Machine Tool Toolholders - Industrial Engineering and Productivity Aspects

Lesson 53 of Industrial Engineering ONLINE Course.

Lesson 10 of Process Industrial Engineering ONLINE Course (Module)

Industrial engineers have to first know alternatives to produce to specification. Then ways to increase productivity of the best alternative.

Industrial engineering work spans from system level improvements to engineering element level improvement. When one thinks of the subject "Design of Machine Elements", the element level improvement can be understood. Similarly in time study and work measurement, work is divided into elements. In time study perspective, work is to be improved at element level. When we take the machine work as the improvement target, effect of modifying each machine element or each element of the  machining process on productivity is to be evaluated. Machine tool holder is an element of the machine or machining process. It has considerable impact on productivity and hence needs to be studied and various developments in tool holders are to be monitored by industrial engineers.

Toolholders -  Industrial Engineering and Productivity Aspects

The design and structural properties of toolholders have a strong influence on machining cost, accuracy, and stability.

The toolholder is often the weakest link in the machining system, which has even limited full utilization of the potential of advanced cutting tool materials in some applications. This means some effort can be devoted to improve tool holders further.

TOOLHOLDING SYSTEMS

1. Introduction

Properly engineered tool–toolholder and toolholder–spindle interfaces are critical to achieving high
performance and high throughput (productivity).

There are many important structural and dynamic characteristics of a tooling structure and its interface with spindle. They are the manufacturing tolerances of tool holding system elements, static and dynamic runout, radial and axial positioning accuracy and repeatability, connection rigidity (static and dynamic stiffness), force transmission capability, momentum and torque characteristics, clamping forces, balance requirements, fatigue life and durability, retention force requirements, safety, locking/unlocking forces, coolant capability, ease of connection and disconnection, chemical and thermal stability, maintenance requirements, sensitivity to contamination, and cost. Other aspects to be addressed include the efficiency of the connection over a long period, tool presetting requirements, and provisions for data storage modules.

The cutting tool body and the tool holder can be made in one solid piece.

Modular systems in which the same tool holder can be used for various tools will provide flexibility with some reduction in inventory.


2. Modular  Toolholding Systems

Modular toolholding systems consist of stationary or rotating adapters in a variety of configurations to develop tooling systems of various size that fit various machines with a common toolhoder-spindle  coupling. There are several major types of toolholder-spindle connections with respect to centering and locating characteristics. These include different types of cylindrical shafts including single and multiple cylinders, face and nonface contacts, as well as different types of tapers and taper/face contact systems. There are also several designs of connections with respect to torque transmission, such as polygon, straight, and spiral gear designs, the more conventional key and pin drive methods, and mounting bolt patterns or draw bars.

3. Quick-Change Toolholding Systems

This is also a modular system. Quick-change tooling is important for increasing productivity. Reducing tool change time is also important.  A quick-change tooling system consists of a tool or holder that can be changed for another as quickly as possible. It allows the correct length tool to be built off line to maintain maximum performance. The presetting capability of quick-change tooling, in conjunction with the repeatability of the coupling between the cutting unit and the toolholder, ensures that the cutting edge is properly positioned in relation to the workpiece.

Toolholder-Spindle Connection Methods  

1. General

There are A to K types described in Stephenson-Agapiou book that have variations in types of cylindrical shafts including single and multiple cylinders, face and nonface contacts, as well as different types of tapers and taper/face contact systems.

2. Conventional Tapered "CAT-V" Connection
3. Face-Contact CAT-V Interface
4. HSK Interface
    Kennametal KM
    NC5
    Sandvik Capto


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Sandvik Coromant Capto Tool Holder

Coromant Capto by Sandvik is a modular system that can be used to create extended-length toolholders. Coromant Capto adapter has a spindle side to put in the machine spindle  and then  different types of milling cutters, drills or boring heads are mounted on the machining side of the assembly end of the adapter by adding extensions to make it longer and stack them out as far as you need. On the same tool assembly, different diameter extensions can be used, which gives a lot of versatility. You usually would start with a larger diameter at the base and then reduce it to the required diameter in steps or  keep it all the same diameter for the entire assembly.

https://www.sandvik.coromant.com/en-gb/products/coromant_capto/pages/default.aspx

2019
https://www.cnctimes.com/editorial/new-connected-driven-tool-holder-solution-maximises-machine-utilisation-sandvik-coromant

https://www.ctemag.com/news/articles/extended-reach-toolholders-remain-requirement

https://www.tradeindia.com/fp4207315/Coromant-Capto-Modular-Tools.html

https://www.grainger.com/product/SANDVIK-COROMANT-Coromant-Capto-Adapter-14L475

https://www.indiamart.com/proddetail/sandvik-coromant-capto-tooling-system-22046925255.html

1998
https://www.americanmachinist.com/cutting-tools/article/21892978/modular-means-more
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5. Quick-change interfaces
6.Turning Tool Holders

7. Evaluation and Comparison of Toolholder/Spindle Interface

The following measurements can be done to evaluate Toolholder/Spindle Interface.


The static and dynamic bending stiffness and the torsional stiffness can be  measured from a bench test. The reliability can be based on an evaluation matrix using factors such as fracture fatigue, dirt/nick sensitivity, wear/corrosion sensitivity, sticking extra force, torque slippage, temperature sensitivity, maintenance, lubrication, coolant feed, and gauging. The ease of tool change is assessed based on an evaluation matrix with the factors of holder weight, length engagement, surface cleanliness, drawbar force, critical location, and coolant through ease.

Toolholder–spindle interfaces can be evaluated and compared based on experimental and analytical/finite element results.  Bench tests provide a relative comparison between toolholders. The static and dynamic stiffness seen at the tip of the cutting tool also depend on the stiffness of the tool, the spindle geometry and bearings, the housing, and the overall machine structure. Bench tests results that reflect only the stiffness of the toolholder–spindle interface may thus be misleading in applications in which the properties of the spindle and bearings largely determine the structural response.

The characterization of the toolholder/spindle interface is made using the joint stiffness parameters. A methodology for estimating the joint stiffness parameters of a toolholder/spindle interface using one linear spring and one rotational spring  has been found to be very effective. The method  is based on the FRF of the interface system. It involves FEA and experimental measurements of a bench fixture. The most important assumption is that the behavior of the test system is linear. After the joint stiffness parameters are estimated, they can be used in any machine tool spindle FEM  to estimate the static and dynamic characteristic at the tool tip.

