Papers by Keyword: Diamond Grinding

Abstract: A method of calculation of cutting forces at diamond grinding of brittle materials is proposed in article. The cutting forces: normal, tangential and fracture, acting to single grain are calculated. Total grinding forces are defined by average number of grain in contact zone. Calculating values of forces are compared with result of experimental approximation of measuring force at grinding of glass-ceramic workpiece. Grinding forces increase with increasing of diamond grains wear and can be indicative of grinding wheel blunting.

Abstract: The present study investigates the relationship of process parameters in electro-discharge diamond face grinding (EDDFG) of tungsten carbide and cobalt composite (WC-Co). The central composite rotatable design had been utilized to plan the experiments and response surface methodology (RSM) was employed for developing experimental models. Analysis on machining characteristics of EDDFG was made based on the developed models. In this study, wheel RPM, current, pulse on-time, and duty factor are considered as input process parameters. The process performances such as material removal rate (MRR) and average surface roughness (Ra) were evaluated. Analysis of variance test had also been carried out to check the adequacy of the developed regression models. The observed optimal process parameter settings are wheel RPM of 1500, current of 6.9029 A, pulse on-time of 137. 8208 µs, and duty factor of 0.79 for achieving maximum MRR and minimum Ra; finally, the results were experimentally verified. A good agreement is observed between the results based on the RSM model and the actual experimental observations. The error between experimental and predicted values at the optimal combination of parameter settings for MRR and Ra lie within 6.18% and 12.33%, respectively.

Abstract: High density and isotropic poreless structure of Glass-like-carbon makes it practically used for fuel cells of space-shuttles and hard disk substrate etc. Glass-like-carbon is one of the new materials which attract attention, but it is so hard and brittle that precise machining of this material is difficult. Surface grinding and slicing were performed to collect the fundamental data of precise machining. The main results obtained in this study are as follows. (1) The transition from brittle mode to ductile mode in surface grinding occurs at a grain mesh size between #5000 and #3000. (2) The maximum grain depth of cut ‘dg’ necessary for ductile mode grinding is 0.021-0.006 mm or less. (3) When it is being sliced, the kerf width of the #1000 grinding wheel becomes wider than that of the #2000 grinding wheel because of the fact that the material removal capability of the #1000 grinding wheel is bigger than that of the #2000 grinding wheel. (4) It is extremely effective to use the fine grinding wheel, since the Young's modulus of glass-like-carbon is considerably low and eventually causes compression transformation,.