Production Machining

OCT 2016

Production Machining - Your access to the precision machining industrial buyer.

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Ensuring Zero Defects in Internally Threaded Fasteners Edited by Lori Beckman I t is critical to inspect formed metal fasteners to ensure zero defects, either for safety, critical performance, or to optimize the manufacturing process. Conventional methods to do this exist, such as sorting mechanically for size or hand sorting with optical comparators. Yet tradi- tionally, it has been difficult to inspect internal threads for tiny defects such as chips, tears, weld splatter, and short or missing threads. Inspecting the vertical walls of a fastener hole and its threads is difficult for the human eye because of its small size as well as lighting and viewing issues. Not only is such an inspection process slow, labor intensive, and subject to interpretation, but also it is prone to human error, particu- larly over long periods when fatigue can degrade accuracy. "Because many of our parts such as small fuel fittings and unions for the auto industry are safety parts, our customers will not accept anything but 100-percent quality, so we carefully check key areas including internal threads," says Chuck Abbate, V.P. of operations at H&L Tool (Madison Heights, Michigan), a manufacturer of precision turned and cold formed fastener products. "We needed a way to make sure that all the internal features were perfect and within the print." However, even typical cameras and laser-based equip- ment have difficulty detecting required features inside of parts, and the deeper the hole or recess, the more challenging this becomes. "One of the problems that arises when looking at internal features on a machine is the different color in the plating and different lighting," Mr. Abbate says. "It is important to get a machine that determines what it is looking at; that it is truly looking at the part and not at glare or a shadow." To help manufacturers ensure zero defects in their fasteners, a number of advanced high-speed sorting :: (Above Photo) To ensure couplers, tube nuts and internal female nuts contained zero defects, this company turned to a high speed, vision-based measuring machine called the GI-100DT from General Inspection. CASE IN POINT 42 PRODUCTION MACHINING :: OCTOBER 2016

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