Saturday, July 30, 2016

Operation Analysis Sheet

The entire process commonly known as "operation analysis" consists principally of finding out all known facts that affect a given operation and redesign the operation to give better efficiency.

Importance of Systematic Procedure in Operation Analysis

In making operation analysis, a systematic procedure is to be followed  so that points of cardinal importance are analyzed without giving a miss. The simple question "What is the purpose of the operation?" is very important as it may disclose that the operation can be eliminated or combined with another operation.

Nine Points of Primary Analysis (Maynard). There are nine main points or factors that should be considered in every operation analyzed. These, arranged in order of importance, are as follows :

1. Purpose of operation.

2. Complete survey of all operations performed on part.

3. Inspection requirements.

4. Material.

5. Material handling.

6. Setup and tool equipment.

7. Common possibilities for job improvement.

8. Working conditions.

9. Method.

The suggested sequence has to be followed, but in actual practice, it is seldom possible to complete the analysis of one factor at a time and then leave it for good. Several of the factors, as for example setup and method, are interdependent, and scope for affecting an improvement by modifying an earlier factor may be noticed when analyzing another factor at a later stage. So, the complete analysis of all the factors is over only when the last item method is completely analyzed.

Mental Analysis of Process and Operation 

The analysis which is made by observation alone may be either mental or written. The mental analysis is, of course, the quicker, but it is also the less satisfactory. Because of the quickness with which mental analyses can be made, they are used on jobs where low activity or labor expenditure makes it uneconomical to make an elaborate analysis. A mental analysis is far superior to no analysis at all. Mental analysis is advised to the time study analyst. He has to do it at least briefly before time measurement is begun.

On work of a jobbing nature, the conditions surrounding the class of work as a whole should be analyzed in considerable detail the first time the work is subjected to detailed study. Such factors as material handling and working conditions should be gone into thoroughly, and all improvements that seem advisable should be made at once. Then, when individual jobs are studied, it will not be necessary to analyze repeatedly these factors, which are common to all jobs, and full attention may be directed to those factors which concern only the operation being studied.

Mental analyses if systematically made will produce many good results. Many jobs can be improved relying solely on mental analysis to bring about the results.

The danger in this type of analysis is that some factor will be overlooked or at least be questioned too briefly. It is easy to give an improperly considered answer to a question when the answer need not be committed to writing. The necessity of recording a clear and concise answer on paper insures that the question will receive proper consideration.

When the analysis should be conducted systematically. the analysis sheet described below is used. The general arrangement of this form may profitably be memorized. It can then be followed step by step in making even a brief mental analysis, with the result that when the analysis is completed one can be certain that no step has been overlooked.

The completedf analysis sheets, if accessibly filed, will often prove valuable for future reference, since they show most completely the conditions that existed at the time the study was made. They will also prove valuable at a later date when making reports of accomplishment.

In brief, written analyses offer the same advantages that any other class of written records offers. Hence, it is strongly recommended that written analyses be used wherever methods studies are conducted.

The Operation Analysis Sheet

In order to simplify the work of making written analyses, a form known as the " analysis sheet" has been designed by the Methods Engineering Council. Since its introduction, its use has spread rapidly, In securing the information needed to fill out the form completely, one will be certain to make a complete analysis.

The front of a blank analysis-sheet form is shown by Fig. 40 (Maynard) and the back by Fig. 41. At the top of the form on the front side, space is provided for identifying completely the analysis, the part, and the operation.

Item 1.  The first point considered is the purpose of the operation. If analysis shows that the operation serves a definite purpose, various other means of accomplishing the same result are considered to see if a better way can be found.

Item 2. If operation or flow process charts have not been constructed, all the operations performed on the part are next listed. The purpose of this is to determine just how the operation being analyzed fits in with the other operations that are performed on the part. This study frequently brings to light the fact that the operation being analyzed can be eliminated altogether or that, by combining it with other operations or performing it during the idle period of another operation, the time for doing it can be materially reduced. Again, it is sometimes found that the sequence of operations is not the best possible and that unnecessary work is being performed for this reason. Another common condition which is discovered at this stage of the analysis is that the part is being shipped about among departments more than is necessary. It may be that, instead of sending a part to a distant department to have a simple operation performed upon it, it would be better to move the work station. These possibilities and all others mentioned here will be covered more fully in the chapters devoted to a complete discussion and illustration of each of the nine points of primary analysis.

