBA focuses on “Improve While You Move”. In many cases, we look to improve the process of manufacturing, assembly, and distribution in a proactive fashion early in the industrial space design.
JBA’s team of engineers, MBAs and project managers have a wealth of experience in improving productivity in industrial engineering best practices.
https://www.jbateam.com/process-improvement

MCPD
https://exegens.com/?lang=en


Siemens Easy Process Plan Software
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Feature-Based Framework for Inspection Process Planning
inspection process planning, including the design and selection of the technical system to realize the dimensional and geometrical verification of the manufactured artefacts, has been traditionally considered separately from the rest of the manufacturing process planning, and even also from the product functional specification tasks. In this work, a feature-based framework for inspection process planning, based on a similar approach to the one applied in GD&T (Geometrical Dimensioning & Tolerancing) specification, analysis and validation of product artefacts, is presented. With this work, the proposed framework and feature concept ability to model interaction components belonging to both the product and the inspection system (inspection solution) is proved.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6164215/


Process plan optimization: A case of plastic manufacturing company
www.newengineeringjournal.in/download/244/4-2-38-872.pdf


Relay RPRODUCTION LINE OPTIMIZATION
MAKING SMART.
SMART MANUFACTURING

Smart manufacturing is the primary goal of all production line digital transformation journeys, where the deployment of new technologies helps businesses gain control over their machines and processes. Smart manufacturing requires smart planning and delivery from the outset. There are myriad ways in which a production line’s data can be harvested and visualized. RelayR, helps you to determine the optimum deployment of sensors and process data for effective goal-oriented results.

Case Studies
https://relayr.io/production-line-optimization/



More Productive Machines


LEAN. MEAN. PRODUCTIVITY MACHINE.
More features that make the QUICKBOOSTTM fierce.
https://www.sanitairecommercial.com/pages/quickboost


Innovative automation solutions for additive manufacturing 2.0
Peter Berens  June 2018
http://blogs.boschrexroth.com/en/connected-automation-en/innovative-automation-solutions-for-additive-manufacturing-2-0/


We determined Azure SQL Database Managed Instance was the best choice for us in terms of scalability, cost, and performance.… We’ve seen a 49 percent cost reduction and 25 to 30 percent performance gains.
Nipun Sharma: Analytics Architect, Business Technology and Systems, Komatsu Australia
https://customers.microsoft.com/en-gb/story/komatsu-australia-manufacturing-azure

BLANKING SYSTEM

Master Blanker CBL
Master Blanker Top Range model "CBL"
The Master Blanker CBL is high-speed blanking machine that features automated removal, which used to be done by hand.
Fully automated including waste ejection product palletizing.
Specification
One pallet is completed in 7 minutes.7 to 8 pallets (24,000 to 28,000 sheets) per 1 hour.
This calculation is based on paper thickness of carton board as 0.4mm.
CBL saves 6 to 7 workers.
These productivity may change depends on job.
https://www.laserck.net/ms_cbl.html



Verification operations on large machine tools typically require ‘days’ of downtime. Checks are scheduled infrequently, and manufacturing schedules often result in them being cancelled altogether. When used, verification checks usually only measure single axes independently of one another and dynamic machine tests cover highly restricted small volumes, limiting their utility. INSPHERE’s BASELINE system places a high-accuracy laser tracker within a machine tool and tracks a target held in the machine’s tool-holder. A G-code program is then run to gather precise three-dimensional static and dynamic datasets throughout the working volume of the machine. It can be used in simple 3-axis machines, or equally easily in those with more complex configurations of linear and rotary axes. The system runs a rapid machine check, reducing machine verification downtime from five days to as little as one hour! This allows checks to be conducted far more frequently, INSPHERE NATEP 1generating deeper insights into machine performance. Clear, actionable data is generated for maintenance, and manufacturing process confidence can be increased.
http://www.natep.org.uk/BASELINE-Project

ACCUMECH PESADA laser cutting machines for High Prodictivity

• Low energy consumption.
• Low cost per component.
• Optimized focal distance for all thickness values.
• Maintenance free operation.
• Compact design, fast installation.
• Rigid body structure, high durability.
https://www.cncaccumech.com/fiber-laser-cnc/

SCORPION
DOUBLE BOX FILLING MACHINE
“PATENTED”
Scorpion is an automatic high-productivity machine for filling 60×40 cm with 10 punnets arranged in two lines of five (40×30 cm with 8 punnets arranged in two lines of four, for what concerning the SCORPION34 version).
It is possible to use both carton boxes and plastic containters (IFCO, CPR, STECO and similar).
SUITABLE FOR:
Strawberries, peaches, nectarines, kiwis, apricots, plums, tomatoes, avocados, citrus, cherries, green beans, pears, grape, zucchini, carrots, peppers, etc. (all products usually contained in punnets).
http://www.revsrl.com/en/portfolio/scorpion-double-box-filliing-machine/

Made for the city, the Volvo P2820D ABG and P2870D ABG are the most compact pavers in the Volvo line-up. The perfect partners for small-to-medium paving applications, they offer low operating cost, safety and operator comfort.
https://www.volvoce.com/europe/en/about-us/news/2019/compact-and-agile-volvo-p2820d-abg-and-p2870d-abg-pavers-run-rings-around-competition/


2019 ZMorph VX – Review the Specs of this Multitool 3D Printer
Picture of All3DP
by All3DP
Feb 7, 2019


A SEAS KIT TO INSTALL ON YOUR SEWING SYSTEM
Get more from a standard machine

The SEAS Universal Kit is a set of accessories that transform a normal sewing machine into a high quality and productivity machine to sew Silicone or PVC.
The focus on the development of this solution was to allow companies that already own a sewing machine to start or significantly increase the finishing of textile panels with Silicone or PVC Keder.
With a quick and easy installation, which can be done by any employee of the company, with intuitive use without the need for training, simple maintenance and reduced delivery times, this is the right solution for anyone who wants to be present in one of the areas of highest growth in the Soft Signage world.


Automated Clamp Carriers for Productivity - Taylor Dual Automated Line - James L. Taylor Manufacturing

Tandem Roald Roller | ct160 / ct260 - Kemach Equipment
kemachjcb.co.za/wp-content/uploads/2018/11/tandem-roller-CT160-CT260.pdf


 SPM, Special Purpose Machines is a high productivity machine which is committed for mass production. We find ourselves great at designing the SPM as per need of our clients. All we need is the basic idea of your operation and after that just leave it to us.

Designing a machine from scratch, with just a concept is what we do here at technocadd, machine designing is a broad area where our expertise shows there intellectual skills to design a complete machine as per the need of our clients. Here’s some of our Machine design works to catch your eyes
https://technocaddapl.com/our-work

SEM 656D – Five Ton
WHEEL LOADERS
The perfect model for a range of applications but especially for those requiring high productivity. Machine characteristics:

Durable: The sturdy design makes it the perfect machine for port cargo handling, mineral yards, steel mills and other demanding applications.

Efficient: In quarry, aggregate and coal mining applications the 656D can load more, move faster and burns less fuel.

Versatile: Multiple work tools are available for varied delivery.
https://www.deltatanzaniasem.com/portfolio-item/sem-wheel-loader-656d/


midi excavator | 65r-1/67c-1 - Hunter JCB
Increzsed  productivity. Machine location information can help improve efficiency and perhaps even reduce insurance costs.
https://www.hunterjcb.com.au/wp-content/uploads/2018/09/JCB_65R-1_MiniExcavator.pdf

Equipment Technology Specialist for Constructing Productive Practices
http://news.samsungcnt.com/want-good-equipment-technology-specialist/


Jigs and Fixtures


design and development of modified jig for angular drilling
https://www.irjet.net/archives/V6/i3/IRJET-V6I3577.pdf

Aluminum Cast Tool and Jig Plate
Because they are aluminum, these plates are approximately one-third as heavy as steel plate, which usually eliminates the need for heavy handling equipment for installation or set up, and reduces the load on ways and screws. It is highly resistant to corrosion so it requires no protective treatment. After the tool is obsolete, Aluminum Tool and Jig plate has a higher salvage value than Steel Tool and Jig Plates.
https://www.alro.com/divsteel/metals_gridpt.aspx?gp=0164

Wire Clamp Jig CW-5000N
https://www.forcegauge.net/en/tension-attachment/13512.html

Create jigs and fixtures faster, while lowering the cost of production. Lighter alignment tools, rigid holding devices, conforming grips – 3D print all the customized tools you need, on demand. And more cost-effectively than machined tools. The result? Tooling done more efficiently, with shorter lead times and improved productivity.

Reduce costs.
Increase profitability.

Compared to CNC machining, 3D printing jigs and fixtures takes 25% of the time to produce, wastes less material and costs don’t increase with complexity. And you can run near labor-free production. All of which unleashes your creativity to design and test, with rapid iterations. It all adds up to increased production and gets you to market faster.
https://www.stratasys.com/tooling/jigs-and-fixtures-made-simple


Don’t let fixturing be an afterthought
Increase your machine's performance with the right fixtures.

R&R Home Page Banner - Final

Modular and custom fixturing to save you time and money
By using R&R CMM and Vision fixtures and a large variety of modular components and custom design fixturing you can setup a part within minutes, reducing inspection time and eliminating the search for ways to hold your parts. Let us help you to improve your productivity, reduce fixturing costs and become more competitive.
https://www.rrfixtures.com/en/dont-let-fixturing-be-an-afterthought--21037


SMED


(PDF) SMED Methodology Implementation in an Automotive Industry
https://www.researchgate.net/publication/325546090_SMED_Methodology_Implementation_in_an_Automotive_Industry_Using_a_Case_Study_Method


Applying SMED methodology in cork stoppers production
https://www.sciencedirect.com/science/article/pii/S2351978918312204


SMED implementation on Automated Stamping Line - SlideShare
https://www.slideshare.net/ParthPatel1322/smed-implementation-on-automated-stamping-line

Master thesis - DiVA portal

by N Hansen
This thesis brings up the implementation of a tool within Lean Manufacturing called SMED to a production line with the aim to increase the machine availability.
www.diva-portal.org/smash/get/diva2:1217977/FULLTEXT02.pdf


Saving Minutes with SMED
By Annie Krieger on May 16, 2018

When Mr. Ritsuo Shingo - whose father developed the process of SMED (Single Minutes Exchange of Die; a literal translation) - visited Cambridge Watch a brief summary of his presentation to Cambridge employees and Lean tour guests.  The operational engineers at Cambridge, having been familiar with SMED through their Lean training, found the first two opportunities to perform our own SMED events in the M-Series and S-Series lines.
https://www.cambridge-eng.com/resources/blog/saving-minutes-with-smed

Centerline-SMED integration for machine changeovers improvement in food industry
J. Lozano, J.C. Saenz-Díez, E. Martínez, E. Jiménez & J. Blanco
Published online: 25 Mar 2019
https://www.tandfonline.com/doi/abs/10.1080/09537287.2019.1582110?journalCode=tppc20

Optimization of Production Process Time with Network/PERT Analysis ...
https://iopscience.iop.org/article/10.1088/1757-899X/453/1/012050/meta
by M Kholil - ‎2018 - ‎Related articles
Nov 29, 2018 - Optimization of Production Process Time with Network/PERT Analysis Technique and SMED Method.

