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Molded plastic wash baskets help automaker cut weights by nearly 80%, reduce rejections by 50%, and lowers costs by up to 40% in gear cleaning operations.

06/01/08

Molded plastic wash baskets help automaker cut weights by nearly 80%, reduce rejections by 50%, and lowers costs by up to 40% in gear cleaning operations.

This case history about automaker comes courtesy of PolyFlex Products. It has been selected and edited by the MHM editorial staff for clarity, content and style.

When manufacturers are hobbing and machining drive train gearing and transmission components, the process typically uses large amounts of lubricants and produces volumes amounts of chips. If not thoroughly cleaned away, this can play havoc with the finished product. Noise, excessive wear, premature failure and improper operation may result if even the smallest shards or degraded fluids are allowed to contaminate the parts. Then too, gears have a multitude of sharp edges and surfaces where the slightest ding or impingement could also create quality problems. The challenge is to meticulously wash the gearing components, removing all traces of metal chips and coolants, yet preventing part-to-part contact or other impacts during the vigorous procedure. For one North American automaker, though, much of its cleansing task and concerns have been eased with the implementation of a series of new molded plastic dunnage trays and inserts used into its parts wash cycle.

Prior to incorporating the new trays into the process, the original wash baskets used were perforated welded stainless steel containers. They were heavy, weighing in at over 7.8 lb. and measured 12.9" long x 9" wide x 5.1" high and two different styles of baskets were required to accommodate two different gear sizes. There was also the very real risk of part damage in the metal baskets as their formed pockets did not restrain the gears from lateral movement or from tipping into one another.

Exacerbating the problems encountered by the use of the metal baskets was the fact that the gear components are loaded from the machining cell into the containers by robotically assisted handling, then the baskets (and parts) are 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 could occur, or where the extra weight of the container could create ergonomic issues.

After reviewing the process and its problems, the applications specialists at PolyFlex Products, Inc. (Livonia, MI)  proposed their solution...a new custom tray design.  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. The resin was formulated to be resilient to both the cleansing chemicals and the high temperatures used in the gear washing process.

According to the automaker’s processing staff, the new custom molded trays, as compared to the previously used perforated metal baskets, weigh approximately one fourth the weight for easier handling, loading and unloading, and provide a 40% cost savings. The new units, when empty, also save storage space and require less transport space when moved. In addition, the custom molded trays are better equipped to prevent contact between parts and have resulted in a 40 to 50% decrease in part rejections due to dinged or scratched surfaces. And these results are in part thanks to PolyFlex Products, Inc.,  designer and manufacturer of custom material handling containers and dunnage systems. PolyFlex engineers worked with the automaker to devise the economical and efficient handling solution that has made the washing procedure for the gear components more ergonomic for the operators, more protective for the parts, and at substantial cost reductions for both the trays and for repair and salvage work.

The PolyFlex design requires only one size custom molded tray, with supplementary molded inserts made from thermoplastic urethane, also developed to withstand severe chemicals and extreme temperatures. There are two styles of inserts to accommodate the gear variations, and each insert cradle is precision molded with form and contour accuracy that allows the system to hold the gear secure and upright in its nested position—without tipping or leaning into other parts. Though the gears are held securely, the inserts provide open access to all part surfaces to assure wash chemicals and flushing action penetrate to all areas. The inserts are fabricated in two colors to provide easy visual identification for matching to appropriate gear selections.

The other element of the tray design that PolyFlex engineers addressed was the design of the bottom of the trays. The bottom, inner shape of the tray surface has to first, allow for the positioning of the cradle and gear. Second, the outer shape has to provide a conveying surface for the wash system’s chain conveyor. Third, the bottom needs ample uniform surface to travel along the flow rack’s surface. The development team was able to incorporate three separate conveying points for which the chain transfer can engage while not interfering with the performance of the wash process or the movement along the flow rack.

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.

PolyFlex Products engineers and manufactures plastic, urethane and rubber solutions for material handling and manufacturing process applications. Products include custom returnable part handling containers, protective shipping containers, plus custom and standard dunnage systems for containers and steel rack units. Offered are design, prototype, tooling and production services that include cast solid elastomer urethane, foamed urethane, thermoplastic injection, thermoset molding of rubber and urethane, and structural foam/low pressure injection to answer virtually any material handling and part protection challenge.