Regression analysis.......how worthy is the effort in plastic injection molding atmosphere?

Anyone have any experience?

After reading a few articles, I don't believe standard SPC efforts are going to be worthwhile due to the variability of the plastic and measuring them after they have cooled and shrunk.

Regression analysis.......how worthy is the effort in plastic injection molding atmosphere?

Anyone have any experience?

After reading a few articles, I don't believe standard SPC efforts are going to be worthwhile due to the variability of the plastic and measuring them after they have cooled and shrunk.

You are right, as I like to say, injection molding is very "organic".

You might want to read through the following thread for starters.

SPC and Injection Moulding (http://elsmar.com/Forums/showthread.php?t=14619)

It really depends on the process, and what controls you have. A while back, I molded Torlon. Since I was moving less than the prescribed amount of material, the process was capable of locking up the screw on material baked onto the surface of the barrel. So, to catch the problem before I had to bang the daylights out of the screw to get it out, I tracked the heaters with charting. When I saw the heaters cycling less (or not at all), I started purging - saving myself LOADS of misery. It is one example of using some kind of charting to control the process...and that is better than nothing. Might chart cooling temp, mold temp, injection time, who knows. It depends.

Yes I have read that. It's ok.

Yes I have read that. It's ok.

The nature of molding is that there is no magic bullet - each individual process has to be analyzed for the key control factors. That makes it difficult to exhibit the secrets of life on a forum like this for molding capability analysis or SPC. In fact, molding makes for interesting design of experiments opportunities, just because of the factors involved.

Oh don't I know that from felling the pain! lol