Friday, March 6, 2020

Operation Analysis - Methods Efficiency Engineering

Operation Analysis

Process Analysis, Operation Analysis and Method Study are the popularly known methods in Process Industrial Engineering. Japanese industrial engineering improvements brought out new techniques like SMED, Poka Yoke, 5S and Seven Waste model etc.

The term 'Operations Analysis" was used by Arthur Anderson in his book on Industrial Engineering published in 1928. He said operation analysis is the short form for long form "Job Standardization, Motion Study and Time Study."  The job standardization implies what Taylor did with machine tools, cutting tools, and power transmission to machine tools before he undertook study of operator's activities and movements.

At Westing house, process improvement and industrial engineering were carried out under an approach termed "Operation Analysis." H.B. Maynard and Stegemerten have authored a full book on operation analysis.

Importance of Operation Analysis in IE Practice

Operation analysis was made the central focus of IE department in the article "Value Creation Model for Industrial Engineering - Productivity Engineering" by Narayana Rao (Principles, Functions and Focus Areas of Industrial Engineering).

According to the model, A team consisting one  BS industrial engineer + Supervision by MSIE + staff support will have total staff cost of $10,000 per month. which is equal to $120,000 per year. The team is expected to generate a saving of $600,000 per year in 50 IE projects with each project saving 12,000 dollars on average. The IE projects will study operations in a process that incurs  cost of  $30,000 per month ($360,000 per year). Industrial engineers have to find $12,000 savings out of that expenditure every year. To do productivity improvement/cost reduction, IEs use Operation Analysis  on One Machine + Operator combination. It is possible that multiple machines are operated by one operator in which case we may think of one machine + part operator.  Maynard and Stegemerten authored a full book on operation analysis and Niebel explained it well in a chapter in his book on Motion and Time Study. At department level, the IE department's expenditure per month is $60,000 ((1 MSIE + 5 BSIEs + Staff)). They have to find savings of $300,000 per month. $3,600,000 per year on $100,000,000 cost of production per year.

The complete operation analysis and design of new SOP has to be completed in 5 days to facilitate study of 50 operations in year by the IE team. All  IE techniques and methods are to be applied on the operation as well as on the full system required within these 5 days allotted to an operation.

Operation - Process Component Analysis - The First Step in Process Productivity Analysis and Productivity Engineering

The first step in the study of any process/job is to resolve it into its component parts or elements. The component parts a process are called operations. Shigeo Shingo clearly gives the difference between process and operation.

Process is the course by which material (input into the process) is transformed into product (output). Process has stages and each stage is termed as operation.

Operation: In each operation, some work is carried on the input of the process. The work is done by machines, devices and workers (operators).

The operations are categorized as operation, inspection, transportation, temporary delay and permanent storage in process charts used for recording and analysis work. The term "operation" in the process chart refers to the actual value addition to the input through work such as production, maintenance, heat treatment etc. In operation process chart or outline process chart operations and inspections are shown. This chart is used analyze the manufacturing activities and inspection activities and improve them.  In flow process charts in addition to operation and inspection, transportation is also shown and delays in flow are shown as temporary delay and permanent storage. The flow chart concentrates on the material handling and delays in taking up the input for various operations.

After a process is captured in a operation process chart or flow process chart, each part or operation has to be recorded separately in an operation analysis sheet and each element of the operation, machines, tools, work station set up and conditions and the work of operators are to be evaluated from productivity improvement perspective.

Process Analysis - ECRS

A process consists of operations. In process analysis,  each operation is examined to rationalize it for doing it (purpose of the operation) as well as doing it at that step in the sequence of operations. Eliminate, combine, rearrange and split (ECRS) analysis is done for each operation of the process. Eliminate option examines whether the purpose of the operation is appropriate for the process. The combine option examine whether the operation can be combined with earlier or later operation.  The rearrange option identifies if the operation can be done at any time before or after to give economic benefit. Split or Divide examines whether it is beneficial to do the operation in multiple steps.  In a way, it is an examination of the division of a process into operations to improve the efficiency of the process.

