Heller Machine Tools (heller-us.com) and Voith (voith.com), a Germany-based transmission manufacturer, have developed a process that permits the pre-milling and milling operations to produce bevel gears and gear components on a five-axis machining center rather than on a dedicated gear-making machine. To produce gears, they start with the drawing of the part. The gear parameters are entered into the machine control, which then uses the data to generate the five-axis paths for roughing and finishing are generated in real time. Data collected by a measuring machine can be used to provide compensation data to the machine control; current tool data provides the information needed for real-time compensation.
They’ve developed the process to go from blanks, with the pre-machining of external and internal contours being performed in the first setup, then tool milling in the second.
They’ve worked with Sandvik Coro-mant (http://www.sandvik.coromant.com/US) for the development of a customized crow-milling cutter with indexable inserts for the machining operation.
Heller has a range of machining centers that can handle diameters ranging up to 1,800 mm (its MCH-C with a HSK 100 spindle taper); a new series of machines will handle diameters up to 3,000 mm.
The process is not aimed at high-volume gear manufacturers, but those who perform more limited runs, or for gearbox manufacturers, who have a requirement for several gear sizes.