Category Archives

I recently received this from an extruder manufacturing PP film… RB We are processing a 1.1mil 3-layer PP film with a random copolymer. Initially, we were processing at 210ºC with a kinetic COF (coefficient of friction) = 0.5 initially, and 0.2 after two weeks. Currently, if we process at 210ºC, we get a COF of 0.8, […]

As a follow-up to one of my recent posts, I received this question… Matt The problem we are encountering is the different opinions on how to measure the screw and barrel wear. Is there a procedure that is widely used throughout the industry to determine screw wear? My Response Regarding the screw – Most screw manufacturers […]

A friend of ours recently asked this question about screw wear… Jim I can get maintenance to measure the screw, but their philosophy is that there’s no reason to do so. Typically we replace barrels and check rings, but do not know what the state of the screw is.  I think we should know, and […]

I receive this question very often, and feel it would be great for the blog… Larry Can you briefly explain melt flow index, and how processors use it? My Response Melt flow indexing is the most popular, and yet least accurate way to determine material viscosity. The melt flow index (MFI) is the measure of […]

I received this question over the weekend… Milan I heard about the platen deflection test. How should I do it and what information can I obtain from the test? My Response Most platen deflection occurs within the stationary platen due to the fact that it receives the least amount of support. It also has a […]