Defect evolution during machining of brittle materials
A simple stress based defect evolution model is developed to assess the influence of various process paramters on material removal rate (MRR) and induced damage during ceramic grinding processes. Model predictions for normal and lateral damage zones under normal indentations are first compared to fracture models as well as experimental observations on pyrex glass. The proposed model is then extended to simulate oblique indentation events depicting abrasive grit-workpiece interactions during ceramic grinding. It is also easily extendable to real grinding situations involving multiple interacting abrasive grits. Process design options for reducing induced damage in the finished part, and increasing MRR are considered next. In particular, the potential of a new design avenue involving intermittent unloading is investigated. For pyrex glass, it is observed that intermittent unloading can facilitate significant increase in force per abrasive grit without increasing the associated surface and sub-surface fragmentation in the finished part. This design feature may enable significant increase in MRR, while maintaining a very low level of process induced damage in the finished product. © 1997 Elsevier Ltd. All rights reserved.
Studies in Applied Mechanics
Defect evolution during machining of brittle materials.
Studies in Applied Mechanics,
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