Technology of ultrasonic machining of advanced ceramics

Ultrasonic lapping is classified, according to DIN (GS), as cutting with a geometrically undefined cutting edge. Both simple bore-holes and complex contours can be produced using this diesinking process. Analysis of the cutting mechanisms has demonstrated that the width of the gap between tool and workpiece influences both the material removal rate and the wear characteristics of the tool. The gap width is determined by the lapping pressure exerted on the tool and by the amplitude of vibration. When there is an optimum combination of these two parameters, the removal rate increases and wear distribution becomes more even. The machining result is also affected by the oscillation characteristics of the sonotrodes. The oscillation quality has been improved and both the material removal quantity and machining accuracy have been increased by the application of the Finite Element Method. It has also emerged that the use of PCD-tipped tools can greatly reduce tool wear. The deployment of a pr ocess monitoring system increases the reproducibility in ultrasonic machining operations, which is also beneficial to the level of quality which can be reached.