SRC Forum - Message Replies
Forum: Reliability & Maintainability Questions and Answers
Topic: Reliability & Maintainability Questions and Answers
Topic Posted by: Reliability & Maintainability Forum
Organization: System Reliability Center
Date Posted: Mon Aug 31 12:47:36 US/Eastern 1998
Posted by: Diane Gordon
Organization:Reliability Center, Inc.
Date posted: Wed Sep 19 10:23:29 US/Eastern 2001
Subject: Physical Properties of Polypropylene
What are the effects of variation in processing (mold temperature, material temperature, clamp pressure etc.) on the physical properties of polypropylene?
Subject: Polypropylene Variables
Reply Posted by: B.W.Dudley
Organization: Reliability Analysis Center
Date Posted: Wed Sep 19 14:34:52 US/Eastern 2001
The question on process variations for polypropylene manufacturing is best answered on the DOW web page at http://www.dow.com/polypro/ . This page has shrinkage guidelines for mold temperature, cavity pressure and part thickness and includes data charts for shrinkage versus pressure, mold temperature, injection speed and melt temperature.
Other sources that have guides include: Saint Gobian Vetrotex at http://www.twintex.com/fabricatiom_processes/ and Plastic Material for Industry at http://www.plasticmaterials.com .
In order to determine the real factors that drive the polypropylene processes, one needs to apply a "design of experiment" test to the multitude of variables. This type of multiple testing is explained in our Reliability Toolkit; Commercial Practices Edition on page 257 and in numerous article on quality control.