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.

LG, Reifenhauser Combine on MDO Push
Film Extrusion

LG, Reifenhauser Combine on MDO Push

Resin and machinery companies also aim to look for further downgauging opportunities.  

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ESSENTIAL READING

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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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Extrusion

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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Film Extrusion

Follow These Tips to Fire Up Your Cold Blown Film Line

Firing up a cold blown-film line after a shutdown involves multiple pieces of equipment that all interact. Here’s a look at those components individually and some best practices on how to get your line up and running as quickly and safely as possible.

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How to Select the Right Tooling for Pipe Extrusion

In pipe extrusion, selecting or building a complementary set of tooling often poses challenges due to a range of qualitative factors. Here’s some guidance to help you out.  

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Latest Extrusion News And Updates

Elastomers

Ether-Based TPUs for Broad Range of Industry Applications

BASF’s Elastollan 1400 TPU series can be used for applications ranging from railway pads, hoses and profiles to show soles.

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Extrusion

2025 Extrusion Conference Shifts to Standalone Event in Boston

The annual technical conference organized by Plastics Technology magazine was scheduled to co-locate with the PTXPO trade show next March. Both events will now occur independently.

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‘Revolutionary’ Extrudable PPS for Sustainable Piping

Syensqo’s Ryton PPS XE-5000NA boasts exceptional chemical and permeation resistance.

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Insight Polymers & Compounding Unveils New Conductive Products Line

The new conductive products line will also be produced for injection molding and extrusion.

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Film Extrusion

New Owners for Alpha Marathon

After bankruptcy, new group purchases intellectual property and forms Alpha Marathon Film Extrusion Technologies.  

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Compounding

PCE Adding Space to Help European Suppliers Enter US Market

‘Nesting strategy’ aims to provide established European companies with economical entry to U.S. market.  

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Featured Posts

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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Testing

Using a Melt Flow Indexer to Test Your Pressure Transducer

The MFI tester enables collection of meaningful pressure data in transducers in a relatively short time, providing realistic measures of the response time of a pressure transducer. This information is critical in the interpretation of pressure data measured in an extrusion process.  

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New Screw Boosts Mixing, Enhances Polymer Properties

Device mixes at the ‘molecular level,’ inventor says, to boost mechanicals and in some cases make pre-drying redundant.

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processor's edge

Leading Cast Film Processor Adding Blown Film Capacity

Malpack adds two multilayer blown film lines for agricultural, stretch hood and shrink films.  

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Extrusion

What's Restricting My Output Rate?

In a single-screw extruder, it could be an improperly designed barrier flighted entry section. Here’s why.    

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Materials Suppliers Team on PFAS-Free Solutions

Baerlocher PFAS-fee process aid passes muster in resin manufacturer’s testing on production-sized blown film line.

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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.

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