best practices
Fundamentals of Polyethylene – Part 6: PE Performance
Don’t assume you know everything there is to know about PE because it’s been around so long. Here is yet another example of how the performance of PE is influenced by molecular weight and density.
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Fundamentals of Polyethylene – Part 5: Metallocenes
How the development of new catalysts—notably metallocenes—paved the way for the development of material grades never before possible.
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Polyethylene Fundamentals – Part 4: Failed HDPE Case Study
Injection molders of small fuel tanks learned the hard way that a very small difference in density — 0.6% — could make a large difference in PE stress-crack resistance.
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Fundamentals of Polyethylene – Part 3: Field Failures
Polyethylene parts can fail when an inappropriate density is selected. Let’s look at some examples and examine what happened and why.
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Understanding the Effect of Pressure Losses on Injection Molded Parts
The compressibility of plastics as a class of materials means the pressure punched into the machine control and the pressure the melt experiences at the end of fill within the mold will be very different. What does this difference mean for process consistency and part quality?
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Improve Production Rates Via Screw Design — Barrier vs. General Purpose vs. Melt Uniformity
I’m looking for a few good molders to help trial a new screw design, and share data and results for a future article to prove the benefits of a melt uniformity screw.
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APR Expands Design Guide for Plastics Recyclability With Polypropylene Categories
Six new packaging categories will be eligible for third-party validation of compatibility with North American recycling programs.
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Avoiding Common Cosmetic Defects in Molded Parts
Identify familiar flaws and then work to eliminate them with these mold and part design tips, and process considerations.
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Is There a More Accurate Means to Calculate Tonnage?
Molders have long used the projected area of the parts and runner to guesstimate how much tonnage is required to mold a part without flash, but there’s a more precise methodology.
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Where and How to Vent Injection Molds: Part 3
Questioning several “rules of thumb” about venting injection molds.
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