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.
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ESSENTIAL READING
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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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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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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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Latest Extrusion News And Updates
ENTEK Gets DOE Loan for Battery Separator Plant
Government loan of $1.2 billion to largely fund lithium-ion battery-separator plant using “wet process.”
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Compact Extruder for High-Output Compounding, Recycling
Sleek, flexible machine can process PET up to 6 tons per hour.
Read MoreAmcor, Berry Merge in All-Stock Deal
Move unites two complementary businesses to create a global leader in consumer packaging.
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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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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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Featured Posts
Sheet Extrusion, Thermoforming Tips for PLA/aPHA Blends
Biopolymers like PLA and PHA are able to meet sustainability goals while also delivering the performance attributes needed in rigid food packaging. Here’s what testing has shown.
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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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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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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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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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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.
Extrusion Supplier Categories
- Web Winders, Unwinds, Rewinds
- Single-screw Extruders
- Saws
- Orientation and Tentering Equipment (for Webs)
- Pipe Corrugators
- Slot Orifice Coaters
- Extruder Screens, Screen Packs, Screen Changers, Breaker Plates, Other Melt-Filtration Equipment
- Sheet Take-off Systems
- Film Take-off Systems
- Web Brakes, Clutches, Chucks
- Extrusion Dies
- Pipe Bellers
- Web Inspection Systems
- Pipe Take-off Systems
- Web Guides, Edge Detectors
- Wire and Cable Take-off Systems
- Pipe Thickness Measuring Equipment
- Roll Coaters
- Dispensing Equipment for Reactive Resin Systems
- Melt Pumps for Extrusion
- Curtain Coaters
- Profiles, Tubing, Hose Take-off Systems
- Calenders
- Cutoff Equipment
- Plastic Lumber Extrusion/Molding Systems
- Web Slitter/Rewinders
- Knife Coaters
- Film, Sheet, Coated Web Thickness Measuring Equipment
- Web Tension Controls
- Multiple-screw Extruders
- Web Cleaning Equipment
- Coextrusion Dies, Feedblocks
- Web Slitters
- Plasma Coating Systems
- Ram Extruders
- Air Knife Equipment
- Monofilament/Multifilament Take-Off Systems
- Rotary Screwless Extruders
- Pelletizers
- Solution Casting Equipment (for Film)
- Air Rings and Internal Bubble Cooling Units
- Profiles, Tubing, Wire Thickness Measuring Equipment
