Saturday, November 23, 2013

Using the Operation Analysis Sheet for Methods/Process Improvement

Refer to Maynard's Operation Analysis for More Details, Figures and Examples

Using the Operation Analysis Sheet

The analysis sheet acts as a guide to systematic operation analysis. It directs the analyst step by step through the various factors that should be considered and insures that none will be overlooked.

For each point, the ascertains all known facts, and upon the basis of the information, answers various raised during analysis and generates suggestions for improvement. The nature and extent of these
suggestions depend largely upon the knowledge, originality, inventiveness, and experience of the analyst and other members participating in the analysis work. For solving various problems analysts do external search first. It involves referring to various magazines and journals related to industrial engineering to absorb knowledge of various new applications of industrial engineering techniques in organization related to the problem to be solved.

The facts that are gathered and the suggestions for improvement that occur should be noted on the analysis sheet. The manner in which these notations are made is important. The analysis sheet serves the dual purpose of acting as an aid to clear analysis for the present and  a record of the conditions in effect at the time of the analysis and of the changes suggested and made. Therefore, the analysis sheet should be filled in completely with clear descriptions of the various points considered. The descriptions should be sufficiently explicit to enable anyone who consults the analysis sheet to understand what the job is and what was decided in connection with each point considered. At the same time, in order to avoid over-elaboration and an accompanying waste of time and effort, the descriptions should be concise. Either too brief or too lengthy descriptions are undesirable. The analyst will learn with practice based on the remarks of other analysts to fill out his analysis sheets with adequate description that provides maximum clearness.

Example of Filled-in Analysis Sheet. Figures 42 (Maynard) and 43 show the front and back of an analysis sheet covering a simple milling machine operation. The operation consists of milling a slot in a solid brass casting.

First, the purpose of the operation: A solid casting is to be made into a clamp. It must be cut away to fit the part it is to hold. Thus, the purpose of the operation is to mill a slot, and it is a necessary operation.

When this decision is reached, item 1 is filled in. The purpose of the operation is described as "to mill slot in casting." This answers the purpose, but an additional note ''slot fits regulator shaft Dwg. 122301 " gives further information which may be useful later on.

He considers various other ways a slot might be made. A cast slot would not be accurate enough. A die casting might do; but the same blanks are milled out to various sizes, and the cost of
providing dies for the different sizes would not be offset by the saving made. Hence, the purpose of the operation seems best accomplished by milling.

Item 2. All operations in the process. There are only three operations performed on the part from the time the casting is made until it is ready for the assembly. They are listed showing the work stations and departments where they are performed. His mental process will then be something as follows. He asks himself the questions listed in the column on the right of the sheet under the heading " Details
of Analysis" The operations are quite dissimilar, and the sequence is seen to be proper. One possibility for improvement occurs, namely, that the drill-press operation might be performed by the operator on one part while the milling machine is making a cut under power feed on another. This, however, would necessitate moving a drill press beside the milling machine. Since there are a number of milling machines in the department and since the job is likely to be done upon any one of them, a drill press would have to be set up by every milling machine or else the production-control system would have to be changed to route the clamp job to a particular machine near which the drill press could be located. Neither plan appears practical under existing conditions, and the analyst decides to shelve this suggestion. He does not abandon the idea altogether but makes a mental note to watch for other jobs on which there are similar possibilities to see if one or two machine groups consisting of a milling machine and a drill press might sometime be justified.

Item 3: the inspection requirements of the job. The inspection requirements of the foundry operation are not difficult to write, for they are standard for all castings. The analyst, therefore, turns his attention to the requirements of the mill-slot operation. He finds that the dimensions of the slot must be held to within plus or minus 0.002 inch of the drawing dimensions and that the slot must be free from tool marks. For his own satisfaction, he investigates the use of the clamp in the finished apparatus to discover whether these requirements are necessary. After consulting the drawing of the shaft which the clamp is to hold and learning the tolerance to which it is machined, he examines an assembly to learn how the parts function. As a result of this careful check, he 'decides that the inspection requirements with respect to the size of the slot are more accurate than is necessary and that an allowance of plus or minus 0.005 inch will be close enough for satisfactory performance. The wider tolerance will make it somewhat easier for the operator to set up and run his machine, and it will also effect a slight saving in grinding cutters in the tool room. When the decision has been reached, the analyst records it on the analysis sheet.