SMED Game - Implement Lean by ELSE Inc.
https://implementlean.com/shop/smed-game/
US$ 99.00 -
Mar 17, 2019 - The SMED Quick Change-Over Game is a Lean simulation game developed by ELSE Inc. that brings your team together to learn how to institute SMED


Tracking for SMED
https://www.magnatag.com/single-minute-exchange-dies

Poka Yoke


10 Examples of Poka Yoke in Everyday Life
December 27, 2018
https://tulip.co/blog/lean-manufacturing/poka-yoke-examples-everyday-life/


Mistake Proofing, Poka-Yoke Style in BMW plant
- 11/05/2018
Assembly associates are always looking for a way to do things better, quicker, and smarter. There’s one assembly team in Hall 52 that has adapted the poka-yoke concept with a production cart that has improved quality and efficiency.
https://www.bmwusfactory.com/team10_articles/mistake-proofing-poka-yoke-style/

Poka Yoke combined manual workstation
Accurate production, assembly, order picking and logistics are achieved by combining our core competencies

- Individual assembly technology by workplace specialist Handke Industrie-Technik
- Poka Yoke-Controller by automation specialist Mitsubishi Electric
- the japanese Lean-Approach
https://nl3a.mitsubishielectric.com/pokayoke

Productivity Improvement by using Poka-Yoke - IRJET
https://www.irjet.net/archives/V5/i12/IRJET-V5I12139.pdf

Cluster Assembly Poka-Yoke Workstation
We design, fabricate, assemble & execute Instrument Cluster line assembly projects for all 2 Wheeler, 3 Wheeler, 4 Wheeler & Commercial Vehicles. It includes station-to-station fixtures, Poka-yoke (if required), Traceability at every station, Integration of the whole system. Labview developed user interface which makes operability user friendly & hassle free. Every station will have its own interlocks & has the provision for to keep the rejected parts if any.
Maestrotech Systems Pvt. Ltd. - Enhancing Operational Productivity
http://www.maestrotechsystems.com/cluster_assembly_poka-yoke_workstation.htm

Poka-yoke design of rubber rail
www.diva-portal.org/smash/get/diva2:1223994/FULLTEXT02.pdf
by E Lilja - ‎2018 

Cutting Tools


A New Cutting Tool Design for Cryogenic Machining of Ti–6Al
https://www.mdpi.com/1996-1944/12/3/477/pdf


May 10, 2018
KYOCERA’s New Industrial Cutting Tool with Ultra-Durable Coating Materials Maximizes Steel Cutting Performance
New CA025P CVD coating technology and base material with excellent durability ensures long-term cutting performance for automotive and industrial machining.
Kyocera Corporation (President: Hideo Tanimoto) announced today that it has developed a new ultra-durable coating technology and base material for indexable industrial cutting tool inserts to improve steel machining.
https://global.kyocera.com/news-archive/2018/0502_bfid.html

Researchers at Linköping University have developed a theoretical model that enables simulations for showing what happens in hard cutting materials as they degrade. The model will enable manufacturing industry to save both time and money.

The model has been published in the open access scientific journal Materials.

Titanium-aluminium nitride is a ceramic material commonly used as coating for metal cutting tools. With the aid of a titanium-aluminium nitride thin film, the cutting edge of a coated tool becomes harder, and the lifetime of the tool longer. A very particular feature of the coated surface is that it becomes even harder during the cutting process, a phenomenon that is known as age hardening.
https://www.sciencedaily.com/releases/2019/03/190308102134.htm

Ceramics materials and their application to cutting tool technology: A review
Ulanbek Auyeskhan, Asma Perveen



Development of new manufacturing processes and new materials for various industrial applications has pushed the development of cutting tool towards its limit. Recent ceramic cutting tool shows capability of cutting hard to machine materials with high spindle speed as well as supports the concept of green manufacturing. Two major categories of ceramic tools such as alumina and silicon based are thoroughly discussed along with their properties.
https://systems.enpress-publisher.com/index.php/CSE/article/view/867

Latest cutting tools and solutions - Sandvik Coromant
https://www.sandvik.coromant.com/en-gb/products/news/pages/default.aspx

New Products - Cutting Tools
Here's a quick look at new cutting tool products introduced by suppliers in the industrial supply channel
https://industrialsupplymagazine.com/pages/New-Products---Cutting-Tools.php


Top 8 Milling Tools for New CNC Machinists
By: Marti Deans
In this article we’ll be covering the top 8 milling tools that form the backbone of every professional machining job.
https://www.autodesk.com/products/fusion-360/blog/top-8-milling-tools-new-cnc-machinists/

Industry 4.0 Strategies To Inspire Metalworking Solutions - Iscar
https://www.iscar.com/Catalogs/publication-2018/Iscars_World_Brochure_2018.pdf

Tool innovations and new developments in milling
placeholder
M5130 shoulder milling cutter – Xtra·tec® XT
Fullscreen
M5130 shoulder milling cutter – Xtra·tec® XT – performance und reliability extend your perspective.
https://www.walter-tools.com/en-gb/tools/innovations/milling/Pages/innovations-milling-2/new-products-milling-2.aspx


In this chapter, tool wear investigation of uncoated and PVD-coated AlTiN, TiAlN tungsten carbide end mills in high-speed micro-end milling of alpha + beta Ti-6Al-4V ELI titanium alloy (Grade 23) under dry cutting conditions was presented. A comparison for machining performance with the three tools is reported.
https://www.intechopen.com/online-first/the-comparison-of-cutting-tools-for-high-speed-machining-of-ti-6al-4v-eli-alloy-grade-23-


New Material GRANMET SF

A material that takes durability to new frontiers
Characteristic
・New material with excellent temperature resistance
 (Hot-hardness) and wear resistance
・Tremendous improvement against crater-wear
・High efficiency machining, equivalent to carbide hob at cutting Speeds of 300 m/min or more.
https://www.mhi-machinetool.com/en/technology/news/cutting/20181031_01.html

THE PERFORMANCE OF LOW COST CUTTING TOOLS WHEN MACHINING HARDENED STEEL OF 60 HRC
journal.utem.edu.my/index.php/jamt/article/download/8/7


Updated on 1 July 2019, 28 April 2019





Machine Work Study - Machine Tool - Metal Cutting - Taylor - Part 4



NATURE OF WEAR ON TOOLS DEPENDS UPON WHETHER IT HAS BEEN CHIEFLY CAUSED BY HEAT

175 The appearance of tools which are worn down so as to re- quire regrinding differs widely according to whether or not the heat produced by the pressure of the chip has been the chief cause of wear ; and according to the part which heat has played in producing the wear, worn out tools may properly be divided into three classes.

THE FIRST CLASS 

176 Tools in which the heat, produced by the pressure of the chip, has been so slight as to have had no softening effect upon the surface of the tool.

177 Tools in which the heat has been so great as to soften the lip surface of the tool beneath the chip almost at once after starting the cut, and in which, therefore, heat has played the principal part in the wear of the tool.

WEAR OF THE SECOND CLASS

178 Tools in which the heat only slightly softens the surface of the tool during the greater part of the time that it is cutting, while during the latter part of the time heat is the chief cause of wear because, as described in‘ the third class, it greatly softens the lip surface under pressure of the chip.

179 In the FIRST CLASS, in which heat plays no part in the wear of tools, all tools (whether made from carbon tempered steel, or from the old style self-hardening steel, or from the modern treated tools) wear in about the same manner. Namely, the lip surface just back of the cutting edge is slowly rubbed or worn or ground down through the friction of the chip, as shown in Folder 3, Fig. 17d.

180 As the surface of the tool through the long rubbing of the chip becomes slightly roughened, the tool wears away somewhat more rapidly, but the increase in the rapidity of wear is in this case by no means marked.

181 On the other hand, tools which wear according to the THIRD CLASS begin to distinctly deteriorate within from one to three minutes after the chip has started to cut, depending upon the length of time required for the friction of the chip to raise the tool from its normal cold state to the high temperature which corresponds to the combination of pressure and speed which produces the heat. And the moment the nose of the tool has reached a degree of heat at which the metal under the chip becomes distinctly soft, the wear then proceeds with great rapidity. Sometimes after arriving at a certain degree of softness, the heat remains approximately constant, and the wear upon the tool continues at a uniformly rapid rate until a comparatively deep groove or gutter has been worn into the lip surface. At other times after the lip surface of the tool begins to soften, it appears to become rougher and cause a still greater amount of friction and heat, in which case the wear of the tool proceeds at an increasingly rapid rate, and the tool is soon destroyed. There are rare instances in which after the rapid wear has started, the friction between the chip and the tool, for some unaccountable reason, appears to become less and the tool slightly cools down. Cases have come under the  observation of the writer in which tools which had been running with their noses at a visible dark red heat, cooled off  to such an extent that the chip which had been very dark blue in color changed to a color but slightly darker than a brown. This indicated a very marked diminution in friction, although the cutting speed was maintained at a uni- form rate throughout. This case, however, is of rare occurrence.

182 While a deep groove worn by the chip is a characteristic of wear of the third class, by no means all of the tools in this class wear into a deep groove. Most of them give out before the groove has had time to wear deep. After wear of the third class has started, tools will generally be completely ruined in a time varying from 20 seconds to 15 minutes, and the time which elapses between the softening of the lip surface and the final mining of the tool is exceedingly irregular. One of two tools—which have been proved through standardization to be uniform within, say, 1 or 2 per cent, may give out within one minute after this action starts, while the other may last 15 minutes. On the other hand, occasional lots of tools are found which. after having been proved uniform through standardization, will last under this softening speed for approximately the same length of time.

REASON FOR ADOPTING A STANDARD TEST PERIOD OF 20 MINUTES

183 It is this irregularity in the ruining time of tools belonging to the third class which has led us to adopt a trial period of 20 minutes as being the SHORTEST RUINING TIME from which it is safe to draw any correct scientific conclusions from tests in the art of cutting metals. See paragraphs 703-704. '

184 A cutting speed which causes the tool to be ruined in a shorter period than 20 minutes is accompanied by such a high degree of heat as to produce irregularity in the ruining time; on the other hand, a speed which ruins at the end of 20 minutes is accompanied by that degree of heat at which tools, generally speaking, can be depended upon to wear uniformly. In other words, it represents the degree of heat at which a lot of uniform tools will all give out at about the same time.

ECONOMICAL CUTTING SPEEDS

185 Cutting speeds which are sufficiently slow to cause the tool to war as described in the first class are entirely too slow for economy. On the other hand, tools when run at the high cutting speeds which  produce wear of the third class last so short a time that these high speeds are entirely out of the question for daily shop use.

