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[May 2002]
Alliance Will Offer Economic Machining of Brittle Materials
Ceramics, glass and stellite may have brought the benefits of low weight and improved resistance to chemicals, temperature and wear but machining components made from these materials is notoriously difficult, time consuming and costly, says Gildemeister. Now, thanks to its acquisition of Herman Sauer GmbH & Co KG, the company has introduced what it describes as "a revolutionary and economical cutting method" that boasts a five-fold increase in productivity compared to conventional methods - with excellent surface quality and assured process safety.Herman Sauer has over 30 years' experience in ultrasonic technology which has now been combined with the metal cutting expertise of the Gildemeister Group. The result of this collaboration is the new DMS Ultrasonic, offered in two variations with 350mm and 500mm X-paths. Deckel Maho is responsible for the manufacture of the basic machines while Sauer equips them with highly developed ultrasonic components. These include the ultrasonic spindle and generator, oscillation sensors and the diamond tooling. Special requirements such as micro-machining can also be accommodated within the product range.
The DMG/Sauer combination allows a milling, boring or grinding tool studded with self-sharpening industrial diamonds to be driven into a workpiece at a frequency of 20kHz or 20,000 per second. As a result, says Gildemeister, even the hardest materials can be machined at high feed power with low contact forces. This protects both workpiece and tool and dramatically reduces process costs.
The ultrasonic process starts as a high frequency electrical signal that is converted to a mechanical movement. A booster subsequently amplifies the oscillation amplitude, in effect causing the diamond cutting tool to expand and contract in a pulsing action. At peak of amplitude, the diamonds impact on the workpiece, breaking the surface into miniscule particles.
The simultaneous rotation of the tool - at speeds between 3,000 and 40,000rpm - mainly achieves the workpiece roundness but also removes excess workpiece particles from the working zone. These are eventually removed simply with water. Rinsing is deployed during grinding whilst rinsing and cooling respectively are achieved through the spindle during milling and drilling.
ENDS