**Its a little hard to follow you here, but let's work together to get the best information to continue. Just about everything shrinks when it solidifies (except for water and Wood's metal, if we must be absolutely correct.) I guess you mean excessive shrinkage? But how much did you expect? How much is acceptable? 1mm? 0.1 mm? 0.0000001 mm? 0.000000000? How will you easily remove it from the mold, if it doesn't shrink at least a little bit?**

you are right, I must to give more detail. As you said, I mean excessive shrinkage so about to 1.5cm - 2 cm therfore we face to montage problem. We dont want to more than 1 cm of shrinkage pp

**Interesting. How much did the longer cooling time help? Did it change 0.01% shrinkage into 0.005% shrinkage? Is that adequate? How much cooling time increase? Consider, if you go from 10 min cooling time, to 30 min cooling time, for slight improvement, what do you get at 20 min cooling time? Moderate benefit? The same benefit? Negligible benefit?**

We inrease cooling time aproximate 5sec, or 10sec however this stuation disadvantage in terms of manufacturing.

**Now this is interesting, if the input isn't simply polypropylene, you can get a variety of different effects. But which one, and where to start?**

Yes you re right, I already ask this question? I expect to help on this one