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18 MoldMaking Technology April 2015 Case Study / Cutting Tools sor. "Tooling deficits in so-called high-feed button cutters can hide within the more limited range of motions inherent in three-axis processing," he says. "We had to slow down in the corners for reasons that no longer exist in the five-axis environment." He also noticed corner violations and chatter problems whenever he tried to push feed rates to levels made possible by the new machine. Fast, Consistent Feed Rates Seeking a solution, Hunt called Shaun Towe of distributor Ramstar Carbide. Towe had heard of successes with the Power- Feed+Mini mill in stateside mold shops, so he brought along Ingersoll's Paul Poirier to size up the application and run a demo on core blocks in hardened P20 tool steel. At 600 sfm and 0.020-inch stepover, the face mill ran at a feed rate of 900 ipm. That's a 9-to-1 increase compared to the old button cutter, which fed at only 100 ipm using the same synthetic, water-based cutting fluid and required 100-percent attendance because of unreliable insert life. Moreover, the Power-Feed+Mini maintained 900 ipm throughout the entire cut, including the corners. Chatter and corner violations also disappeared. In addition, the projected 5-to-1 increase in tool life raised the possibility of unattended operation, which wasn't possible before. However, Hunt wasn't ready to commit to the new cutter just yet. First, he ran competitive trials against similar high- feed face mills from other manufacturers. In terms of pure material-removal rate, the Ingersoll tool outperformed two of the other tools and equaled the third. However, he recognized that the Power-Feed+Mini would help save on consumable costs because its inserts offer four cutting edges, compared with only two on the others. The face mill's performance is largely a function of insert geometry, Poirier says. "It looks like a rectangle with radiused ends, which do the cutting," he explains. "This enables a small- er tool to cut as fast as a bigger one, yet go deeper into the corners of mold cavities and turn the corners without slowing down." He adds that the inserts are thick and feature the clas- sic high-feed geometry, in which a positive rake face reduces cutting forces and chatter. Streamlining Roughing Poirier's input didn't stop with finishing and semi-finishing applications on the new machine. While walking the floor at Reko, he also observed a potential opportunity to improve roughing operations on the company's gantry mills, which it designs and builds in house. These rugged machines feature 100-by-135-inch X-Y travel, 100-hp spindles with speeds rang- ing to 3,000 rpm and 300-ipm feed rates—muscular, but not really high-feed. Reko's standard parameters for roughing on these machines are 600 sfm with 0.05-inch-deep passes at 150 ipm. Experience from other applications led Poirer to believe these operations could be improved with a Hi-QuadF high- feed roughing face mill running at medium feeds. "Although it's a high-feed tool, the Hi-QuadF has the geometry to take much deeper cuts where the feed rate is limited," he explains. "It combines high-feed and deep-cut geometry in the same tool." The Hi-QuadF also incorporates an IN 4030-grade alumi- num oxide coating, which is deposited by a pressure vapor deposition (PVD) process to create a more durable bond. The insert is etched more deeply to enlarge the gripping area, and then the PVD coating is deposited at a lower temperature than the chemical vapor deposition (CVD) process. According to the Compared to the standard high-feed button cutter that previously ran on Reko's fve-axis machine, Ingersoll's Power-Feed+Mini high-feed mill fnishes mold cavities faster and closer to near-net shape. Brad MacNeil, CNC machinist at Reko, indexes inserts on the Hi-QuadF face mill. The inserts combine high-feed, deep-cut geometry and a new coating to increase removal rates, improve tool life and reduce cutting forces.