186 It is then with cutting speeds causing wear of the SECOND CLASS that we are chiefly concerned; as it is within this range of cutting speeds that almost all roughing tools in every day use should be run for maximum all-round economy. CUTTING SPEEDS OF THIS CLASS ARE REFERRED TO AS “ ECONOMICAL SPEEDS” on “ MOST ECONOMICAL srasos. ” Our experiments, therefore, have been practically confined to a study of cutting speeds of the second class.

187 By referring to paragraph 701, and Folder 15, Table 105, it will be noted that a cutting speed which will cause a given tool to be ruined at the end of 80 minutes is about 20 per cent slower than the cutting speed of the same tool if it were to last 20 minutes. By referring also to paragraph 717, it will be noted that, on the whole, we have concluded it is not economical to run roughing tools at a cutting speed so slow as to‘ cause them to LAST FOR MORE THAN ONE AND ONE-HALF HOURS  without being reground. Tools which are ruined in one and one-half hours, however, are still within the second class as far as the causes for wear are concerned; and the wear of tools of the second class may be again referred to as being during the greater part of the life of the tool similar to the wear of the first-class tools, in which the heat is not sufficiently great to materially soften the lip surface. In the second class, however, the cutting speeds are so high as to cause the lip surface of the tool to gradually become rougher, and rougher, and as this surface roughens, the heat increases so that in their final wearing out, say, during the last five to fifteen minutes of their life, tools of the second class wear in a manner similar to those of the third class. Thus it is seen that wear in tools of the second class is a combination of the type of wear of the first class with the type of wear of the third class, the first class type of wear extending through the greater part of the time that the tool is cutting.

 HOW CARBON STEEL TEMPERED TOOLS AND TOOLS MADE FROM OLD FASHIONED SELF-HARDENING STEEL WEAR

189 With carbon steel tempered tools at standard speeds the cutting edge begins to be injured almost as soon as the tool starts to work, and is entirely rounded over and worn away before the tool finally gives out, and the tool works well in spite of its cutting edge being damaged. While with high speed tools at standard speeds, the cutting edge remains in almost perfect condition until just before the tool gives out, when even a very slight damage at one spot on the cutting edge will usually cause the tool to be ruined in a comparatively few revolutions.

190 Carbon tempered tools and also, to a considerable extent, the old fashioned self-hardening tools (such as Mushet), when run at their “ economical ” or “ standard ” speeds, pass through the following characteristic phases as they progress toward the point at which they are finally ruined. It will of course be understood that the “rounding of the cutting edge, ” the “mounting of the steel upon the lip ” and the “ rubbing away beneath the cutting edge” all progress simultaneously, although each of these phenomena is separately described.

191 The line of the cutting edge of the tool, which is at first keen, becomes very slightly dull so that it shines when held in the light, and it is then gradually rounded over until it finally loses all resemblance to a cutting edge, and after severe use frequently looks as if it had been purposely rounded over. This action is referred to in recording our experiments as “CUTTING EDGE ROUNDED.”

192 The lip, or top surface of the tool, soon becomes slightly roughened and whitened as the shaving presses against it, then the surface of the tool near the cutting edge becomes discolored as if the temper of the tool were being drawn, and this discoloration increases both in the extent of its area and in its approach toward almost a black color, until the tool is entirely ruined. This action is referred to as “ DISCOLORED BACK FROM CUTTING EDGE.”

193 The flank of the tool begins to discolor in a manner similar to the lip and this discoloration continues to increase until the tool is finally ruined. This action is referred to as "DISCOLORED BELOW CUTTING  EDGE."

194 Long before the tool is ruined, also, the fine particles of steel or dust scraped offiby the cutting edge begin to weld or stick to the lip of the tool and mount upon it sometimes from 1/16 inch to 1/4 inch  in height, as shown in Folder 3, Fig. 17d; referred to as “STEEL MOUNTED ON  LIP.”

195 The flank of the tool just below the cutting edge begins to wear or rub away slightly, and this wear gradually extends further and further below the cutting edge until the tool is ruined; referred to as “RUBBED BENEATH CUTTING EDGE.”

196 Small portions of the metal being cut wedge themselves in between the flank of the tool and the work, and are partly welded or stuck to the tool, and these lumps which are welded on to the tool, and the rubbing away of the flank as the tool grows dull, prevent the feed from being uniform in thickness, and cause the tool sometimes to entirely skip its feed for one or two revolutions; referred to as “ TOOL JUMPED.” These lumps also force the work and the tool away from one another, and so leave the work rough and lumpy in these places; referred to as “LEFT LUMPY FINISH.” Also the particles of metal which are welded on to the flank of the tool frequently leave scratches on the finished part of the work; referred to as “LEFT SCRATCHY FINISH."

197 The tool is finally completely ruined by having so much of its flank rubbed away beneath the cutting edge, that no amount of pressure can force it into the work, and when it reaches this condition it must be immediately removed from the tool post, or there is danger of breaking either the tool, the machine, or the work.

198 As a result of our experiments it became evident that in case of tools made from the “low speed” self-hardening steels, for instance, such as the old fashioned Mushet steel, the tools would in many cases run successfully long after the line of the cutting edge had become slightly injured; also that in the case of “roughing” tools made from the carbon or tempered steels, it was economical and right in daily shop practice to run these tools at such a cutting speed that their actual cutting edges rounded off quite soon after starting to do their work. These tools continued to cut with their edges rounded, somewhat as shown in Folder 7, Fig. 42, successfully through the whole cut.

199 As stated in paragraph 67, all of our experiments made with these two types of tools (carbon and Mushet types) to determine the laws for cutting metals were rendered much more difficult, owing to the judgment required in deciding the exact amount of damage which was appropriate both to the tool and the particular thickness of shaving which was being taken.

200 In paragraph 506 will be found a further discussion of the very great part which the heat caused by the friction of the chip against the lip surface of the tool plays in ruining tools, and in para- graph 965 we refer to the peculiar property of retaining their hardness even at a high heat, which is called “red hardness,” as being the essential novelty in the discovery of new “high speed” tools. HOW MODERN HIGH SPEED TOOLS WEAR

201 As stated above, in the case of modern high speed tools, the damage caused to the tool through the action of cutting is confined almost entirely to the lip surface of the tool. Doubtless also the metal right at the cutting edge of the tool remains harder than it is directly under the center of pressure of the chip, because the cutting edge is next to and constantly rubs against the cold body of the forging, and is materially cooled by this contact.

202 Whether the lip surface be ground away at high speeds or at slower speeds, the nose of the tool is generally “ruined” in a very short time after the cutting edge has been so damaged that it fails to scrape off smoothly even at one small spot the rough projections which have been left on the body of the forging by tearing away the chip. The moment the body of the forging begins to rub against the clearance flank of one of these high speed tools at or just below the cutting edge, even at one small place, the friction at this point generates so high a heat as to soften the tool very rapidly. After a comparatively few revolutions (particularly when cutting medium or soft steel or cast iron), the cutting edge and flank of the tool beneath it will be completely rubbed and melted away, as shown in Folder 3, Fig. 17b.

203 The above characteristic of holding their cutting edges in practically perfect condition while running at economical speeds up to the ruining point is a valuable property of the high speed tools, since it insures a good finish, and the maintenance throughout the cut of the proper size of the work, without the constant watchfulness required on the part of the operator in the case of old slow speed tools with their rounded and otherwise injured cutting edges, which when run at economical speeds were likely at any minute to damage the finish of the work. -

204 When one of these high speed tools is nearing its ruining point, a very trifling nick or break in the line of the cutting edge will beat once noticed by its making a very small but continuous scratch, projecting ridge, or bright streak, on the flank of the forging (namely, upon that part of the forging from which the spiral line of the chip has just been removed). When the skilled operator notices this line, he at once removes the tool from its cut, and notes upon the record “tool began to ruin”; the abbreviation for which in our case consists of the letters B R. ‘

205 The letter R is used to indicate a tool which has been entirely ruined; the word “Good” (G) indicates a tool which is removed from the cut showing but very small damage or wear even to the lip surface; the word “Fair” (F) indicates a tool which shows considerable wear upon the lip surface, such, for instance as is shown in tool, Folder 3, Fig. 17c, the cutting edge of which has, however, not as yet absolutely started to ruin.

206 It is a curious fact that high speed tools which differ in their chemical compositions, and perhaps also slightly in their high heat and subsequent treatment, give very different indications while cutting that they have begun to ruin. For instance, the kind of scratch, shiny streak, or ridge, which on high speed tools made from steel of one chemical composition would indicate the approach of the ruining point, may possibly be no indication of the approach of the ruining point if made by another type of high speed tool.

207 It is therefore necessary for the operator with each new batch of tools which are to be used in an experiment to absolutely ruin a number of these tools so as to be thoroughly familiar with that exact appearance of the flank of the forging which unquestionably indicates the approach of the ruining point. After the operator has assured himself beyond doubt of this indication, it will not then be necessary for him to ruin each tool completely. The writer has in mind many instances, however, in which from the appearance of the scratches or shiny streaks, etc., on the flank of the forging, he was convinced that the tool was about to ruin, and in which the same tool continued to run for many minutes afterward, and even, in some cases, at an increase in cutting speed. In this element in making experiments, as in all others, nothing must be taken for granted, everything must be proved.

208 In paragraphs 353 and 354 two other reasons for the cutting edges of tools giving out are referred to: a The spalling off or crumbling away of the tool due to the ' pressure of the chip at its extreme cutting edge, as shown in Folder 6, Fig. 31a; and b The spalling off or crumbling away of the extreme cutting edge due to the feeding pressure at this point, as shown in Folder 6, Fig. 31b.

209 As both of these types of yielding must be chiefly considered in their relation to the acuteness of the lip angle of the tool, we refer to them later in the paper.

HOW TO MAKE AND RECORD EXPERIMENTS ART OF EXPERIMENTING

DEFINED AS DETERMINING EFFECT OF VARYING ONE ELEMENT WHILE ALL OTHERS ARE HELD CONSTANT

210 In paragraph 55 (Part 1) we have broadly defined the art of experimenting on this subject as an attempt to hold uniform and constant all of the elements which affect the final results under investigation except the one variable which is being studied, while this one is systematically changed and its effect upon the problem carefully noted.

211 It is the necessity of holding these variables constant which makes all these experiments so difficult, causes the apparatus and forgings tested to be so large and expensive, and consumes perhaps four-fifths of the time of the experimenter. Time and again in our work it has required days and sometimes weeks to prepare for an experiment which, after we have succeeded in obtaining uniformity in all the elements, has been made in a few days or hours.

212 A description of how to maintain uniform conditions is then virtually a description of the art of experimenting on cutting metals. The writer will, therefore, begin by explaining in detail the precautions which must be taken to secure this uniformity.

THE METAL WHICH IS TO BE CUT

213 In determining the effect which any one of the more important elements has upon the cutting speed,—such, for instance, as the effect of the feed or thickness of shaving upon the speed,-—it is necessary to make many standard cuts of 20 minutes’ duration in succession for each thickness of shaving, in order to find the exact speed at which the tool will be ruined at the end of 20 minutes, as described in paragraph 137. For this reason the information required for each thickness of shaving may cause hundreds of pounds of metal to be cut up into chips; and since in determining the law many different thicknesses of shaving must be experimented with‘, and the metal cut must be of uniform hardness, in order to obtain accurate results not only a. large experimental forging is called for, but the metal throughout the forging must be as nearly as possible uniform.

