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Theory of Inventive Problem Solving (TRIZ)  313


               It is clear that we want to reduce the space between wrench and nut to
             improve operation reliability, however, this led to the deterioration of oper-
             ations. From a TRIZ standpoint, a technical contradiction is present when a
             useful action simultaneously causes a harmful action.
               A problem associated with a technical contradiction can be resolved either
             by finding a trade-off between the contradictory demands, or by overcoming
             the contradiction. Trade-off or compromise solutions do not eliminate the
             technical contradictions, but rather soften them, thus retaining harmful
             (undesired) actions or shortcomings in the system. A trade-off solution in
             this example would be to make the clearance neither too big nor too small.
             An inventive solution for this problem can be found if the technical contra-
             diction can be overcome completely. Forty principles and the contradiction
             table are important tools for overcoming contradictions.
             1. Build contradiction model. Look into the problems and find a pair of con-
                tradictions. The contradiction should be described using 2 parameters of
                the 39 parameters for technical contradictions. In this problem, the con-
                tradiction is:
             Things we want to improve: Reliability (parameter 27)
             Things are getting worse: Ease of operation (parameter 33)
             2. Check contradiction table. Locate the parameter to be improved in the
                row and the parameter to be deteriorated in the column in the contra-
                diction matrix for inventive principles. The matrix offers the following
                principles 27, 17, and 40 (see the partial matrix show below).



                                              What is deteriorated?








                               25. Waste of time  26. Quantity of substance  27. Reliability  28. Measurement accuracy  29. Manufacturing precision  30. Harmful action at object  31. Harmful effect caused by the object  32. Ease of manufacture  33. Ease of operation  34. Ease of repair  35. Adaptation




           What should be improved?
           25. Waste of time     35 38 10 30 24 34 24 26 35 18 35 22 35 28 4 28  32 1  35 28
                                 18 16 4  28 32 28 18 34  18 39 34 4  10 34 10
           26. Quantity of substance  35 38  18 3  3  2  33 30 35 33 3  35 29  1 35 29 2 32 15 3
                             18 16   28 40 28     29 31 40 39 35 27 10 25 10 25 29
           27. Reliability   10 30 21 28  32 3  11 32 27 35 35 2  27 17 1  11 13 35
                             4   40 3     11 23 1  2 40 40 26  40       824
           28. Measurement accuracy  24 34 2  6  5 11 1  28 24 3  33 6  35 1  13 1  32 13 35
                             28 32 32  23         22 26 39 10 25 18 17 34 13 11 2
           29. Manufacturing precision 32 26 32 30 11 32  26 28 4  17  1 32 25 10
                             2818    1            1036 3426    3523
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