Development of New Techniques for Impregnated Diamond Coring Bit Wear Measurement in Conventional Rotary Drilling and Vibration Assisted Rotary Drilling

Drilling cost is controlled to a large extent by the drilling rate which is heavily influenced by the wear condition of the bit. The wear characteristics of bits are controlled by a range of factors. The principal factors which need to be considered in predicting wear rates are the bit, the bit operating parameters and the characteristics of the penetrated rock. This is a study of bit wear and a report on techniques developed and used to investigate bit wear. Two types of material were drilled with impregnated diamond core bits using a fully instrumented laboratory drilling rig at one rotational speed and over a range of weights on bit under a conventional rotary drilling condition as well as vibration assisted drilling.;Replicas of cutting segments on impregnated coring bits were made to record the status of the bits after drilling. Wear (weight loss and height loss) of each bit were measured after a series of holes were drilled in concrete specimens. The wear of diamonds and the matrix on each bit used in hard rock drilling was measured on replicas with optical microscopes. The wear amount after each drilling increased with an increase in weight on bit. Comparing the wear amount in conventional drilling with that in vibration assisted rotary drilling, the vibration assisted drilling produced more cutting tool wear than the conventional rotary drilling under the same weight on bit.