214 We have finally adopted as the standard size of forging best suited for experiments apiece about 10 feet long by 24 inches in diameter and weighing about 15,000 pounds. For this purpose we prefer  forging made from a large ingot cast from a carefully melted heat of open hearth steel, and forged with a large reduction in the diameter so as to obtain as nearly as practicable uniform working of the metal throughout from the outside to the central portions of the forging. This forging in all cases requires thorough annealing,and in some cases an oil hardening previous to the annealing. Before using it, experimental standard tensile test bars should be cut from each end of the forging and broken so as to prove the uniformity of the metal, and, if necessary, the metal should be re-treated by tempering and annealing until it has been demonstrated through breaking a sufficient number of test specimens to be uniform.

215 Masses of cast iron upon which tools are to be tested should in all cases have their central portion cored out, so that the metal will be cooled from the center outward as well as from the outside inward, thus producing an annular ring of cast iron from three to four inches thick; which, if sufficient precautions are taken to insure regular cooling,will be comparatively uniform throughout. We have used annular masses of cast iron, made in this manner, of 24-inch diameter with 12- inch cores, 12 feet long; of 15-inch diameter, 10-inch cores, 8 feet long; of 13-inch diameter, 7 feet long; of 13-inch diameter, 9-inch cores, 10 feet long. On the whole, we have obtained the most uniform results from a casting of 24~inch diameter, 16-inch core, and 10 feet long, walls of casting having a maximum thickness of 4 inches poured on end. We have found the central portion of the annular rings which were 6 inches in thickness to be very materially softer than the outer or inner portions of the ring. It has proved to be much more difficult to obtain sufficiently large and uniform masses of cast iron than of steel.

216 A large diameter is called for in both forgings and castings, not only for the sake of obtaining a large quantity of uniform metal, but also to avoid as far as possible the effect of chatter upon the tool, caused by the deflection of the work; and the writer wishes to emphasize the necessity for large masses of metal if the experimenter hopes for trustworthy results.







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Machine Work Study - Machine Tool - Metal Cutting - Taylor - Part 3



130 There are three principal objects in writing this section of the paper.

131 (A) To record and make public the results of our experiments to date as embodied in laws, etc., and the incorporation of these laws in slide rules for practical, everyday use.

132 (B) To describe the methods, principles and apparatus which should be used in making investigations of this type, and warn future experimenters against the errors into which we, as well as most other investigators in this field, have fallen.

I33 (C) To indicate the additional experiments which are needed K0 perfect our knowledge of the art, in the hope of inducing others to join us in carrying on and completing this work, both in the interest of science and of the many users of machine tools the world over; and to warn others against a certain class of experiments which are allur- ing. appear to ofler great opportunities, but which, in fact, are fruit- less.

134 The writer wishes to emphasize the fact that, while many of our experiments have a certain scientific value, and while it has been our effort to conduct all of our work upon scientific principles, yet the main object of this investigation has been the thoroughly practical one of enabling us to get more, better and cheaper work out of a machine shop.

135 The problem before us may be again briefly stated to consist cf a careful study of the effect which each of the twelve following variable elements has upon the selection of the CU'I'I‘ING srnnn or THE root: “The subjects treated in this section of the paper are from their nature so dependent one upon another, and so interwoven, that the writer has had difficulty in treating them consecutively and logically. He therefore trusts that a certain amount of repetition and the necessity for referring frequently from one part of the paper to another will be pardoned.

 a The quality of the metal which is to be cut, i. e., its hardness or other qualities which affect the cutting speed; b The diameter of the work; c The depth of the cut, or one-half of the amount by which the forging or casting is being reduced in diameter in turning; d The thickness of the shaving, or the thickness of the spiral strip or band of metal which is to be removed by the tool, measured while the metal retains its original density ; not the thickness of the actual shaving, the - metal of which has become partly disintegrated; e The elasticity of the work and of the tool; f The shape or contour of the cutting edge of the tool, to- gether with its clearance and lip angles; g The chemical composition of the steel from which the tool is made, and the heat treatment of the tool ; h Whether a heavy stream of water, or other cooling medium, is used on the tool; j The duration of the cut, i. e., the time which a tool must last under pressure of the shaving without being reground; ' k The pressure of the chip or shaving upon the tool; l The changes of speed and feed possible in the lathe; m The pulling and feeding power of the lathe at its various speeds.

136 It is of course superfluous to call the attention of those who have given much thought to the subject of cutting metals as an art, to the fact that the ultimate object of all experiments in this field is to learn how to remove the metal from our forgings and castings in the quickest time, and that therefore the art of cutting metals may be briefly defined as the knowledge of how, with the limitations caused by some and the opportunities offered by others of the above twelve variable elements, in each case to remove the metal with the highest appropriate cutting speed. And yet a walk through almost any machine shop will convince anyone that if those in charge of the shop are aware of the effect of speed upon economy, they are acting upon this information only in a few sporadic cases and by no means systematically.

137 Before entering upon the details of our experiments, it seems necessary to again particularly call attention to the fact that “standard cutting-speed” is the true criterion by which to measure the efect of each of these twelve variables upon the problem. The writer therefore repeats what he has before said in paragraph 64 (Part 1): “THE EFFECT or sacs vxnraann oron THE 1>noa1.r-11.1 rs assr DETERMINED at rrsnrrqo THE nxxca" nun or corrrno srann (ear, IN FEET ran MINUTE) WHICH wnx. cause THE TOOL TO an COMPLETLY numnn arrsn nxvmo sass aux son 20 armuwss UNDER rmrsorm CONDITIONS."

138 To give another illustration of our practical use of this standard. If, for example, we wish to determine which make of tool steel is the best, we should proceed to make from each of the two kinds to be tested a set of from four to eight tools. Each tool should be forged from tool steel, say, 5- inch x 1§ inch and about 18 inches long, to exactly the same shape, and after giving the tools made from each type of steel the heat treatment appropriate to its chemical com- position, they should all be ground with exactly the same shaped cutting edge and the same clearance and lip angles. One of the sets of eight tools should then be run, one tool after another, each for a period of 20 minutes, and each at a little faster cutting speed than its predecessor, until that cutting speed has been found which will cause the tool to be completely ruined‘ at the end of 20 minutes, with an allowance of a minute or two each side of the 20-minute mark.

139 Every precaution must be taken throughout these tests to maintain uniform all of the other elements or variables which aflfct the cutting speed, such as the depth of the cut and the quality of the metal being cut. The rate of the cutting speed must be frequently tested during each 20-minute run to be sure that it is uniform throughout. For further details in making tests, see paragraphs 175 to 262.‘

140 Throughout this paper, “the speed at which tools” give out in 20 minutes, as described above, will be, for the sake of brevity, referred to as the “standard speed.” ~

141 After having found the “standard speed” of the first type of tools, and having verified it by ruining several more of the eight tools at the same speed, we should next determine in a similar manner the exact speed at which the other make of tools will be ruined in 20 minutes; and if, for instance, one of these sets of tools exactly ruins at a cutting speed of 55 feet, while the other make ruins at 50 feet per minute, these “standard speeds," 55 to 50, constitute by far the most important criterion from which to judge the relative economic value of the two steels for a machine shop. ‘For the advantage of completely ruining a tool in experimenting as 8- standard method see paragraph 151.

142 Other properties of the steels, as mentioned in paragraphs 934 to 1094, must of course be considered in choosing a tool steel. But if the steels are in other respects equal, their maximum cutting speeds then represent the exact measure of their values.

143 Perhaps the best criterion by which to judge of the value of any standard or test is the ability to duplicate the results which have been once obtained. We have repeatedly been able to reduplicate the results obtained through this standard within an error of 2 per cent. For our reasons for adopting the 20 minute period as our standard running time see paragraphs 175 to 184. “STANDARD SPEED" BEST TEST FOR DETERMINING VALUE or TOOLS, ETC.

144 It seems necessary early in this paper to emphasize the importance of the “standard speed” as being the true test for the relative value of tools as well as for the other elements involved in the art of cutting metals——the more so since the accuracy and delicacy of this standard are but vaguely recognized.

145 Among those commonly referred to, the most deceptive and unreliable standard as to the relative value of tools is THE LENGTH or TIME A TOOL WILL RUN BEFORE REQUIRING GRINDING or before being ruined. So many people are continually being misled by this standard that its inadequacy can scarcely be over-emphasized.

146 To illustrate: Let us assume, for instance, that three tools have been proved to be uniform within, say, 2 per cent by our standard method, described in paragraph 138, and to have a “standard speed” of 60 feet per minute for a run of 20 minutes. If then the cutting speed of each of these tools is increased, say, to 63 feet per minute, THE LENGTH OF TIME wmcn THEY WILL RUN at this slight increase in cutting speed will be almost sure to vary greatly. One of the tools will be ruined, say, in six minutes, another in nine minutes, while the third may last 15 minutes. Thus if tools which are uniform within 2 per cent are run only slightly beyond “standard speed,” they are likely to vary to the extent of more than 2 to 1 in time which they last before ruining or requiring regrinding; and so the misleading nature of the standard becomes apparent.

147 The great variation in the time which carefully standardized tools will last when run at an increase in cutting speed of only one foot per minute will be seen by examining table {in paragraph 619. In this case it will be seen that an increase of only one foot in cutting speed causes standardized tools to vary in their running period, in the two extreme cases, between the periods of 1.5 minutes  and 17.5 minutes. A study of this table will show that the value of the tools is closely given by standard cutting speeds, but that it is in no sense proportional to the time which the tool runs before being ruined. This matter will be further discussed in paragraph 619. etc.

148 The inadequacy of this standard is, however, so little recognized that even as able an experimenter as Dr. Nicolson, after having written the record of the “Manchester Experiments,” and then made his own admirable “ Dynamometer Experiments, ” falls into the error of adopting this false standard in his “Experiments on Durability of Difierent Cutting Angles,” described in his paper in Tabla 5, 6 and 7, and in paragraphs 38 to 44 inclusive, pp. 657 to 661. Yet in these very experiments the misleading nature of this standard will be seen. Note that in Table 7, for instance, a 75 degree angle tool at a cutting speed of 74 feet per minute lasts only 2 minutes 10 seconds, while the same tool when run only one foot per minute slower at a cutting speed of 73 feet per minute lasts 10 minutes and 37 seconds.

149 For many years it has been usual for salesmen of tool steels to give detailed accounts of the number of hours which tools made from their steels, would cut metals without the necessity of regrinding. In fact, tool steel literature abounds in statements of the long life of tools with one grinding, implying that this is the proper standard for measuring their value. By referring, however, to paragraphs 693 and 710 it will be seen that for ninety-nine one-hundredths of the work of a shop, this criterion is of no value whatever, and that the man who boasts of having run a tool without regrinding, say, for a longer period than one and one-half hours on ordinary shop work, is merely boasting of how little he knows about the art of cutting metals cheaply.

