Extrusion Know How
Extrusion: Where's the Data? The Importance of Melt Strength in Extrusion
All extrusion processes depend to some degree on the melt strength of the polymer, and this property is generally a no-show on data sheets.
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The Cause of Catastrophic Screw Wear
Erratic feeding can be the culprit. This is not uncommon when dealing with recycled material.
Read MoreThe Limits Of Compression Ratio
Don't rely just on this value during the screw design process.
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Cooling Tips for Crystalline Polymers
If a little cooling is good, is a lot of cooling better?
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The Evolving Barrier Screw
There has been a gradual transition from the earlier Maillefer designs used in Europe to the Dray/Lawrence design using the parallel barrier design with an increased helix angle to accommodate wider channels.
Read MoreWhy I Still Like Analog Meters
They may not look as slick as their digital cousins, but I find them more helpful in identifying and troubleshooting extrusion problems.
Read MoreScrew Design Is a Matter of Balance
In order to achieve a balance between feeding, melting, and pumping it’s necessary to use proven calculations and/or tested empirical data in the design of each section.
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What Output Should You Expect?
You can get a rough estimate of the potential output if you know the drive horsepower of your machine and the thermal characteristics of one of the materials you’ll be running.
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New Frontier for Single Screw R&D: Mixing & Melting by Extensional Shear
Extensional shear generally has been associated only with twin-screw extruders. However, I am now convinced it can be done with a single moving force (screw) by changing the geometry of the flow field perpendicular to the direction of flow.
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The Power-Law Coefficient
By referring to the power-law coefficient, the effect of barrel override in the metering section of many screws can be explained and anticipated.
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