ATLANTA — The increasing acceptance of gas-assist injection molding may have been the talk of the town at the annual awards competition put on by the Society of the Plastics Industry Inc.'s Structural Plastics Division.
But the winners of the two top awards — a collapsible shipping container and a plastic walker for the injured and infirm — both employed tried-and-true, low-pressure structural foam technology.
The awards represented a melting pot of 14 processing technologies, including coinjection, straight injection, and reaction injection molding. Structural foam molding was the contest's most popular technology, used in 27 percent of the 66 entries, followed by gas-assist at 19 percent, injection at 16 percent and RIM at 13 percent.
Still, what struck the judges was the big increase in gas-assist molding, said Ciro Petrucelli, president of Springfield Mold Works Inc. in Westfield, Mass., and chairman of SPD's parts recognition competition.
"You can see that more and more parts are being designed with [gas-assist] in mind. It's becoming a legitimate process," he added. "It's not a new kid on the block."
Total attendance at the conference hit 251, up from 225 last spring in Vancouver, British Columbia. The number of first-time attendees — 98 — was more than triple what division officials said is typical.
Still, attendance for the event is roughly half what it was in the early to mid-1990s. The most striking absence this year was the lack of participation by GE Plastics, a Structural Plastics Division stalwart that a decade ago used to send 25 or more people to the event. Harsh economic realities also helped keep perennial SPD participants Xerox Corp. and Eastman Kodak Co. from attending.
The winners are ...
Here's a summary of this year's winners, announced April 3 at SPD's annual conference in Atlanta:
Conference Award: The grand prize went to a collapsible, HDPE shipping container designed and made by Arca Systems in Tacoma, Wash., using low-pressure structural foam molding. MSI Mold Builders in Cedar Rapids, Iowa, built the mold. The Gemini Smooth Wall Container certainly does not look sexy — just drab gray walls and an entry form that brags about having 80 percent less surface area to clean than more conventionally designed containers with more ribs. But that simplicity is deceptive, the judges said.
"There was a hell of a lot more engineering and design that went into it," Petrucelli said.
All the reinforcing ribs and structure are inside the welded side walls, and the walls offer twice as much stiffness with no increase in size or part weight. The container has 42 different product designs, and includes some parts that are made with gas-assist molding, reducing the weight, cycle time and clamp tonnage of the press. Judges were impressed that the container used 16 tools, Petrucelli said. The product also took top honors in the Materials Handling category.
Judges' Award: This prize went to an AmbulMate walker molded by Horizon Plastics Co. Ltd. in Cobourg, Ontario, from molds made by Cardinal Tool and F.G.L. Precision Works Ltd. in Concord, Ontario. The concept originally was developed by a designer who was injured and did not like the steel walkers he was forced to use. The product uses a polypropylene homopolymer with a 10 percent glass filler, and is made with low-pressure structural foam molding, gas injection molding and traditional injection molding. The walker includes ergonomic handgrips and storage pouches, and can be folded to a depth of 5 inches for portability. The product primarily is sold in Japan. It also won top honors in the Medical & Scientific category.
Recreation & Leisure: A gas-assist injection molded canopy for a golf cart took this award. Thomson Plastics in Thomson, Ga., molded it from a 20 percent calcium-carbonate-filled copolymer of PP. Petrucelli said judges were impressed by the large-part gas-assist design, which enables it to be molded on a 2,200-ton press, compared with a 6,000-ton press that would be needed for the same part using traditional injection molding.
The part, made for the world's largest golf cart manufacturer, Club Car of Augusta, Ga., had to survive a test not quite ready for ASTM certification — the two-iron test. The first version of the canopy cracked when hit with a two-iron golf club, so Thomson had to go back and tweak the resin formulation to strengthen the canopy. It now survives that test.
Retail/Consumer Products and People's Choice: A desk for office-furniture manufacturer Herman Miller took top honors in both these categories. Horizon Plastics Co. Ltd. makes the Red Snapper desk, using a mold built by MSI Mold Builders. The product uses a mixture of ABS, copolymer PP and 40 percent glass-filled PP to be lightweight yet still support hundreds of pounds of material. The processes used were structural foam molding and structural web.