150 The writer has already referred in paragraph 92 (Part 1) to another error into which all experimenters in this art fall sooner or later: namely, that of concluding that the effect which the size, shape and angles of the tool has upon the problem of cutting metals can best be determined by a careful investigation of the effect which each of these elements has upon the pressure required to remove a given sized chip or shaving. The reasoning used is that that tool is the best which is so shaped as to remove a given chip or shaving with the least amount of pressure or cutting force. The utter fallacy of this as a measure of the value of the tool has already been referred to in paragraph 92, and will be again referred to in paragraph 135.

151 In paragraph 59 (Part 1) the writer has described several false standards which were adopted by us, one after another, for determining when a tool had been run at its maximum cutting speed. Even with these defective standards we obtained most useful results. Broadly speaking, however, our reason for successively abandoning each of these standards was the impossibility of accurately reduplicating the results obtained. And this after all remains the best gage of the value of experimental methods. In all cases the earlier standards adopted by us required very close observation and judgment on the part of the experimenter to determine when the tool had reached that state of deterioration which was appropriate to its highest cutting speed. The advantage of our present standard, namely, that of completely ruining the tool, lies in-the fact that it is an unmistakable, clear-cut phenomenon which calls for a minimum of judgment on the part of the operator, and thus eliminates one of the sources of human error in the experiments, and enables us to reduplicate our results with accuracy.

152 On Folder 3, Fig. 17b, are shown two views of a tool which has been completely ruined according to this standard.

ACTION OF TOOL AND ITS WEAR IN CUTTING METALS
THE ACTION OF THE NOSE OF THE TOOL

153 On Folder 8, Figs. 42, 43 and 44, is illustrated in enlarged views the action of a tool in cutting a chip or shaving from a forging at its proper normal cutting speed. It may be said in the case of all “roughing cuts ” that the chip is torn away from the forging rather than removed by the action which we term cutting. The familiar action of cutting, as exemplified by an axe or knife removing a chip from a piece of wood, for instance, consists in forcing a sharp wedge (11. e., one whose two flanks form an acute angle) into the substance to be cut. Both flanks of the wedge press constantly upon the wood, one flank bearing against the main body of the piece, while the other forces or wedges the chip or shaving away.

154 While a metal cutting tool looks like a wedge, its cutting edge being formed by the intersection of the “ lip surface” and “clearance surface” or flank of the tool, its action is far different from that of the wedge. Only one surface of a metal cutting tool, the lip surface, ever presses against the metal. The clearance surface, as its name implies, is never allowed to touch the forging. Thus “cutting” with a metal cutting tool consists in pressing, tearing or shearing the metal away with the lip surface of the “ wedge” only under pressure, while in the case of the axe and other kinds of cutting, both wedge surfaces are constantly under pressure.

155 After the cut has once been started, and the full thickness of the shaving is being removed, the action of the tool may be described as that of tearing the chip away from the body of the forging and then shearing it up into separate sections; the portion of the chip which has just been torn away, and which is still pressing upon the lip surface of the tool, acting as a lever by which the following portion of the chip is torn away from the main body of the metal.

156 It may be of interest to analyze to a certain extent the nature of the forces to which a chip and the forging from which it is being removed are subjected through the tearing action of the tool. The enlarged view of the chip, tool and forging, shown in Folder 8, Fig. 42, represents with fair accuracy the relative proportions which the shaving cut from a forging of mild steel (say, 60,000 lbs. tensile strength and 33% stretch) finally assumes with relation to the original thickness of the layer of metal which the tool is about to remove. It is, of course, impossible to accurately determine the extent to which various parts of the chip and forging close to the tool are under compression and tension, but in general the theory advanced is believed to be correct.

157 Referring to Folder 8, Fig. 42, the forging being cut and the nose of the tool which is removing the chip are shown on an enlarged scale. The thickness of the layer of metal about to be removed is indicated by L between the dotted line and the full line which represents the outside of the forging. It will be observed that the chip is in process of being torn apart and broken up into three sections: Section 1, which is adjoining the forging; section 2, which comes next to it, and in which rupture or cleavage has started and proceeded a a little way up from the bottom of the chip and on the left hand side, the shearing action having progressed as far as T,; section 3, in which shearing has progressed about two-thirds of the way to the top of the chip and is taking place at T,. Section 4 has been entirely sheared from its adjoining section, and has already left the lip surface of the tool.

158 On examination of the proportions of the chip it will be noticed that the width of the sections into which the chip breaks up is at their base about double the thickness of the original layer of metal which is to be removed, and that their upper portions are not enlarged to the same extent. These sections are about three times as high as the original thickness of the layer of the metal to be removed.

 It should be clearly understood that the dimensions of the section of the chip will vary with each hardness of metal which is being cut, and also to a certain extent with the side and back slopes of the lip surface of the tool. The harder the metal of the forging, the less will each section into which the chip has been broken up be found to be enlarged. In other words, if the same shaped tool be used in each case the chip from soft metal enlarges or distorts very much more than the corresponding chip from hard steel. This will be referred to in paragraph 506, in explaining the reason why the total pressure on the tool has but little relation on the one hand to the cutting speed, and on the other hand to the hardness of the metal which is being cut.

159 The chip bears on the surface of the forging, say, from point H to point G, and throughout this distance is under constant compression from the lip surface of the tool. This compression is transmitted through each of the sections 1 and 2 of the chip, in the direction indicated by the small arrows, to the upper portions of these sections, which are still unbroken and act like a lever attached to the upper part of section 1 to tear‘ section 1 away from the body of the forging, as indicated at point T,. The tearing away of section 1 is also assisted by the pressure of the tool upon its lower surface.


160 After this tearing action has started, the further breaking of the chip into independent sections would seem to be that of simple shearing. It should be borne in mind that in shearing a thick piece of steel the whole piece is not shorn or cut apart at the same instant, but the line at which rupture or cleavage takes place progresses from one surface of the piece down through the metal until within a short distance from the other surface, when the whole remaining section rather suddenly gives way. '

161 In shearing steel, the metal at the point of rupture is pulled apart under a tensile strain, although on each side of the shearing line the metal is under heavy compression.

162 As each of the sections of the chip successively comes in contact with the lip of the tool, its lower surface is crushed, and the metal flows and spreads out laterally until it becomes about twice its original thickness. As in all shearing, when the full capacity for flowing of the metal has been reached, it tears apart under tensile strain from the body of the adjoining metal of the forging. The compression on the chip from the tool still continues, however, and the chips continue to flow and spread out sideways at a part higher up; i. e., farther away from the surface of the tool, at the portions marked F. In the same way shearing continually takes place at the left side of the portion of the chip which is flowing or spreading out sideways.

163 There is no question that shearing takes place constantly along the left hand edges of two of the sections of the chip at the same time, and it is probable that this action occurs most of the time along three lines of cleavage. See paragraph 167.

164 Dr. Nicolson’s dynamometer experiments show that the pressure of the chip on the tool in cutting a chip of uniform section varies with wavelike regularity, and that the smallest pressure of the chip is not less than two-thirds of the greatest pressure. From this it is evident that shearing must be taking place along at least two lines of cleavage at the same time; since if each of the sections into which the chip is divided were completely broken off before the tool began to break off the following section, it is evident that there would be times when there was almost no pressure from the chip on the tool.

165 It is at first difficult to see how it is possible for the chip to be shearing at two or three places at the same time. It should be noted, however, that above the points T, , T,, T3, the metal of the chip is still a solid part of the forging, and moves down at the same speed as the forging in a. single mass, or body, toward the lip surface of the tool; and with sufficient force to cause each of the three sections of the chip to flow or spread out at the same time at the parts indicated by the three letters F. According to the laws which govern shearing, rupture or cleavage in each case must take place as soon as the maximum possibility for flowing has been reached, and in each case shearing must occur at the left of the zone where the metal is flowing.

166 It is probable that after the shearing action has progressed in section 3 to about the point indicated by Ta, that the whole of this section gives way or shears with a rather sudden yielding of the metal from T, , to the upper surface of the chip. It is this rather sudden shearing point which undoubtedly causes the wavelike diminution in the pressure of the chip indicated in Dr. Nicolson’s experiments, referred to in paragraph 316.

167 By suddenly stopping one of our standard tools when cutting at full speed, we have clearly seen this shearing action taking place at two sections of the chip at the same time, and rupture had not completely taken place at the extreme upper part of the third section. In making an observation of this kind great care must be taken before stopping t-he lathe to be sure that in the tool to be observed there is not the slightest tendency to chatter, and the lathe driving parts should be massive in proportion to the sized cut being taken, as other- wise the elasticity left in the driving shafts causes an abnormal action of the tool at the instant the work stops, and produces a chip, of thicker section than the normal, which is completely severed from the body of the metal.

168 While the proportions of the chip and the section into which it is broken are fairly true representations of fact, yet it must be borne in mind that the lines illustrating the strains to which the chips are submitted, as well as the progress made in the shearing of the chip, are merely submitted as illustrating a theory advanced by us to explain the facts. We are, however, more or less suspicious of all theories, our own as well as those of others.

169 Throughout this paper the important facts stated by us have been verified by many and carefully made experiments; and we therefore trust that our readers, if unable to accept our theories, will at least have respect for our facts.

ACTION OF CUTTING EDGE OF TOOL IS THAT OF SCRAPING - CUTTING EDGE NOT UNDER HEAVY PRESSURE

170 It would appear that the chip is torn off from the forging at a point appreciably above the cutting edge of the tool and this tearing action leaves the forging in all cases more or less jagged or irregular at the exact spot where the chip is pulled away from the forging, as shown to the left of T1. An instant later the line of the cutting edge, or more correctly speaking, the portion of the lip surface immediately adjoining the cutting edge, comes in contact with these slight irregularities left on the forging owing to the tearing action, and shears these lumps off, so as to leave the receding flank of the forging comparatively smooth.

171 Thus in this tearing action, particularly in the case of cutting a thick shaving, while the cutting edge of the tool is continually in action, scraping or shearing off or rubbing away these small irregularities left on the forging, yet that portion of the lip surface close to the cutting edge constantly receives much less pressure from the chip than the same surface receives at a slight distance away from the cutting edge. This allows the tool to run at higher cutting speeds than would be possible if the cutting edge received the same pressure as does the lip surface close to it.

172 There are many phenomena which indicate this tearing action of the tool. For example, it is an everyday occurrence to see cutting tools which have been running close to their maximum speeds and which have been under cut for a considerable length of time, guttered out at a little distance back of the cutting edge, as shown in Folder 3, Fig. 17e. The wear in this spot indicates that the pressure of the chip has been most severe at a little distance back from the edge.

