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Advanced Manufacturing 38 MoldMaking Technology —— AUGUST 2016 The top image shows the individual pieces of an investment casting mold after machining, which are then assembled into a complete mold (bottom left image). The resulting wax pattern (bottom right image) was used to create a ceramic mold into which molten metal is poured to make the desired part. Note the number of aluminum mold cavities that were machined for this project and the complex details within each. The details are even more evident with the unmolding of the wax pattern. cutting complex contours, and that comes from experienced toolmakers, each of whom designs and builds his own molds, taking every job from concept to completion. The shop cur- rently has eight employees, including one apprentice, and it operates out of a 7,500-square-foot building that houses 12 Mori Seiki CNC machining centers plus a wax-injection sam- pling machine. Supporting equipment includes drill presses, band saws, manual-engine lathes (non-CNC), small surface grinders and more. Of the dozen CNC machines, two are four-axis and the balance three-axis. "While our 12 Mori Seiki machines are different models, they all operate the same," Novak says. "Once a new hire or apprentice learns to operate one machine, he or she can operate all of the machin- ing centers in the shop. One NC program will run on any machine. Furthermore, all of the machines use the same tooling, and the maintenance across all of the machines is very similar. This is no coincidence. We've operated this way from the beginning and it has proven to be an effective strategy. Our toolmakers work simultaneously on multiple machines and, for us, the simplicity and consistency in using uniquely Mori Seiki machines has no doubt saved us time and money in pro- duction. It's a seamless way to operate." Its machining operation does not include any EDMs, which might seem very unusual for a mold builder, but it's just part of the overall machining strategy the company follows based on the type of molds it builds. "Our foremost goal, aside from qual- ity, is speed. Cutting, for us, is faster than EDM," Novak says. The shop aims to machine to a fine finish, however, which Novak says is time-consuming but necessary to minimize pol- ishing. "Since finish-machining is unattended, CNC programs that run a little long don't hinder us. We might need some pol- ishing at times, but we would only spend hours, not days like with injection molds," he says. "The wax has to look good; that's the main thing. No mirror polish is ever required, and what little is polished is done in- house. On those rare occasions when we are building a mold with steel inserts, we farm out the polishing work." Novak says this machining strategy has decreased mold build times by about 25 to 30 percent overall. Lead times for large, complex investment casting molds like those in a 10-mold pack- age for a knee implant project South Coast recently finished can be upwards of six months, he says. Such molds might be as large as 30 inches in diameter by 40 inches long, or require press tonnage between 30 and 150 tons. More common, smaller "Just this week, we ran a CNC cutting program for over 72 hours. That three-day program is not even a record for us; it's just routine, unattended machining." components. The average lifecycle of an aluminum invest- ment casting mold reaches into the thousands before it requires replacement or refurbishment. Machinery by Design In the 43 years since its doors opened, the company has manu- factured more than 7,000 investment casting molds. Novak says that a chief competitive advantage is its expertise in