Ultrasonic lapping

Through-holes are only possible in very thin substrates. This process can be combined with other means of structuring glass for example, microsandblasting or ultrasonic lapping (Figure 2.14). 

Design of vibration system and vibration course for the example of ultrasonic lapping. (From Bonsch, C.W., Dissertation RWTH Aachen, Germany, 1992 Haas, R., Dissertation RWTH Aachen, Germany, 1991.)... 

Process of ultrasonic lapping and machining (Photo from MAFELL Company, Oberndorf, a.n., Germany.)... 

Influences on machining result during ultrasonic lapping. 

There are different removal mechanisms listed for ultrasonic lapping in literature that rate the various identified mechanisms partially according to... 

Figure 17.5 presents the predominant mechanisms of material removal during ultrasonic lapping. 

Recent investigations (Hilleke, 1998) confirm the statement that direct and indirect impacts as well as grain spinning-on onto the workpiece surface represent the predominant mechanisms of material removal during ultrasonic lapping. The contribution of cavitation phenomena is considered to be trivial (Rozenberg et al., 1964). 

Since the material removal during ultrasonic lapping is based, as described, on the embrittlement of increasingly stressed material areas, materials with a distinctive elastic-plastic behavior are used as coimterpart materials. The wear, however, cannot be avoided despite a specific material selection therefore, the following effects on the process result emerge (Noelke, 1980 Bonsch, 1992) ... 

The use of PCD counterparts could significantly reduce the wear and distinctly improve the reproducibility of the accuracies of shape and dimension (Noelke, 1980 Konig and Bonsch, 1991). Owing to the high material costs, however, PCD counterparts have not been accepted for ultrasonic lapping. 

Material removal rate in relation to contact pressure and rotational speed during ultrasonic lapping of AI2O3 with rotating shape-generating counterpart. (From Cartsburg, H., Dissertation TU Berlin, 1993. With permission.)... 

Ultrasonic lapping and polishing machines are available as easily manageable, effective, and thus economical equipment (Figure 4.74) for the superfinishing of small and very small areas, bars, and slits. 

---