FRIABILITY AND CRUSHING STRENGTH OF MICROMETER-SIZE DIAMOND ABRASIVESUSED IN MICROGRINDING OF OPTICAL-GLASS

In abrasive grinding, the properties of the abrasives and their respon se to impact loading play a significant role in determining the result s achievable. For micrometer-size diamond abrasives used for bound-abr asive microgrinding of optical glass, friability testing is used to es timate the related particle properties. Friability and crushing streng th of diamond abrasives are estimated based on the data from comminuti on of sample powders on a commercial SPEX mixer/mill. Different diamon d abrasives as well as a CBN abrasive are tested. Evolution of powder size and size distribution with comminution time is characterized with a HORIBA laser scattering analyzer. Correlation is established for th e impact stress and the probability of fracture during comminution. Th is study demonstrates how to combine the ease of data acquisition foun d in a conventional friability test with the capability of predicting specific mechanical properties normally found only by crushing individ ual abrasive particles.