Materials Know How

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best practices 1 Aug 2018

A Processor's Most Important Job, Part 7: Reviewing Crystallinity

There are several process-related issues that influence crystallinity besides cooling rate. Let’s examine a few.

Materials 1 Jun 2018

A Processor's Most Important Job, Part 6: Long-Term Effects

The importance of mold temperature to the development of the desired polymer crystalline structure becomes absolutely crucial in the case of high-performance materials.

Materials Know How 27 Apr 2018

A Processor's Most Important Job, Part 5: POM Polymers

Using a mold temperature above a polymer’s Tg ensures a degree of crystallinity high enough to provide for dimensional stability, even if the part must be used at elevated temperatures. But POM is an exception. Why?

Commodity Resins 29 Mar 2018

A Processor’s Most Important Job, Part 4: Mold Temperature

Engineering polymers require higher mold temperatures to achieve their ideal structure. The temptation to turn down the mold temperatures can hurt part performance.

best practices 1 Mar 2018

A Processor’s Most Important Job, Part 3: Unintended Consequences

Processors are often expected to compensate for ill-advised decisions made earlier in the product-development process. In the case of shrinkage, one of the most common ‘fixes’ is to simply reduce the mold temperature.

best practices 23 Jan 2018

A Processor’s Most Important Job, Part 2: Crystallinity

Process conditions help determine the difference between the maximum degree of crystallinity that can be achieved in a polymer and the degree that is present in a molded part.

best practices 2 Jan 2018

A Processor’s Most Important Job, Part 1: Molecular Weight

Many processors don’t realize that preserving material characteristics is crucial to product success and failure. The focus here is on molecular weight.

scientific molding 1 Dec 2017

Materials: Cycle Time—Science vs. Rules of Thumb, Part 6

This installment—on elastomers—completes a series, whose theme is to bring more science to the discipline of molding. The overall message: Ask a lot of questions whenever someone posits this or that ‘rule of thumb’ about processing.

Materials Know How 27 Oct 2017

Materials: Cycle Time: Science vs. Rules of Thumb—Part 5

Let’s examine the behavior of semi-crystalline materials that never reach their glass-transition temperature as they cool.

Materials Know How 25 Sep 2017

Cycle Time: Science vs. Rules of Thumb—Part 4

While laboratory tests are helpful in determining how polymers behave, you must remember the fundamental differences between laboratory measurements and the real world of plastic processing. Let’s examine semi-crystalline polymers here.