External to Internal Gear Grinding in 30 Minutes or Less
Based on Liebherr’s Opal system, the IG Opal 4.0 internal geartooth profile-grinding technology fits a belt-drive spindle to the company’s standard GH 4.0, GH 5.0 and GH 6.0 grinding heads.
Based on Liebherr’s Opal system, the IG Opal 4.0 internal geartooth profile-grinding technology fits a belt-drive spindle to the company’s standard GH 4.0, GH 5.0 and GH 6.0 grinding heads. The internal gear-grinding arm will be available in two sizes at first, with more to follow. The company also takes requests for custom internal gear-grinding arms.
This technology is said to enable switching from external to internal grinding in half hour at most. The user detaches external gear grinding disk or worm, hangs the internal gear grinding arm on the hardened stop bars to ensure repeat accuracy, and fixes it in place with a handful of screws. After tensioning the belt-drive disk and the belt, internal gears can be ground using a grinding disc of 100 or 125 mm in diameter.
IG Opal 4.0 functions at a maximum spindle speed of 12,000 rpm. A larger version, the IG Opal 4.1, features a maximum grinding disk diameter of 125 mm. Both arms have been successfully tested using cubic boron nitride (cBN) and corundum disks. Dressable wheels can be tended by the same dresser used for external gear grinding.
All internal gear grinding arms are modeled in 3D and can be used in very confined spaces. The company says that collision inspections are simple and reliable to ease machining of small-diameter internal gear teeth. As in the case of external gears, this new internal gear teeth technology works with a multi-rib grinding disk system that can perform rough- and finish-grinding. Grinding disks made of dressable corundum or electroplated cBN can be used in conjunction with the spindle.
Two enabling technologies -- superabrasive wheels and high precision servo control -- come together to provide a contour grinding process that resembles an OD turning operation. For many medium volume OD grinding applications, this method may be a means to consolidate several manufacturing steps into a single setup.
In vertical grinding, the workpiece is held upright in a rotary chuck with the grinding spindle overhead. This configuration can improve roundness, facilitate single-setup processing and prolong the life of the machine. Loading and unloading may gets easier, too. Workpieces with relatively large diameters and short lengths benefit the most from vertical grinding.
Because of the high material removal rate creep-feed grinding can deliver in challenging materials, grinding might not be just the last step in the process—it might be the process.