It is interesting to note that Hamilton Church in his 1914/18 books, includes limits and tolerances as coordinating mechanisms for independent production of components by different operators. Hence designers have to specify limits and tolerances to the extent required and should not increase cost of production by specifying tighter tolerances than required.
The following questions should be raised and, as always, answered only after careful consideration regarding tolerance and finish:
1. What are the inspection requirements of this operation?
2. What are the requirements of the preceding operation?
3. What are the requirements of the following operation?
4. Will changing the requirements of a previous operation make this operation easier to perform?
5. Will changing the requirement of this operation make a subsequent operation easier to perform?
6. Are tolerance, allowance, finish, and other requirements necessary?
7. Are they suitable for the purpose the part has to play in the finished product ?
8. Can the requirements be raised to improve quality without increasing cost?
9. Will lowering the requirements materially reduce costs?
10. Can the quality of the finished product be improved in any way even beyond present requirements?
Observe the relation between succeeding operations is being evaluated in this case also.
In value engineering analysis techniques, Miles has indicated that giving a cost estimate for each tolerance will bring out excess cost created by tolerances.
Value Analysis Technique 8. Get a Dollar Sign on Key Tolerances
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Updated on 4 August 2019, 27 August 2015
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