Tag: drnick
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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…
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“The Seven Stages of Rotomolding” Questions and Comments
As part of ARM’s on-going commitment to member service, we are ramping up our webinar program for 2020. The latest webinar was presented on March 19 by Dr Gareth McDowell of 493K. I thoroughly recommend that, if you missed the live show, you catch up with it on the ARM website. Many of you will be…
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Ask Dr. Nick: Warpage in a polypropylene tank
Question: In a cylindrical tank made of PP powder, we have experienced a problem of warpage (internal and external waves). I wonder if you could give me your technical opinion. The inside part of the mold is welded with an additional metal stripe and in this part of the mold we are facing warpage in…
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Ask Dr. Nick: A Basic Review of Foam in Rotational Molding
ARM often receives questions about the foaming process as it relates to rotomolded parts and we thought a basic review might be useful. A number of different foam products have been used in conjunction with rotomolded articles, in order to impart enhanced properties. These include: Polyurethane (PU) Foam, injected into a cavity in the final…