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Case Study / Topic 42 MoldMaking Technology —— SEPTEMBER 2017 Case Study / EDM A shop-floor view shows that Extreme Wire EDM is an all-AgieCharmilles wire EDM company. In addition, it is the first—and currently the only— U.S. company to own the CUT P 1250, which can be seen on the back wall, center, of this image. GF Machining Solutions just unveiled the new wire EDM to the North American market last July, but Extreme has owned one for more than a year now. "Before we took delivery of the CUT P 1250, we had to turn away anything taller than 20 inches and anything longer than 43 inches. This is because the upper head on our next-largest wire EDM, an AgieCharmilles FI 640 CC, wouldn't go any higher than 20 inches, and its doors are only 43 inches wide," Bernt says. Sometimes, big workpieces were loaded into a machine with a forklift, which required setting the work- piece on rails above the table. "It wasn't much of a solution, though, because we were losing Z height from having to raise the part up onto the rails," he says. For example, if the rails are 5 inches high, the machinist could only fit a part that is 15 inches tall into the machine. Raising the workpiece off the table also reduces the EDM's flushing system efficacy. As the wire cuts, the upper and lower heads direct high-pressure water along the cutting wire to keep cutting paths clear of the micro-sized steel particles. Raising the workpiece off the table reduces the ability to flush particles, causing the machine to compensate by decreasing its cutting speed. This, in turn, increases the cutting time and may also compromise cutting accuracy as a result. Conversely, the CUT P 1250 has doors that lower all the way around the front and sides, which allows Extreme's machinists to load up workpieces as large as 90.551 x 51.181 x 29.528 inches from virtually any angle. "We can now set parts up to 90 inches in X and 54 inches in Y right on the table," Bernt says. Even better, flushing is no longer an issue because the heads remain close to the workpiece. Plus, the increased capacity that the CUT P 1250 offers saves time and increases opportunities for Extreme. "It is hard to measure benefits to things like time and money because we've never had this kind of capacity in the past. Still, I will say that not having to do multiple setups or deal with rails and forklifts saves a lot of time." Extreme also has customers who need wire EDM services for large steel cylinders typical of the food and oil industries. "Before we had the CUT P 1250, customers would give us the large cylinders cut in half so we could do the work, and then they would dowel the cylinders back together. Now they don't have to do that. With the capacity of the CUT P 1250, Big Taper-Cutting Capability is Key In addition to needing a very large capacity wire EDM to grow its business, Extreme Wire EDM Services Inc. knew that its new AgieCharmilles CUT P 1250 offered another valuable feature: the ability to cut tapers to the full height of the machine. The heads on a wire EDM are like arms and hold the wire above the table and below it for cutting. Most other machines only offer limited side head movement to cut tapers between 5 and 30 degrees. More and more frequently, Extreme has needed to cut these angles at greater heights, which requires greater side head movement. On these occasions, Extreme has also needed heads that can move apart more than the typical four or five inches to achieve four-axis cutting and taper cuts. "It's because the heads are tied together, which is fine when you have short and small parts. But, if you raise the head up higher, the degree of your angle lessens," Bernt says. "The 1250 provides heads that are fully independent, so you can move the heads up and out as far as you want and still maintain the angle for taller parts." GF Machining Solutions offers the Profil-Expert feature on all CUT P Series machines. According to GF Machining, the Profil-Expert feature au- tomatically adapts the machining parameters and the cut path for rough and skim passes to provide better control of fine details and to ensure positioning and contour accuracies of ±2 µm, regardless of the workpiece height. By contrast, the Taper-Expert technology cuts angles from 0 to 30 degrees to maximum Z heights. "We've even been able to cut 45-degree angles on the 1250. Being able to cut tapers on large parts is so much faster and easier with the 1250," Bernt says.