Machine Work Study - Machines and Tools Related Efficiency/Productivity Analysis
The machines, accessories and tools used to perform the operation needs to analysed logically to identify process improvement opportunities to increase productivity and engineering has to be done to modify the process to use new equipment, accessories, tools and modified equipment, accessories or tools.
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What are the question that can be asked and evaluated in machine work study? - Barnes
Based on the questions suggested Barnes:
1. What is the operation?
2. What is the purpose of the operation?
3. What is the transformation of the material required?
4. What is the equipment now used?
5. What are the alternative equipments?
6. What are the cutting tools now used?
7. What are alternative cutting tools?
8. What are the cutting parameters now used?
9. What are the alternative cutting parameters?
10. What should be the best specifications for machine and machine parameters for the minimum cost that does the required material transformation reliably and accurately?
Questions on Machine, Equipment and Tools: The tools and equipment used to perform the the machine operation needs to analysed using appropriate questions. The following is a list of questions that are related to machines and machine related tools, accessories and other inputs that have an effect on productivity.
1a. Is a better a machine or machine tool available in the market?
2. Would the purchase of a better machine be justified (Replacement analysis - Industrial Engineering Economic Analysis needs to be done)?
3. Work holding: Can the work be held in the machine by other means to better advantage?
4. Should a vise be used?
5. Should a jig be used?
6. Should clamps be used?
7. Is the jig design good from a motion-economy standpoint?
8. Can the part be inserted and removed quickly from the jig?
9. Would quick-acting cam-actuated tightening mechanisms be desirable on vise, jig, or clamps?
10. Can ejectors for automatically removing part when vise or jig is opened be installed?
11. Is chuck of best type for the purpose?
12. Would special jaws be better?
13. Should a multiple fixture be provided?
14. Should duplicate holding means be provided so that one may be loaded while machine is making a cut on a part held in the other?
15. Are the cutters proper?
16. Should high-seed steel or cemented carbide be used?
17. Are tools properly ground?
18. Is the necessary accuracy readily obtainable with tool and fixture equipment available?
10. Are tools pre-positioned ?
20. Are tools best suited to purpose?
21. Will ratchet, spiral, or power-driven tools save time?
22. Are all machines provided with the same tools?
23. Can a special tool be made to improve the operation?
24. If accurate work is necessary, are proper gages or other measuring instruments provided?
25. Are gages or other measuring instruments checked for accuracy from time to time?
Because of the wide variety of tools available for different kinds of work, this list could be extended almost indefinitely with specific questions.
Foundries, forge shops, processing industries, assembly plants, and so on all have different kinds of tools, and different questions might be asked in each case.
The list given above is for machine tool work primarily and will indicate the kind of searching, suggestive questions that should be asked. A special list might well be drawn up by each individual plant to cover the kind of tools that might be advantageously applied upon its own work.
Foundries, forge shops, processing industries, assembly plants, and so on all have different kinds of tools, and different questions might be asked in each case.
The list given above is for machine tool work primarily and will indicate the kind of searching, suggestive questions that should be asked. A special list might well be drawn up by each individual plant to cover the kind of tools that might be advantageously applied upon its own work.
Equipment.—A study of existing equipment may suggest changes and improvements or repairs. Machine operations should be those which combine economy with uniformity of standard quality. Standard times and methods are dependent upon standardization of machines within each class (using the best machines for operations), and the maintenance of normal conditions with respect to their upkeep. (https://nraoiekc.blogspot.com/2019/07/operation-study-arthur-g-anderson-1928.html)
Tools: For the most part, it may be said that the tools do function properly from the standpoint of the finished job. But from a productivity angle, industrial engineer has to examine the productivity possible from the existing tool and has to compare it with productivity possible from alternative tools to decide the appropriate alternative. Industrial engineers have to receive information regarding new tools from purchase department, representatives of organizations selling tools, consultants and technical literature being procured by the company. Industrial engineers have to monitor technology and engineering developments on a continuous basis and have to set up libraries for their departments or there have to sections within the company library for industrial engineering materials.
Similarly, whether, the jigs and fixtures etc. function properly from a motion-economy standpoint is subject to evaluation by industrial engineers. The tool designer is usually more concerned with making a tool that will do a certain job than he is with the motions that will be required to operate it. Therefore, unless he has made a study of the principles of methods engineering or has had the importance of motion economy impressed upon him in some other way, it is probably safe to say that the motions required to operate the tool are the last thing he thinks of.
