How Does Screw-Barrel Wear Affect Capacity, Pressure and Energy Consumption?

09.09.2026

Screw-barrel wear is not just a matter of part life — it is an efficiency problem that directly affects production economics. Understanding the effect of wear on capacity, pressure and energy consumption makes it easier to decide when to intervene.

How Does Capacity Loss Occur?

As the clearance between the screw and the barrel increases, some of the melt that should be conveyed forward leaks backward through this clearance (backflow). This leakage reduces net conveying efficiency; less material is conveyed forward at the same screw speed, and production capacity (kg/hour) decreases.

Change in Melt Pressure

A healthy screw-barrel system produces stable, predictable melt pressure. As wear progresses, pressure both drops and fluctuates; this leads to filling inconsistencies in injection molding and deviations in product dimensions and wall thickness in extrusion.

The Cause of Increased Energy Consumption

Increased friction between worn surfaces and inefficient conveying require the motor to do more work to achieve the same output. This raises specific energy consumption (kWh/kg). Over the long term, this difference translates into a measurable increase in energy costs.

Combined Effect with Quality Costs

Capacity loss and pressure fluctuation are usually accompanied by an increase in the scrap rate. Reprocessed or discarded material further increases energy and time losses; this combined effect (capacity, energy, scrap) can significantly increase total production cost.

When Should You Intervene?

When you notice a persistent deviation in capacity, pressure or energy consumption, it is recommended to have the screw-barrel measured to understand the source of the problem. Early detection both preserves production quality and prevents unnecessary energy cost.

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