News

Kellenberger Grinding & Aerospace:

Kellenberger Grinding & Aerospace:

Tuesday, July 08, 2014

Aerospace materials and superalloys pose tough machining problems. The supply chain demands almost impossible levels of tolerance. And in case that's not enough of a challenge, can you please add mirror finish?
 It's no secret that titanium, Inconel, nickel-based superalloys, and tungsten-molybdenum alloys are difficult to machine. But aircraft engines, landing gear, and hydraulic parts must be made of these various materials. Should you cut it or grind it? And why?
 THROUGHPUT magazine recently caught up with Jeff Hilliard from HardingeInc. at Morris Madness, a recent technology show at Morris Midwest in Roselle, Illinois. Jeff is an engineer and National Sales Manager for the Hardinge Grinding Group. We wanted his take on the role of grinding in the aerospace market, and the newest developments in grinding technology. "When you walk into just about any sophisticated aerospace shop, large or small, you'll see grinding machine tools. Historically, grinding was viewed as just a finishing technology, but that's old news. Modern grinding machines are capable of removing significant amounts of material in addition to delivering the finest finish and dimensional tolerance on the market," says Hilliard. "Instead of trying to cut aerospace superalloys, consider using a less stressful manufacturing technology- grinding."
The Kellenberger Kel-Varia
 The Kellenberger® Kel-Varia™ CNC- controlled universal cylindrical grinding machine is used extensively in aerospace applications to process a large spectrum of parts and wide range of geometries. Combinations of cylindrical grinding, outside diameter (OD) and inside diameter (ID) out of round grinding, thread, and jig grinding can be performed in one set-up. Advanced operation allows precise grinding of grooves as well as satellite and centering bores. Other competitive advantages include:
1 Hydrostatic guideways and a strict separation of the machine base from the superstructure minimize heat and vibration, delivering precision to ten millionths of an inch. Optional gauging and flagging technology measures the face or shoulder of any part and automatically adjusts for any shifting of the part along the Z-axis.
2 Cycle time may be reduced by as much as 30% with the optional Kel-Touch™ gap control. This unique control allows an accelerated feed rate until contact is made - significantly reducing air time. For heat sensitive materials like those used in aerospace work, acceleration time may be adjusted to each material by the control.
3 Standard Kel-Easy™ menu-based CNC programming software greatly simplifies programming and operation. Operators no longer need to know (ISO) G and M Code programming, reducing programming time to seconds. For aerospace work, the software also allows the operator to interrupt the cycle at any time to measure the part or dress the wheel.
4 A robust and rigid direct-drive workhead is a key feature of the Kel-Varia and provides reliable and accurate grinding of large, heavy parts. A powerful torque drive allows rapid and precise acceleration and braking with zero backlash bidirectional movements of heavy workpieces. The enhanced direct-drive system provides 5 times the indexing speed of older models. Indexing from OD to ID wheels takes less than two seconds!
Aerospace Repair Work
 One area that is often overlooked by shops looking to break into the aerospace market is the ongoing demand for repair work. Many aircraft components are extremely expensive in their unfinished, cast form. When they are worn or damaged, they may often be stripped and replated instead of being scrapped.
 The replating process produces a very secure bond, but can yield inconsistent results. Kel-Touch and Active Flag probe technology make it possible to regain the original precision even when it is a "one-off" repair job.
Hardinge and Kellenberger
 Hardinge uses Kellenberger grinders in their own Elmira, New York manufacturing facility.  One of the most common applications is to create the spindle used in their SUPER PRECISION® T-Series line of lathes (pics of the spindle accompany this article). Both the OD and ID of the spindle are ground to ensure the highest level of concentricity. Ironically, many of these lathe spindles spend much of their manufacturing lives making- aerospace parts!


<>
distributed by