The Spindle Analysis program (SPA) from Manufacturing Laborites, Inc. can be used to create a two-dimensional axisymmetric model of a spindle for evaluating the interfaces. The spindle shaft, the housing, and the toolholder structure can be  modeled.  The SPA program can model a 2-DOF spring to include a linear direction and rotational direction to represent the joint between the spindle and the toolholder. The SPA FEA program simulates both the dynamic and static behavior of a spindle and tooling system.  The static bending deflection of the tool can also be defined analytically using the joint stiffness parameters; the bending deflection of the tool includes the elastic deflection of the bar itself.

The material removal rate that a machining center can achieve is strongly dependent upon the static and dynamic characteristics of the machine–tool–workpiece system as seen at the tip of the tool. In the  selection of the best spindle–toolholder interface,  the stiffness is one of the important parameters to consider in the selection. The static stiffness measures the deflection at the end of the tool in response to a static force. It provides some indication of the ability to create a surface or hole with the tool in the intended location. In milling, drilling, reaming, boring with a relatively low spindle speed, the error in location of the machined surface or hole is related to the static stiffness. The higher the static stiffness, the more accurately the surface or hole will be located with smaller form error. If static stiffness is the performance criterion, then the data show that the face contact connections perform better than the nonface contact connections in a machine tool spindle.  Therefore, the static stiffness of the tool should be estimated by consideration of the spindle stiffness in order to properly select an interface style. The static stiffness can be estimated using the FEA or analytically assuming the joint stiffness parameters are available.

In the case of  high metal removal rate,  accurate surface location at higher spindle speeds, the better selection criterion is dynamic stiffness (or chatter criterion)  at the tip of the tool. The dynamic stiffness is a combination of stiffness and damping in a particular mode of vibration (at a particular frequency).  The damping is estimated from the FRFs while the natural frequencies and modal stiffness can be estimated using several programs, including commercial FEA solvers and advanced codes, which consider bearing preload and other nonlinear effects. For dynamic cutting performance at the tip of the tool, FEA can be also used assuming the joint parameters are available. There are cases where the bore quality or surface flatness are very critical, in which case the quality of the interface taper and face including the quality of the tool point (runout) with respect to the taper interface are very important. In addition, the static bending stiffness becomes important assuming it is not a high-speed application. Rigid face contact interfaces provide higher static stiffness or normalized bending stiffness at higher moments assuming: (1) the taper quality for the nonface contact interfaces is worse than AT3 tolerance, and (2) the clamping force is high enough to sustain larger bending moments without losing contact between the toolholder and the spindle face.


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Toolholder types other than modular toolholders

https://www.engineering.com/AdvancedManufacturing/ArticleID/11710/Toolholding-101-Top-Tips-for-High-Productivity-Machining.aspx

VDI and BMT Turrets
https://www.mylascnc.com/en/tech/tech_detail-2.htm



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Cutting Tool Clamping Systems - Tool Holders

1. Milling cutter drives
2. Side-Lock-Type Chucks
3. Collet chucks
4. Hydraulic Chucks
5. Milling Chucks
6. Shrink-Fit Chucks
7. Proprietary Chcuks
8. Tapping Attachments
9. Reaming Attachments
10. Comparison of Cutting Tool Clamping Systems

Balancing Toolholders

Balancing of toolholders is an important task.

Fundamentals of balancing - Good description
https://www.haimer-usa.com/products/balancing-technology/knowledge/fundamentals-of-balancing.html

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MTD CNC
_____________

2020
February 13, 2020: HAIMER at GrindTec 2020: hall 2, booth 2113 - Fine balancing increases productivity during the grinding process
https://www.haimer-usa.com/news/news/news-article/item/haimer-at-grindtec-2020-hall-2-booth-2113-fine-balancing-increases-productivity-during-the-grind-1.html

2014
https://www.ctemag.com/news/articles/balanced-equations-toolholder-vibration-makes-miserable-machining-balancing-can-help

2008
https://www.americanmachinist.com/archive/features/article/21892676/toolholder-balancing-101

1/1/2017
Toolholding for Heavy-Duty Machining
Heller Machine Tools needed to improve metal removal rates during roughing and heavy-duty machining. Haimer's Safe-Lock system enabled high-feed slotting of up to 2 times diameter in difficult materials.
Haimer Safe-Lock system with HSK-A100
https://www.mmsonline.com/articles/toolholding-for-heavy-duty-machining

December 2019

Tool Holder Essentials - Haas

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_______________________ 

Updated 22.7.2022,  23 July 2021

Pub 9 July 2020

ATRO - DIY Modular Robots

 Beckhoff Robots

https://www.automationworld.com/factory/robotics/article/22340170/beckhoff-introduces-the-atro-modular-robot

https://www.beckhoff.com/en-en/products/motion/atro-automation-technology-for-robotics/

https://www.design-engineering.com/products/modular-industrial-robot/

https://www.controlsdrivesautomation.com/multi-axis-automation-robot-system

https://engmag.in/automation-technology-for-robotics-atro/

https://www.controlengeurope.com/article/191348/Compact-multi-axis-robotic-system.aspx

Product and Process Design Principles: Synthesis, Analysis and Evaluation - Book Information

 Product and Process Design Principles: Synthesis, Analysis and Evaluation  4th Edition

Warren D. Seider, Daniel R. Lewin, J. D. Seader, Soemantri Widagdo, Rafiqul Gani, Ka Ming Ng

ISBN: 978-1-119-28263-1 May 2016 784 Pages

https://www.wiley.com/en-us/Product+and+Process+Design+Principles%3A+Synthesis%2C+Analysis+and+Evaluation%2C+4th+Edition-p-9781119282631

TABLE OF CONTENTS

PART ONE INTRODUCTION TO PRODUCT AND PROCESS DESIGN 1

Chapter 1 Introduction to Chemical Product Design 3

1.0 Objectives 3

1.1 Introduction 3

1.2 The Diversity of Chemical Products 3

1.3 Product Design and Development 7

1.4 Summary 16

References 17

Exercises 17

Chapter 2 Introduction to Process Design 19

2.0 Objectives 19

2.1 Introduction 19

2.2 Experiments 21

2.3 Preliminary Process Synthesis 21

2.4 Next Process Design Tasks 40

2.5 Preliminary Flowsheet Mass Balances 41

2.6 Summary 45

References 45

Exercises 45

Chapter 3 Design Literature, Stimulating Innovation, Energy, Environment, Sustainability, Safety, Engineering Ethics 47

