MEDICAL MACHINING
To illustrate, Ware shared the example of Mazak cus- tomer OneSource Manufacturing Technology (Leander, TX). OneSource manufactures primarily medical implants— knees, hips and a variety of spinal components—along with some associated supportive instrumentation. Parts range in size from 3.2 mm2
up to 457 mm2 . Typical toler-
ances are ±0.227 mm and as tight as ±0.0127 mm, and materials include stainless steels, titanium, cobalt chrome, PEEK and others. When the company fi rst moved into medical work a few years ago, they did their fi ve-axis machining with three-axis VMCs outfi tted with fourth and fi fth-axis trunnion units. They soon discovered that such an approach hindered their part processing speed and cost-effectiveness. The communica- tion between the trunnion units and the VMCs on which they were mounted caused lags in positioning; the units’ additional mounted weight restricted how fast the machine
According to Ware, for every job the shop has moved to the VCU 400A 5X, it has immediately reduced cost per part by at least 15% through shorter cycle times. In some instances, cycle times were reduced by more than 25%. “The small-footprint VCU VMCs feature trunnion-style ro- tary/tilt tables that make it possible for shops like OneSource to cost-effectively add full-axis machining to their operations, especially for producing medical components,” Ware said.
‘That’s the Priority’ At toolmaker Iscar Metals (Arlington, TX), the focus is
The stages of machining done on titanium spinal cages at OneSource Manufacturing.
tables could rapid traverse; and the extra inertia involved with moving the added weight also accelerated machine wear and tear as well as generated vibration that affected part surface fi nishes. But what really hindered operations was the amount of time and effort it took to achieve required levels of machining accuracy. OneSource purchased a Mazak VCU 400A 5X VMC that
features an integrated tilt/rotary trunnion table with roller gear cam technology. The machine has as 40-taper 12,000-rpm spindle, automatic toolchanger and 30-tool storage capacity. With an X-axis stroke of 505 mm, the VCU 400A 5X handles parts up to 400 mm in diameter and 304 mm in height.
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AdvancedManufacturing.org | March 2016
also on reducing cycle times—a more important concern than increasing tool life, according to Grip Systems Product Manager Clay East. “Tool life is important, East said, “But what Swiss-style machining shops and medical shops realize is that if we can extend their tool life by 20%, that’s great—but if we can extend their productivity by 20%, well, they’re jumping over buildings at that. That is going to allow the customer to get 20% more usage out of their machines. It frees up their machines—by 20%!—for other jobs. “That’s the priority,” East said. “You want to squeeze every penny out of every machine you’ve got when you’re in the medical industry.” East offered two examples of recent innova- tions at Iscar that are helping to increase produc- tivity for their medical customers. The fi rst is an update to a decade-old product called Swisscut. In its original design, a user would have to com- pletely remove a screw in order to index the tool insert or remove the insert completely. “It sounds like a small thing,” East says, “but I used to work in a Swiss machine shop and I can tell
you fi rsthand that when you drop a screw, it’s very frustrating” as your work comes to a halt while you search for it. “And if it happens several times a day, and 52 weeks a year, that adds up to real loss in productivity.” So about two years ago the Swisscut was redesigned so that the user need not completely remove this screw in order to index or remove the insert. “About three turns and you can take the insert off,” East
said. “It’s accessible from either side of the tool. This allows you to change that insert without removing the tool from the machine, saving time.”
His second example involves precision boring an inner diameter with solid carbide tools such as boring bars or
Photo courtesy Mazak
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