Sunday, February 16, 2014

Process Analysis and Operation Analysis - Methods Efficiency Engineering





The First Step - Process Analysis


The first step in the study of any process/job is to make a thorough analysis by resolving it into its component parts or elements. Each part or element may then be considered separately, and the study of the process thus becomes a series of fairly simple problems.

A process consists of operations. In process analysis, each operation is examined to rationalize it for doing it as well as doing it at that step in the sequence of operations.  Eliminate, combine, and rearrange (ECR) analysis is done for each operation of the process. In a way, it is an examination of the division of a process into operations to improve the efficiency of the process.

During primary analysis of an operation, the operation is broken down into such general factors as material, inspection requirements, equipment & tools, man  and working conditions. 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 available. Motion study, for example,  is 'focused on the method of the operator. The method is resolved into terms of basic divisions of accomplishment or basic operations, a process that is a highly refined type of analysis.The analysis of the factors continues even during stop-watch time study with the objective of setting up the standard time, although it is not so detailed as that occurs during the detailed examination of each factor.

Approach to Operation Analysis


To conduct analysis work successfully, a distinctive mental attitude must be developed. .  In order to improve an operation, it must be approached with the idea that it can be improved. Otherwise, progress is not made in the improvement effort. 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.

If a job has previously been carefully studied, the best method may conceivably have been devised, and no further improvement may be possible, immediately. Experience has shown, however, that there are few established methods which cannot be improved at a later point in time. In, this connection, the history
of a certain bench operation furnishes an excellent and by no means uncommon illustration of this point (Maynard). The job originally was done on daywork, 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 job was a prominent one, and the improvements 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 was thus improved to an extent where the time required was only approximately one-eleventh of that taken at first on the old daywork basis.   An improvement of such great magnitude justifies the statement that the latest method is a very good method; but in view of the past history of the job, it would be unwise to say that the best method has been attained.

As the result of many similar experiences, methods engineers are using 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. Such mental obstacles as "it won't work' "it can't be done" and "it was tried before and didn't work"  are cleared away at the outset. Lack of success in improving any job is not interpreted to mean that the job cannot be improved, but rather that no way of improving it has yet been discovered. There is a vast difference in the two interpretations. The first induces contentment with things as they are and leads to stagnation; the second inspires further attacks from different angles and leads to progress.

The Questioning Attitude.


An open mind paves the way for successful analytical work, but it is not sufficient in itself. One can be open-minded in the passive sense of being receptive to suggestions, but this will not lead to accomplishment. The analyst must take the initiative in originating suggestions himself if he wishes to get results.

Other things being equal, the greatest amount of originality, or what passes for originality in a world where it is often said that there is nothing new, is evinced by those who have an inquiring turn of mind. The man who constantly asks questions and takes nothing for granted is often a disturbance to the contentment of those who are willing to accept things as they are, but he is the one who originates new things. 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, and the influence of emotions, likes and dislikes, or preconceived prejudices should be guarded against.

One who is successful in bringing about improvements in operating methods has few deep-seated convictions. He accepts little or nothing as being right because it exists. Instead, he asks questions and gathers answers which he evaluates in the light of his knowledge and experience. He questions 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? 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. Typical questions that arise during the study of industrial operations are as follows:

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?

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?

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?

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 conveyer facilitate handling? Can the parts be placed aside by means of a chute?

Is the design of the 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 apparatus? Are tools designed so as to insure minimum manipulation time? Can eccentric clamps or ejectors be used?

Is the job on the proper machine? Are the correct feeds and speeds being used? 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? 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 bettor than a standard bench? Is the work area properly laid out?

This list of questions could be extended almost indefinitely, but enough have been given to illustrate the sort of questions that should be asked during a methods efficiency study. 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 Need Not Be Confined to Methods Engineers. Although the questioning attitude is developed by the methods engineer as an aid to thorough analysis, it need not be and should not be solely his property. The other 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 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 systematic job analysis will be discussed in this knol book in sufficient detail to give a thorough understanding.

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

Signed

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.


Source: Maynard's Operation Analysis

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



Process analysis is an examination of the division of a process into operations to improve the efficiency of the process. Process analysis examines the sequence of steps specified to convert inputs into outputs.

Process analysis now is extended to analyzing the process in other dimensions.



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
http://link.springer.com/article/10.1007%2Fs10845-006-0025-1


Updated 28 June 2015
First posted 16 Feb 2014

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