3.0 Objectives 47

3.1 Design Literature 47

3.2 Stimulating Invention and Innovation 50

3.3 Energy Sources 51

3.4 Environmental Protection 56

3.5 Sustainability 60

3.6 Safety Considerations 63

3.7 Engineering Ethics 70

3.8 Summary 73

References 73

Exercises 74

3S Supplement to Chapter 3—NSPE Code of Ethics (Online www.wiley.com/college/Seider)

PART TWO DESIGN SYNTHESIS—PRODUCT AND PROCESSES 77

Chapter 4 Molecular and Mixture Design 79

4.0 Objectives 79

4.1 Introduction 79

4.2 Framework for Computer-Aided Molecular-Mixture Design 81

4.3 Case Studies 98

4.4 Summary 107

References 107

Exercises 108

Chapter 5 Design of Chemical Devices, Functional Products, and Formulated Products 110

5.0 Objectives 110

5.1 Introduction 110

5.2 Design of Chemical Devices and Functional Products 112

5.3 Design of Formulated Products 117

5.4 Design of Processes for B2C Products 123

5.5 Summary 126

References 127

Exercises 127

Chapter 6 Heuristics for Process Synthesis 132

6.0 Objectives 132

6.1 Introduction 133

6.2 Raw Materials and Chemical Reactions 133

6.3 Distribution of Chemicals 135

6.4 Separations 141

6.5 Heat Removal From and Addition to Reactors 145

6.6 Heat Exchangers and Furnaces 148

6.7 Pumping, Compression, Pressure Reduction, Vacuum, and Conveying of Solids 150

6.8 Changing the Particle Size of Solids and Size Separation of Particles 153

6.9 Removal of Particles From Gases and Liquids 154

6.10 Considerations that Apply to the Entire Flowsheet 154

6.11 Summary 155

References 159

Exercises 160

Chapter 7 Simulation to Assist in Process Creation 162

7.0 Objectives 162

7.1 Introduction 162

7.2 Principles of Process Simulation 163

7.3 Process Creation through Process Simulation 176

7.4 Case Studies 184

7.5 Principles of Batch Flowsheet Simulation 194

7.6 Summary 201

References 202

Exercises 202

Chapter 8 Synthesis of Networks Containing Reactors 209

8.0 Objectives 209

8.1 Introduction 209

8.2 Reactor Models in the Process Simulators 210

8.3 Reactor Network Design Using the Attainable Region 215

8.4 Reactor Design for Complex Configurations 220

8.5 Locating the Separation Section with Respect to the Reactor Section 224

8.6 Trade-Offs in Processes Involving Recycle 227

8.7 Optimal Reactor Conversion 228

8.8 Recycle to Extinction 229

8.9 Snowball Effects in the Control of Processes Involving Recycle 231

8.10 Summary 231

References 232

Exercises 232

Chapter 9 Synthesis of Separation Trains 234

9.0 Objectives 234

9.1 Introduction 234

9.2 Criteria for Selection of Separation Methods 241

9.3 Selection of Equipment 244

9.4 Sequencing of Ordinary Distillation Columns for the Separation of Nearly Ideal Liquid Mixtures 245

9.5 Sequencing of Operations for the Separation of Nonideal Liquid Mixtures 257

9.6 Separation Systems for Gas Mixtures 277

9.7 Separation Systems for Solid-Fluid Mixtures 279

9.8 Summary 280

References 280

Exercises 282

Chapter 10 Second-Law Analysis 287

10.0 Objectives 287

10.1 Introduction 287

10.2 The System and the Surroundings 289

10.3 Energy Transfer 289

10.4 Thermodynamic Properties 290

10.5 Equations for Second-Law Analysis 295

10.6 Examples of Lost-Work Calculations 297

10.7 Thermodynamic Efficiency 299

10.8 Causes of Lost Work 300

10.9 Three Examples of Second-Law Analysis 300

10.10 Summary 310

References 310

Exercises 310

Chapter 11 Heat and Power Integration 316

11.0 Objectives 316

11.1 Introduction 316

11.2 Minimum Utility Targets 319

11.3 Networks for Maximum Energy Recovery 325

11.4 Minimum Number of Heat Exchangers 329

11.5 Threshold Approach Temperature 334

11.6 Optimum Approach Temperature 336

11.7 Multiple Utilities 337

11.8 Heat-Integrated Reactors and Distillation Trains 342

11.9 Heat Engines and Heat Pumps 348

11.10 Summary 351

Heat Integration Software 351

References 352

Exercises 352

11S-1 Supplements to Chapter 11—MILP and MINLP Applications in HEN Synthesis (Online www.wiley.com/college/Seider)

11S-1.0 Objectives

11S-1.1 MER Targeting Using Linear Programming (LP)

11S-1.2 MER Design Using Mixed-Integer Linear Programming (MINLP)

11S-1.3 Superstructures for Minimization of Annual Costs

11S-1.4 Case Studies

Case Study 11S-1.1 Optimal Heat-Integration for the ABCDE Process

Case Study 11S-1.2 Optimal Heat-Integration for an Ethylene Plant

11S-1.5 Summary

11S-1.6 References

11S-2 Supplement to Chapter 11—Mass Integration (Online www.wiley.com/college/Seider)

