Glass filled resin vs. unfilled resin processing

[jason8598]

I have a project that requires me to design a high strength plastic part. My question has to do with if there should be any major difference in the way a glass filled acetal is injection molded versus an unfilled acetal. After trying 111P, 311P, and 511P acetals I was obtaining strengths between 350lbs to 400lbs. I tried a 510GR acetal (10% glass) and obtained a strength of just over 200lbs. The trials were all run on the same macine with relatively equal conditions as far as velocities, pressures, etc. Assuming that the cavities are being fully packed, does it take more/less pressure/velocity to run glass filled acetal or will conditions be approximately the same?

 

[dgallup]

You can get all the recommended processing guidelines form DuPont's website.

http://www2.dupont.com/Plastics/en_US/Products/Delrin/delrin_amer_design.html

 

[patprimmer]

The more glass the harder it is to pack. You will tend to need a hotter mould and more speed and more pressure, all depending on what you are doing with the unfilled and the part and mould design of course.

You will also get less shrinkage but a greater variation in shrinkage accross the part leading to a much greater tendency to warp.

Regards
Pat
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