In the realm of plastic extrusion, ensuring that single-screw extruders run at peak performance is an ongoing challenge, especially for those operating older machines. As highlighted in the article “Troubleshooting Screw and Barrel Wear in Extrusion” from Plastics Technology Online, one inevitable concern is the wear and tear that screws and barrels undergo during production.
The telltale signs of this wear are a reduction in specific rate and higher discharge temperatures. Specific rate, a critical parameter, is simply the rate of material flow divided by the screw speed.
For minor reductions in specific rate, processors can compensate by increasing the screw speed to maintain the desired output rate. However, this workaround can lead to higher screw speeds and material leakage over the flight clearance, causing a spike in discharge temperatures.
As wear progresses, processors may eventually face the dilemma of reducing throughput to maintain product quality. This, in turn, impacts profitability and production capacity, necessitating a critical decision regarding barrel and screw replacement, one that must be grounded in sound economic considerations.
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Photo and article with all rights reserved, courtesy of ptonline.com