As a result, tools are designed and built that require much more time to use than they should. The common machine vise is a good example. The quick-acting vise is far superior. On machining operations where the cutting time is short, it will save 20 to 40 per cent of the total operation time. The jaws of the vise are cam-actuated. They are tightened by moving the two levers in opposite directions which conforms to the principles of motion economy. They hold securely without hammering on the levers. They are adjustable to a variety, of sizes of work. In short, they possess many real advantages over the standard vise.
Suggestions that will improve the quickness of operation of tools should be made to tool designers as they are conceived. If they are presented with a summary of the yearly saving in dollars and cents that they will effect, interest in better tool design from a use-time standpoint will be aroused. This is very desirable, for tool designers as a group are clever arid ingenious, and if the importance of reducing the time required to operate tools Is clearly demonstrated, they will be able to assist materially toward this end by producing more suitable designs.
Hand Tools. Even the hand tools used by operator in connection with machine work have to analyzed as part of machine work study. There is a tendency to pay too little attention to the hand tools used upon even the more repetitive operations. To many, a screw driver is a screw driver, and if it fits the slot in the screw to be driven, it is considered satisfactory. This is far from being the case, however. Screw drivers vary widely in design, and some are more suitable than others. Screw drivers come in a number of different styles. There are the solid screw drivers, the ratchet screw drivers, the spiral screw drivers, and the various types of power-driven screw drivers. Even the variation among screw drivers of a given type is tremendous. They vary in size, of course, but in addition they vary in about every other way imaginable. The handles vary in diameter, length, cross section, shape, and nature of gripping surface. Points are wide, narrow, blunt, sharp, taper toward the point like a wedge, or are narrower right above the point than at the point. A lately introduced type has a special point to fit a special screwhead which offers many advantages.
When all these factors are considered, the wide variation in even such a simple tool as a screw driver becomes apparent.
There is, of course, one screw driver that is better for a given application than any other. For medium work with the conventional screw-head if a solid screw driver is to be used, the one with the largest cylindrical handle which can be comfortably grasped by the operator should be chosen. The handle should, of course, be fluted to prevent slipping. The diameter of the handle will vary with the size of the operator's hand, but two or three standard sizes are sufficient for most hands. The diameter of the handle should be large, because the larger the handle within the limits of the human hand, the more easily can a given torque be applied. To prevent slipping, the point should not be wedge-shaped but should be slightly larger at the point than just above it. Few screw drivers commonly encountered in industry meet these simple specifications.
If many screws have to be driven, a ratchet, spiral, or power-driven screw driver can often be used to good advantage. If many screws of the same size are to be driven, a piece of hardened tubing slipped over the end of the screw-driver point will make it much easier to locate the screw driver in the slot.
The same sort of searching analysis can be made for every type of hand tool used. Wrenches, hammers, chisels, saws, scissors, knives, pliers, and drills all come in a great variety of styles. Standardization on a limited number of the better styles within a plant will tend to prevent the use of the more inefficient tools. Tests must be made to determine which styles are actually the most efficient. Time taken for the element is the decision criterion.
Judgment must be used, of course, in determining the amount of time that can economically be spent in analyzing the tools used on any one job. Unless a job is highly repetitive, it will not pay to try to discover the best screw driver for that particular job. Instead, the whole subject of hand tools including screw drivers may be investigated in a general way, and good tools may be adopted for standard use. The tool supply should be plentiful, for it is not uncommon to see operators not only using the wrong size of tool, but also using a chisel for a hammer or a screw driver for a crude chisel merely because the proper tool is not available. An insufficient supply of proper tools may reduce the amount expended for tools, but it will prove costly in the long run.
Source: Operation Analysis by Maynard & Stegemerten, 1939
Full Knol Book - Method Study: Methods Efficiency Engineering - Knol Book
Modern Developments in Tools
2001
Duraspin Screw Fastening System increases productivity by 31%.
https://www.rsmeans.com/consulting/Senco.pdf
Updated 5.7.2024, 31 July 2019, 5 June 2019, 17 February 2019, 4 July 2015
First published 23 Nov 2011
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