Tag: drnick
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What causes oven fires and how to respond
A rotomolder member of ARM asked about recommended actions in relation to fires in rotomolding ovens. These fires are typically caused by powder spilling out of a mold during the cooking process. This can be due to: Incorrectly closed clamps, or clamps that fail, causing the mold to open as it rotates A missing vent…
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Will future rotomolders be gas-free?
As a representative of ARM, I was recently asked in a discussion with some other ARMO groups about whether electromagnetic induction heating could be suitable for rotomolding. The issue was raised because of how the Emissions Reduction Plan of New Zealand may limit rotomolders’ ability to use gas to power their rotomolding machines. Today there…
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What constitutes ADEQUATE venting?
When I train machine operators, I tell them that, most likely, venting problems are the biggest cause of scrap parts they will come across. This statement was originally based on a survey conducted by the ARM many years ago. After 30 years in this business, the statement still holds true, as far as I’m concerned.…
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Ask Dr. Nick
Technical Director Nick Henwood’s Ask Dr. Nick series allows ARM a way to share his feedback on interesting technical questions we receive at ARM. Here’s a handy list of the ten posts we’ve published so far. Avoiding “Angel Hairs” Can I fix gaps in a parting line? Foam in Rotational Molding How does cold weather…
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Long-term properties of roto materials: Should I worry?
ARM recently held its Annual Meeting as a virtual event and this new format seemed to be a great success. Obviously, we all missed the normal human contact; the chance to meet contacts, former colleagues and friends, in person. However, as a way of presenting information and opening up discussion, the on-line format certainly seemed…
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A designer’s questions on rotomolding properties
Recently ARM presented Class 5 of its Design Webinar Series, which was focused on material properties, as they relate to product design. The webinar consisted of an initial presentation by ARM’s Technical Director Dr Nick Henwood, followed by a series of questions from Michael Paloian of Integrated Design Systems, the regular presenter of the Design…
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Rotomolding Schematic and Automation Results
We shared this schematic of the rotational molding process (drawn by ARM Technical Director Nick Henwood and spruced up by Anthony Kozelka of Quantum Polymers) with our members last week. We asked them which part of the process they saw the most opportunity in automating. See the responses below and let us know your opinion…
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ARM Leak Testing Summary
On Thursday April 30, 2020 ARM held a discussion on Leak Testing, moderated by Education Committee Chairman Ron Cooke (ExxonMobil) and Sandy Scaccia (Norstar Aluminum Molds). The session was very well attended and the discussion between everyone on the call was excellent. There was so much useful information exchanged that we decided to try to…
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Ask Dr. Nick: What’s the difference between hexene and butene?
Question: I have been discussing rotomolding resin made from butene versus hexene and have received mixed feedback. Is there a real difference between the two and are there applications where one is preferred over the other? Or is it just a question of price and availability, when it comes to using prime material in natural…
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Ask Dr. Nick: XLPE v. PE heating and cooling cycles
Question: What are typical heating cooling cycles compared between XLPE and PE? Dr. Nick: Crosslinkable polyethylene (XLPE) rotomolding grades work in a different way to standard linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) grades. During the cook stage of rotomolding standard PE grades, two separate things need to be achieved: Sintering – ensuring…