Tungsten and ceramic coatings from two suppliers raise the bar on wearand
corrosionresistancefor plasticizing equipment.
The efficiency of plasticizing equipment decreases dramatically when
mechanical and physical components that process the polymers wear. “When
the clearance between the outer diameter of the feed screw and the inner
diameter of the barrel increases to twice the gap tolerance set by the original
equipment manufacturer, output can decrease by 25 percent,” said Greg
Quinn, senior VP for the plastic and rubber industry, Extreme Coatings
Engineered Surfaces. The St. Petersburg, Fla., company supplies tungstencarbide
“A widening of the gap between the top of the screw flight and the inner barrel
wall of as little as 0.015 inch can cause excessive scrap generation and
machine downtime,” Quinn said.
Poor melt quality is more likely as the wear increases. When wear widens the screw and barrel clearance, a
processor has several choices to remedy the problem.