Great Expectations
Since the day some ingenious machine tool engineer first mounted a metal tube on an engine lathe, machinists have been looking for a better way to cut off parts. From hand-ground bits to high speed steel blades to indexable carbide inserts, cut-off tool technology has continued to improve over the years, increasing metal cutting efficiency and lowering operational expenses along the way. One large step in that evolution came in recent years with the development of multi-purpose cut-off tools that are able to switch hit as grooving, turning, and profiling tools, giving job shops the ability to simplify setups, shorten production cycles and, in some cases, keep fewer tools in the crib.
One such company is Elyria Manufacturing Corporation (EMC Precision; Elyria, OH), a family-owned and operated precision machining job shop that has provided prototype to production machining and value-added services to a range of industries since 1925, including fluid management, hydraulic fluid and power, automotive, recreational, and other OEMs. Ian Dotson, a manufacturing engineer at EMC’s facility in Sheridan, IN, says he was happy with the tool life and performance of his existing cut-off system and was only looking for a reduction in his tooling costs when he called his local distributor CCA Inc. (Indianapolis, IN), who introduced him to Beyond EvolutionTM, a single-sided grooving and cut-off system from Kennametal Inc. (Latrobe, PA) with multidirectional turning capability, through the tool coolant, proprietary chip control, and “Triple V” secure seating geometry.
Dotson admits he wasn’t too concerned about the bells and whistles as long as the tool performed as well as what he was already using and saved the shop some money. He was pleased with the results. “We were using a 0.118 in wide (3 mm) PVD-coated insert to cut off 0.75 in diameter (19 mm) 4140 steel hydraulic actuators,” he explains. “We swapped out the old tool for a Beyond Evolution cut-off and kept the feeds and speeds the same. After several runs, we determined that the tool life was essentially identical, so from a performance perspective there was no difference, at least not on this job. But these new inserts are dramatically less expensive, roughly 40 percent of what we were paying for our previous tools. It was a clear win for us.”
The next win came on a job that Dotson was running on one of the shop’s Daewoo Lynx 220 CNC lathes, a transmission gear shaft made of 1-1/4 in (32 mm) 8620 steel. He was using a 0.236 in (6 mm) wide tool to back-turn a journal on the left side of the part prior to cut-off. In this application, the insert cost was still a concern, but his primary goal was tool life improvement. “This Daewoo isn’t equipped with high pressure cutting fluid, and the standard pump was unable to generate enough pressure for us to utilize coolant through the tool on our old cut-off system,” he says. “Because of this we’ve been stuck with flood coolant and have always had some chip control issues as a result. The chip would roll back on itself and starve the cutting edge of coolant.”
Despite these less than perfect cutting conditions, the Beyond Evolution tool performed beyond expectations. “We achieved very good results,” notes Dotson. “This time we increased the cutting speed from 350 sfm to 400 sfm and bumped up the feed rates by about 30 percent. Even so, tool life increased threefold to just over 2,600 pieces per insert. I’m confident we could have cranked up the feeds and speeds even more, especially if we had plumbed the tool for coolant through, but there was no need. This operation supplies another machine that was already running as fast as it could go. The big thing for us was getting more parts between tool changes – and that’s exactly what this new system did. It’s an excellent cutting tool at a very competitive price point.”
Elyria Manufacturing Corporation, 145 Northrup Street, Elyria, OH 44036, 866-365-4171, Fax: 440-365-4000, www.emcprecision.com.
CCA, Inc., 1225 Brookville Way, Indianapolis, IN 46239-0627, ccatools.com.
Kennametal Inc., 1600 Technology Way, PO Box 231, Latrobe, PA 15650-0231, 724-539-5000, www.kennametal.com.
