That's a wrap




Film dispenser gets top honors in plastics design competition.

 
 
 
 

A handle and frame for a portable stretch-film dispenser from Tyco Plastics, Minneapolis, must have impressed judges at the Society of Plastics Industry conference. They made it the Single Part winner in the Structural Plastics Div. (SPD) competition. The contest recognizes innovative designs that use plastic parts to bear loads, provide support, or enclose a product.

The Precisionrap's ABS handle and frame are made by Horizon Plastics Co. Ltd., Cobourg, Ont. Canada, using structural web molding. Structural web molding adds gas-assist to conventional structural-foam molding. Nozzles in the mold disperse gas in a network of hollow channels in thick sections to reduce part weight and boost structural integrity. The handles and frame have a Class-A surface finish comparable to injection molding but with no sink marks or swirl-patterns as is the case with classic structural foam.

An injection-molded bumper system earned the Automotive award. The "New VN" Volvo truck bumper is a three-piece assembly that will make replacement and repair easier. The injection-molded PC/ABS assembly replaces a one-piece SMC part and reportedly gives trucks better fuel-saving aerodynamics. The three-piece assembly consists of seven injection-molded parts from Mack Molding Co., Arlington, Vt. The Class-A surface requirements are met by molding show surfaces with no core side features. This eliminates surface flaws such as sink marks and flow lines. The structure is assembled using a molded bucket-type reinforcement that adhesively attaches to the show surface. Several internally mounted steel stud plates and brackets provide extra support. After the two-part adhesive cures, assemblies go in tight-tolerance master jigs. Total tolerance on the bumper width span is held to less than ±4 mm. Mack Molding Co. also took Furniture and Computer/Business honors for a gas-assist injection-molded A3 Office system and a structural-foam Creo Veris business machine.

Panels on Buell X/B9R Firebolt motorcycles raced away with Recreation & Leisure honors. According to the molder, Bemis Manufacturing Co., Sheboygan Falls, Wis., early in the design Buell Motorcycle Co., East Troy, Wis., wanted to get away from painted steel and vacuum-formed parts and go to a single molded-in color material. Parts also needed a high-gloss finish in a variety of colors with an automotivelike color depth. In addition, parts had to withstand marring, UV, impacts, and be strong enough to support a rider. An ultrahigh-gloss ionomer/nylon alloy provides scuff resistance to withstand mud and gravel. It is also resilient. It won't crack if hit by flying rocks or if kept outdoors in temperature extremes.

Bemis also took the Judge's Choice award with the Polaris MSX Personal Watercraft. According to Bemis, looks and speed now drive watercraft design. For the MSX Model, Polaris Industries Inc., Medina, Minn., replaced traditional marine materials, particularly handlaid fiberglass, in areas such as the controls, instrumentation, and storage units with a specially formulated UV-resistant polycarbonate/polyethylene terephthalate resin. The plastic withstands intense sunlight and the heat generated by the craft's high-output engine. Parts were molded using a patent-pending technology that endothermically produces foam cores in coinjection dies to make lighter and stronger parts. The new foam-core technology reportedly "lifts" sink marks on surfaces opposite ribs and bosses for better aesthetics and strength. Parts are coated with a metallic base coat and topped off with a high-gloss urethane.

Exterior trim panels for the Case IH AFX7010 Combine harvested the Agriculture/Lawn & Garden award. Twelve parts were reaction-injection molded by GI Plastek, Newburyport, Mass., using a soybean-based, high-density structural polyurethane foam. The Baydur 730S RIM from the Polyurethane Div. of Bayer Polymers LLC, Pittsburgh, lets combine designers replace steel trim parts and reduce trim weight by 25%. The soy-based material works with GI's in-mold decorating process, ProTek, to give the panels a Class A surface straight from the mold. The 19-part assembly measures 15 X 32 X 17 ft, and weighs 38,000 lb.

Other winners in the competition included Accurate Molded Plastics Inc., Coeur d' Alene, Idaho, for a soft-touch overmolded defibrillator enclosure and Envirotech Molded Products Inc., Salt Lake City, for an injection-molded aircraft canopy. For more information on the winning parts visit www.plasticparts.org.