Plastics Extrusion

Extrusion is a continuous process through which parts of a fixed cross-sectional profile are made. Material is fed through a hopper into an extruder, essentially a rotating screw surrounded by a heated barrel, where it is mixed, melted and pumped through a die. The die gives the part its shape. Types include film extrusion, sheet extrusion, pipe, profile and tubing extrusion.

Novel Profile Cooling Technology Promises Big Output Boost
Pipe, Profile & Tubing Extrusion

Novel Profile Cooling Technology Promises Big Output Boost

Aimed at complex profiles such as PVC lineals, retrofittable system adds turbulent cooling to calibrator to boost output by 25-50%.  

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ESSENTIAL READING

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Postindustrial

Shredding Thin Film: How to Do It Right

While many processors recoil at this task, a little know-how in shredding equipment, processing, and maintenance should add the necessary confidence.

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What You Need to Know About Melt-Temperature Measurement in Single-Screw Extruders

Measuring the discharge temperature is not so simple, especially when using thermocouples positioned in the transfer line just upstream of the die.

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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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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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best practices

What to Know About Your Materials When Choosing a Feeder

Feeder performance is crucial to operating extrusion and compounding lines. And consistent, reliable feeding depends in large part on selecting a feeder compatible with the materials and additives you intend to process. Follow these tips to analyze your feeder requirements.

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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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Latest Extrusion News And Updates

Compounding

Nordson, Fimic Announce 'Enhanced' Partnership

Details of partnership to be divulged at K 2025.  

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Extrusion

Maag to Buy Sikora

Complementary products to deepen companies’ “joint value proposition and integration with OEM partners and end customers.”  

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Recycling

No-Dry Twin Screw Extruder Series Can Handle Multiple Resins

Machine can process a variety of virgin, postconsumer, postindustrial resins and flake without first having to crystallize, dry or change screws.  

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dies

Extrusion Veteran Scuralli Starts Sales Rep Firm

Former owner of Wayne Machine & Die to represent suppliers of extrusion systems and components.  

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Extrusion

Extruder Drives, Motors Ease Switch from DC to AC

Advances bring extruder drives and motors closer to Industry 4.0 technology.  

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Novel Extruder Takes Unique Approach to Feeding, Melting

MixFlow extruder relies on conductive heating to melt plastics, upending conventional wisdom on how plastics melt inside conventional screw extruders.

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Blending & Dosing

Featured Posts

sustainability

Shredding Thin Film: How to Do It Right

While many processors recoil at this task, a little know-how in shredding equipment, processing, and maintenance should add the necessary confidence.

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polyolefins

How Compression Ratio Impacts Extruder Performance

Let’s investigate how compression ratio affects performance of an extruder processing LLDPE.  

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A Processor's Guide to Making World-Class Multilumen Tubing

Process innovation is pushing catheter design to the limit. Here are Lubrizol’s tricks of the trade.

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Sheet Extrusion

New System Utilizes EMF Technology to Measure Sheet Thickness, Temperature

An altogether different approach to in-line measurement is said to provide direct thickness measurement, is impervious to material density changes, installs quickly and does so without radiation.  

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Film Extrusion

Use a Process Assessment to Determine the Benefits of Screw-Design Modification

This type of analysis analysis will provide the converter with a clear picture of whether changes to the screw could provide economic gains through increased rate, yield, and quality.   

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Automated Die, Feedblock System Improves Efficiencies at Cast Film Processor

Reifenhäuser's PAM automation systems helps Bogucki Folie reduce waste at startup while slashing time between changeovers.  

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FAQ: Extrusion

However, there are actual limits on increasing output as L/D is increased. Usually these limits are due to the inability of the feed section to deliver more polymer. On smaller-diameter screws, that limit often is determined by screw strength. On small screws you can only go so deep in screw channels before the screw is over torqued and fails. On larger extruders, the efficiency of feeding decreases as the channels get deeper until there is no further increase in output.

There are four main things to consider in selecting the correct stack for your application: the overall cooling capacity, the products to be processed, the mechanical capability, and the rolls’ internal design. Considering just the cooling capacity, the top roll is there to set the sheet thickness as well as its uniformity.

One of the most useful evaluations is the relatively simple calculation of drag flow. Drag flow is simply half the volume of one turn of the metering section per second at a specific screw rpm, which, when multiplied by a units conversion and the melt specific gravity of the polymer, is a very accurate approximation of the output in lb/hr at no head pressure.

Process Cooling