Item. 3. The inspection requirements of the job must be looked into thoroughly, for the accuracy required has a direct bearing on the methods used to produce the work. The analyst should consider it his duty to investigate them in order to satisfy himself as to their necessity. Occasionally, inspection requirements are hurriedly and incorrectly established, and a subsequent check will bring this to light. Usually, the requirements err in the direction of unnecessary accuracy; for if the requirements are too loose, the part will not function properly in the final assembly and the error will be caught. Occasionally, however, the analyst will find that if the requirements are made more exacting on one operation, a subsequent operation will be made easier to perform.

Item 4. The material of which the part being studied is made is specified by the design engineer and theoretically should not concern the analyst. Design engineers, however, like all other human beings are not infallible and sometimes specify an unnecessarily costly material. It is proper and necessary that the methods engineer should check on cases of this kind and bring them to the attention of the designers.

In other cases, certain materials present shop difficulties that may not be known to the designer. A certain cheap, brittle material may be so difficult to machine that an excessive amount of scrap results. Here investigation might show that it would be less expensive in the end to specify a more costly but more easily machined material.

Item 5. Material handling is a study in itself. That it has received a great deal of attention on the part of management is evidenced by the wide application of conveyers, cranes, trucks, and other mechanical handling devices. Manual handling, however, is encountered frequently, and should be carefully studied where found. Handling problems are as numerous and varied as the parts handled, but they offer a fertile field for savings. In general, the part that is the least handled is the best handled.

Although it is commonly thought that conveyers can be used to advantage only in mass-production work, there are types on the market that are equally successful in jobbing work. Not only do the latter conveyers eliminate material-handling labor, but if they are used in conjunction with a dispatching system they permit far better production control than is usually obtained in miscellaneous, small-quantity work.

Many plants are laid out, if a careful study has not been made, so that a great deal of unnecessary handling is required, particularly if the plant has gone through a period of rapid expansion. Major changes of layout do not usually result from the analysis of a single job, although they may. However, the matter of general layout should be given at least passing consideration under items 2, 5; and 8 of the analysis sheet. As a result of this preliminary work, the analyst will be in a good position to undertake a major layout revision when the occasion arises.

Item 6. The term "setup" is loosely used throughout industry to signify the workplace layout, the adjusted machine tool, or the elemental operations performed to get ready to do the job and to tear down after the job has been done. More exactly, the arrangement of  the material, tools, and supplies that is made preparatory to doing the job may be referred to as the " work-place layout." Any tools, jigs, and fixtures located in a definite position for the purpose of doing a job may be referred to as "being set up'  or as "the setup." The operations that precede and follow the performing of the repetitive elements of the job during which the workplace layout or setup is first made and subsequently cleared away may be called " make-ready" and "put-away" operations. For the sake of clearness, the more exact phraseology will be used throughout this book, although the workplace layout, the setup, and the make-ready and put-away operations are all considered under item 6 on the analysis sheet.

The workplace layout and the setup, or both, are important because they largely determine the method and motions that must be followed to do the job. If the workplace layout is improperly made, longer motions than should be necessary will be required to get materials and supplies. It is not uncommon to find a layout arranged so that it is necessary for the operator to take a step or two every time he needs material, when a slight and entirely practical rearrangement of the workplace layout would make it possible to reach all material, tools, and supplies from one position. Such obviously energy-wasting layouts are encountered frequently where methods studies have not been made and when encountered serve to emphasize the importance of and the necessity for systematic operation Analysis.

