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Volume One, Number Nine
Nov. 25, 2003
Rotomolding fans - this issue offers new information to help design engineers, product managers and others use plastics. Email me with questions and comments. If you need to leave the newsletter, see the end for instructions.
Now boldly mold!
For more information, contact Meese Orbitron Dunne Co., American Rotational Molding Group; 16404 Knott Ave., La Mirada, CA 90638; Phone: 888.724.1228; Fax: 877.904.1670; www.modroto.com.
YOU, TOO, CAN DESIGN FOR ROTOMOLDING
#2 In A Series
If you're selecting a material to rotomold parts or products that need to withstand cold temperatures without deforming, cracking or becoming brittle then you'll need to consider:
- How long the part will be exposed: continuously or intermittently?
- The temperature: fairly constant or fluctuating?
- How long the part needs to last: the winter or the decade?
- Thickness of the part
Cross-linked polyethylene (PE), linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) all excel in cold temperatures and withstand impacts without cracking or shattering better than many materials. Using data from the Association of Rotational Molders Low Temperature Impact Test, all three materials support approximately 60 ft.-lbs. on a .125-inch thick part at 40 degrees below zero C before becoming brittle. Now double the thickness to .250 inches and the HDPE part delivers triple the impact strength, a greater percentage increase than the other materials.
But wait. There's more to it than just specifying HDPE. Designers also need to consider whether the part needs UV resistance, fire resistance or colorants. Each additive blended into the resin weakens the resin's ability to withstand the cold, along with its impact strength.
And quality control becomes even more important. In severe cold, minor surface flaws, failure to meet wall thickness tolerances and poor handling of secondary operations, for example, could become major problems. Our quality assurance policies and procedures are compliant with NQA-1 and ISO 9002 principles.
For details on quality assurance in rotomolding, see here
Tell us about your hot cold temperature project and get a free estimate at http://www.modroto.com/cgi-bin/request or call 800.772.7659.
DESIGNERS GIVING COLD SHOULDER TO METAL
Now that rotomolded plastics deliver comparable strength to metal in cold applications along with chemical and rust resistance, knowledgeable designers are replacing metal components with plastic in:
- Underground fuel cells - Ice machines - Rotary lift reservoirs
In fact, MOD recently earned the NSF Certification Mark for food equipment from the independent, not-for-profit public health and safety organization NSF International for a plastic part used in ice machines. It earned certification under Standard 012 for Automatic Ice Making Equipment and Standard 025 for Vending Machines for Food and Beverages. Not only does it resist attack from chlorine, iron and other water-borne elements, but it also withstands the industrial strength chemicals used to clean the liner and machinery.
Plus, your tongue won't stick to plastic if anyone "double dog dare's you" to test it.
For more on converting metal to rotomolded plastic, see here or call 800.772.7659.
For a free brochure, call 800.772.7659 or go to http://www.modroto.com/cgi-bin/request.
Adventures In Rotomolding is published by Meese Orbitron Dunne Co., Saddle Brook, NJ, http://www.modroto.com; 800.829.3230. Copyright 2003 Meese, Inc. May not be reprinted without permission. Please feel free to pass along to other engineers and colleagues.
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