Merely noting the possibility of making an improvement will be of little value. The suggestion must be presented to someone who has the authority to take action upon it in this case, the design engineer or the chief inspector and the matter must be followed up until definite action is taken. Many otherwise capable analysts fall down at this point. They conceive worthwhile suggestions for improvement, but they fail to follow them up aggressively enough to secure action. Changes are not made in industry any more easily than elsewhere, for human nature is much the same in all walks of life. If conditions that have been in existence for a number of weeks, months, or years without giving any apparent trouble are attacked, the tendency is to let well enough alone and not to bother with a change. All progressive supervisors in industry know how difficult it is to get changes made when the change affects the work of someone else.

In the case under consideration, the suggestion for changing tolerances may be presented either at the time it is conceived or when the entire analysis has been completed. When the suggestion has been made, a note showing to whom it was offered should be recorded on the analysis sheet. If possible, the promise of a date when a definite decision will be made by that person should be secured and noted.

This procedure should be followed in the case of every suggestion offered. When action is taken, a further note should be made. The analysis sheet will then show the status of the job at any time. It will show the suggestions which were made, those which were accepted or rejected, and those which are still awaiting action. The analysis sheet has to be used to follow up all suggestions till they have been acted upon.

This definite, systematic follow-up accomplishes two worthwhile results. In the first place, it insures that no suggestion of merit will be neglected through oversight. Secondly, because follow-up action is required, it insures that few impractical, half-worked-out suggestions will be offered. The analyst will soon learn not to waste his energies on the "I have often thought of it but haven't had time to do anything about it " type of suggestion.A man whose conversation abounds with hazy ideas of this nature is in need of a mental housecleaning, and nothing will give it to him like a clean-cut follow-up plan religiously adhered to.

On the analysis-sheet example, the action that was taken with regard to increasing the slot tolerances is clearly shown. When it was decided that present tolerances were too close, the matter was taken up with a man named Schauer. He promised a definite decision on Oct. 19. A longhand note shows that on that day the suggestion was accepted and the inspection requirements changed.

The description of the material of which the clamp is made is a good example of brief, clear phrasing. When the suitability of the material was investigated, it was found to be satisfactory in every respect. The easiest thing to do would be to make a note "O.K." and let it go at that. This, however, would not satisfy one who might have occasion to restudy the job at some future time, and a duplicate investigation would be made. To avoid this, the reason that the material is satisfactory should be stated. A noncorroding material must be used to avoid rusting which is likely to occur under the conditions under which the apparatus operates. Common brass will not rust. In addition,it is inexpensive and easy to machine. Therefore, it is well suited to the requirements of the job. The brief description makes this clear. An elaborate write-up describing service  conditions, the chemical analysis of common brass, and the relative machinability of various nonferrous alloys could do no more.

When the problem of handling material has previously been studied for the department as a whole, little need be recorded on the analysis sheet under the head of " Material Handling" with regard to the manner in which the material is brought to and removed from the workplace but a word or two describing the methods in effect at the time the analysis was made. If, however, in a certain plant or department, the first formal analysis which is made of material-handling methods on a single Job reveals the fact that the general material-handling situation should be improved, the analysis of the single job will probably be temporarily abandoned, and a study of handling will be commenced. After a standard material-handling procedure has been worked out, the job analysis will again be taken up. A few words on the analysis sheet will serve to describe the standard system that has been evolved.

