Modern Machine Shop

OCT 2017

Modern Machine Shop is focused on all aspects of metalworking technology - Providing the new product technologies; process solutions; supplier listings; business management; networking; and event information that companies need to be competitive.

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Page 79 of 188 Month 2017 MMS 77 FEATURE the workpiece to final size." Using this method enables the shop to push a tool until it stops repeating. Wear is normal and expected, and can be managed as long as the insert is wearing at a repeatable amount. However, inserts must be changed or indexed to a fresh edge if the current edge isn't repeating. Except for interrupted cuts, the shop runs with coolant in nearly all cases. It uses coolant not to flush chips or provide lubrication, but rather to keep the part cool. "We'll sometimes direct the coolant flow away from the inert tip, even on the opposite side of the par t in some cases," Mr. McCleary says. "The high-hardness powder metal materials generate a lot of heat during hard turn- ing to the extent that thermal expansion from the heat can exceed our allowable tolerances. Plus, if coolant isn't used, the operator would have to cool the workpiece af ter hard turning before measuring it. Using coolant enables us to measure a part instantly." The shop doesn't use coolant for interrupted cuts because of the possibility of thermal fracturing of the cutting edge. DEDICATE MACHINES TO HARD TURNING WHEN POSSIBLE One of True Die's two Quickturn Nexus machines is reserved for hard-turning work, while the other is sometimes used when capacity is needed for conventional turning. In fact, Mr. Stahl believes it is important to dedicate a turning center to hard- turning processes if possible. "If you have the work to f ill a machine's schedule with hard- turning finishing operations, then why beat up that machine by roughing with it, too?" he asks. "Long term, you're better off keeping one machine dedicated to hard turning, as I believe it extends the length of time that machine can effectively perform those precise operations. Plus, it enables you to keep all the appropriate turning, facing and boring tools set up in the machine, which speeds setups. That said, it's not always practical to commit a machine to hard turning, especially in a low-volume, high-mix job shop." U LT R A P R E C I S I O N P R O B I N G Marposs Diamond systems redefine the rules of on-machine part measurement, where precision requirements are pushed to the limits daily. VOP40p Diamond probe allows the inspection of extremely complex parts and 3D surfaces, even on the smallest machines, guaranteeing high part precision and less scrap. T H E B R I L L I A N T T O U C H Y O U R G L O B A L M E T R O L O G Y P A R T N E R

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