What is a feedscrew or barrel wear problem?
A wear problem occurs when any screw or barrel, that due to any amount of wear, and without operating parameter modifications(1), will no longer deliver QUALITY(2), plasticized resin to the die or mold at the desired out-put rate, within the desired recovery/cycle time, or at the proper head pressure.
Operating Parameter Modifications
- Compensating for screw/barrel wear through machine parameter modifications can cause excessive shear, burning, and polymer degradation!
- Modifications are typically made to maintain out-put rates or decrease scrap rates
Costs of wear!
- Quality - Resin of quality may be defined as resin that is free of unmelt, was exposed to minimal shear, has seen standardresidence time, and is therefore free of degradation.
- Degradation - Loss of polymeric physical properties such as compression strength, tensile strength, impact strength, torsional strength, or other tangible or intangible engineered properties
Production Efficiency Advantage Factor! (PEAF)
- Defined as the quantified cost of inefficiency on a per machine, per month basis, and in most cases factors in as a reduction to feedscrew and barrel expense.
Surface Engineering
Definition of Wear 