If a single job has large activity, a study of the material handling problem for that job only may be justified, particularly if little attention has been paid to the matter before. Usually, on active work some study will have been given to material handling; for if a system is haphazard or inefficient on repetitive work, the piling up of material will soon bring the problem to the attention of the management. Therefore, most material-handling procedures on repetitive work will be found to be work-able when examined. This does not mean, however, that they cannot be improved when analyzed with the idea of reducing to a minimum the effort necessary to move material. On the contrary, even where conveyer systems have been installed, it will often be found that changes can be proposed that will bring the material to the operators more conveniently and eliminate use-
less motions on their part.

A good example of this was encountered in the shipping department of a large industrial plant. Conveyers were used to bring material to the packers and to remove the packed cartons. They were located in such a position, however, that it was necessary for the packer to take a total of 20 steps during the course of packing a single carton. Belocation of the conveyers eliminated this and increased production 20 per cent, at the same time materially reducing fatigue.

The procedure used for handling material at the work station should be examined on each job analyzed. A detailed consideration of the motions used to handle the material properly belongs under the heading of motion study. The larger aspects of the problem, however, should be investigated at the time item 5 is analyzed. If the material is handled by hand, the possibility of handling it more effectively by a mechanical means should be considered. If a mechanical device is used, it should be the best available for the purpose. When the best general method of handling material at the work station has been decided upon, a few words describing it should be recorded on the analysis sheet.

Under the head of "Setup," a description is given of the work-place layout and the arrangement of tools, fixtures, and so on. This description may be written if the setup is simple, but a photograph will be found more useful and infinitely clearer if the arrangement is at all complex.

When the machine setup is being considered, the tool equipment also is examined. The tools and the setup are so closely related that it is difficult to separate them, and nothing is gained by attempting to do so. In examining the setup of the mining machine, it is noted at once that a standard vise and a special side cutter are used. A description of these items of tool equipment is therefore recorded. Often, when tool equipment is examined with thoughts of job improvement uppermost in mind, suggestions for improving the tool equipment will immediately occur to the analyst. These should be recorded as they arise, even though they may reoccur during the consideration of items 7 and 9. It is better to duplicate the small amount of writing involved than to risk the possibility of overlooking a good idea.

The recommended action on the 10 possibilities for improvement listed under item 7 should not be filled in too hurriedly. It is all too easy to run over the list rapidly and to form opinions as to the practicability of each possibility on the basis of snap judgment. This should be avoided. The 10 points are listed because one or more of them will usually be found applicable to nearly every job analyzed.

In the example, it was seen that a gravity delivery chute would transport the finished part from the vise to the tote pan without a motion on the part of the operator. The clamp, of course, must be moved from the vise to the chute, but the desirability of an automatic ejector had already been discovered when analyzing the setup. Hence, it was recommended to Riley that a simple chute be provided. A note shows that the change was made the following day.

This arrangement, of course, makes drop delivery unnecessary, and a note is recorded to that effect.

Since only one operator works on this job, the note covering the third possibility, "compare methods if more than one operator is working on same job," is self-explanatory. The point is of paramount importance, however, and is one that was stressed repeatedly by F. W. Taylor. At a meeting of the American Society of Mechanical Engineers in 1910, Taylor said:

... owing to the fact that the workmen in all of our trades have been taught the details of their work by observation on those immediately around them, there are many different ways in common use for doing the same thing, perhaps forty, fifty, or a hundred ways of doing each act in each trade, and for the same reason there is a great variety in the implements used for each class of work. Now, among the various methods and implements used in each element of each trade there is always one method and one implement which is quicker and better than any of the rest. And this one best method and best implement can only be discovered or developed through a scientific study and analysis of all of the methods and implements in use, together with accurate, minute, motion and time study.

Procedures for operator training, to be sure, have improved since the time this statement was made; and yet today, wherever detailed methods studies and detailed methods instruction have not been undertaken, it is the rule rather than the exception to find every operator on a given job using a different method. The methods may appear the same to the untrained observer who has not taught himself truly to observe; but careful analysis will reveal many differences, which, although they may individually be minor, in total cause a wide difference in output.

