Saturday, November 23, 2013

Scope and Limitations of Methods Efficiency Engineering



Wide Scope of Methods Efficiency Engineering


Methods efficiency engineering principles have been applied to a wide variety of work. But still there are men who wish to know what value methods efficiency engineering steps have for their particular processes. Therefore, it will be useful to outline the scope of methods efficiency engineering and to define the limits of its application.

Many executives feel "Our Work Is Different."  They agree that  methods efficiency engineering  has unquestionably accomplished worth-while results in certain lines of work or in certain industries. But still they feel , it has no value in their particular line of work.

 If it happens to be of a jobbing or small-quantity nature, it is felt that the field of operation analysis is limited to mass production. A foundry feels that the technique is more applicable to a machine shop, and the machine shop feels that it is useful chiefly in assembly work.

Wherever the Methods efficiency engineering technique has been properly applied by a competent engineer, beneficial, almost spectacular, results have been obtained. This, if it were generally known, should do much to offset the feeling described above. The principles of methods efficiency engineering are fundamental, and they can be applied to any class of work. It makes no difference if a plant is manufacturing toys, tools, trains, or tractors ; the principles apply equally to all.

The reason for this is that all work may be resolved into terms that are more or less basic. During operation analysis, one of the points that are considered is the purpose of the operation. It is just as useful to consider the purpose of grinding a part that goes inside a large steam turbine as it is to consider the purpose of
the bending of a part that fits in an agricultural machine. It is as important to analyze the inspection requirements of a toy shovel as it is to analyze those of a gear bushing. The inspection requirements partly determine "the operations that must be performed in. either case and hence should be gone into carefully.
Material handling presents problems that must be solved whether the product handled is bread, tooth paste, shoes, or patent medicine.

Working methods present points of remarkable similarity when closely analyzed.

The motion made by a mechanic in reaching for a screw driver is the same as that used by a sewing-machine
operator in reaching for a pair of scissors or by a fitter in reaching for 'a piece of material or by a molder in reaching for his rammer or, for that matter, by a dentist reaching for his chisel. If one can be shortened and made less fatiguing, the others can also be made less fatiguing..

The same logic equally to large parts. The problems involved in lifting a ladle of molten metal with a crane are the same regardless of whether the metal happens to be copper, iron, or steel. Castings and forgings both present handling problems that are related. Countless similar examples can be taken from all types of industry.

Hence, it may be seen that the application of the principles of operation analysis is not limited by the nature of the product. In view of the prevalence of the " our-work-is-different " attitude, this point cannot be too highly stressed.

Effect of Quantity on Field of Operation Analysis

If a large number of man-hours are expended upon a certain line of work, a 1 per cent saving may be important, whereas a 10 per cent saving on inactive work might not offset the cost of making the
study. Hence, it is almost axiomatic that it is more profitable to study the work with the greatest activity. This does not mean, however, that only mass-production work can be studied. There is need for cost reduction in jobbing production also and jobbing processes can also improved using methods efficiency engineering.

An operation may be repetitive from the viewpoint of the methods engineer in so far as analysis is concerned even though the quantities in which individual parts are made are quite small. This viewpoint is different from that which considers a job repetitive only when a large number of duplicate parts are produced.

For purposes of analysis, the methods engineer looks at an operation not as a single quantity but rather as a series of elemental operations. Therefore, when a number of different but similar jobs are reduced to their elements, it is found that several of the elements are common to all jobs. If an element is shortened on one job, it may be shortened on all jobs in which it occurs, and thus a saving is obtained over the entire line of work that may be of great magnitude.

Jobs that are molded on the bench in a foundry are not considered as being repetitive. Any one casting that was ordered in quantities would be made on a molding machine, However, if several bench molders work continuously at making molds, the operation will be considered as repetitive by the methods engineer.

The first operation performed by a bench molder in beginning to put up a mold is "place match or molding board on bench. If a standard flask is used and 10 molders put up 20 molds per day on the average, the operation will be performed 200 times per day or 60,000 times a year. Hence, it may be seen that under
these conditions, the element  "place match or molding board on bench"  is truly a repetitive operation. It will be worth while to, study the location of the molding boards and the motions used for handling them. If by careful analysis of the type described for laying out the bookkeeper's desk the time required to place
the match or molding board is reduced from 0.0030 to 0.0015 hour, 0.0015 X 60,000 or 90 hours per year will be saved. This at an average bench molder's rate will amount to a worth-while total.

Similarly such elements as " place drag " apply parting sand, "fill riddle,' and so on, are repetitive elements. They occur on every mold made and are not affected by the nature of the patterns In the mold. Hence, it will be profitable to consider each of these elements in detail, for any improvement made will apply
to the entire bench-molding activity.

Certain elements vary with every job. Therefore, they are not repetitive in the sense that the element "place match or molding board on bench'  is repetitive. The variation is in degree rather than in kind,, however, and hence even the variable elements have repetitive characteristics. When a mold must be reinforced with nails, the time for the element "reinforce mold " will vary with the number of nails placed. However, the same
motions are used whenever a nail is placed, and hence an improvement in the method of securing and placing a nail will amount to a sizable saving in the bench-molding work as a whole.

This same principle applies to all lines of work. Machine work even in the jobbing shop is repetitive if the machines work steadily. Most machine work may be reduced to less than 100 elements which are repeated over and over again.

Therefore, it will be seen that operation analysis is not limited to large-quantity work but may be applied to advantage to any line of work on which a fair number of man-hours are expended. Usually, if a line of work has not been studied with the modern analysis approach, it is profitable to study it if one or more men
are engaged full time upon it.

Class of Work to Which Operation Analysis Is Not Applicable

If job-analysis methods may be applied to any product and to all lines of work requiring the full-time services of one or more men, it follows that the only work to which it is not applicable is that which occupies only part of the time of one individual. A general machine shop may possess a broaching machine to take care of
special jobs. If jobs requiring broaching are so infrequent that the machine operates only two days a month, detailed study of the operation will not be economically justified.

Source: Operation Analysis by Maynard

Full Knol Book - Method Study: Methods Efficiency Engineering - Knol Book


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