Operation Analysis

During primary analysis of an operation, the aspects of the operation are broken down into such general factors as  design and inspection requirements, material, production equipment & tools, material handling equipment, working conditions and man.  Each one of these factors is then examined minutely and critically in order to discover possibilities for improvement. This kind of analytical work of the operation is covered by the term " operation analysis." 

For examining the factors that go into an operation, more detailed methods are described by Maynard and Stegemerten. Narayana rao proposed "Machine work study"  to examine the  machine related elements.   Motion study was developed by Gilbreth to study the work done or motions of the operator. It was also developed as part of work study by European productivity improvement practiotioners.

Approach to Operation Analysis

During the training for operation analysis, number of examples of operation analysis and consequent improvement of the operations have to be given to develop favorable attitude in operation analysts and its team members toward potential of operation analysis to improve productivity and reduce cost.

Operations can be improved periodically due to increased technical knowledge and its application possibilities.  Maynard illustrates the possibility with the improvements that were carried on an item. The job originally was done on day-work, and past production records showed that the time taken per part was 0.0140 hour, or slightly less than 1 minute. The job was time-studied and put on an incentive basis with an allowance of 0.0082 hour. The operator worked made a fair bonus on this job, and the feeling existed for some tune that the proper method was being followed.

After the operation had been set up for 6 months, however, a suggestion for improvement was advanced say by the foreman. The suggestion was not based upon systematic analysis but rather was the result of inspiration. The suggestion was put into effect;  the job was restudied, an allowance of 0.0062 hour was set. This last method was followed for 6 months more, when another suggestion, also of the inspirational type, was advanced. It was adopted, and a new time value of 0.0044 hour was established. The improvements implemented attracted considerable attention. The job was selected for detailed motion study. A completely new method was devised which followed the principles of correct motion practices. The new method was time-studied and standard time of 0.0013 hour was set. The operation now required approximately one-eleventh of that taken at the start.  An improvement of such great magnitude justifies the statement that the latest method is a very good method. But technical developments may offer scope in the future also for further improvement. 

As the result of many similar experiences, industrial engineers use the terms  "the best method yet devised"  implying recognition of the fact that further improvement may be possible (Even Gilbreth stressed this point). Carrying this thought to a logical conclusion, the .best method of doing an operation from a labor-economy standpoint is reached only when the man-machine time required has been reduced to zero. Until this point has been reached, further improvement is always possible.

This example  furnishes a foundation for the approach to operation analysis. If it is clearly recognized, it insures an open mind. It inspires further attacks from different angles periodically as well as at the time when relevant technical developments become available and leads to progress in productivity.

The Questioning Attitude.

An open mind paves the way for successful analytical work, The operation analyst must take the initiative in raising question and  originating answers (suggestions) himself, answering them and involving others in answering them. 

Other things being equal, the greatest amount of originality or creativity is evinced by those who have an inquiring turn of mind.  Improvements come from first examining "what is" with an open mind and then inquiring into "what might be".

This point should be clearly understood, and what is known as the " questioning attitude" should conscientiously be developed. In making an investigation of a job, nothing should be taken for granted, and everything should be questioned. Then the answers should be determined on the basis of facts.

One who is successful in bringing about improvements in operating methods  asks questions and gathers answers which he evaluates in the light of his knowledge and experience. He questions equipment, methods, tools, and layouts. He investigates all phases of every job he studies, in so far, at least, as he has time. He even asks questions when the answers appear obvious, if he thinks he can bring out something by so doing.

