Extrusion Know How
Understanding the Influence of Screw Geometry on Melting Rate
They are not as closely connected as most processors think. Here’s why.
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Understanding Roll Deflection in Sheet Processing
Because of roll deflection, sheet stacks made for PS don’t work nearly as well with PP. One solution is to try a top roll that bends in the opposite direction.
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How to Select the Right Cooling Stack for Sheet
First, remember there is no universal cooling-roll stack. And be sure to take into account the specific heat of the polymer you are processing.
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Put Science into Glass-Fiber Compounding on Single Screws
There are still companies that compound glass fibers on single screws. The process is considered an “art,” but can be made more predictable with attention to screw design, speed and length, as well the choice of mixer.
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Extrusion: Follow These Tips to Get Profile Die Design Just Right
Calculating polymer flow is fairly straightforward when designing a die for a simple round profile, but as the shapes get more complicated these calculations can get extremely challenging. Here’s what you need to consider.
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General-Purpose Screws on the Comeback?
They are being specified more often for recycling applications to increase flexibility. But there is still no such thing as a GP screw and recyclers need to consider other processing approaches.
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The Three Causes of Screw Wear
You run the risk of wasting time and money by not understanding what’s causing your screws to wear.
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Extrusion: Solving Surging in Two-Stage Screws
This usually crops up when the two stages are not matched in output. The best solution is to install a pressure-adjusting valve at the discharge end of the extruder.
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Understanding the Effect of Polymer Viscosity on Melt Temperature
Every processor should get hold of the viscosity curves for the polymers they use or contemplate using in their operations, and learn how to read them.
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Extrusion: Evaluating Screw Design for Multi-Material Recycling
Since many plastic products are made of a combination of materials with very different melting points, careful consideration must be given to designing screws when it comes time to recycle these products.
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