Michigan manufacturer protects precision parts

Modern Machine Shop, March, 1994

Services like in-house anodizing to protect soft aluminum alloy components, parts washing, and, since grinding is often the final process, packaging of parts. ACRA Grinding Company of Sterling Heights, MI, is taking that extra measure of precaution, such as a parts handling system from Panel Controls Corporation (PCC) of Detroit, MI. The system protects ground surfaces--providing quality and care to ACRA's customers.

A case in point involved a series of hydraulic valves for transmissions. "When we were awarded the contract to provide complete sleeves and spool valves that were washed, anodized, and packaged, we immediately took steps to make sure the job would be done right," says Jim Lindsay, president and CEO of ACRA. "One step included an approximate $1,000,000 investment in new grinders, and environmentally compatible, state-of-the-art parts cleaning equipment. Little did we realize that, even with all of that new technology, a key element of our success, or failure, would hinge upon our creating a parts handling system to protect the valves from nicks and gouges."

The problem was quickly identified during preliminary runs of the valves. After grinding to a 0.0003" tolerance and a finish of Ra 20, the parts required a wash cycle to remove the coolant prior to anodizing and packaging. Customer-supplied wire baskets were to be used so that residual coolant and cleaning solution could drain after the four step washing, which included rotation cycles to dry the parts.

"At first, the parts were merely placed horizontally in the baskets," notes Mr. Lindsay, "which proved to be ineffective to cleaning and drying the inner cavities. More importantly, however, were the nicks and marred surfaces the pans would get from contact with one another. Any raised surface will impede the operation of the valve, and we estimated that up to 50 percent of the valves could have been damaged in production runs if we had continued.

At this point, Mr. Lindsay contacted PCC, specialist in the manufacture of tote boxes for industrial and office storage and material handling needs. At the suggestion of PCC, a sample lot of parts and a wire basket were submitted to PCC for review and study. "We still needed a system that would allow the parts to drain and were hopeful that they could come up with something to utilize the existing baskets," explains Mr. Lindsay.

Within a few days, PCC not only had proposed a solution, but provided ACRA with a test product--a series of interlocking H.D.P.E. plastic dividers designed to fit snugly in the wire basket and to compartmentalize the container and safeguard against part-to-part contact. Each valve was now placed vertically for more efficient and effective cleaning and drying method. "Considering the high volume of parts, and the speed at which centerless grinding can process them, our second concern after quality was productivity," says Mr. Lindsay. "We couldn't have the material handling portion of the equation outweighing the production cycle.

By simply making the dividers slightly shorter than the parts and the wire basket, ACRA machine operators can easily place and pick up the valves by the protruding end. "Ergonomically, the separators have not been a hindrance to our operations, and since the parts do not impinge upon one another, our quality is second to none," notes Mr. Lindsay.