Centro Inc. won top honors for a John Deere tractor roof during a competition for rotational molded parts at the Association of Rotational Molders' annual meeting, held in Minneapolis from Jan. 27-29.
Centro, of North Liberty, Iowa, uses a drop-box foam technology, which produces a structural tractor roof with several air-duct chambers molded inside the part. The roof provides all mounting points needed to assemble a complete heating and air-conditioning system, including heater lines, evaporator and heater cores, wire harnesses, air blowers and air filters. The foam layer on the inside of the part ensures the air plenums are sealed, a key to the system.
The foam also provides structural integrity for the roof, plus thermal and acoustical insulation.
Centro used two drop boxes, eight draw pins, a rapid-fill hopper and 63 molded-in inserts. The part went into production in March 2001. The resin for both the skin and the foam inner wall is linear low density polyethylene.
Centro mounts a thermoformed cap to the roof, giving it a Class A colored surface.
Other ARM awards include:
Conversion Award. Meese Orbitron Dunne Co., of Saddle Brook, N.J., won for a golf merchandising cart, which had been metal. The rotomolded version consists of five LLDPE parts. The wheeled cart features a sliding top panel that provides security for the clubs, an integrated door and work surface and a storage area. Meese has been molding the car since last October.
PVC Award. A detailed statue of a cowboy roped this award for Dutchland Plastics Corp. of Oostburg, Wis. Dutchland rotomolds the PVC skin, then fills the cowboy with a combination of cement and urethane foam before decorating it. Daven Claerbout, sales director, described the statue as ``a great example of how PVC can be used to highlight very detailed areas.'' The part has several thin-wall sections, including the hat brim and saddle, that mold as a solid piece. Undercuts make the cowboy difficult to remove from the two-piece mold.
Large Product. The award went to a four-seater peddle boat called the Encore, molded by Nauticraft Corp. of Muskegon, Mich. The boat is a single rotomolded piece. Two suppliers submitted the boat - the Rotational Molding Division of Chroma Corp. in McHenry, Ill., and Lakeland Mold Co. of Brainerd, Minn. ``Pre-colored melt compounded LLDPE micropellets were used because they provide superior flow characteristics to help reduce the problem of filling intricate sections,'' said Stuart Lipsteuer, director of sales and marketing at Chroma. Lakeland used the split-ram process of sand casting to build the big mold, which weighed about 1,500 pounds.
Recycled Product. Formed Plastics Inc. of Carle Place, N.Y., grabbed the award for its ball-return system for a pool table, dubbed the Billard Table Ball Return Subway. The part is made from 100 percent recycled polyethylene, colored black. The series of tracks is rotational molded in two pieces and assembled. Formed Plastics trims the part on a five-axis, computer numerically controlled router.
ARM, based in Oak Brook, Ill., said the next parts competition will be held Oct. 6-9 at Rotoplas '02 in Toronto.
