Ship-shape machine beats gear deadlines.
Philadelphia Gear Corp. has installed a gear-shaping machine at its plant in King of Prussia, Pa., that can make gears up to four times faster than the company's best grinders.
The new SH 450/500 SE machine was manufactured by Maag-Zurich (Zurich). It can cut gears and pinions from soft workpieces with Brinell hardness up to 400, as well as from those that have been case-hardened to Rockwell 58-62.
The new machine relies on a cutter shaped like a gear rack that moves in reciprocating motion as the workpiece is indexed through an angle of 360 degrees. It can cut gears with exterior diameters from 9 to 199.6 inches and face widths up to 35.9 inches.
Philadelphia Gear uses the machine mostly for the manufacture of helical and spur gears. The company makes power transmission systems and components for several industries, including gear drives for compressors, generators, pumps, wind turbines, hydro turbines, and ships.
In addition to outperforming grinders, the new gear shaper can cut teeth faster than hobbing machines on gears that have a pitch coarser than 2, or more than 2 teeth per inch of the gear's diameter, said Richard Borelly, technical manager of gear manufacturing at Philadelphia Gear. Unlike the shaper, a hobbing machine uses a cutter that is shaped like a worm shaft, which rotates to cut teeth while the workpiece remains still, similar to a milling operation.
Three separate attachments are used with the new shaper to broaden its machining capabilities. The first is a tool holder that has a "goose-neck" shape, which allows the cutting of teeth on the inside diameter of gears. With this setup, machinists can cut teeth in bore sizes from 15.7 to 179 inches in diameter and face widths up to 20.4 inches.
In other cases, a swivel-head cutter is employed for the machining of double-helical gears with gap widths as narrow as 1/2 inch. Here, a special holder allows the cutting tool to be set up at the same angle as the gears it is cutting.
A third attachment facilitates the machining of case-hardened workpieces. Machinists use a cutting tool with a 1/16-inch layer of cubic boron nitride fused to a carbide surface, which has material properties that can withstand the hard surfaces it encounters during machining.
Because of the new shaping machine, the grinding department can now focus on finishing gears that have a fine pitch.
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|Title Annotation:||Technology Focus: Power Transmission and Motion Control; Philadelphia Gear Corp.'s new gear-shaping machine|
|Date:||Apr 1, 1992|
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