Know-How

Understanding Postmold Shrinkage — Why Do Part Dimensions Change Over Time? — Part 1
Injection Know How

Understanding Postmold Shrinkage — Why Do Part Dimensions Change Over Time? — Part 1

What role does the glass transition temperature (Tg) of a polymer play in whether a molded part will continue to shrink after it’s molded?

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Extrusion

Let's Take a Deeper Dive on Compression Ratio for Single-Screw Extruders

Two real-world processes illustrate the importance of compression ratio.  

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Polymer Showdown — POM vs. POK — May the Best Material Win!

Third in a series, an expert from plastics engineering consultancy The Madison Group pits leading thermoplastics against each other to see how they differ in processing characteristics, chemical resistance, thermal and mechanical performance and more.

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When Injection Molding Simulation Can Be a Great Troubleshooting Tool

Injection molding simulation can serve as a powerful tool not just for design but also for ongoing production optimization.

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Extrusion

How Compression Ratio Impacts Extruder Performance

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

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Materials

Polymer Science for Those Who Work With Plastics: Why Entanglements — Not Just Molecular Weight — Drive Plastic Performance

Ever try running your fingers through tangled hair? Yeah … that’s not fun, but that’s what happens at the molecular level when polymer chains reach the right length. They wrap around each other, intertwine and … get stuck — and those tangles are the real reason plastics perform the way they do.

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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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Latest Know-How News And Updates

Solving Issues with Gloss

Your problem may be related to tooling, material, processing, or combinations thereof. Here’s how to find the root cause.

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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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Featured Posts

Polymer Showdown — PPO vs. PA66: May the Best Material Win

Second in a series, an expert from plastics engineering consultancy The Madison Group pits leading thermoplastics against each other to see how they differ in processing characteristics, chemical resistance, thermal and mechanical performance, and more.

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Screw Bounce — What Causes It and Why You Should Care

There are a lot of theories about screw bounce in injection molding it, but what’s the actual cause? Through a series of experiments, and some good old-fashioned math, the author found out.

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Moving Beyond the Relative Viscosity Curve — Determining Optimum Plastic Flow Rates: Part 1

Should injection molders consider using a range of plastic flow rates, versus the selection of one plastic flow rate from the relative viscosity curve?

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Extrusion

How To Identify Resin Degradation in Single-Screw Extruders

Degradation can occur in many single-screw extrusion operations, and typically occurs due to minor design flaws in the screw. Here is how to track it down.  

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Bulk, Solid and Melt Density: How to Calculate These Values and Why They Matter — Part 2 of 2

Understanding and calculating solid density and melt density will help molders with everything from material and machine selection to determining piece part costs.

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Compounding

Optimizing Melt-Fed Single-Screw Extruders on Compounding Lines

The main problem with melt-fed extruders that are starve-fed is setting the depth of the metering channel. In this scenario, we describe how this problem was solved.  

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