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Level II

## Mixture Design 14 factors or more... some needs to be equal to each other...

I'm new with JMP and I was hoping to set up a basis for our experiments for economical and time efficiency reasons.

I'm working with Epoxy and Polymers. For our products we use a component 1 and a component 2 system. When these components are mixed it get cured over time. Those component 1 and component 2, excist out of two parts. Part 1 is now called Liquid. These ingredients need to be equal to each other(reacting to each other in a ratio) or can hardly change. Part 2 is now called solid. These ingredients can easily change and influence the responses on their own.

Component 1                                   Component 2

GGREEN003A                                  GRED0007A

GPURPLE009A                                GRED0008A                          (liquid part, total 7 ingredients)

GBROWN018A                                 GPURPLE007B

GBLUE003A

GGREY019A                                     GBLACK001A

GGREY025A                                     GGREY031A                       (solid part, total 7 ingredients)

GGREY013A                                     GGREY006A

GGREY006A

Everything together is 100%

In Custom Design you can Specify a factor with Hard-to-Change levels. But my factor is part of a mixture, so I'm not sure how to set this up with a Mixture Design.

Can someone help me with this?

If you need more explanation, please let me know.

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Staff

## Re: Mixture Design 14 factors or more... some needs to be equal to each other...

You can easily exclude the constant components. First, do not explicitly define them as mixture factors. Next, click the red triangle and select Advanced Options > Mixture Sum. Enter the value the represents the portion of the mixture that contains the non-constant components. I think that is 1.0000 - (0.4468 + 0.3385) = 0.2147 in your case. That is, only 21.47% of the total mixture is changing from run to run.

Learn it once, use it forever!
15 REPLIES 15
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Staff

## Re: Mixture Design 14 factors or more... some needs to be equal to each other...

Hi,

This sounds a bit like a "Mixture of Mixtures" design (see help files: http://www.jmp.com/support/help/14-2/mixture-of-mixtures-design.shtml).  I've set something up based on the example you described in the table below.  I assumed equal portions of Component 1 and Component 2.  Please take a look and let me know if it makes sense if it is something you can work with.

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Level II

## Re: Mixture Design 14 factors or more... some needs to be equal to each other...

I have looked into it and it has answered a couple of my issues!

My only issue right now is that my C1 liquid has 1 value and my C2 liquid has 1 value. They need to react to a specific ratio for all the functional groups to react.

I have attached a file with the minimum and maximum as an example.

Unfortunately you can't open it as a "Load Factor". It gives the alarm "The current JMP Data table is not a valid factor table."

C1 Liquid is 0.4468 nothing lower and nothing higher

C2 Liquid is 0.3385 nothing lower and nothing higher

So they are part of the mixture, but they are also a constant factor.

Do I need to exclude them from the mixture factore then?

If I ad the constrain of:

1 C1 liquid + 1 C2 liquid  </= 0.7853 (0.4468+0.3385)

-1 C1 liquid + -1 C2 liquid </= 0.7853

It changes back the minimum and maximum values as 0 and 1.

I'm sorry if it is standing obvious in the online handbook. All the infromation is kind of overwelming at the first glance.

The hardest part is to understand what for factors do I have and how do I place it into JMP?

I have read quiet a bit, but I figured it would be faster to just ask.

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Staff

## Re: Mixture Design 14 factors or more... some needs to be equal to each other...

You can easily exclude the constant components. First, do not explicitly define them as mixture factors. Next, click the red triangle and select Advanced Options > Mixture Sum. Enter the value the represents the portion of the mixture that contains the non-constant components. I think that is 1.0000 - (0.4468 + 0.3385) = 0.2147 in your case. That is, only 21.47% of the total mixture is changing from run to run.

Learn it once, use it forever!
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Level II

## Re: Mixture Design 14 factors or more... some needs to be equal to each other...

Thanks, I understand!

I was thinking too difficult. Due to the fact that all my factors were ingredrients, I was too focused on the mixture part.

Not realising I have constant factors and that it is ok to exclude them, even if they are part of the mixture.

Thank you Mark and Hadley it is solved.

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Level VII

## Re: Mixture Design 14 factors or more... some needs to be equal to each other...

It sounds like you've got what you want, but for posterity...mixture designs are intended for number of variables typically ≤ 4.  I recommend reading "Tips for JMPing into Mixture Experimentation", Daniel J. Obermiller and, of course papers and THE book by John Cornell.

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Staff

## Re: Mixture Design 14 factors or more... some needs to be equal to each other...

Thanks for the plug for an old paper, @statman !  Hopefully there is some usable information in that paper, as I did cover more than just software. But I will have to say that the paper was written based on version 3 of JMP, so many of the software specific tips have been incorporated into the software by now. The software specific information may not be as useful.

Dan Obermiller
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Level VII

## Re: Mixture Design 14 factors or more... some needs to be equal to each other...

Hey Dan, I still find that paper very useful for folks just getting started with thinking about mixtures! Well written.
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Level II

## Re: Mixture Design 14 factors or more... some needs to be equal to each other...

I was already afraid of that. Due to the fact I hadn't found an example in the Handbook for that the Mixture Design section with more then 5 factors(ingredrients).

Thanks for the recommendations. I will look into that!

"papers and THE book by John Cornell", you mean the writer John A. Cornell, who has written:

Experiments with Mixutres Designs, Models and the Analysis of Mixture Data.

A Primer on Experiments with Mixtures.

And then I guess you mean the first book as THE book.

I just want to make sure.

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Staff

## Re: Mixture Design 14 factors or more... some needs to be equal to each other...

If you are referring to the comment that mixture experiments are generally restricted to less than five components, I disagree. I have designed many experiments for mixtures with dozens of components and many linear constraints. The design methods, especially custom design, are not limited by the number of components. I will say, though, that the more components you have in an experiment, the more complicated it is. But that should not limit your experimentation.

I just (finally) bought the third edition of Cornell's book. It is one of the best DOE books in my opinion, but it is very technical and mathematical.There is another book written by Snee and Hoerl, "Strategies for Formulations Development: A Step-by-Step Guide Using JMP," that might be more useful at this time. It is also rigorous but more on the practical side. I don't want to discourage you from reading Cornell's book. I just want to set realistic expectations.

Learn it once, use it forever!
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