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Flexible Automation Cell Designed for Insert Molded Plastic Gears

Plastic Injection Molding Tooling

MANCHESTER, Conn.--Earlier this year, ABA-PGT, a Manchester, Connecticut-based injection molder and mold builder specializing in plastic gears and precision motion transfer components, introduced its Flexible Automation Cell for insert molding of plastic gears. ABA-PGT designed, built, and is now operating the flexible cell, which features a 110-ton, fully electric Cincinnati Roboshot molding machine that can mold parts up to 4 inches (101mm) in diameter and up to 60 g (depending on material type) in weight in a single-cavity mold.

The Flexible Automation Cell allows a number of functions--the loading of inserts to plastic gears, the removal of delicate precision parts, and packaging--to be performed automatically with minimal capital investment by the customer. The company conceived and designed the cell for insert molding of plastic gears with annual production volumes--between 40,000 and 500,000--that aren't high enough to justify the purchase of a full-time, fully automated, independent manufacturing cell. Customers purchase end-of-arm (EOA) tooling, pallet inserts, and trays, if required, and ABA-PGT "will handle the rest," the company says.

According to ABA-PGT, manual labor is used only a few times per shift to orient and present inserts to the automation cell in ABA-PGT precision pallets. From there, a five-axis servo robot automatically loads inserts, removes parts, and palletizes the finished product, where required. The cell reportedly provides a number of advantages versus manual insert loading and parts removal, including repeatable cycle time, which results in more dimensionally stable parts with consistent material properties; reduced chance of part damage during handling; reduced chance of mold damage due to human error; and reduced cost with faster cycles and less labor.

Inside the cell, the fully-electric Cincinnati Roboshot molding machine uses a shot size of 3.42 ounces of polystyrene (PS) resin. A mold-open distance of 9 inches (228mm) or more is generally needed, and a hot-sprue bushing maximizes the mold-open distance. Two- or three-plate molds can be used, as can molds 16 inches (406mm) wide by 24 inches (609mm) tall by 17 inches (432mm) in stack height.

Molds of one or two cavities are said to generally provide optimum performance. Consideration may be given to 4-cavity tools, but a dedicated fully-automated cell may be more cost-effective at this cavitation, the company says. Various inserts, such as screw-machined shafts and stamped inserts, can be used in the cell. For shaft-style inserts, the length must be less than 3.5 inches (89mm). Also, thermoformed tray sizes of up to 14 inches (355mm) x 17 inches (432mm) can be used.

ABA-PGT comprises two divisions--ABA (Anderson, Bertsche, and Anderson) and Plastics Gearing Technology--that work together to meet customers' injection molding and mold making requirements. The ABA division, established in 1944, designs and builds injection molding dies. Plastics Gearing Technology, formed in 1969, provides precision injection-molded plastic gears and complementary motion control parts, including pulleys, bearings, and sprockets.

The company's mold making, plastic gear design and engineering, and injection molding services are used for applications in a variety of industries, including automotive, surgical instruments, electric motors, HVAC, irrigation, and architectural, building, and construction.

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