The questions asked take the general form of "what," "why," "how," "who," "where," and "when. " What is the operation? Why is it performed? What equipment/machine is used? How is it done? Who does it? Where is it done? When is it done in relation to other operations? These questions, in one form or another, should be asked about every factor connected with the job being analyzed. It is important to think of alternative ways of doing or alternative machines, tools and accessories. Typical questions that arise during the study of industrial operations are as follows:

Is the design of the product/component/apparatus the best from the viewpoint of manufacturing economy?
Can the design be changed to facilitate machining or assembly without affecting the quality of the product/component/apparatus?
Are the specified tolerances correct for the use to which the part is to be put? Is the material the most economical for the job?
Is the job on the proper machine?
Are the correct feeds and speeds being used?
Can the operator run more than one machine or perform another operation while the machine is making a cut?
Would a bench of special design be better than a standard bench?
Is the work area properly laid out?
Are tools designed so as to insure minimum manipulation time?
Can eccentric clamps or ejectors be used?
Can a fixture be used?
Are the position and height of the fixture correct?
Is the fixture the best available?
Is the fixture designed in accordance with the principles of motion economy?
Would a fixture holding more than one piece be better than one holding a single piece?
Can the same fixture be used for more than one operation?
Can a clamp, a vise, or a fixture be substituted for the human hand for holding?
Are semiautomatic tools such as ratchet or power-driven wrenches or screw drivers applicable?

Are raw materials properly placed?
Are there racks for pans of material and containers for smaller parts?
Can the parts be secured without searching and selecting?
Are the most frequently used parts placed in the most convenient location? Are the handling methods and equipment satisfactory?
Would a roller or a belt conveyor facilitate handling? Can the parts be placed aside by means of a chute?

If more than one operator is working on the same job, are all operators using the same method?
If not, why not?
Is the operator comfortable?
Sitting down as much as possible?
Has the stool or chair being used a comfortable back and a seat that is wide enough? Is the lighting good?
Is the temperature of the work station right?
Are there no drafts? Are there arm-rests for the operator?
If the operation can be done either seated or standing, is the height of the chair such that the elbows of the operator are the same distance from the floor in either case?

Is the operator using both hands all the time?
If so, are the operations symmetrical?
Do the hands move simultaneously in opposite directions?
Can two pieces be handled at one time to better advantage than one?
Can a foot device be arranged so that an operation now performed by hand can be done by foot?

The importance of asking such questions is paramount. The chief difference between a successful analyst and one who seldom accomplishes much is that the former has developed the questioning attitude to a high degree. The latter may be capable of making the same improvements as the former, but they do not occur to him as possibilities because he accepts things as they are instead of questioning them.

Operation Analysis is developed as part of Methods Efficiency Engineering to be carried out by industrial engineers. But it need not be confined to methods engineers. The shop engineers and shop supervisors will find it equally useful for attacking their particular problems and finding solutions for them. If they focus it on operating methods, they will be able to make many improvements in the course of their daily work. Thus, methods-improvement work will progress more rapidly than it would if it were left entirely to the methods efficiency engineer.

If a plant is small and has insufficient activity to justify employing anyone in the capacity of methods engineer, it will be particularly desirable for all members of the supervisory force to develop the questioning attitude. It is extremely easy to view things without seeing them when they are supposedly familiar. Those most familiar with the work are the least likely to see opportunities for improvement, unless they consciously try to remain as aware of their surroundings as they would be were they new to the plant. Where the supervisory group does not change often, the cultivation of the questioning attitude is almost essential to progress.

Questions should not be asked at random, although this would be better than asking no questions at all. Rather, it is better to proceed systematically, questioning points in the order in which they should be acted upon. It would be unwise, for example, to question the tools, setup, and method used on a certain job before the purpose of the operation was considered. Better tools might be devised, and the method might be changed; but if it were later found upon examination of the purpose of the operation that it need not be done at all, the time and money spent on tool and methods changes would be wasted.

The steps of systematic operation  analysis will be discussed in this online book in sufficient detail to give a thorough understanding.
(An Illustration: Operation Analysis of Grinding - Examples of Improvement Opportunities in Elements of Grinding)

Making Suggestions for Improvement. 

When a job is examined in all its details with an open mind and when all factors that are related to it are questioned, possibilities for improvement are almost certain to be uncovered if the job has not been studied in this way before. The action that is taken upon the possibilities will depend upon the position of the one who uncovers them. If he has the authority to take action and approve expenditures, he will undoubtedly go ahead and make the improvements without further preliminaries. If, however, he does not have that authority, he must present his ideas in the form of suggestions to the one who does.