173 Still another manner in which in many cases the tearing action of the tool is indicated is illustrated in Folder 3, Fig. 17a, in which a small mass of metal D is shown to be stuck fast to the lip surface of the tool after it has completed its work and been removed from the lathe. When broken off, however, and carefully examined, this mass will be found to consist of a great number of small particles which have been cut or scraped off of the forging, as above described, by the cutting edge of the tool. They are then pressed down into a dense little pile of compacted particles of steel or dust stuck together and to the lip surface of the tool almost as if they had been welded. In the case of the modern high speed tools, when this little mass of dust or particles is removed from the upper surface of the tool, the cutting edge will in most cases be found to be about as sharp as ever, and the lip surface adjacent to it when closely examined will show in many cases the scratches left by the emery wheel from the original grinding of the tool.

174 With roughing tools made from old fashioned tempered steel, however, and which have been speeded close to their “standard speeds," in most cases after removing this “dust pile” from the lip surface, the cutting edge of the tool will be found to be distinctly rounded over. And in cases where the tool has been cutting a very thick shaving, the edge will be very greatly rounded over, as shown in the enlarged view of the nose of a tool in Folder 7, Fig. 41.



-----------------

‘For further evidence that the chip is torn away from the body of the forging somewhat as shown at T,, see paragraphs 170-174.




Machine Work Study - Machine Tool - Metal Cutting - Taylor - Part 2



66 A change is then made in the thickness of the shaving, and another set of 20-minute runs is made, with a series of similar uniform tools, until the cutting speed corresponding to the new thickness of feed has been determined; and by continuing in this way all of the cutting speeds are found which correspond to the various changes of feed. In the meantime, every precaution must be taken to maintain uniform all the other elements or variables which affect the cutting speed, such as the depth of the cut and the quality of the metal being cut; and the rate of the cutting speed must be frequently tested during each 20-minute run to be sure that it is uniform.

67 The cutting speeds corresponding to varying feeds are then plotted as points upon a curve, and a mathematical expression is found which represents the law of the effect of feed upon cutting speed. We believe that this standard or method of procedure constitutes the very foundation of successful investigation in this art; and it is from this standpoint that we propose to criticise both our own experiments and those made by other investigators. For further discussion of our standard method of making experiments see Par. 137.

68 It was only after about 14 years’ work that we found that the best measure for the value of a tool lay in the exact cutting speed at which it was completely ruined at the end of 20 minutes. In the meantime, we had made one set of experiments after another as we successively found the errors due to our earlier standards, and realized and remedied the defects in our apparatus and methods; and we have now arrived at the interesting though rather humiliating con- clusion that with our present knowledge of methods and apparatus, it would be entirely practicable to obtain through four or five years of experimenting all of the information which we have spent 26 years in getting.

69 The following are some of the more important errors made by us:

70 We wasted much time by testing tools for a shorter cutting period than 20 minutes, and then having found that tools which were apparently uniform in all respects gave most erratic results (particularly in cutting steel) when run for a shorter period than 20 minutes; we erred in the other direction by running our tools for periods of 30 or 40 minutes each, and in this way used up in each single experiment so much of the forging that it was impossible to make enough experiments in cutting metal of uniform quality to get conclusive results. We finally settled on a run of 20 minutes as being the best all-round criterion, and have seen no reason for modifying this conclusion up to date. 71 We next thought a proper criterion for judging the effect of a given element upon the cutting speed lay in determining the particular cutting speed which would just cause a tool to be slightly discolored below the cutting edge at the end of the 20 minutes. After wasting six months in experimenting with this as our standard, we found that it was not a true measure; and then adopted as a criterion a certain definite dulling or rubbing away of the cutting edge. Later it was found, however, that each thickness of feed had corresponding to it a certain degree of dullness or injury to the cutting edge at which point regrinding was necessary (the thicker the shaving the duller the tool should be before grinding); and a third series of experiments was made with this as a standard. While experimenting on light forgings a standard dullness of tool was used which was just sufficient to push the forging and tool apart and so slightly alter the diameter of the work.  All of these criterions were discarded, however, when in 1894 we finally bit upon the true standard, above described, of completely ruining the tool in 20 minutes.

72 As will be pointed out later in the paper, this standard demands both a very large and expensive machine to experiment with, and also large, heavy masses of metal to work upon, which is unfortunate; but we believe without apparatus and methods of this kind it is out of the question to accurately determine the laws which are sought. See paragraphs 210-263.

73 Experiments upon the art of cutting metals (at least those experiments which have been recorded) have been mainly undertaken by scientific men, mostly by professors. It is but natural that the scientific man should lean toward experiments which require the use of apparatus and that type of scientific observation which is beyond the scope of the ordinary mechanic, or even of engineers unless they have been especially trained in this kind of observation. It is perhaps for this reason more than any other that in this art several of those elements which are of the greatest importance have received no attention from experimenters, while far less fruitful although more complicated elements, have been the subject of extended experiments.

74 As an illustration of this fact we would call attention to two of the most simple of all of the elements which have been left entirely untouched by all experimenters, namely: a the effect of cooling the tool through pouring a heavy stream of water upon it, which results in a gain of 40 per cent in cutting speed; b the effect of the contour or outline of the cutting edge of the tool upon the cutting speed, which when properly designed results in an equally large percentage of gain.

75 Both of these elements can be investigated at comparatively small cost, and with comparatively simple apparatus, while that element which has received chief attention from experimenters, namely, the pressure of the chip on the tool, calls for elaborate and expensive apparatus and is almost barren of useful results.

76 This should be a warning to all men proposing to make experiments in any field, first, to look thoroughly over the whole field, and, at least, carefully consider all of the elements from which any practical results may be expected; and then to select the more simple and elementary of these and properly investigate them before engaging in the more complicated work.

77 The most notable experiments in this art that have come to the writer’s attention are those made at Manchester, England, during the years 1902 and 1903. All these experiments were made jointly by eight of the most prominent English manufacturing companies, among whom were Armstrong, Whitworth & Co.; Vickers’ Sons & Maxim, John Brown & (‘/0., Thomas Firth & Sons, and others, who combined with the Manchester Association of Engineers and the Man- chester Municipal School of Technology, the latter being principally represented by Dr. J. T. Nicolson, who made the final report entitled “Report on Experiments with Rapid Cutting Steel Tools, ” for sale by Mr. Frank Hazelton, Secretary, 29 Brown St., Manchester, England.

78 In 1901, a committee of the V erein Deutscher Ingenieure (Union of German Engineers), together with the managers of some of the larger engineering works in Berlin, made an interesting series of experiments which was published September 28, 1901, in the “Zeit- schrift des Verein Deutscher Ingenieure,” and in November 15, 1905, there were published in Bulletin No. 2 of the University of Illinois, experiments made by Prof. L. P. Breckinridge and Henry B. Dirks.

79 The work of all these men belongs to the second type of experiments above referred to, in which the joint effect of two or more variables is studied at the same time. In the case of the Manchester experiments, the work appears to have been, to a considerable extent, a test as to the all-round knowledge in the art of cutting metals possessed by eight of the prominent English firms. These firms each presented tools made from their own tool steel, treated their own way, and ground to whatever shapes and angles the particular company considered would do the largest amount of work. Each company was allowed to have one guess on each of the qualities of metal worked upon, with each change of feed and depth of cut, as to the cutting speed at which they believed their tool would do the most work. If, under this cutting speed, the tool failed to hold out throughout the stipulated period of time, they were then given no opportunity to find the exact cutting speed at which the tool would do its best work. And, on the other hand, in those cases in which a tool did good work throughout its specified period of time, no efiort was made to find how much faster it could have run and still do good work.

80 A glance at Plates 13, 14 and 15 at the end of Dr. Nicolson’s report shows the great variety in the shapes of the tools used in the experiments. Yet no effort was made to definitely determine which make of tool steel or which shape of the tool was best, or even in case a tool did exceptionally good work, no effort was made to determine whether this was due to the shape of the tool or to the quality and treatment of the tool steel.

81 As was to be expected from any such test, each one of the eight companies repeatedly made guesses as to the proper speeds for their tools to run which were very wide of the mark. Yet in spite of this, it is notable that in each case some one of the eight firms guessed fairly close to the proper cutting speed, so that by selecting the best of those various guesses Dr. Nicolson, in writing the report, gives a very valuable and interesting table on p. 250 of the Manchester Report, summarizing the best speeds attained in cutting the soft, medium and hard steels, and the soft, medium and hard cast irons experimented on, in each case with four combined changes of depth of cut and thickness of feed.

82 This table conclusively proves the practical value of experiments of this nature, even when carried on in a thoroughly unscientific manner. There is, however, one element in these experiments which was very carefully investigated, and the results of which are of general scientific value; namely, the determination of the pressure of the chip or shaving upon the nose of the tool.

83 That the conclusions reached as to pressure are of value is due to the fact that upon this particular element, neither the shape of the tool nor the composition or treatment of the tool has very great effect, and in each case the pressure of the chip upon the tool appears to have been carefully observed and tabulated, so that experiments which are valueless from a scientific standpoint for most of the elements, confirm substantially, as to the pressure of the chip on the tool, the nsults of some of our previous experiments on this element.

84 The writer has a great respect for Dr. Nicolson as an experimenter, as his later work in this field has shown him to be a thoroughly scientific investigator; but feels it necessary to call attention to an error which even he has fallen into, namely, that of attempting to deduce a formula for the cutting of metals from a summary of the Manchester and German experiments. These experiments, from a scientific standpoint,were so defective as to make it out of the question to deduce formulae, because no effort was made to keep the following variables uniform: (1) the shape of the cutting edge and the lip and clearance angles of the tool varied from one experiment to another; (2) the quality of the tool steel varied; (3) the treatment of the tool varied; (4) the depth of the cut varied from that aimed at; (5) the cutting speed was not accurately determined at which each tool would do its maximum work throughout a given period of time; and (6) in reading the report of these experiments it does not appear that any careful tests were made to determine whether each of the various forgings and castings experimented on was sufficiently uniform throughout in quality to render the tests made upon them of scientific value. The same criticism, broadly speaking, applies to both the German and the University of Illinois experiments.

85 In fact, in none of these sets of experiments have they appreciated the necessity of MEASURING sarxnxrany the effect produced upon the cutting speed of two of the most important elements in the problem, (a) the thickness of the feed, and (b) the depth of the cut. In all of these investigations and in formulae given by Dr. Nicolson on p. 249 of the Manchester report, as well as in a formula published by him in “Technics,” for January, 1904, summarizing the results of the Manchester and German experiments, the area of the cut “a” is used as though it were a single variable, whereas the sectional area of the shaving is, in fact, the product of the depth of the cut multiplied by the feed. The fact is, however, that the thickness of the shaving or the feed has a greater effect upon the cutting speed than any other element, while the depth of the cut has only a comparatively small effect. When this is realized, it becomes apparent that any formula or even any data containing the area of the cut (or shaving) as a single element is valueless from a scientific standpoint. To illustrate: a cut which is 1} inch deep with 311 inch feed has the same sectional area as a 1; inch depth cut by § inch feed; namely, 7;‘; inch sectional area. Our experiments show that if a cutting speed for a § inch by § inch cut were 10 feet per minute, then the cutting speed for a 1} inch by 31; inch cut would be 18 feet per minute. From which the impossibility of using the area of the cut as an element in a formula is apparent.

