Jim Frankland

Jim Frankland President

Extruding PCR? Consider a Vented Extruder

You’ll need two-stage screws to extract volatiles that post-consumer reclaim will likely contain. Screw design can be a complex balancing act. Here’s what you need to know.

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The Importance of Viscosity in Melting

The calculations required to determine the right melt temperature for each polymer are complicated. Knowing the power-law coefficient and the consistency index of the polymer you run might prove useful.  

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Extrusion

Why Are There No 'Universal' Screws for All Polymers?

There’s a simple answer: Because all plastics are not the same. 

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Understanding Melting in Single-Screw Extruders

You can better visualize the melting process by “flipping” the observation point so the barrel appears to be turning clockwise around a stationary screw.

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Minimize Sheet Gauge Variation by Roll Design

‘Hour-glass’ sheet gauge can be avoided through a reverse-bending roll design that is out of patent and freely available.

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Extrusion

Considering Scaling Up for More Output? Follow These Tips

Keep these calculations handy when you are trying to decide whether a bigger extruder will get you the output you need.

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The Importance of Specific Heat in Screw and Extruder Design

If you ever have to size an extruder drive, knowing the specific heat of the polymer can help you to determine the capability of your equipment.  

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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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Sheet Extrusion

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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Extrusion

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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dies

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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Plastics Size Reduction
Process Cooling