# Which Metric?

| On 01, Jan 2010

Message: 1926
Posted by: ZetaUMa
Posted on: Wednesday, 29th September 2010

I'm just getting started  with TRIZ, and am doing so to help solve problems here.  The type of probem [not the exact problem at hand] is this:  As the density variation of the object increases, the wear on the machine is increased.

I searched this forum for density, variation, non-uniform, etc. and have not recognized which metric should be selected for density, or non-uniformity, when using the contradiction matrix.     I'm asking for some assistance in the short-term:  I'm not in a TRIZ class.  A TRIZ book has been ordered, but it as not yet arrived.

Thanks

Message: 1927
Posted by: Claude Meylan
Posted on: Thursday, 30th September 2010

There is an easy answer to your question. The term “density” is linked to the parameter “amount of substance” and “wear” to “loss of substance”. You may also consider the parameter “stability” (linked to “homogeneity”)- probably a better option! But be careful! The matrix is not a starting point, only one among other tools after an in-depth problem formulation. So, don?t be happy too early with such quick help. Ask further what is the main problem (improve a useful function or eliminate an undesirable effect)? ?if you really want to increase ?density? in your system??a.s.o.

Message: 1928
Posted by: Ellen Domb
Posted on: Thursday, 30th September 2010

Absolute agreement with Claude's words of caution. The matrix only shows you the relative popularity of the top few of the  40 principles as solutions to a problem.  The best solution for you could be one of the less popular.       Here's an example for Claude's caution about doing a full analysis before using the matrix:  :   Is the density (mass per unit volume) varying because the mass is varying and the volume is stable, or because the mass is stable and the volume is varying?  Or both?    These are 3 different problems, and there will be different solutions for each problem.  Is your problem to make the density less variable?   Or to reduce the wear no matter what happens to the density (a much higher level problem!)

Message: 1930
Posted by: ZetaUMa
Posted on: Thursday, 30th September 2010

Thanks for the replies from you and Ellen.

In looking at TRIZ I realized that I needed to way to begin “linking” such things as density to amount of substance to progress (if that is done “wrong” then the Principles highlighted would likely not be useful at all).  Thanks for the assistance on this one.  When my book gets here I hope to learn the generalities of that as time goes on.

I'm not jumping into TRIZ to the exclusion of other problem solving processes.  The first application I'm trying is in parallel with other techniques, and seeing where “the solution” first comes to light.

I agree with Ellen, that I'm tending to state the problem in cause-and-effect terms and that is not what is needed.  For my actual problem I'm working on stating it in terms of a contradiction so that the contradiction table is applicable.

One follow on question:  In my actual case the parameter of interest is with the product produced, yet the detrimental area is with the machine that produces the product.  So far as I can tell that (different areas in a probelem statement) is not an issue.  Correct?

Thanks for the kind replies as I get started with TRIZ.

Message: 1931
Posted by: Ellen Domb
Posted on: Thursday, 30th September 2010

This thread should really be called “which tool?”

The System Operator (also called 9 Windows and Multi-Screen Method) would be very useful for looking at your problem in the sub-system, system, and super-system, so that you can be very careful about solving it at the right level. (See The TRIZ Journal Archive for many examples, tutorials, etc.)   Mixing levels is not WRONG, but it can make the situation very confusing.    The tools help you solve the problems in a simple direct way, after you do the work of defining the problem.

Message: 1932
Posted by: ZetaUMa
Posted on: Friday, 1st October 2010

Thanks for the further advice … I've started to learn about the System Operator.  Interesting …  I hope by first books arrive soon!

Thanks yet again.