A Wisconsin automotive component manufacturer recently faced a chip control problem on an ID turning operation. General Automotive (Franklin, Wisconsin) produces high-precision components for engines, fuel systems, hydraulics, air systems, brake systems and transmissions. This particular job involved injector bodies that were being machined out of AISI/SAE 1055 steel. The ISO inserts being used had problems with chip breakage and buildup. This chip buildup would periodically lead to poor quality parts that would need to be scrapped. Constant monitoring was imperative to ensure that quality was upheld. The company needed a reliable tool that could run without the need for constant monitoring.
To find a solution, the company contacted its Iscar representative, Gary Hammer. “We needed more dependable tooling to enable us to operate more efficiently,” states Steve Gunter, shop supervisor at General Automotive. After analyzing the situation, Mr. Hammer offered a creative solution, suggesting replacing traditional ISO style inserts with Iscar’s Bayo T-Ream reaming system and running it with the Gyro toolholder. He believed this combination would provide a more reliable setup compared to the tooling that was being employed.
The Bayo T-Ream from Iscar Metals, Inc. (Arlington, Texas) features interchangeable heads for facilitating quick tool changes and high speed reaming. This system is designed to minimize setup time while indexing, and it offers indexing repeatability to 3 microns. It consists of an interchangeable carbide reaming head with a quick-change bayonet mechanism. This mechanism is mounted on a Hard Touch coated steel shank using a bayonet screw and custom key to clamp and release the interchangeable head.
The versatility of the shank and head combination enables using one shank for a myriad of hole diameters and types of cutting edges, says the manufacturer. Also appropriate for blind holes, through holes and holes with cross holes or keyways, this combination of carbide head and steel shank provides the level of durability essential to machine a range of materials. To further increase efficiency, the reamer has internal coolant holes for effective head lubrication and chip evacuation.
For General Automotive’s project, the system was mounted onto an adjustable Gyro toolholder, which is designed to eliminate problems resulting from radial or angular misalignment. Its design allows for adjustment of misalignment between chuck and turret on drilling, tapping and reaming operations. Using the Gyro, operators can machine a hole in one setup while achieving tolerances as close as 0.0004 inch. By automatically executing alignment adjustments, cutting tool life can thus increase tenfold, while speeds and feeds can be accelerated by as much as 300 percent.
With this system in place, the company has been able to increase the pieces per edge from 550 pieces to 5,800 pieces. This 1,000 percent increase in tool life was accomplished by running at 3,257 rpm at 0.024 ipr while making a 0.012-inch depth of cut. The ream was within 0.0002 inch of the actual reamer size and produced a reliable and consistent cut, says General Automotive. In fact, not one part was scrapped because of chip buildup.
“In the past, chip buildup had been a major concern on this project,” states one machinist. “It caused unnecessary delays for tool changes, in turn causing a large amount of scrap parts.”
An added benefit to this tooling life improvement is a reduction in the time required to complete the project. Formerly, with the ISO setup, the project was completed in 584 days. However, as a result of the increase in the number of parts produced per day, the company completed the project in 571 days.
The Bayo T-Ream was able to operate at 78 ipr compared to 13 ipr with the ISO inserts. This change reduced the time in cut from 0.14 minutes down to 0.02 minutes and decreased the total cycle time from 5.14 minutes to 5.02 minutes. Although the company’s primary objective was to increase tooling life, the resulting increase in productivity was a pleasant surprise. The added productivity helped to reduce the amount of time needed to complete this project by 13 days, and saved labor and shop hours helped to further reduce costs on the overall project.