86 Broadly speaking, it is unwise to draw conclusions and make formulae from experiments in which more than one variable is allowed to vary in the same trial. This criticism is made in no sense to
belittle the value of the work done by others, but with the object to pointedly call the attention of future experimenters to such errors as have been made primarily by ourselves and also by others.

87 The results obtained by Dr. Nicolson from the Manchester experiments led him to make another set of experiments for the purpose of determining accurately the pressure of the chip or shaving upon the cutting edge of the tool. In carrying out this work Dr. Nicolson has designed and constructed what appears to be by far the most scientific apparatus which has yet been made for this purpose. In his paper (published in Transactions, Vol. 25), he has very fully illustrated the apparatus with which he weighs separately the pressure of the chip upon the tool in three directions: a the VERTICAL raassunn; b the outward pressure or the pressure horizontally at right angles to the axis of the piece being turned; called by him SURFACING PRESSURE; c the feeding pressure or the pressure horizontally parallel to the axis of the piece being turned; called by him TRAVERSING PRESSURE.

88 His determination of that lip angle of the tool which cuts the metal with the least pressure was of great interest; but, in the writer’s judgment, by far the most important and original fact developed by him was brought out by a series of experiments in which he determined the wave-like increase and decrease of the pressure upon the nose of the tool which occurs in cutting metals.

89 In these experiments the chip was removed at a cutting speed of about one foot in five hours. It is notable that no other apparatus heretofore designed was sufficiently scientific and accurate to demonstrate this fact.

90 The writer has taken the liberty of reproducing on Folder 12, Figs. S2 and S6, Dr. Nicolson’s diagram, showing this variation in pressure. His discovery is most important in explaining one of the causes for the chattering of tools, and becomes a thoroughly scientific aid in selecting the shape or contour of the cutting edge for standard tools to be used in “roughing work.”

91 These experiments form a substantial and permanent addition to our knowledge of the art of cutting metals; and the writer regrets that Dr. Nicolson has not since then investigated other elements immediately affecting the more vital problem of the cutting speed in a similarly thorough manner; since he chose for investigation that element which on the whole is least fruitful in its practical results upon the art of cutting metals, namely, the pressure of the chip upon the tool.

92 However, in choosing this element for investigation Dr. Nicol son made the same error (if such it may be called) into which a most every experimenter in this field fall's sooner or later. From all theoretical standpoints it appears to the novice that a thorough investigation of the effect of the pressure of the chip upon the tool under varying conditions must furnish the key to the whole problem of the variation of cutting speed due to varying feeds, depths of cut, shape of the tool, etc. The fact is, however, that every one who exploits this field finds out sooner or later that there is no traceable relation whatever between the pressure of the chip on the tool and the cutting speed, and but little connection even between the hardness of the metal and the pressure upon the tool. The following is the reasoning which has led us all, at one time or another, into the same error:

'93 The ultimate cause for a tool giving out when cutting metal is the dullness or wear of the tool produced by the rubbing or pressure of the chip upon the lip surface of the tool and the chief element causing this wear, particularly at the high speeds at which tools should he run to do their best work, is the softening of the tool due to the heat produced by the friction of the‘ chip upon its lip surface. Now, it seems perfectly evident that this heat ‘will be increased directly in proportion to three elements: a the pounds of pressure of the chip upon the tool ; b the speed with which the chip slides across the nose of the tool ; c the coefficient of friction between the chip and the surface of the tool. And yet, paradoxical as it may seem, the writer again repeats that there is no traceable relation between the pressure of the chip upon the tool and the cutting speed. (The reasons in detail for this will be found later in paragraphs 503 to 519.)

94 So convincing, however, is the above theory that each successive experimenter who has joined the writer in his work has been thoroughly convinced that, through some error in our early experiments upon the pressure of the chip on the tool, we failed to establish the relation between the pressure and the cutting speed which would be demonstrated by a more carefully tried set of experiments; and the writer thinks it is not an exaggeration to state that each of these men in succession remained unconvinced until he had had the opportunity of verifying this fact for himself. 1 Dr. Nicolson, in his criticism of this paper, calls attention to the fact that more heat is generated in bending the chip or causing the molecules of the metal of the chip to flow past one another, than through the pressure of the chip on the tool.

95 As an illustration of the mental effect of this theory upon these experimenters: In one case, a bright and thoroughly honest young man, who was employed by the writer to help on the mathematical side of this work, became so thoroughly convinced through the above reasoning that the main lines on which we were carrying on our investigation would be rendered entirely unnecessary by a series of pressure tests made by himself, that upon being told by the writer that he would not allow the expense to be incurred for another series of pressure tests, he wrote a memorial of many pages to the Board of Directors of the company in which the experiments were being car- ried on, explaining his own thorough scientific attainments and the m'iter’s lack of the same, and that, therefore, our relative positions ought to be reversed, that he should do the directing and the writer should do the work. And, finally, when his protests were not heeded, he resigned his position; and the writer has been told that he subsequently induced another company to allow him to experiment on his own account. However, up to date there has not appeared any published record of these experiments.

96 We are dwelling at such length upon this element in the art because it has constituted the pit into which so many experimenters have fallen; and upon failing to trace any scientific relation between the pressure and the cutting speed they are very apt to conclude that the whole subject of cutting metals belongs to the domain of “rule of thumb" rather than to that of exact science, and give up further work in this field.

97 It may almost be said that investigations heretofore made upon the general subject of the pressure of the chip upon the tool have proved barren of useful and practical results, except in so far as they have furnished the knowledge needed by tool builders for giving their machines the proper driving power. It is with little hesitation that the writer makes the assertion that if no experiments whatever had been made in this field, the knowledge of the art of cutting metals would be on the whole in a more advanced state than it is now, since experimenters in all countries instead of studying pressures would have given their attention to some one of the other lines of investigation which bear directly and yield valuable information upon the one most important subject of cutting speed.

98 It is a noteworthy fact that when thorough investigations are attempted by earnest men in new fields, while frequently the object aimed at is not attained, yet quite often discoveries are made which are entirely foreign to the purpose for which the investigation was undertaken. And it may be said that the indirect results of careful scientific work are, generally speaking, fully as valuable as the direct. Two interesting illustrations of this fact have been furnished by our experiments.

99 The discovery of the Taylor-White process of treating tools by heating them almost to the melting point, or, in other words, the introduction of modern high speed tools the world over, was the indirect result of one of our lines of investigation.

100 The demonstration of the fact that the rules for using belting in common practice furnished belts which were entirely too light for economy was also one of the indirect results of our experiments.

101 The manner of making these discoveries was each time in a way so typical of what may be expected in similar cases that it would seem worth while to describe it in some detail.

102 During the winter of 1894-1895, the writer conducted an investigation in the shop of Wm. Sellers & Co., at the joint expense of Messrs. William Cramp & Sons, shipbuilders, and Messrs. Wm. Sellers & Co., to determine which make of self-hardening tool steel was, on the whole, the best to adopt as standard for all of the roughing tools of these two shops.

103 As a result of this work, the choice was narrowed down at that time to two makes of tool steel: (1) the celebrated Mushet self- hardening steel, the chemical composition of the particular bar analyzed at this time being as follows:

PER CENT PER CENTlPER CEN’1'l PERCENT PER CENT PER CENT PERCENT HIUM , 5.441 0.398 1 2.150 l 1.57s 1.044 BRO E i TUNGSTEN C CARBON HIANGANESE SILICON l PHOSPHORUS SULPHUR and
(2) a self-hardening steel made by the Midvale Steel Company of the following chemical composition:
4 ] 1 TUNGSTENi cHRO— CARBON MANGANIEE SILICON ‘ PHOSPHORUB SULPHUR PER CENT PER CEN'l‘,PEIl CENTl PERCENT PER CENT PER CENT PER CENT MIUM 1 | . , , 1.723 1.s30 ; 1.143 ' 0.180 l 0.246 0.023 0.00s 104

‘Of these two steels, the tools made from the Midvale steel were shown to be capable of running at rather higher cutting speeds. The writer himself heated hundreds of tools of these makes in the course of his experiments in order to accurately determine the best temperatures for forging and heating them prior to grinding so as to get the best cutting speeds. In these experiments he found that the Mushet steel if overheated crumbled badly when struck even a light blow on the anvil, while the Midvale steel if overheated showed no tendency to crumble, but, on the other hand, was apparently permanently injured. In fact, heating these tools slightly beyond a bright cherry red caused them to permanently fall down in their cutting speeds; and the writer was unable at that time to find any subsequent heat treatment which would restore a tool broken down in this way to its original good condition. This defect in the Midvale tools left us in doubt as to whether the Mushet or the Midvale was, on the whole, the better to adopt as a shop standard.

103 In the summer of 1898, soon after undertaking the reorganization of the management of the Bethlehem Steel Company, the writer decided to continue the experiments just referred to with a view to ascertaining whether in the meanwhile some better tool steel had not been developed. After testing several additional makes of tools, our experiments indicated that the Midvale self-hardening tools could be run if properly heated at slightly higher speeds than those of any other make.

106 Upon deciding to adopt this steel as our standard the writer had a number of tools of each make of steel carefully dressed and ground to exactly the same shape. He then called the foremen and superintendents of the machine shops of the Bethlehem Steel Company to the experimental lathe so that they could be convinced by seeing an actual trial of all of the tools that the Midvale steel was, on the whole, the best. In this test, however, the Midvale tools proved to be worse than those of any other make; 1'. e., they ran at slower cutting speeds. This result was rather humiliating to us as experimenters who had spent several weeks in the investigation.

107 It was of course the first impression of the writer that these tools had been overheated in the smith shop. Upon careful inquiry among the smiths, however, it seemed as though they had taken special pains to dress them at a low heat, although the matter was left in much doubt. The writer, therefore, determined to make a thorough investigation before finally adopting the Midvale steel as our shop standard to discover if possible some heat treatment which would restore Midvale tools injured in their heating (whether they had been underheated or overheated) to their original good condition.

108 For this purpose Mr. White and the writer started a carefully laid out series of experiments, in which tools were to be heated at temperatures increasing, say, by about 50 degrees all the way from a black heat to the melting point. These tools were then to be ground and run in the experimental lathe upon a uniform forging, so as to find: a that heat at which the highest cutting speed could be attained (which our previous experiments had shown to be a cherry red); b to accurately determine the exact danger point at which if over or underheated these tools were seriously injured; c to find some heat treatment by which injured tools could be restored to their former high cutting speeds.

109 These experiments corroborated our Cramp-Sellers experiments, showing that the tools were seriously broken down or injured by overheating, say, somewhere between 1550 degrees F. and 1700 degrees F.; but to our great surprise, tools heated up to or above the high heat of 1725 degrees F. proved better than any of those heated to the best previous temperature, namely, a bright cherry red; and from 1725° F. up to the incipient point of fusion of the tools, the higher they were heated, the higher the cutting speeds at which they would run.