The manner in which the make-ready and put-away operations are performed is worthy of study, particularly if manufacturing quantities are small, necessitating frequent changes in layouts and setups. On many jobs involving only a few pieces, the time required for the make-ready and put-away operations is greater than the time required to do the actual work. The importance of studying carefully these nonrepetitive operations is therefore apparent. When it can be arranged, it is often advisable to have certain men perform the make-ready and put-away operations and others do the work. The setup men become skilled at making workplace layouts and setups, just as the other men become skilled at the more repetitive work. In addition, on machine work it is usually possible to supply them with a standard tool kit for use in making setups, thus eliminating many trips to the locker or to the toolroom.

The tool equipment used on any operation is most important, and it is worthy of careful study. Repetitive jobs are usually tooled up efficiently, but there are many opportunities for savings through the use of well-designed tools on small-quantity work which are often overlooked. For example, if a wrench fits a given nut and is strong enough for the work it is to do, usually little further attention is given to it. There are many kinds of wrenches, however. The list includes monkey wrenches, open-end wrenches, self-ad justing wrenches, socket wrenches, ratchet wrenches, and various kinds of power-driven wrenches. The time required to tighten the same nut with each type of wrench is different. The more efficient wrenches cost more, of course, but for each application there is one wrench that can be used with greater over-all economy than any other. Therefore, it pays to study wrench equipment in all classes of work. The same remarks apply to other small tools.

Jigs, fixtures, and other holding devices too often are designed without thought of the motions that will be required to operate them. Unless a job is very active, it may not pay to redesign an inefficient device, but the factors that cause it to be inefficient may be brought to the attention of the tool designer so that future designs will be improved.

Item 7. There are a number of changes that can be made to workplace layouts, setups, and methods which are brought to light by job analysis. Of these, there are 10 that are encountered frequently, and 1 or more may be made on nearly every job studied.

1. Install gravity delivery chutes.

2. Use drop delivery.

3. Compare methods if more than one operator is working on
same job.

4. Provide correct chair for operator.

5. Improve jigs or fixtures by providing ejectors, quick-acting
clamps, etc.

6. Use foot-operated mechanisms.

7. Arrange for two-handed operation.

8. Arrange tools or parts within normal working area.

9. Change layout to eliminate backtracking and to permit coupling of machines.

10. Utilize all improvements developed for other jobs.

These improvements are comparatively easy to make. If the analyst is observant and on the alert for inefficient operating practices, the possibility of applying them can be recognized without resorting to detailed motion or time study. Specific applications of each point will be discussed later.

Item 8. Working conditions have an important influence on production. This has been widely recognized during recent years, and the more modern plants usually provide working conditions that the methods engineer considers to be suitable. In the older plants, or in modern plants where methods studies have not been made, poor working conditions are frequently encountered. In most cases, it is best to correct them. It is sometimes difficult to justify the cost of making such improvements by direct labor savings, but there are other factors that must be considered in this connection. The human element cannot be neglected. Conditions that are unhealthy, uncomfortable, or hazardous breed dissatisfaction. Besides lowering production, they increase labor turnover and accidents and often lead to labor unrest.

There are certain other factors that are worthy of at least passing consideration during analysis, and the most important of these are listed as "other conditions" under item 8. The design of the part, of course, plays an important role in the methods that must be used to produce it. In the majority of cases, the design is fixed by the engineering, functional, or appearance requirements of the product, but occasionally a part is encountered that can be redesigned to make its production easier without in any way affecting its ultimate purpose. In addition to this, certain minor features of design can sometimes be suggested that will help to fit the product to the limitations of the tools which are to produce it.

Item 9. The analysis of the method followed in performing the operation is the most important part of the study. The consideration of the method is seldom, if ever, complete at the time the analysis sheet is filled in but goes on in one form or another during the remainder of the time the job is studied.

The method that is established after analysis and motion study is recorded under 9 in order that the analysis sheet may provide a complete record of the job, although, strictly speaking, this information does not belong under the head of analysis.

Usually the analysis of the method requires the drawing of one or more types of process chart, and often a number of computations are involved. This information should be gathered together in the form of a supplementary report and identified by a note on the analysis sheet.

The foregoing gives a general description of the items on the analysis sheet. Specific methods of approaching the analysis of each item, illustrated by examples are given in the chapters related to each factor.

Source: Operation Analysis by Maynard

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Updated 1 August 2016,  28 February 2014

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