Monday, August 10, 2015

Method Study - Ralph M. Barnes - Important Points of Various Chapters



Chapter 1. Productivity

Productivity Definitions

The ratio of output to some or all of the resources used to produce the output.

Labor productivity
Capital productivity
Material productivity

Productivity Index

Calculated by US Bureau of Labor Statistics for the entire economy as well as parts of the economy

An input-output model of the firm - Figure 1

Example of Eli Lilly - century long record of productivity improvement

Technological innovation

Productivity increases by technological innovations - Example Dial telephone, farm machinery, computers

Examples Texas instruments
Hewlett Packard

Measurement of Individual Worker Productivity

Standard Time

Actual output * Standard time per unit/Hours of effort  = productivity index

Productivity of Capital


Motion and Time Study and Productivity



Chapter 2  Definition and Scope of Motion and Time Study


Motion Study or Work Methods Design (Barnes equates Motion Study to Work methods design)

1. Developing the Preferred Method.
2. Standardizing the Operation - Written Standard Practice
3. Determining the Time Standard - Work Measurement
4. Training the Operator


3 Patterns in which Motion and Time Study is used

A.  By industrial engineers - staff specialists - Originated in 1880s
B. By Managers and Line Supervisors -Introduced in 1930s
C. Workers themselves in teams or groups - Came into use in 1950s


Chapter 3. History of Motion and Time Study


Taylor's Use of Time Study

Time study was initially started by F.W. Taylor in 1881 in the machine shop of hte Midvale Steel Company. (Detailed note by F.W. Taylor)

Taylor's Principles of Management

Taylor's Investigation of Shovelling

Taylor found that shovelers were lifting loads of 3.5 pounds when handling rice coal and up to 38 pounds to the shovel when moving ore. Taylor's experiments showed that with a load of 21.5 pounds on the shovel, a man could handle a maximum tonnage of material in a day.

The Beginning of Motion Study
In 1885, Gilbreth, as a young man of seventeen, entered the employ of a building contractor. Gilbreth observed that brick layers were using different set of motions and some set of motions were more productive. Gilbreth developed interest in developing more productive motion sets and methods in bricklaying.  He invented a scaffold which could quickly and easily raised as the wall height is increasing due to construction. The scaffold on which the bricklayer is standing has a bench for holding the bricks and mortar at convenient height. The bricks were placed in an orderly manner by a helper. With such improvements, the motions to be made by a bricklayer were reduced to 4.5 from the earlier 18, The average bricks laid increased to 350 per man per hour from the old rate of 120 bricks  per man per hour.

Chapter 4. General Problem Solving Process


1. Problem Definition

Example: A farm plants peas in 7000 acres each year from early March to the the first of April. Harvesting is a problem and  the harvesting crew works round the clock and still cannot harvest all the acres. Dr. C.W. Thornthwaite, climatologist for the farm attacked the problem from planting side. He scheduled planting in such a way that a definite number of acres are ready for harvesting every day during the harvesting season and hence there was no confusion and overload on the harvesting team. The problem could have been tackled from the side of harvesting also. But this solution is more ideal according to the author.

2. Analysis of the Problem

The author highlights that some time certain restriction are told by the persons who are using the current process. They need to be examined carefully. He gives the example of citrus fruit packing. They were packed in wooden crates wrapped in tissue paper with the assumption that they need ventilation. But now they are packed in cardboard cartons without any ventilation. Hence the earlier assumption was not correct.

3. Search for Possible Solutions
Study of texts, handbooks, magazines, technical brochures of various companies, search of relevant websites.

The author gives two examples of new technology to support the idea that search for possible solution should extent to new technologies.

Examples one is an electronic thermometer. The thermometer has a probe onto which a disposable probe is placed and inserted under the patient's tongue. In the 15 to 25 second, the digital reading will come. As a disposable probe is used, there is no possibility of infection spreading to other patients and also the thermometer need not be sterilized. There is no danger of patients biting the thermometer also.