110 Thus,the discovery that phenomenal results could be obtained by heating tools close to the melting point, which was so completely revolutionary and directly the opposite of all previous heat treatment of tools, was the indirect result of an accurate scientific effort to investigate as to which brand of tool steel was, on the whole, the best to adopt as a shop standard; neither Mr. White nor the writer having the slightest idea that overheating beyond the bright cherry red would do anything except injure the tool more and more the higher it was heated.

111 During our early Midvale Steel Company experiments, extending from 1880 to 1883, the writer had so much trouble in maintaining the tension of the belt used in driving the boring mill upon which he was experimenting that he concluded: (1) that belting rules in common use furnished belts entirely too light for economy; and (2) that the proper way to take care of belting was to have each belt in a shop tightened at regular intervals with belt clamps especially fitted with spring balances, with which the tension of the belt was accurately weighed every time it was tightened, each belt being retightened each time to exactly the same tension.

112 In 1884, the writer designed and superintended the erection of a new machine shop for the Midvale Steel Company, and this gave him the opportunity to put these conclusions to a practical test. About half the belts in the shop were designed according to the ordinary rules and the other half were made about two and one-half times as heavy as the usual standard. This shop ran day and night. The belts were in all cases cared for and retightened only upon written orders sent from the shop ofiice; and an accurate record was kept through nine years of all items of interest concerning each belt, namely: the number of hours lost through interruption to manufacture; the number of times each belt interrupted manufacture; the original cost of each belt; the detail costs of tightening, cleaning and repairing each belt; the fall in the tension before requiring retightening; and the time each belt would run without being retightened. Thus at the end of nine years these belts furnished a record which demonstrated beyond question many important facts connected with the use of belting, the principal of these being that the ordinary rules gave belts only about one-half as heavy as should be used for economy.‘ This belting experiment illustrates again the good that often comes indirectly from experiments undertaken in an entirely different field.

113 After many years of close personal contact with our mechanics, I have great confidence in their good judgment and common sense in the long run, and I am proud to number many of them among my most intimate friends.

114 As a class, however, they are extremely conservative, and if left to themselves their progress from the older toward better methods will be exceedingly slow. And my experience is that rapid improvement can only be brought about through constant and heavy pressure from those who are over them.

115 It must be said, therefore, that to get any great benefit from the laws derived from these experiments, our slide rules must be used, and these slide rules will be of but little, if any, value under the old style of management, in which the machinist is left with the final decision as to what shape of tool, depth of cut, speed, and feed, he will use.

116 The slide rules cannot be left at the lathe to be banged about by the machinist. They must be used by a man with reasonably clean. hands, and at a table or desk, and this man must write his instructions as to speed, feed, depth of cut, etc., and send them to the machinist well in advance of the time that the work is to be done. Even if these written instructions are sent to the machinist, however, little attention will be paid to them unless rigid standards have been not only adopted, but ENFORCED, throughout the shop for every detail, large and small, of the shop equipment, as well as for all shop methods. And, further, but little can be accomplished with these laws unless the old style foreman and shop superintendent have been done away with, and functional foremanship has been substituted,—consisting of speed bosses, gang bosses, order-of-work men, inspector, time study men, etc. In fact, the correct use of slide rules involves the substitution of our whole task system of management for the old style management, as described in our paper on “Shop Management” (Transactions, Vol. 24). This  involves such radical, one might almost say, revolutionary, changes in tho mental attitude and habits both of the workmen and of the management, and the danger from strikes‘ is so great and the chances for failure are so many, that such a reorganization should only be undertaken under the direct control (not advice but CONTROL) of men who have had years of experience and training in introducing this system.

117 A long time will be required in any shop to bring about this radically new order of things; but in the end the gain is so great that I say without hesitation that there is hardly a machine shop in the country whose output cannot be doubled through the use of these methods. And this applies not only to large shops, but also to comparatively small establishments. In a company whose employees all told, including officers and salesmen, number about one hundred and fifty men, we have succeeded in more than doubling the output of the shop, and in converting an annual loss of 20 per cent upon the old volume of business into an annual profit of more than 20 per cent upon the new volume of business, and at the same time rendering a lot of disorganized and dissatisfied workmen contented and hard working, by insuring them an average increase of about 35 per cent in their wages. And I take this opportunity of again saying that those companies are indeed fortunate who can secure the services of  men to direct the introduction of this type of management who have had sufficient training and experience to insure success.‘

118 Unfortunately those fundamental ideas upon which the new task management rests mainly for success are directly antagonistic to the fundamental ideas of the old type of management. To give two out of many examples: Under our system the workman is told minutely just what he is to do and how he is to do it; and any improvement which he makes upon the orders given him is fatal to success. While, with the old style, the workman is expected to constantly improve upon his orders and former methods. Under our system, any improvement, large or small, once decided upon goes into immediate use, and is never allowed to lapse or become obsolete, while under the old system, the innovation unless it meets with the approval of the mechanic (which it never does at the start) is generally for a long time, at least, a positive impediment to success. Thus, many of those elements which are mainly responsible for the success of our system are failures and a positive clog when grafted on to the old system.

119 For this reason the really great gain which will ultimately come from the use of these slide rules will be slow in arriving—mainly, as explained, because of the revolutionary changes needed for their successful use—but it is sure to come in the end.

120 Too much emphasis cannot be laid upon the fact that standardization really means simplification. It is far simpler to have in a standardized shop two makes of tool steel than to have 20 makes of tool steel, as will be found in shops under the old style of management. It is far simpler to have all of the tools in a standardized shop ground by one man to a few simple but rigidly maintained shapes than to have, as is usual in the old style shop, each machinist spend a portion of each day at the grindstone, grinding his tools with radically wrong curves and cutting angles, merely because bad shapes are easier to grind than good. Hundreds of similar illustrations could be given showing the true simplicity (not complication) which accompanies the new type of management.

121 There is, however, one element in which the new type of management to all outward appearance is far more complicated than the old; namely, no standards and no real system of management can be maintained without the supervision and, what is more, the hard work of men who would be called by the old style of management supernumeraries or non-producers. The man who judges of the complication of his organization only by looking over the names of those on the pay-roll and separating the so-called non-producers from the producers, finds the new style of management more complicated than the old.

122 No one doubts for one minute that it is far simpler to run a shop with a boiler, steam engine, shafting, pulleys and belts than it would be to run the same shop with the old fashioned foot power, yet the boiler, steam engine, shafting, pulleys and belts require, as supernumeraries or non-producers on the pay-roll, a fireman, an engineer, an oiler and often a man to look after belts. The old style manager, however, who judges of complication only by comparing the number of non-producers with that of the producers, would find the steam engine merely a complication in management. The same man, to be logical, would find the whole drafting force of an engineering establishment merely a complication, whereas in fact it is a great simplification over the old method.

123 Now our whole system of management is quite accurately typified by the substitution of an elaborate engine to drive and control the shop in place of the old fashioned foot power. There is no question that our human managing machine, which is required for the maintenance and the effective use of both standard shop details, and standard methods throughout the establishment, and for giving each workman each day in advance a definite task which must be finished in a given time, calls for many more non-producers than are used with the old style management having its two or three foremen and a superintendent. The efficiency of our engine of management, however, compared with the old single foreman is like a shop engine as compared with foot power or the drafting room as compared with having the designing done by the pattern maker, blacksmith and machinist.

124 A study of the recommendations made throughout this paper will illustrate the fact that we propose to take all of the important decisions and planning which vitally affect the output of the shop out of the hands of the workmen, and centralize them in a few men, each of whom is especially trained in the art of making those decisions and in seeing that they are carried out, each man having his own particular function in which he is supreme, and not interfering with the functions of other men. In all this let me say again that we are aiming at true simplicity, not complication.

125 There is one recommendation, however, in modern machine shop practice in making which the writer will probably be accused of being old fashioned or ultra-conservative.

126 Of late years there has been what may be almost termed a blind rush on the part of those who have wished to increase the efficiency of their shops toward driving each individual machine with an independent motor. The writer is firmly convinced through large personal observation in many shops and through having himself systematized two electrical works that in perhaps three cases out of four a properly designed belt drive is preferable to the individual motor drive for machine tools. There is no question that through a term of years the total cost, on the one hand, of individual motors and electrical wiring, coupled with the maintenanace and repairs, of this system will far exceed the first cost of properly designed shafting and belting plus their maintenance and repairs (in most shops entirely too light belts and counter shafts of inferior design are used, and the belts are not systematically cared for by one trained man and this involves a heavy cost for maintenance). There is no question, therefore, that in many cases the motor drive means in the end additional complication and expense rather than simplicity and economy.

127 It is at last admitted that there is little, if any, economy in power obtainable through promiscuous motor driving; and it will certainly be found to be a safe rule not to adopt an individual motor for driving any machine tool unless a clearly evident and a large saving can be made by it.

128 In concluding let me say that we are now but on the threshold of the coming era of true cooperation. The time is fast going by for the great personal or individual achievement of any one man standing alone and without the help of those around him. And the time is coming when all great things will be done by the cooperation of many men in which each man performs that function for which he is best suited, each man preserves his own individuality and is supreme in his particular function, and each man at the same time loses none of his originality and proper personal initiative, and yet is controlled by and must work harmoniously with many other men.

129 And let me point out that the most important lessons taught by these experiments, particularly to the younger men, are:

THAT SEVERAL MEN WHEN HEARTILY COOPERAT1NG, EVEN IF OF EVERYDAY CALIBER, CAN ACCOMPLISH WHAT WOULD BE NEXT TO IMPOSSIBLE FOR  ANY ONE MAN EVEN OF EXCEPTIONAL ABILITY.

THAT EXPENSIVE EXPERIMENTS CAN BE SUCCESSFULLY CARRIED ON BY MEN WITHOUT MONEY, AND THE MOST DIFFICULT MATHEMATICAL PROBLEMS CAN BE SOLVED BY VERY ORDINARY MATHEMATICIANS; PROVIDING ONLY THAT  THEY ARE WILLING TO PAY THE PRICE IN TIME, PATIENCE AND HARD WORK.

THE OLD ADAGE IS AGAIN MADE THAT ALL THINGS COME TO HIM WHO WAITS, IF ONLY HE WORKS HARD  ENOUGH IN THE MEANTIME.

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‘The writer feels free to give this advice most emphatically without danger of having his motives misinterpreted, since he has himself given up accepting professional engagements in this field.


‘The danger from strikes coznes from the false steps often taken by men not familiar with the methods which should be used in introducing the sf s‘em. The writer has never had a single strike during the 26 years he has been engaged in ti-is work. - - — * i->>-~‘






 ‘The writer presented a paper to this Society in 1893 (published in Transactions, Vol. 15) upon this series of experiments. He has since found, however, that in the minds of many readers the value of the conclusions arrived at have been seriously brought into question largely through the criticism of one man, which at the time appeared to the writer so ridiculous that he made the mistake of thinking it not worth answering in detail. This should be a warning to writers lo answer carefully all criticism, however foolish.