Extrusion Know How
The 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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Mission (Nearly) Impossible: Estimating Extrusion Melt Temperature
Extrusion processors often ask screw designers to estimate the output and melt temperature of a new design in the works. Projected output of a new screw can usually be estimated fairly accurately. Melt-temperature estimate, however, is another story
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Get Smarter on Extruder Sizes
Processors tend to recommend a much larger extruder than what’s really necessary for the job and the capabilities of the downstream equipment.
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