It is seldom that the close study of a number of operators on the same job will reveal the best method of doing the job as an already developed whole. Probably even a synthesis of the best methods in use on each element of the job will not do this. The analysis will, however, put the analyst in possession of a knowledge of the best-known methods for doing the work and will enable him to proceed with his developments without going over ground that has already been covered.

Possibility 4 under item 7 deals with the correct chair for the operation. If the operation must be done standing, a note to this effect is all that is required. If the operation is done sitting or partly sitting and partly standing, the matter of providing a proper chair should be considered carefully, and when a decision has been reached the necessary recommendations should be made and recorded on the analysis sheet.

Possibility 5 suggests providing a vise with both a quick-acting clamp and an ejector. The advisability of using these labor-saving devices was recognized under item 6, although a less capable analyst might easily have overlooked them.

Under possibility 6, the fact that a foot-operated air hose could be provided for blowing chips out of the vise is recognized. This, however, would tend to make the setup somewhat special which should be avoided where possible on miscellaneous work. By this time, the analyst has a good idea of how he is going to improve the job, and he foresees that the foot-operated air hose may be an unnecessary refinement. Therefore, he records the possibility but postpones definite recommendation until later.

"Two-handed operation" possibility 7, is an abbreviated term used to describe an operation performed by means of motions of the arms made simultaneously in opposite directions over symmetrical paths. This is a highly effective arrangement where practical but cannot very well be used on the job being analyzed. The analyst, therefore, records "not practical" opposite this possibility. This is dangerously easy to write if job analysis is allowed to become a routine procedure, and the analyst must be very sure that he does not fall into the habit of deciding too quickly that two-handed operation cannot be attained. It is seldom easy to set up a two-handed workplace layout, for considerable detailed study is involved. Therefore, it is usually wise in any case of uncertainty as to the absolute impracticability of two-handed operation to make a note "determine after motion study" and then reconsider the point later on when the detailed motions used in doing the work have been more fully studied.

Tools and material should always be arranged within what is known as the " normal working area" but they seldom are if the arrangement is left to the operator. A rearrangement can usually quickly be made; and if the reasons for the rearrangement are carefully explained to the operator, he will probably adhere to it on future jobs even when instruction sheets are not provided.

On machine work where the machine works part of the time under power feed, it is often possible to give the operator another machine to run. The second machine may be set up for the same job as the first, or it may be set up for a different job if the handling and machining times are nearly the same as those for the first job. The job under analysis is ideal for this kind of setup. The part-handling elements consume somewhat more time than the machining element, but the suggested improvements will reduce the part-handling time until it is less than the machining tune. The analyst, of course, has had this improvement in mind from the start. Being experienced, he recognized the fact that the foot-operated air hose would only add to the operator's idle time once the other improvements had been made and that, since this was not necessary for overcoming the effects of fatigue, there was no reason for providing the air hose.

In describing working conditions, it would be possible to go into great detail. The working conditions, however, in most modern shops are practically the same in all parts of a given department. Hence, considerable repetition will be involved if conditions are described completely for every job analyzed. A worth-while saving in time will be effected and a better description will be given if a report describing conditions in detail is prepared and kept on file. Reference may be made to it on the analysis sheet, and duplication of effort will thus be avoided. Any unusual conditions will, of course, be recorded on the analysis sheet. Any permanent changes that affect working conditions such as the installation of an improved lighting system should be described in a dated addition to the general report. This procedure will make it possible to check the conditions in effect at the time that any job analysis was made.

The conditions that apply only to the job being analyzed are recorded briefly under the subheading of "other conditions" under item 8.

Under item 9, the method being followed at the time the analysis is made is recorded. If several methods are in use, they should all be listed. If there is not room for this on the analysis sheet, a supplementary report should be prepared. The method at this point may usually best be described in terms of the elements of the operation. This does not give so detailed a description as an operator process chart showing every motion made by both hands, but the preparation of such a chart requires some time and is not always justified by the activity of the job.

