Understanding the Influence of Screw Geometry on Melting Rate
They are not as closely connected as most processors think. Here’s why.
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.
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.
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.
Cast vs. Integral: Which Feed Section Is Best for You?
Here are seven factors extrusion processors should weigh to help them decide between cast feed section versus an integral extrusion feed section.
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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.
Try This Approach to Clean Up Your Recycled Material
CO2 can be used as a totally “green” solvent to remove many kinds of contamination in recycled plastics without the need for toxic solvents.
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.
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.
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.
Extrusion: 'Melt-Blown' Fiber: What You Need to Know to Enter the Face Mask Market
Coronavirus pandemic has made extrusion processors curious about entering the face-mask market. But melt-blown fiber is very different from most other extrusion processes and requires specialized equipment.
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Extrusion: The Importance of Zone 1 Barrel Temperature
Tweaking the temperature settings of the first barrel zones may not yield the desired result. In fact, they may yield the opposite. Here’s why.
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What You Should Know About Miniature Extrusion Screws
Very small screws have become more common with the growth of additive manufacturing. Designing such screws requires balancing their output requirements with their torque strength.
Extrusion: Important Polymer Melting Equations for Extrusion Processors
The more you know about what happens in a screw, the more you’ll be able to work with your supplier to optimize design.
Try This Lower-Cost Purging Method
You might be able to reduce purging times and save money by scheduling processing jobs in order of the increasing material viscosity. But to get started, you'll need shear rate/viscosity curves for your polymers.
How to Optimize Usage of Recycled Material
Processors need to “engineer” feeding properties similar to virgin pellets into their regrind to efficiently and economically utilize more of their scrap.
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EXTRUSION: Melting 101
Learn the basics on how polymer melts in a single screw. Barrel temperature plays less of a role than you might think.
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Extrusion: How Much L/D Do You Really Need?
Just like selecting the extruder size and drive combination, the L/D should be carefully evaluated.
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What You Need to Know to Get into Coextrusion
Key considerations range from determining the right extruder sizes to tooling, matching material viscosities, and lots more. Take a look.
Extruder Alignment: Important, but Only Half the Equation
The other half? Aligning and supporting downstream equipment. Here are best practices.
Understanding Viscosity in Extrusion
Both the power-law coefficient and the consistency index must be considered to calculate viscosity.