11S-2.0 Objectives

11S-2.1 Introduction

11S-2.2 Minimum Mass-Separating Agent

11S-2.3 Mass Exchange Networks for Minimum External Area

11S-2.4 Minimum Number of Mass Exchangers

11S-2.5 Advanced Topics

11S-2.6 Summary

11S-2.7 References

Chapter 12 Heat Exchanger Design 358

12.0 Objectives 358

12.1 Introduction 358

12.2 Equipment for Heat Exchange 363

12.3 Heat-Transfer Coefficients and Pressure Drop 375

12.4 Design of Shell-and-Tube Heat Exchangers 380

12.5 Summary 384

References 384

Exercises 384

Chapter 13 Separation Tower Design 386

13.0 Objectives 386

13.1 Operating Conditions 386

13.2 Fenske-Underwood-Gilliland (FUG) Shortcut Method for Ordinary Distillation 387

13.3 Kremser Shortcut Method for Absorption and Stripping 388

13.4 Rigorous Multicomponent, Multiequilibrium-Stage Methods with a Simulator 389

13.5 Plate Efficiency and HETP 391

13.6 Tower Diameter 392

13.7 Pressure Drop and Weeping 393

13.8 Summary 395

References 395

Exercises 396

Chapter 14 Pumps, Compressors, and Expanders 397

14.0 Objectives 397

14.1 Pumps 397

14.2 Compressors and Expanders 401

14.3 Summary 403

References 404

Exercises 404

Chapter 15 Chemical Reactor Design 405

15.0 Objectives 405

15.1 Introduction 405

15.2 Limiting Approximate Models for Tubular Reactors 405

15.3 The COMSOL CFD Package 407

15.4 CFD for Tubular Reactor Models 410

15.5 Nonisothermal Tubular Reactor Models 418

15.6 Mixing in Stirred-Tank Reactors 423

15.7 Summary 424

References 425

Exercises 425

Chapter 16 Cost Accounting and Capital Cost Estimation 426

16.0 Objectives 426

16.1 Accounting 426

16.2 Cost Indexes and Capital Investment 434

16.3 Capital Investment Costs 438

16.4 Estimation of the Total Capital Investment 444

16.5 Purchase Costs of the Most Widely Used Process Equipment 449

16.6 Purchase Costs of Other Chemical Processing Equipment 470

16.7 Equipment Costing Spreadsheet 486

16.8 Equipment Sizing and Capital Cost Estimation Using Aspen Process Economic Analyzer (APEA) 486

16.9 Summary 493

References 493

Exercises 494

Chapter 17 Annual Costs, Earnings, and Profitability Analysis 498

17.0 Objectives 498

17.1 Introduction 498

17.2 Annual Sales Revenues, Production Costs, and the Cost Sheet 499

17.3 Working Capital and Total Capital Investment 509

17.4 Approximate Profitability Measures 510

17.5 Time Value of Money 513

17.6 Cash Flow and Depreciation 520

17.7 Rigorous Profitability Measures 525

17.8 Profitability Analysis Spreadsheet 529

17.9 Summary 545

References 546

Exercises 546

PART THREE DESIGN ANALYSIS—PRODUCT AND PROCESS 551

Chapter 18 Six-Sigma Design Strategies 553

18.0 Objectives 553

18.1 Introduction 553

18.2 Six-Sigma Methodology in Product Design and Manufacturing 553

18.3 Example Applications 557

18.4 Summary 564

References 564

Exercises 565

18S Supplement to Chapter 18 (Online www.wiley.com/college/Seider)

18S.1 Penicillin Fermenter Model

18S.2 Reactive Extraction and Re-extraction Model

References

Chapter 19 Business Decision Making in Product Development 566

19.0 Objectives 566

19.1 Introduction 566

19.2 Economic Analysis 566

19.3 Make-or-Buy Decisions 570

19.4 Microeconomics of Product Development 572

19.5 Company and Societal Factors Affecting Product Development 573

19.6 Summary 574

References 575

Exercises 575

Chapter 20 Plantwide Controllability Assessment 576

20.0 Objectives 576

20.1 Introduction 576

20.2 Control System Configuration 579

20.3 Qualitative Plantwide Control System Synthesis 584

20.4 Summary 590

References 590

Exercises 591

20S Supplement to Chapter 20 (Online www.wiley.com/college/Seider)

20S.0 Objectives

20S.1 Generation of Linear Models in Standard Forms

20S.2 Quantitative Measures for Controllability and Resiliency

20S.3 Towards Automated Flowsheet C&R Diagnosis

20S.4 Control Loop Definition and Tuning

20S.5 Case Studies

Case Study 20S.1 Exothermic Reactor Design for the Production of Propylene Glycol

Case Study 20S.2 Two Alternative Heat Exchanger Networks

Case Study 20S.3 Interaction of design and Control in the MCB Separation Process

20S.6 MATLAB for C&R Analysis

20S.7 Summary

References

Exercises

Chapter 21 Design Optimization 597

21.0 Objectives 597

21.1 Introduction 597

21.2 General Formulation of the Optimization Problem 598

21.3 Classification of Optimization Problems 599

21.4 Linear Programming (LP) 601

21.5 Nonlinear Programming (NLP) with a Single Variable 603

21.6 Conditions for Nonlinear Programming (NLP) by Gradient Methods with Two or More Decision Variables 605

21.7 Optimization Algorithm 607

21.8 Flowsheet Optimizations—Case Studies 609

21.9 Summary 611

References 612

Exercises 612

Chapter 22 Optimal Design and Scheduling of Batch Processes 616

22.0 Objectives 616

22.1 Introduction 616

22.2 Design of Batch Process Units 617

22.3 Design of Reactor–Separator Processes 620

22.4 Design of Single-product Processing Sequences 622

22.5 Design on Multiproduct Processing Sequences 625

22.6 Summary 626

References 626

Exercises 627

PART FOUR DESIGN REPORTS—PRODUCT AND PROCESS 629

Chapter 23 Written Reports and Oral Presentations 631

23.0 Objectives 631

23.1 Contents of the Written Report 632

23.2 Preparation of the Written Report 636

23.3 Oral Design Presentations 638

23.4 Award Competition 641

23.5 Summary 641

References 641

PART FIVE CASE STUDIES—PRODUCT AND PROCESS DESIGNS 643

Chapter 24 Case Study 1—Home Hemodialysis Devices 645

24.0 Objectives 645

24.1 Hemodialysis Technology 645

24.2 Design Specifications of Home Hemodialysis Device 652

24.3 Summary 655

References 655

Bibliography Patents—Hemodialysis Devices—General 655

Patents—Hemodialysis Devices—Hollow-Fiber Membranes 656

Patents—Hemodialysis Devices—Dialysate Regeneration 656

Patents—Hemodialysis Devices—Alarms/User Interface 656

Exercises 656

Chapter 25 Case Study 2—High Throughput Screening Devices for Kinase Inhibitors 657

25.0 Objectives 657

25.1 Background Technology For High Throughput Screening of Kinase Inhibitors 657

25.2 Product Concept 665

25.3 Prototyping 669

25.4 Product Development 672

25.5 Summary 672

References 672

Patents 673

Exercises 673

Chapter 26 Case Study 3—Die Attach Adhesive: A Case Study of Product Development 674