In the first place, the true worth of each suggestion should be carefully evaluated before it is offered. If he establishes a reputation for offering only suggestions of real merit, one will find it easier to secure an attentive hearing than if he is continually advancing suggestions that have to be examined to separate the good from the impractical.

The quickest way to prove the merit of any suggestion is to make or obtain estimates of the cost of adopting it and of the total yearly saving it may be expected to effect. These two figures will show just how much must be spent and how long it will be before the expenditure will be returned. If a suggestion costs $1,000 to adopt and will save $100 per year, it is not worth presenting unless there are unusual circumstances. If, on the other hand, the expenditure will be returned within a reasonable length of time, the suggestion is worthy of careful consideration.

When it has been definitely decided that the suggestion is sound and valuable, it should be presented to the proper authorities for approval. Here, again, estimates of expenditure and return will prove valuable. The statement that much time will be saved or even that a saving of 0.0050 hour per piece can be made is not likely to mean so much as figures showing a saving of a certain number of dollars per year. A complete presentation which includes cost and savings totals will be appreciated, for if they are not furnished, they must be requested anyway, and this will only postpone final action.

An example of a good presentation of a labor-saving idea is as follows :

Works Manager:

By analyzing the cork-tube winding operation in the Cork Department, it has been found that one-third of the winder's time is spent in doing work requiring a high degree of skill and the remaining two-thirds in doing work that could be satisfactorily performed by unskilled labor.

The time consumed by the portion of the cycle that requires high skill is almost exactly one-half of that required for the balance. Therefore, it will be entirely feasible to place four winding machines in a group, using one skilled man with two unskilled helpers to run them. In this manner, the average production of three skilled workers running three machines will be obtained at a greatly reduced cost.

Under the proposed setup, the skilled worker will apply the cork to the cloth core which has been set up by one helper and will then move to another machine which the other helper has set up. Each helper will tie the ends of a finished cork-covered tube, will remove the tube, and will set up another while the skilled man is busy at other machines.

The skilled man receives 60 cents per hour and the unskilled men 40 cents per hour each. The labor cost per tube will therefore be approximately 0.76 cent as compared with the present cost of 1 cent each.

On the basis of present activities, this will amount to a yearly saving of $2,361.55. There will be a certain amount of idle machine time under the proposed arrangement; but since we have more machine equipment than we require for our present volume of business, this need not be considered.

This matter has been discussed with the foreman,  and he believes that the arrangement will work satisfactorily. In order to proceed with the proposed change, it will be necessary to relocate 12 machines.  Maintenance Department estimates that this can be done for a cost of $480.

In view of the savings that can be made, the suggestion is recommended for acceptance by you


In this report, enough details are given to explain the general nature of the suggestion. The total yearly saving of $2,361.55 is shown, as also are the cost of adopting the suggestion and the source of the estimate. The fact that the suggestion meets with the approval of the foreman of the department, always a most important point, is also clearly stated. As a result, all questions that are likely to arise in the mind of the manager are answered in advance, and there is a good likelihood that he will give immediate approval.

Occasionally, ideas occur which appear to possess advantages to the originator other than those which can be measured in dollars and cents. In presenting suggestions of this nature, advantages and disadvantages should be presented in tabulated form, so that a decision can be quickly made.

Steps in Operation Analysis

Source: Maynard's Operation Analysis

Full Online  Book - Method Study: Methods Efficiency Engineering - Knol Book
Next Article on the Topic - Scope and Limitations of Methods Efficiency Engineering

Journal of Intelligent Manufacturing
October 2006, Volume 17, Issue 5, pp 571-583
Evaluation of techniques for manufacturing process analysis
J. C. Hernandez-Matias, A. Vizan, A. Hidalgo, J. Rios

Updated 7 March 2020,  12 July 2019, 17 February 2019, 30 July 2017,  28 June 2015
First posted 16 Feb 2014

No comments:

Post a Comment