View Full Version : Problem of brittleness / breakage in thin wall moulding
chintu2525
7th September 2016, 08:54 AM
We are facing problems of breakage in thinwall food containers made from 65 mfi homopolymer pp.lid fitting ribs break on normal impact.can anyone suggest a solution
brentb
7th September 2016, 01:29 PM
Copolymer PP or LOWer homopolymer!
KPM
brent
JayDub
8th September 2016, 02:40 PM
Check that there is at least some radius at the base of the ribs - a sharp corner is a stress riser. Also watch your mold temperature - you don't want to freeze the plastic faster than it can crystallize.
chintu2525
9th September 2016, 08:58 AM
Thanks.can any additive help
rickbatey
10th September 2016, 04:29 PM
What are your process settings? You may be degrading the resin in the barrel due to residense time, improper screw geometry or compression ratio, too high back psi or screw rpm, or shear induced when filling the mold. Actual values will help root cause the issue.
Rick.
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