Second example is related to special polypropelene foam material developed by Dupont.

Creative thinking by individuals and groups to be employed.


4. Evaluation of Alternatives

Role of Engineering Economics in Evaluation of Alternatives

In certain types of problems, evaluation would center around the total capital that would be invested in each of the several proposed methods, expected life of the equipment, scrap value and annual operating cost. From these economic or cost figures, the rate of return on the investment per year is calculated.  Direct labour required for each of the proposals need to be worked out. Predetermined motion time systems could be used for this purpose. But to visualize the motions to be made by the operators, mock-ups of jigs and fixture may have to be made. Some companies have special laboratories and workshops for such projects.


5. Recommendation for Action

Chapter 5. Work Methods Design - The Broad View


The over-all process of putting a new product into production

1. Planning
2. Pre-production
3. Production

Planning

Six basic planning functions

1. Design of the product
2. Design of process
3. Design of Operator work method
4. Design of  tools, jigs and fixture
5. Design of plant layout
6. Determination of standard time

Preproduction

Resources are acquired and installed and trial runs are made.

Production

The production system is producing as per market requirement or demand.
Two attention areas of Method study person.

1. Preventing the method from deteriorating or deviating adversely from the planned methods,
2. Constantly being on the look out for improvement options, and when one is found, putting it into effect. Also the methods have to be periodically subjected to methods improvement study.

An ongoing manufacturing process provides opportunities to improve and redesign operator methods, to eliminate manual tasks, and make the job easier for the worker. New equipment and tools make existing facilities obsolete and provide cost reduction opportuties. New and better materials are developed or become available providing scope for changes in product parts design.

Example given - Elizabeth Arden Inc. lipstick manufacturing process

In the zeroth year or the starting of the study, the units produced per labor hour was 76. By end of 7 years, the productivity increased and the unit produced per labor hour was 179.

Chapter 6. Work Methods Design - Developing A Better Method


Approach for developing the preferred method

1. Eliminate all unnecessary work.
2. Combine operations or elements.
3. Change the sequence of operations
4. Simplify the necessary operation (Operation analysis)


2. Combine operations or elements.
Example given: In a furniture factory, an operator unloaded wooden logs from a truck and loaded them into a moulding machine. On the other end, another operator took the moulded item and loaded it into a another truck. In the redesign, another short conveyer brought back the moulded item to the operator who was loading the machine. The truck was partitioned into four comparments and only three were loaded. In the empty compartment the moulded pieces were loaded by the same operator. Thus the operation was completed by only one operator and also the need for another full truck was eliminated,

3. Change the sequence of operations

In one plant small assemblies were made and stored in a stock room. Inspection was done subsequently. This was resulting in certain problems and in the rearrangement inspection was done immediately after the assembly and then only the finished goods were kept in stock for despatch.




Chapter 7. Process Analysis


Process Chart

Gilbreth Symbols
ASME symbols

Flow Diagrm

Gang Process Chart

Example: Installation of a Pipe Bridge in Procter and Gamble Company

The earlier procedure was to pick up the the bridge with a crane and fasten it in place and then install pipe and conduit in the bridge at a height. The procedure was changed to installing pipe and conduit while the bridge is on the ground and then lifting it to the required height and fastening it.

Chapter 9. Operation Analysis

Full details of Operations Analysis - Book by Maynard and Stegemerten

Operation Chart or the left- and right-hand chart.

Bolt and Washer assembly example


Check Sheet for Operation Analysis


1. Materials
2. Materials Handling
3. Tools, Jigs and Fixtures
4. Machine
    A. Setup
    B. Operation
5. Operator
6. Working Conditions


Example: Spraying inside and outside of metal box cover.

Initially one side is painted and the cover is put in an oven and then the other side is painted.

A device was developed that held the cover on two knife points and inside and outside were painted one side first and next side later and then the cover is put in the oven. Production doubled with the same facility.

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