Process Trays: Gear Wash Baskets

  • Process Trays
  • Injection Molding


Molded plastic wash baskets from PolyFlex Products helped a North American auto manufacturer cut parts handling and internal shipping weights by nearly 80%, reduced part rejections from part-to-part damage during cleaning and handling operations by 50%, and lowered overall costs by up to 40% in gear cleaning operations.


Gear components are loaded from the machining cell into the containers by robotically assisted handling. The baskets are then manually loaded onto the wash system’s chain conveyor, and manually offloaded onto a flow rack for transfer to assembly points. All are stages where part damage can occur, or where the extra weight of the container can create ergonomic issues.


When manufacturers are hobbing and machining gearing and transmission components, the process typically uses large amounts of lubricants and produces volumes of chips. If not thoroughly cleaned away, this can play havoc with the finished product. The challenge is to meticulously wash the gearing components, removing all traces of metal chips and coolants, yet prevent part-to-part contact or other impacts during the procedure. The original wash baskets were heavy 7.8 lb. perforated welded stainless steel containers in two different styles to accommodate two different gear sizes. There was also the risk of part damage since the metal basket’s pockets did not restrain the gears from tipping into one another.


PolyFlex application specialists designed a new custom injection-molded tray measuring 13.2″ long x 8″ wide x 2.7″ high and weighing just 1.8 lb. The trays are molded from a special blend polyolefin, a rugged and high strength thermoplastic resin formulated to be resilient to cleansing chemicals and the high temperatures used in the gear washing process.

According to the automaker, the new custom molded trays at a quarter of the weight of the original metal trays make for easier handling, loading and unloading, and provide a 40% cost savings. They also save storage space and require less transport space when moved. Preventing contact between parts resulted in a 40 to 50% decrease in part rejections.

The PolyFlex design requires only one size custom molded tray, with supplementary molded inserts made from thermoplastic urethane, also developed to withstand chemicals and extreme temperatures. Two styles of inserts accommodate the gear variation and provide open access to all part surfaces to assure wash chemicals and flushing action penetrate all areas. The inserts are fabricated in two colors to provide easy visual identification for matching to appropriate gear selections.

The inner shape of the tray surface allows for the positioning of the cradle, and the outer shape provides a conveying surface for the wash system’s chain conveyor. The bottom has ample uniform surface to travel along the flow rack’s surface and the three separate conveying points for the chain transfer can engage without interfering with the performance of the wash process.

The automaker has enhanced its parts washing cycle for these transmission components, going lighter for greater ergonomics in handling; more precise, secure part orientation for less damage and fewer part rejections; and lower costs to improve the bottom line. All from a little bit of plastic and a lot of innovative engineering.