With a growing demand for complex tools, toolmaker Komet of America had to manufacture at higher production rates without sacrificing quality. The company determined that its existing grinders could no longer keep up and a new solution was needed to produce its Dihart multi-step tools effectively. The major bottleneck in production was for tools with a flat diameter and a back taper, as the existing grinders required extra setup to adjust the table to match the angle.
According to Komet, an important factor in the search was to remove this extra setup, grind the tools in one clamping and simplify the process for operators. Further complicating the search was the company’s need for a short machine delivery time and the ability to handle a diamond grinding wheel.
Junker’s customized GAP detection software was developed to grind Komet’s Dihart reamers, pictured here in their rough state.
To meet the necessary requirements, Komet searched for a CNC grinding machine with a freely programmable B axis that could accurately and efficiently grind parts while remaining flexible.
Erwin Junker’s rigid Lean Selection Allround universal cylindrical grinding machine provided a B axis with a resolution of 0.0001 degree, capable of grinding all tapers the company needed to manufacture.
“One of the options that we selected was a choice of two spindle wheel,” says Carbide Group Leader David Zurowski. “We believe that we will have fewer limitations having one wheel per side and more clearance for our complex tools.”
In addition to the proper mechanical features, the company sought a custom-designed grinding software program in order to reduce the amount of air grinding. The carbide inserts ground on each reamer are set at common intervals along the diameter, resulting in an interrupted grinding surface. After several discussions about the problem, Junker offered the solution of using its GAP detection acoustic sensor to control the workhead speed. When the grinding spindle detects air grinding, the workhead rotates quickly until it detects the next carbide insert. At each insert, the workhead slows to the “grind” setting, then speeds up again when finished grinding the insert to the “air” setting.
With machine operation in full swing, Komet says it immediately noticed significant production time savings. Zurowski says that “setting back the taper with the B axis has been easier, hassle-free and faster for operators. In setup we save around 30 to 35 minutes.”
Requiring only one setup to grind each part complete has reportedly increased Komet’s productivity.
The Allround’s design provides savings in setup time but is also said to have cut down Komet’s running time by 5 to 10 minutes per part. The freely programmable B axis enables the operator to grind continuously without having to change out the grinding wheel.
Despite the improved run time and setup time, a final inefficiency was detected after installation. The company’s high mix of parts requires frequent wheel change-overs which can cause quality issues if the new wheels are not properly mounted. As a solution, Komet will be implementing Junker’s three-point grinding wheel mounting system which is said to reduce wheel change-over times and guarantee a wheel concentricity of less than 2 microns. When the system is installed, the company expects a further reduction in setup times, improved grinding times and better part quality.
The tool supplier is able to use the same grinding wheels as before but with simpler setup, faster change-over, better grind time and improved operator experience. The machine comes with the JUWOP/LS programming system, speeding efficient programming. Thanks to graphically supported data entry and to-scale representation on the screen, the company says that programming is easy and requires little or no training.
The Lean Selection Allround comes with the JUWOP/LS programming system, which is said to enable the user to program the machine quickly and efficiently.
“From our experience in grinding reamers and the way we set up and run [the Allround], our finished product is the same quality despite a reduction in production time, which is what we were looking for,” says Zurowski.
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