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END USER: Tivoly Inc., (802) 873-6003, www.tivoly.com. CHALLENGE: Significantly reduce downtime on a flute grinding machine. SOLUTION: Rebuild the flute grinder. SOLUTION PROVIDER: International Tool Machines (ITM), (386) 446-0500, www.itmfl.com
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Tivoly Inc. manufactures private-market HSS taps and reamers, which means it doesn’t sell directly to end users.
Making taps and reamers is challenging compared to producing other cutting tools, according to Scott Gowdy, Tivoly’s plant manager. “Grinding spiral flutes is especially difficult compared to straight flutes because you are dealing with complex wheel forms and multiple angles,” he said. “There’s a lot of different engineering that goes into the flute design and the wheel form.
“You are grinding at an odd angle,” he continued. “You can get wheel deflection or washout to the back or front. Because you are grinding at an angle, you have forces directed across various angles of the wheel.” Washout occurs when unintentionally grinding outside the parameters of the wheel form.
Courtesy of Tivoly
Tivoly’s flute grinder needed to have its entire electrical system replaced.
Located in Derby Line, Vt., Tivoly has 160 employees and 240 machine tools, ranging from lathes and milling machines to virtually every conceivable type of grinder. After 15 years, one of those machine tools, a flute grinding machine from International Tool Machines, succumbed to wear and tear. Tivoly contacted ITM to rebuild the machine last fall. ITM builds CNC grinding machines for the cutting tool, medical instrument, aerospace and automotive markets.
“We operate in a very oily environment, so the flute grinder’s electrical system was becoming brittle,” Gowdy said. “We needed to have the entire machine gutted because of the age and condition of the wires. The electrical system is so thoroughly integrated it is oftentimes not possible to simply replace single wires as they go bad.”
After the rebuild, the cycle times remain about the same on the machine, but uptime is significantly greater. Gowdy noted the machine’s mechanical and electrical problems caused about 400 hours of downtime a year—a $150,000 expense. “Every time it would stop working, we would have to wait on parts and the technicians to repair it,” he said.
The machine had a Windows 3 computer connected to it, but the rebuilt grinder doesn’t have a computer associated with it. “It is all in the new Fanuc control,” Gowdy said.
That control helps reduce downtime by enabling engineers to quickly update and transfer program files. “A huge benefit is the machine is now on our computer network, so our engineers are able to drop program files into the machine for the operators,” Gowdy said. “The operator can pull up a program and make whatever adjustments are needed. He doesn’t have to use a data sheet like before.”
The old system also used separate loader system and machine controls, but the new control combines them.
The rebuild also addressed minor mechanical issues. However, the original machine spindle is “excellent.”
ITM rebuilt the grinder at its facility in Palm Coast, Fla., in about 3 months. “They could have done the rebuild on-site, but it was a lot easier to send the machine to ITM,” Gowdy said, adding that Tivoly used two similar machines to work around the rebuild schedule.
Overall, Tivoly was pleased with ITM’s results. “It was quite a challenge for ITM because of the machine’s age,” Gowdy concluded. “They were exceptional in working with us on the new software, which they had to program from scratch. They tried to get the old programs out of the old controller, but it wouldn’t give them up.”
Gowdy is especially satisfied with only 2 hours of machine downtime so far this year.
Related Glossary Terms
- computer numerical control ( CNC)
computer numerical control ( CNC)
Microprocessor-based controller dedicated to a machine tool that permits the creation or modification of parts. Programmed numerical control activates the machine’s servos and spindle drives and controls the various machining operations. See DNC, direct numerical control; NC, numerical control.
- flutes
flutes
Grooves and spaces in the body of a tool that permit chip removal from, and cutting-fluid application to, the point of cut.
- gang cutting ( milling)
gang cutting ( milling)
Machining with several cutters mounted on a single arbor, generally for simultaneous cutting.
- grinding
grinding
Machining operation in which material is removed from the workpiece by a powered abrasive wheel, stone, belt, paste, sheet, compound, slurry, etc. Takes various forms: surface grinding (creates flat and/or squared surfaces); cylindrical grinding (for external cylindrical and tapered shapes, fillets, undercuts, etc.); centerless grinding; chamfering; thread and form grinding; tool and cutter grinding; offhand grinding; lapping and polishing (grinding with extremely fine grits to create ultrasmooth surfaces); honing; and disc grinding.
- grinding machine
grinding machine
Powers a grinding wheel or other abrasive tool for the purpose of removing metal and finishing workpieces to close tolerances. Provides smooth, square, parallel and accurate workpiece surfaces. When ultrasmooth surfaces and finishes on the order of microns are required, lapping and honing machines (precision grinders that run abrasives with extremely fine, uniform grits) are used. In its “finishing” role, the grinder is perhaps the most widely used machine tool. Various styles are available: bench and pedestal grinders for sharpening lathe bits and drills; surface grinders for producing square, parallel, smooth and accurate parts; cylindrical and centerless grinders; center-hole grinders; form grinders; facemill and endmill grinders; gear-cutting grinders; jig grinders; abrasive belt (backstand, swing-frame, belt-roll) grinders; tool and cutter grinders for sharpening and resharpening cutting tools; carbide grinders; hand-held die grinders; and abrasive cutoff saws.
- high-speed steels ( HSS)
high-speed steels ( HSS)
Available in two major types: tungsten high-speed steels (designated by letter T having tungsten as the principal alloying element) and molybdenum high-speed steels (designated by letter M having molybdenum as the principal alloying element). The type T high-speed steels containing cobalt have higher wear resistance and greater red (hot) hardness, withstanding cutting temperature up to 1,100º F (590º C). The type T steels are used to fabricate metalcutting tools (milling cutters, drills, reamers and taps), woodworking tools, various types of punches and dies, ball and roller bearings. The type M steels are used for cutting tools and various types of dies.
- milling
milling
Machining operation in which metal or other material is removed by applying power to a rotating cutter. In vertical milling, the cutting tool is mounted vertically on the spindle. In horizontal milling, the cutting tool is mounted horizontally, either directly on the spindle or on an arbor. Horizontal milling is further broken down into conventional milling, where the cutter rotates opposite the direction of feed, or “up” into the workpiece; and climb milling, where the cutter rotates in the direction of feed, or “down” into the workpiece. Milling operations include plane or surface milling, endmilling, facemilling, angle milling, form milling and profiling.