26.0 Objectives 674

26.1 Background of Technology 674

26.2 Market Study 674

26.3 Product Design 677

26.4 Process Design 678

26.5 Prototyping 678

26.6 Estimation of Product Cost 679

26.7 Summary 680

References 680

Exercises 681

Chapter 27 Case Study 4—Ammonia Process 683

27.0 Objectives 683

27.1 Introduction 683

27.2 Initial Base Case Design 686

27.3 Design Refinement 692

Postscript 699

References 703

Exercises 703

APPENDICES

I. Residue Curves for Heterogeneous Systems 704

II. Design Problem Statements by Area 705

III. Materials of Construction 709

INDICES

Table of Acronyms 711

Author Index 719

Subject Index 725

NEW TO THIS EDITION

Approximately 100 video clips created by the authors within the enhanced eBook, each accompanied by quiz questions with answer-specific feedback

Expanded and new coverage of chemical product design, design optimization, engineering ethics, molecular and mixture design, mass integration, Six-Sigma design strategies, and more

Original and updated real-world case studies and supplemental resource material

Modern computer-based methods for process synthesis

Extensions and case studies that enhance the coverage of product design, especially of mixture blends, formulated products, and product devices

Updated and expanded resources available on the book companion site: program and simulation files that solve 60 example problems; a solution manual for homework exercises; 93 design problem statements, and multimedia courseware that uses voice, video, and animation to introduce new users of the steady-state simulators to the specifics of two of the most widely used process simulation programs, ASPEN PLUS and HYSYS (UniSim Design)

https://www.wiley.com/en-us/Product+and+Process+Design+Principles%3A+Synthesis%2C+Analysis+and+Evaluation%2C+4th+Edition-p-9781119282631#content-section

Group technology production methods in manufacture

 Group technology production methods in manufacture

C C Gallagher; W A Knight

Publisher: Chichester : E. Horwood ; New York : Halsted, Press, 1986.

Recommended by S.A. Irani

https://www.sciencedirect.com/science/article/abs/pii/0166361587900029

http://courses.washington.edu/ie337/gt.pdf

Group technology production methods in manufacture

Group Technology: A systematic approach to the design of flexible robot grippers for metal-cutting cells

S.A.Irani,  D.L.Kimbler

Robotics

Volume 2, Issue 2, June 1986, Pages 123-138

https://www.sciencedirect.com/science/article/abs/pii/0167849386900495

Facilities Industrial Engineering - F.W. Taylor

 

In the paper on piece rate system in which Taylor's productivity improvement was described in good amount of detail first.

74. The careful study of the capabilities of the machines and the analysis of the speeds at which they must run, before differential rates can be fixed which will insure their maximum output, almost invariably result in first indicating and then correcting the defects in their design and in the method of running and caring for them.

75. In the case of the Midvale Steel Company, to which I have already referred, the machine shop was equipped with standard tools furnished by the best makers, and the study of these machines, such as lathes, planers, boring mills, etc., which was made in fixing rates, developed the fact that they were none of them designed and speeded so as to cut steel to the best advantage. As a result, this company has demanded alterations from the standard in almost every machine which they have bought during the past eight years. They have themselves been obliged to superintend the design of many special tools which would not have been thought of had it not been for elementary rate-fixing.

https://nraoiekc.blogspot.com/2018/07/frederick-taylors-piece-rate-system_68.html

Facilities Industrial Engineering

Productivity Science of Machining - 2016 Update - Stephenson - Agapiou

Lesson 49A of Industrial Engineering ONLINE Course

Lesson 50. Industrial Engineering and Productivity Aspects of Metal Cutting Processes

______________

______________



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_______________

To do machine work study of machine tools, the industrial engineer needs to have good knowledge of metal cutting theory and operation of machine tools. This knowledge has to be supplemented by knowledge of process and operation planning. Then only machine work study, that is operation analysis of the operation being done on a machine tool can be carried out.

Productivity analysis is based on productivity standards, that the productivity that is achievable by ideal machine tool, ideal cutting tool, ideal cutting fluid, and ideal cutting conditions. The current productivity being achieved and the working facilities  and cutting parameters are to be compared with ideal conditions and efforts are to be done to redesign the operation to the extent economically beneficial. Productivity improvement is achieved through productivity engineering: facilities industrial engineering and process industrial engineering.

Productivity Science of Machining - F.W. Taylor

Stephenson - Agapiou Book "Metal Cutting Theory and Practice."

Number of productivity related ideas in the area of metal cutting were given by Stephenson and Agapiou in their book "Metal Cutting Theory and Practice." (Third Edition, 2016) These relationships are to be used in developing ideal machining set up and cutting conditions for the operation under study and they are to be compared with the current set up and conditions in use.

About Dr. Agapiou

Dr. Agapiou’s research and teaching interests include modeling and optimization of metal-cutting operations, including cutting tools and machining systems, and modeling manufacturing part quality for machining lines to improve part quality, process, and productivity.

p16
He (Taylor) felt that shop productivity could be greatly increased if standard best practices were dictated by a central planning department.

As a result of these experiments, Taylor was able to increase machine shop productivity at Midvale by as much as a factor of 5.

p.32

Also, the complexity of the tool has inhibited the introduction of new tool materials, so that productivity gains in drilling have lagged those made in turning and milling over the past 30 years. A number of manufacturers have developed diamond or CBN tipped or coated drills to attempt to address this limitation.

p.98
The number of tools was reduced from 17 to 12. The positioning time (of tools) was found to be the largest contributor to productivity improvement, with the cutting time the second contributor.

p.99
                    Conv. Mc.              Std. HSMC        Adv. HSMC
Productivity   100%                    137%                  179%           (High speed machining gave 179%)

In high speed machining centers (HSMCs), the machining time for a  feature may be significantly lower compared to a conventional machine due to high spindle speed and the resulting feed high feed. But, the machining time is typically one-third of the total time, with the remainder being used for machine travel, tool changes, spindle acceleration/deceleration, and pallet changes and rotations. To increase production rate, reducing the noncutting time has to be attempted. In the HSMCs, fast acceleration capabilities of axis are being used to   permit reduction of noncutting time. A focus on raising only the cutting speed proves cost-effective in just a few applications, such as aerospace applications in which parts are machined from billets or rough forgings.

In  an example, time study comparison of a standard CNC machine, a conventional (STD) HSMC, and an advanced HSMC in machining an aluminum automotive part were given in the book.  The cycle time for the advanced HSMC is lower than that of the standard STD HSMC. The reduction is facilitated by  the process change such that different diameter holes are machined with a single end mill and multifunctional tools. That way, the number of tools was reduced from 17 to 12. The corresponding reduction in positioning time was found to be the largest contributor to productivity improvement, with the cutting time the second contributor.

