Productive Alternative to Helical Interpolation for High-Volume Holemaking Matt Tegelman
The limitations of using milling tools to prepare holes for finishing become apparent as hole depth and volume increase. Enter
and virtually any other holemaking problem. Helical interpolation using milling tools is a useful, tried-and- true method of preparing holes for finishing. Simultaneously rotating the cutter and moving it axially at a defined pitch makes a range of diameters and profiles – such as wide shoulders – possible with one tool by simply making more expanding sweeps. As hole depth and volume increase, however, limitations in this approach reveal themselves. A sufficiently rigid end mill can only be so long, requiring more and more time-consuming
steps as depth increases – and the depth of the hole itself is limited. As the end mill lengthens, deflection becomes harder and harder to avoid because of the dynamic radial load. An operator could always make extremely light cuts as the mill moves through the hole, but that is a drag on cycle time that’s not viable in production. Another variation is to use a helical milling cutter to perform heavy- duty cutting in the same circular pattern, but it’s only possible at very high horsepower – the kind of horsepower that’s not available to every shop. What’s more, in all of
the relatively simple and affordable twin cutter, which can solve this To adjust insert height, simply reverse the insert holders to switch between balanced and stepped cutting.
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