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mmsonline.com April 2017 MMS 81 FEATURE J ust a sliver. Less than 0.01 inch, in fact. Miss- ing the goal by just a few ten-thousandths of an inch would put the thimble-like steel part out of specification. That is, assuming it hadn't already been cracked or deformed before it entered the grinder in the first place. Controlling for that pos- sibilit y would require inspecting ever y single component on the way in, a challenging proposi- tion with more than 100 parts crossing the machine's work zone ever y minute. Of course, the actual machining would require close monitoring and control as well. Given the potential for a single flawed part to relegate thousands to the scrap heap, there would be room for nothing less. This was the scenario presented to engineers from Glebar, a specialist in turnkey grinding, when they first arrived at their prospective new customer's facility. Frustrated by quality problems with outside grinding services for a high-volume engine component, the automotive parts supplier had decided to bring the job in house. In addition to being fully automated, the process had to Putting the Feed in Through-Feed Perfection An automated grinding, inspection and packaging cell churns out two fragile automotive parts per second with zero defects. BY M AT T DA N FO R D churn out a minimum of two parts per second with zero defects. T h e c o m p o n e n t i s d e s i g n e d to i m p r o v e automobile gas mileage by capping off engine cylinders. The part's brittleness proved to be a greater challenge than its precision. Measuring 0.25 inch long, it features a slightly flaring, thin- walled open prof ile that easily cracks under pressure. "It's a delicate grind, to be sure, but Glebar specializes in such operations," says company President John Bannayan. Thus, it didn't take long to identify the compact GT-610 center- less system as the best option for quickly shaving 0.0 08 inch from the par t's diameter without violating critical tolerances. However, confidence in a process goes only so far when that process can be sabotaged by proble ms with incoming wor k pie ce s. O n this job, heat-treat operations had an unfortunate tendency to deform the cold-drawn steel before it could ever meet the grinding wheel. Front- end quality control became a top priority at the outset. "Garbage in means garbage out," Mr. Bannayan says. That's where things got complicated. The challenge wasn't so much ensuring perfection, he explains, but ensuring per fection without slowing production. Through-feed grinding at two parts per second is one thing; singling out bulk- loaded workpieces for qualit y control before sending them hur tling through the machine is Due to the nature of the parts, rotating them within a laser beam to check for out-of-round geometry was not an option. Instead, the cell employs a device designed for extrusion lines that derives ovality from three distinct diameter measurements taken with three intersecting laser beams. Many of the images in this article are stills from a video of the cell in action. To see it, visit short.mmsonline.com/hifeed.