119
Their traveling speed and positional accuracy determine machine tool productivity and part quality in many applications.

Slides are machine components, which move a workpiece or tool on guideways (or ways) to a specified position and hold it in position under machining loads. Their traveling speed and positional
accuracy determine machine tool productivity and part quality in many applications. Therefore, in addition to stiffness and damping, parameters considered in the selection and design of guideways are machine speed and acceleration/deceleration requirements.

Currently, slide speeds are generally around  20 m/min, although machines with slide speeds between 40 and 50 m/min are not uncommon. Speeds between 70 and 100 m/min have been achieved on some high-speed machines. The maximum feed rate is typically between 40% and 50% of the maximum rapid travel rate.

145
A pallet changing system improves productivity because a part is loaded while another is being machined. 

The pallet structure is a component of a machining system contributing to machine performance. The workpiece is clamped to a pallet that is usually located on an indexing table, is clamped in the desired orientation prior to cutting.  A multiple pallet changing system improves productivity because
a part is loaded while another is being machined. A standard pallet may utilize four conic couplings. The clamping unit engages at the center of the conic coupling. This arrangement of four conical couplings has been proven accurate and rigid for up to 1.5 × 1.5 m pallets with load capacity up to 12 tons.

Application example:
2/20/2009
Shop Reduces Setup Time With Multi-Pallet Machines
MAC Machine Company.
Multi-pallet systems from Matsuura contain anywhere between 2 and 32 pallets. With 32 pallet system  the shop can machine as many as 32 different parts, one right after the other, on a single milling machine.
https://www.mmsonline.com/articles/shop-reduces-setup-time-with-multi-pallet-machines

155
152. R. L. Rickert, AC servos increase machine tool productivity, Mach. Des. 57:4 (February 21, 1985) 135–139.

159

An improperly designed tool may wear or chip rapidly or unpredictably, reducing productivity, increasing costs, and producing parts of deteriorating quality. Tooling thus has a major influence on the productivity and economics of a process.

Cutting-tool material and design have a strong impact on machining performance. Properly designed tools produce parts of consistent quality at higher cutting speeds and feeds and also have long and predictable useful lives. An improperly designed tool may wear quickly or chip rapidly or unpredictably, reducing productivity, increasing costs, and producing parts of deteriorating quality. Tooling has a major influence on the productivity and economics of a process. Therefore it is important to consider all material options and tooling geometries for a given application with associated range of speeds and feeds and their typical failure modes. In high-volume applications, perishable tooling costs are typically 3% of the component cost.  Using higher cost tool capable of running at higher material removal rates (MRRs) normally is profitable  since a 20% increase in the MRR could reduce the total cost per component by 15%. Modifying tooling to increase tool life can also be attempted as 50% increase in tool life reduces the total cost per component by 1%–2%.

p.165
 For nonferrous work materials, WC tools will exhibit 2–3 times the productivity and 10 times the life of HSS tools. In steels, they give 2 times the productivity and 5 times the life.

Sintered Tungsten Carbide (WC)

p.166
Basic guidelines for selecting carbide grades are (1) use the lowest Co content and finest grain
size, provided edge chipping and tool breakage do not occur; (2) use straight WC grades when
abrasive edge wear is of concern; (3) use TiC grades to prevent crater wear and/or both crater and
abrasive wear; (4) use TaC grades for heavy cuts in steels.


169
FIGURE 4.8 Comparison of microhardness (VHN-1 kg) at 1000°C and toughness of ceramic tool materials  using P01 carbide as a baseline. (After Mehrotra, P.K., Productivity Improvement in Machining by Applying Ceramic Cutting Tool Materials, A Systems Approach to Machining, ASM, Materials Park, OH, 1993, pp. 15–20.)

187
Even though the range of rake angles is generally −5° to +15°, higher positive angles are slowly being used to improve productivity.

196
Multipoint boring bars are often used to improve stability and to increase productivity in high volume applications.

200
Rotary milling cutters can be used in some applications to improve productivity.

213

Significant improvements in productivity have resulted from the acceptance of solid carbide drills. Compared to HSS drills, carbide drills permit an increase in productivity by a factor of 2–10, and/or increase in hole quality. Solid carbide drills are especially well suited for high throughput precision hole manufacturing.

235
Internal coolant is more effective; this method cools and lubricates the cutting edge and reduces thermal shock in addition to removing chips, and therefore often results in improved tool life and productivity.

276
26. P. K. Mehrotra, Productivity improvement in machining by applying ceramic cutting tool materials, A Systems Approach to Machining, ASM, Materials Park, OH, 1993, pp. 15–20.

279
119. J. Skoglund, Carbide drills: The answer to high-productivity steel drilling, Cutting Tool Eng. (February 1990) 35–37.

290
An important outgrowth of modular tooling has been quick-change tooling, which has led to
significant improvements in productivity.

389
57. T. L. Schmitz and K. S. Smith, Machining Dynamics: Frequency response to Improved Productivity, Springer, New York, 2009.

444
140. Increasing machine tool productivity with high pressure cryogenic coolant flow, Manufacturing Technology Directorate, Wright Laboratory, Air Force Systems Command Report WL-TR-92-8014, May 1992.

507
8.7 PROCESS SIMULATION APPLICATION EXAMPLES
Simulation in current processes helps to increase productivity, part quality, and reduce tooling
and production costs.

541

It should be noted, however, that reducing the cutting speed has no impact on productivity in many transfer machining operations, specifically those in which the cutting time is substantially lower than the cycle time of the line. In transfer machine operations, the cycle time should be determined by optimizing the speed and feed in critical operations; in the other operations, the cutting speed should be reduced to use all of the available cutting time and increase tool life.

554
Since fracture results when the tool is loaded beyond its structural limit, it can be prevented either by reducing the cutting load or by increasing the structural strength of the tool. Since reducing the cutting load usually requires reducing the metal removal rate and thus the productivity of
the process, increasing the structural strength of the tool should be attempted first.

561
Tool wear is one important factor contributing to the variation of cutting forces and surface finish.
In transfer line applications, worn tools are often changed on a statistical basis at a rate dictated
by the shortest life expectancy for multi-tool operations. In such cases, significant useful life of the
tools may be wasted and system productivity may be reduced.

