Ultrasonic machining

Ultraschallschwingläppen ( older: ultrasonic drilling ) is a metal-cutting manufacturing processes with geometrically undefined cutting edges for producing geometrically complex parts made ​​of materials that are prone to brittle fracture behavior. The Schwingläppen associated with the lapping according to DIN 8589. In contrast to other lapping process is not used for fine processing already largely created by other methods workpieces, but the creation of new forms only by Schwingläppen.

A high-frequency electrical energy is converted into mechanical vibration at the same frequency by means of a piezo-ceramic transducer. The amplitude of the longitudinally vibrating transducer is only 5 microns. Between the mold and therefore there is a transducer unit further consisting of the amplitude transformer and the sonotrode ( also called Bohrrüssel ) that amplifies the amplitude of 20-40 microns. The four said interconnected elements together form a vibration- technical system, which is operated at resonance.

The method based on the fact that in the ultrasonic range (19-22 kHz) oscillating shape stuff the grains hammers in the workpiece surface, generated as microcracks and finally detaches fragments. This process takes place in the direction of movement of the ultrasonic vibration mainly. If possible, also the use of the rotating tool is recommended because the removal is much higher here. The grains are in a liquid or paste ( lapping compound ). This mixture is continuously purged or pressed into the gap between the mold tool and workpiece, the gap is about twice as wide as the average grain size.

The choice of the grain material falls because of the good breaking capability and thus self-sharpening almost exclusively on boron carbide, which occupies about 25-35 % by weight of the lapping compound and usually between 50 and 60 microns in size. Since the form of the same stuff straining does not like the work, it must be made of a material which is either harder than the workpiece material or having sufficient resistance to abrasion. Therefore, steel materials are mainly used because with them the impact of the grains leads predominantly to elastic and plastic deformation.

Main area of ​​Ultraschallschwingläppens is the finest three-dimensional contours to work in materials such as ceramic, graphite or glass out. It can be depressions with a diameter less than one millimeter in workpieces incorporated, which are thinner than 200 microns. A typical product is the graphite electrode for the die-sinking EDM.

Swell

  • Wilfried König, Fritz Klocke: Production process 3, ablation and generation. Springer -Verlag: Berlin, Heidelberg, 1997, ISBN 3-540-63201-8, pp. 129-152
  • Alfred Reichard ( Eds.): Manufacturing Technology 1 Publisher's craft and technology: Hamburg 2000, ISBN 3-582-02311-7, p 212
  • Machining
  • Ultrasound
Longitudinal wave
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