Industrial: RIM was employed to make this food-heating tower used in prisons and hospitals. OEM Aladdin Temp-Rite LLC in Nashville, Tenn., had never used RIM before but was persuaded by the lower initial tooling investment. Rimnetics Inc. in Mountain View, Calif., made the mold and did the molding. The polyurethane tower encapsulates aluminum tubing, stainless-steel rod, magnets and plates to help heat the food. Rimnetics said it delivered the first part in six weeks.
Environmental Award: Rimnetics also took top honors in this category, with a futuristic- looking product that delivers an ultraclean, Class 100 air zone to a work area or site. The machine, made for Airex Inc. in Bellevue, Wash., is designed to reduce dependence on "ballroom" type portable clean rooms in manufacturing environments. Judges again were impressed by Rimnetics' use of RIM for a large part. The product uses PU, and both the molding and mold making were done by Rimnetics.
Computer & Business Equipment: Traditional injection molding was used in this category, for a product that does something traditional to the industry: replace metal with plastics. In this case, a 16-pound, steel paper-transport system for a Lexmark printer was replaced by a 7-pound part made of a polycarbonate/ABS blend. The product was designed and molded by APW Plastics in Anaheim, Calif., from a mold by L.B. Molds in Gardena, Calif. APW also combined six parts into four, as part of a process that reduced part cost 60 percent and brought a six-month payback for Lexmark.
Building & Construction: Metal replacement again caught the judges' attention in this winner, a bathroom handrail that uses gas-assist molding but introduces a core sliding technique to get a constant thickness and good appearance. Kokujoh Kanagata Industrial Co. Ltd. in Ann Arbor, Mich., built the tool and did the molding for Naka Corp., an original equipment manufacturer. The long shape requires a long cycle time with conventional injection molding.
Appliances: Cost savings and replacement of traditional materials — in this case thermosets — were noted in this winner, an oven handle for GE Appliance in Louisville, Ky. Mack Molding Co. in Inman, S.C., used gas-assist molding to achieve the cosmetic and performance requirements. The mold was made by Delta Mold Inc. in Charlotte, N.C. The product uses 15 percent glass-reinforced polybutylene terephthalate.
Transportation: Detroit-based General Motors Corp. took home the prize for its GMT-800 pickup box, which will hit the road this year on the Chevrolet Silverado. It is the first full-size composite pickup box in production and represents both a new, large-scale program for RIM and some teamwork between competitors. Bayer Corp. supplies the structural RIM material used inside the box, while Dow Chemical Co. provides the urethane in the reinforced RIM fenders and outer panels. Likewise, Meridian Automotive Systems of Dearborn, Mich., and Budd Co.'s plastics division of Troy, Mich., split responsibility on molding the complete system. The pickup box stands up longer than steel, and resists dents and corrosion, yet comes in 15 pounds lighter.
Lawn & Garden: GI Plastek developed a proprietary, in-mold painting system to supply Deere & Co. with composite parts complete with a Class A finished surface. Now GI Plastek is using that ProTek system to make the 70-pound rear wall using RIM for a John Deere combine.
The in-mold decoration comes in at half the price of using a traditional paint shop, said Phil Cashen, commercial manager at GI's Aurora, Ill., facility. Using RIM technology also gives the tractor maker some leeway in adjusting future engine size without investing in an extensive retooling process, said Greg McCunn, supply management engineer-composites for John Deere Harvester product development.
Best Single Part: Bemis Manufacturing Co. of Sheboygan Falls, Wis., invested in a Milacron triple-barrel, coinjection press to produce an all-polyolefin steering wheel for the John Deere SST lawn tractor. The four-cavity mold has two stations with two cavities at each station and a mold produced by Triangle Tool of Milwaukee. Bemis uses coinjection to mold the base wheel, with a PP core produced with a blowing agent, then covers it with a custom blend of PP and glass-filled PP. At the second station, a third barrel comes in to overmold with Deere's green custom polyolefin detail.
Staff reporter Rhoda Miel contributed to this story.