575

Many parts are machined to produce surfaces with consistent dimensions, forms, and finishes for locating, sealing, or similar applications. In many cases, especially finishing operations, surface flatness, and finish requirements restrict the range of tool sizes, geometries, and feed rates that can be used. Moreover, since the machined surface finish becomes rougher and less consistent as the tool wears, stringent finish requirements may also limit tool life and thus strongly influence machining productivity and tooling costs.

597

Oil-based fluids reduce heat build-up because they have better lubricity  and are also typically used at lower wheel speeds. Burn limits and residual stress predictions can also be computed using grinding simulation programs and used to suitably adjust infeed cycles, the number of passes, and wheel characteristics to maximize productivity.

659
64. J. D. Christopher, The influence of high pressure cryogenic coolant on tool life and productivity in turn ing, SME Technical Paper MR90-249, 1990.

674
FIGURE 12.5 Polar curve of the flexibility of three different milling machines in three directions. (From Schmitz, T.L., and Smith, K.S., Machining Dynamics Frequency Response to Improved Productivity, Springer, 2009.)

707

Although a decrease in rigidity in a machine tool is generally undesirable, it may be tolerated when it leads to a desirable shift in natural frequencies (especially in high speed machining) or is accompanied by a large increase in damping or by a beneficial change in the ratio of stiffnesses along two orthogonal axes, which can result in improved nonregenerative chatter stability. However, reducing the tool–workpiece compliance is not always possible in practice, and other approaches, discussed next, should be examined before productivity is sacrificed by reducing the depth of cut to ensure stable operation.

748
173. P. Vanherck, Increasing milling machine productivity by use of cutter with non-constant cutting-edge pitch, Proceedings of the Advanced MTDR Conference, Vol. 8, Pergamon Press, London, U.K., 1967, pp. 947–960.

751
The selection of optimum process parameters directly affects the productivity, manufacturing cost, and part quality.

755

The second level of a COS interacts with the first level. It uses detailed part geometry, machine motion, and tooling data files to calculate individual machine motions and cutting times based on the optimum cutting conditions identified by the first level of the COS. In this case, the CAD model is imported to be machined, the size of the starting part is specified, the user selects the machine to be used, and whether high speed or conventional conditions are used. The software will select the sequence of operations, cutting tools, tool path, cutting conditions, etc. This analysis can provide information on gross productivity, and estimate of the required investment, and detailed data on individual machine stations and station performance. Such computer programs analyze both the whole system and individual machining stations to balance work loads, increase productivity, and decrease investment. Compared to manual methods, such machine and part processing simulations can significantly reduce the total time required to develop and analyze manufacturing systems. Several variations of the machining system, the processing sequence, and tooling designs can be evaluated with minimal effort once the initial analysis of the system is completed.

765
Noncutting time; the part process sequence for the various operations, which significantly affects the
part cycle time, should be considered in the optimization. There are three stages to planning part
processes for such systems: (1) determining the cutter trajectory from geometric models of machining processes, (2) developing mechanistic models for the machining operations, and (3) applying optimization methodologies for the machining system.

765
The productivity of a conventional transfer line, FTL, or FMS, is affected by the cutting conditions, the rapid machine travel rate, and the speed of the transfer mechanism.

766
Reducing idle time by reducing the cutting speed and feed combinations prolongs tool life, reduces tool failure, and reduces the probability of machine failure. Therefore, the use of all or a substantial portion of the idle time should result in higher system uptime and higher productivity.

There are two approaches to the solution of the tool magazine system reliability problem: (1) the
use of cutting tools of high reliability, and (2) the use of redundant tools. The use of redundant tools
in the machine’s magazine results in an increase in production tooling costs, but tends to increase
productivity and reduce production costs. The mathematical solution for the optimum number of
redundant tools in a magazine can be determined when the reliabilities of the individual tools are
known.

767
The majority of tools have a single function and are used for only one operation or are made to
machine a single part feature. However, the use of multifunctional cutting tools has become necessary in single spindle manufacturing systems in order to increase productivity and/or quality and
to reduce cost.

784
 Even though vegetable oils are more expensive than mineral oil–based formulations, they may be cost effective in some applications due to reduced consumption (less dragout than mineral oils) and improved tool life and productivity.

803

In appropriate applications, MQL implementation may be justified by increased productivity,
capital cost avoidance, or variable cost avoidance. In many drilling operations, such as crankshaft
oil hole or large structural applications, penetration rates are significantly higher for MQL
than for alternative wet or dry processes, leading to an increase in throughput. Capital cost avoidance is a significant driver for applying MQL in high volume machining systems such as those
used in automotive powertrain manufacture, since in these systems the capital associated with a
coolant system (including piping, pumps, filters, and chip driers) may be a significant fraction of the
total system cost. Increased throughput in MQL operations may also contribute to capital
cost avoidance. MQL also permits the avoidance of variable costs for filter media and chip drying,
and often a reduction in costs for maintenance and coolant management resources, but these savings
may be offset to some degree by increased tool costs.

822
14. Anon., Less lubricant, more productivity, Aerosp. Manuf., July 2010, 27.

913
High-speed dry machining (Powercutting) was introduced by Gleason in the 1990s, and dry machining has become standard for completing cutter systems on contemporary bevel gear cutting machines due to its increased productivity over lower-speed wet processes.

920
Recently introduced wheels containing “Cubitron,” a controlled shape alumina sol–gel, have a more efficient cutting action than randomly oriented abrasives and have enabled further gains in productivity.

Advances in fabrication of ceramic corundum abrasives based on sol–gel process

Chinese Journal of Aeronautics

Volume 34, Issue 6, June 2021, Pages 1-17

Open access

https://www.sciencedirect.com/science/article/pii/S1000936120303228

929
96. F. Klocke and A. Klein, Tool life and productivity improvement through cutting parameter setting and tool design in dry high-speed bevel gear tooth cutting, Gear Technol., May/June 2006, 41–48.

Ud. 18.7.2022,  26.5.2022

Pub. 22.4.2020

Gear Machining Productivity Improvement - Case Studies and News

Case 13 of Industrial Engineering ONLINE Course.

Industrial Engineering Case Studies Collection 

CNC Machine Offers Versatile, Productive Solution for Gear Chamfer-Deburring

The Helios TM 250-CNC uses a rotary table with twin work spindles to minimize idle machine time.