If the activity is sufficient to warrant careful motion study, the chart will be made and will compose part of the supplementary report that should be attached to the analysis sheet.

A description of the method by listing the elements of the job is sufficient to give a good idea of how the job was performed. Indeed, many written instruction sheets consist of nothing more than a list of elements. Thus, although it is recognized that a list of elements is far from being a complete description of any method, it is also recognized that this is all that it is practical to give in many cases.

The description of the method after motion and time study may also be given in terms of elements. Reference to the example shows that a clear idea of the changes that were made in the method is thus obtained in comparatively few words.

The Analysis Sheet as a Supervisory Aid. 

The analysis sheet was originally developed by the Methods Engineering Council for the use of methods engineers. Its use has since been greatly extended, and it has been found to be especially valuable to those who must supervise the work of methods engineers.

The value of the analysis sheet as a guide to systematic analysis has been pointed out several times. Before the sheet was available, methods-engineering supervisors did their best to insure thorough work on the part of their men by carefully instructing them in regard to the points they should consider and by cautioning them repeatedly to overlook nothing. There was no way of determining if instructions were being followed, however, unless the supervisor selected a job from time to time and questioned his engineer about it in great detail. In effect, he was forced to ask all the questions that he wished the methods engineer to ask to ascertain if they had been asked and answered. This, of course, meant duplicate work, but there was no other way.

The use of the analysis sheet changes this situation entirely. The supervisor, or for that matter any interested executive, can ask for the analysis sheet and accompanying reports, if any, for any operation he may wish to check. A brief review of the sheet will tell the story of the operation and of the analysis of the operation in a very short time. Hence, the analysis sheet, aside from its other important uses, is seen to be a valuable supervisory tool.

General Use of the Analysis Sheet. 

The use of the analysis sheet need not be restricted to methods engineers. After a careful explanation of its use, it can be filled in by almost any shopman of average intelligence. It is true, of course, that the analysis sheet will be filled in completely and satisfactorily from the methods engineer's point of view only by a trained analyst well grounded in the principles of motion and time study.

At the same time, it is not necessary that the analysis be made complete to the last detail for it to bring about worth-while results. The act of attempting to fill in the sheet causes one to look at a job in its details. A job is seen to be a series of simple problems instead of a single complex problem, and solutions to these problems are found to be comparatively simple when considered individually. The analytical approach is encouraged, and guidance is given through each step of the study.

Thus, the analysis sheet can be a help to shop supervisors other than the methods engineer in studying and improving the work that comes under their jurisdiction. The foreman, for example, does not need to rely altogether on the work of the methods engineer for reducing operating costs and setting up improved methods. He can select any job that seems to offer possibilities, analyze it with the aid of the analysis sheet as he has time, and nine times out of ten discover a better way of doing the job if it has not been previously analyzed by this method.

In other words, the manner of using one of the most potent tools of the methods engineer, namely, operation analysis, is shown by the analysis sheet. Different men will use it with varying success depending upon their experience and ability. Nearly anyone, however, can accomplish something, if he conscientiously tries to make an analysis in the manner outlined on the analysis sheet.

The authors have given the sheet to foremen, tool designers, production men, cost accountants, and so on, and have asked them to select a job, analyze it, and fill in the sheet. In the majority of cases, the filled-in sheets contain worth-while suggestions for improvement. With these experiences in mind, therefore, the hope is expressed that a wide use will be made of the analysis sheet or some similar analytical guide. For example, the key supervisors of a given plant might each be required to analyze one operation coining under their jurisdiction every week and to fill in an analysis sheet. This would unquestionably bring out meritorious suggestions for improvement, and the assembled analysis sheets might form the basis for lively discussions at subsequent supervisors' meetings. There are many worth-while programs that can be inaugurated to suit individual plant conditions. Results in all cases, however, arise from the same source, that is, the stimulation to analytical thought that such a procedure provides.

Refer to Maynard's Operation Analysis for More Details, Figures and Examples

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