EDM
revealed the client would save money, not waste it unneces- sarily, because the 26 hours saved on the custom housing job would allow the client to earn $1300–$3900 in machine time for another piece, based on shop-time estimates of $50–$150 per hour. “What’s more valuable to your operations,” Pfluger asked his client, “saving $100 in manufactur- ing costs, or gaining 26 additional hours of billable machine time?” According to Pfluger, the molli- fied client said: “You know what? I never thought about it that way.” Pfluger’s anecdote underscores the complexity of medical manu- facturing with already-complex wire electric discharge machining. Since the invention of wire EDM in the 1960s, the technology has made difficult-to-machine shapes possible in conductive metals. It’s opened the door to making medical devices such as heart stents, mini-tools for robots that assist during “keyhole” surgery, and implants that replace hips, knees, elbows and shoulders. Just as wire EDM has made more
comes with a guarantee to last 12,000 machining hours, possibly making it a better buy in the long run. The Split-V Guide system also requires less maintenance and offers longer life because the diamond contact area is larger.
Each machine features Hyper- Cut, a fine-finish technology that improves cycle time by producing a surface finish of 3 µm Rz
in three
passes. A competitive product would require four to five passes to achieve the same quality finish, Pfluger claimed. HyperCut also of- fers a 20% reduction in cycle time and 14% reduction in wire con- sumption, compared with previous Makino technology.
This saw guide, used in knee replacement surgery, was cut on a Fanuc RoboCut CiA wire EDM machine.
complex medical devices possible, the machines that make this type of manufacturing possible continue to advance as well.
Wire Guidance
Makino came out with two new wire EDMs in September: the U3 with X, Y and Z axes travels of 370 × 270 × 220 mm, respectively; and the U6, which increases the machine travels to 650 × 450 × 420 mm.
The worktable on the U-Series is stationary, to improve ma- chining precision and provide greater flexibility for workpiece setup. The U-Series offers a choice of wire guide systems on the machine. Customers now have the ability to choose either a PICO (round) guide system or a Split-V Guide system, depending on their applications or preference. Pfluger explained that the PICO round wire guide offers a typical guide life of 2000–3000 machining hours. The V Guide, which is patented Makino hardware, is pricier but
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The U-Series also has a new CNC system, Hyper-i, which fea- tures a 24" (610-mm), user-friendly touch screen that works like many smartphones or tablets, with pinch, pull and drag operations. “It looks like a giant iPad,” Pfluger noted, “And that’s the way it works.”
The software includes digital
manuals and an on-board training tutorial system for the operator. Also, Hyper-i automatically records and translates production process data into pie and bar charts that make assessing machine utilization time quick and intuitive. “So this becomes a piece of management software,” said Pfluger.
Virtually No Recast
The need for speed in wire EDM has manufacturers tweaking flushing rates and other variables to eke out any tiny improvement in the time necessary to finish a workpiece. “That’s actually the holy grail at this point,” said Steve Bond, national sales manager for Methods Machine Tools Inc. (Sudbury, MA).
“In the 1980s and 1990s, the speed chart [showing im- provements] was almost vertical,” says Bond. “But it slowed down in the 2000s.
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