Tag: drnick
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Ask Dr. Nick: Will Your Sieve Shaker Affect ARM Particle Size Test Results?
Question: Can a vibratory sieve shaker be used in place of a rotary and tapping device when running the ARM Test Method for Particle Size of Rotational Molded Powders? The test method sprecifies devices that impart a rotary motion and tapping action, such as devices from WS Tyler. Would a device like the Gilson SS-10…
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Spare Parts: A Remarkably Unexciting Way to Avoid Downtime
I was recently sent an article by Comtherm, the UK-based company that rebuilt the burner train on my gas-fired machine. They manufacture large industrial gas burners for a wide variety of industries, including rotational molding. Although the article is written from a UK perspective, I believe the substance is highly relevant to all rotomolders. The…
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Ask Dr. Nick: What’s in Rotomolding Fumes? And How to Handle a “Smoker”?
Recently I had an extended correspondence with a rotomolder and I’ve included the whole email string, because it raises some common issues. For context, this operation houses rotomolding and injection molding within the same building. Question: We use polyethylene in our rotomolding process. Occasionally, we have a mold failure which results in some product leaking…
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Preventing Yellowing in Rotomolded Parts
During our What’s Your Problem troubleshooting session last week, we discussed why some parts turn yellow when no one expects it. An attendee shared a helpful ARM paper, “Why Did My Product Turn Yellow and Other Questions You Should Never Need to Ask,” presented by Thomas Steele in 2000. The ideas in it remain useful,…
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Dr. Nick Henwood Shares Research on Degradation and Blending in Rotomolding
At the begininng of June, I presented ARM’s Materials Deep Dive seminar for the first time. The format encouraged a lot of open discussion between me and the attendees, which is exactly how these things should go. At one point, the conversation turned to degradation and polymer blending, both of which have been key areas…
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Materials Deep Dive with Industry Expert Nick Henwood
ARM Technical Director Nick Henwood will host a Materials Deep Dive seminar on Tuesday, June 3, in Rolling Meadows, IL. Register here. This seminar will focus on the polymers used in rotomolding, giving attendees an in-depth understanding of the what, how, and why of material selection. Topics include polyethylene and its variants, alternative materials, polymer…
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Ask Dr. Nick: Why Am I Observing Brittle Failures in LLDPE Parts?
Question: I’ve been using the Low Temperature Impact Test to evaluate our LLDPE cooked parts and consistently observing brittle failures. I suspect LLDPE might not be suitable for this test, but I lack supporting data. I’m reaching out to determine if LLDPE is the issue, prompting a material switch, or if our cooking parameters require…
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Ask Dr. Nick: Any Suggestions for an Overheating Hoist?
Question: We are having issues with overheating Hoist. We are using a 2ton electric 208~230V, temperature in the area will reach to 110-125. Any suggestions? Dr. Nick: I’ll try to give you some immediate pointers, but you probably need to approach a specialist hoist manufacturer before you implement any major alterations. Anyone who has ever…
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Ask Dr. Nick: Bleed-Out of Pigment
Question: We are having issues with bleeding/leeching of our dye/powder blend. We have run temperature tests and time tests to see if this would make a difference and only saw small changes to the bleeding. I am wondering if anyone has a solution? Dr. Nick: Your first port of call really needs to be with…
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Ask Dr. Nick: Ignition Properties of Rotomolding Powders
Question: Has anyone ever tested the roto powders for ignition properties? Will rotomolding powders ignite and if so, under what conditions? Dr. Nick: I’m not aware of any formal data on the ignition potential of rotomolding powders available in the public record. However, there should be no doubt that, under certain conditions, the materials we…