June 7, 2022

The TM 250-CNC  uses a rotary table with twin work spindles to minimize idle machine time, thus maximizing potential productivity. Machining is performed on one work spindle while the other is simultaneously unloaded and loaded manually. The machine can easily adapt in the future to an automatic loading strategy via robot, cobot (collaborative robot), pick-and-place, or other systems. The TM 250 shifts the paradigm from a fully manual deburring process to one equipped with a machine tool that allows next-level quality and productivity.

The TM 250-CNC  setup personnel to store all tool spindle parameters. These include radial, axial, and tangential positions, as well as tool speed, direction, and pressure.  Crucially, this allows a single setup per part number, which can be consistently and reliably repeated simply by loading a program. With CNC ability, the TM 250 becomes a versatile workhorse for any gear manufacturers with a high mix of part types.

https://www.fabricatingandmetalworking.com/2022/06/cnc-machine-offers-versatile-productive-solution-for-gear-chamfer-deburring/

Search for Gear Machining Productivity for more online articles.

Scudding

20 May 2020
https://www.americanmachinist.com/machining-cutting/article/21131995/complex-highprecision-machining-from-profilator-gmta


High productive gear manufacturing with Scudding®
March 26, 2017
In the automotive and commercial vehicle sector, hobbing, shaping and broaching are the dominating processes for soft machining of gears. A highly productive alternative to the methods mentioned before is Scudding® of Profilator. Scudding® combines a high flexibility with a high productivity.

Only Scudding® offers the possibility to produce internal and external and gears with and without interfering contours.

The cutting speed results out of the rotation speeds of tool and workpiece as well as the set cross-axis angle. Today cutting speeds, which are now being implemented with modern machine and tool technology, are up to vc = 250 m/min.

Profilator and Samputensili formed an alliance to offer the market the best tool and machine technology. Together they have many years of experience in SCUDDING® and they successfully supply well-known companies in the gear industry all over the world.

https://www.sampspa.com/blog/high-productive-gear-manufacturing-with-scudding/


2015

Scudding - Productivity in Gear Machining - 10 times faster than gear shaping.

An example of the potential speed would be a workpiece that is machined with a 60-tooth scudding cutter at a speed of 4,000 rpm, achieving 240,000 enveloping cuts per minute. This means scudding can be up to 10 times faster than gear shaping.

https://www.mmsonline.com/articles/the-evolution-of-gear-scudding

InvoMilling

Increase productivity by as much as 300 percent - new gear machining tools

28 Jul 2012
Sandvik Coromant

______________

______________



With the high-speed steel hob, you have to take the hob off and then reset.  Today, we can index the hob right on the machine. So we can take an insert and all we have to do is change out the insert.

In an example of a gear wheel that was produced by an HSS hob, which is the usual way of doing it, the time taken was 32 minutes. With our new product line, we are down to four ... going from 32 minutes down to four minutes— a revolution.

Invo-milling process is a great technological event in the gear-milling industry ... And what it does is it gives you the opportunity of taking advantage of the machining technology, which is 5-axis machining and programming, and use standard tools and form a gear out of that combination. Where before you had a special tool on a special machine, now you have a standard tool on a standard machine with special software.

Customers have hands-on access to collaborative insights, training and technologies—including the new Hofler HF1000 gear-milling machine—when they visit the company's Schaumburg, Illinois productivity center.


Coromill® 170 - Rough gear milling with precision
9 Nov 2011
Sandvik Coromant

_______________

_______________


Coromill® 170 is a high performance cutter for machining of large gears in module range 12-22. It will reduce time in your gear machining, leaving minimal and even allowance for subsequent operations. Use it for precision and reliability in roughing of external and internal gears.



CoroMill® 176 - Cost efficient gear milling
9 Nov 2011
Sandvik Coromant

____________

____________

CoroMill® 176 is an innovative indexable insert cutter for productive gear wheel machining. It is a more cost-efficient alternative to regrindable HSS (high speed steel) tools. Its ability to reach higher cutting speeds combined with user-friendly insert changing will reduce cycle times and cost per component, making it the high productivity gear milling choice.


2013

Joining flexibility with high productivity when gear milling.

Imagine a gear milling method where the toolpath—not the tool shape—determines gear characteristics such as diametral pitch or pressure angle. A new concept, involute milling, provides that functionality while delivering machining efficiency and production versatility. The result is a “democratization” of gear milling, moving the process from single-purpose, dedicated machine tools to multipurpose machines that can produce small batches economically because no costly hobs or gashers are needed.

The new gear milling approach is based on using a multiaxis mill/turn machine. Sandvik Coromant Co. developed involute milling and it is being offered in collaboration with DMG / Mori Seiki USA Inc. Involute milling, or InvoMilling, is an alternative to the specialized hobbing process traditionally used to make gears. For gears with 25 to 30 teeth, InvoMilling’s cycle time is comparable to single-start hobbing with HSS tools. However, the possibility to integrate many operations in one setup and on one machine can reduce overall cycle times. Also, the wait time for a new gear hob can be weeks, while acquiring a new CNC InvoMilling code takes a matter of hours.
https://www.ctemag.com/news/articles/shifting-gears  (Detailed article)


2013 - InvoMilling - Sandvik Video
______________

______________

Brochure on Invo-milling
https://www.sandvik.coromant.com/sitecollectiondocuments/downloads/global/brochures/en-gb/c-1140-547.pdf

2017
Cutting of one tooth with multiple tools - InvoMilling
______________

______________

Performance of Gears Manufactured by 5-Axis Milling
The article "Performance of Gears Manufactured by 5-Axis Milling" appeared in the March/April 2017 issue of Gear Technology.
https://www.geartechnology.com/articles/0317/Performance_of_Gears_Manufactured_by_5-Axis_Milling/

Research article: 2018  https://www.mdpi.com/2504-4494/2/3/44/pdf

Power Skiving

2019
https://www.sandvik.coromant.com/en-us/news/press_releases/pages/power-skiving-solution-2-3-times-faster-than-gear-shaping.aspx

Gear Grinding

Grinding Gears for EV Powertrains

https://gearsolutions.com/features/the-advantages-of-shifting-from-machining-to-grinding-gears-for-ev/

Gear Manufacturers

Contacting specialist manufacturers and finding whether they can offer items at lower cost is an important activity for industrial engineers.

https://www.minigears.co.uk/products/gears/

Updated  23.7.2022, 17 July 2022, 10 May 2021

First pub: 20 May 2020