Materials Know How
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.
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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.
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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.
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Materials—Cycle Time: Science vs. Rules of Thumb—Part 3
To properly calculate cycle time, you need to understand how the modulus of a polymer increases as it cools in the mold.
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Materials: Cycle Time: Science vs. Rules of Thumb—Part 2
Understanding cooling—how a given material develops modulus as it solidifies—requires access to data that provides some insight into the relationship between modulus and temperature. Dynamic mechanical analysis is a helpful tool.
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Cycle Time: Science vs. Rules of Thumb, Part 1
What temperature must the polymer reach so the part can be ejected from the mold? Here, more than for any other variable, ‘rules of thumb’ unfortunately prevail.
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The Need for Generalists: Part 4
Solving problems generally requires distinguishing good samples from bad ones. But that can become clumsy when one person runs the test while another analyzes the data.
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The Need for Generalists: Part 3
In failure analysis, there is a tendency to gravitate to a few common test protocols. But this approach can result in a mismatch of techniques to the problem.
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The Need for Generalists, Part 2
Problem-solving requires a team that combines people having academic credentials with others who have hands-on experience.
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Plastics Technology’s Most Popular Know How Columns in 2016
Temperature, pressure and time ultimately dictate plastics processing so it’s not surprising that Know How columns from industry experts on these topics are consistently among the most popular on our site.
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