Papers by Keyword: Diamond Wheel

Abstract: During the dressing process of diamond wheel using laser/ultrasonic-vibration combined dressing method, the removal mode of the local materials on the surface of wheel with the use of laser’s heating effect transits from brittle fracture to plastic flow, so that the wear of diamond dresser can be reduced and the dressing efficiency and surface dressing quality can be improved. Using ANSYS analysis software, the three-dimensional units were used and the nonlinearity of the material’s thermophysical properties was taken into account, and thereby, the finite element model of the temperature field of the diamond wheel heated by the laser during the dressing process was constructed. Then, the distributions of the temperature field on the surface and section of the wheel under different technological parameter were acquired. Moreover, the temperature distribution of the dressed wheel under actual working conditions was measured using infrared temperature measurement method. The results indicate that, under the same working conditions, the simulation results using finite element model fit well with the measured values, i.e., the finite element model has important guiding significance to the selection of technological parameters in dressing.

Abstract: Polycrystalline diamond (PCD) has excellent properties such as high hardness, high chemical inertness, high wear resistance and a low friction coefficient. Thus, it has been expected to be applied to used in various mechanical parts such as sliding parts. However, diamond is difficult to machine owing to its high hardness and chemical inertness. Therefore, a highly efficient and high-quality machining process is required for PCD. In this study, the authors developed fixed abrasive polishing tools for the mirror-like surface finishing of PCD that contain mechanochemical abrasive grains with diamond grains. As a result of fixed abrasive polishing experiments, it was clarified that a mirror-like surface can be obtained by fixed abrasive polishing using a tool containing SiO₂ and diamond abrasives. Moreover, it was found that the removal efficiency can be increased under a high-temperature condition.

Abstract: The zirconia parts are limited by machined surface quality. The grinding force is one of the most important parameters of grinding and has effects on surface quality. The MK2710 grinder and resin bond diamond wheels were used in zirconia grinding. The grinding force was obtained by Kistler dynamometer. The paper focused on wheel speed and grain size on grinding force, and examined the surface by SEM. The research results indicated that decreasing the grain size, the grinding force increased and the surface quality improved, and increasing wheel speed could decrease grinding force to improve grinding surface quality. The results can improve zirconia ceramic parts surface quality and promote application.

Abstract: There is the grade as one of the selection criteria of a grinding wheel like WA whetstone or GC whetstone. The grade of grinding wheel is defined as an index which shows the strength of connection of a grain and a grain, and is usually estimated by bending strength. There are many papers about the relationship between the grade of a grinding wheel and the grinding performance. And, the relationship between the grade of a grinding wheel and the grinding performance is almost clear. Also, the relationship between mechanical properties of a grinding wheel and the grade is also clear. On the other hand, since the grain layer of a super abrasive grinding wheel is thin, it is difficult to apply the conventional evaluation test of the grade. And, the evaluation method of the grade which can be adapted the super abrasive grinding wheel is not established. In addition, since the grade of a super abrasive grinding wheel is a manufacture manufacturer's original standard, there is a minute difference by manufacturer. The super abrasive grinding wheel as well as the grinding wheel is conjectured that the grade influences the grinding performance. Namely, it is important to relate the grade and the mechanical properties of a grain layer. However, researches which relate the grade, the grinding performance and the mechanical properties of a super abrasive grinding wheel are not done so far. Therefore, this study examined the relationship between the mechanical properties of a grain layer of a super abrasive grinding wheel and the grade, the grinding performance. The final objective of this study is to evaluate the grinding performance from mechanical properties of a grain layer of a super abrasive grinding wheel. The purpose of this report is to clarify relationship between the grade and the grinding force in a resinoid bond diamond wheel. The specific experiment procedure is as follows. When carrying out surface grinding of the diamond sticks using a grinding wheel, the relationship of the grade and the grinding force was clarified. And based on the knowledge acquired in this experiment, relationship between the grade of a super abrasive grinding wheel and the grinding force was considered. As the results, it confirmed that the grade of a resinoid bond diamond wheel could be evaluated by the grinding force.

Abstract: This study was examined about the relationship between the fillers added to the grain layer of a resinoid bond diamond wheel and mechanical properties, the grade, the grinding performance. In the abrasion test using a constant pressure grinding, it was shown clearly that the critical grain holding power changed by kinds of fillers. On the other hand, in the constant cut surface grinding, the grinding interval was evaluated based on the grinding force. And, it was confirmed that the grinding interval changed by kinds of filler. Also, it was found that the characteristics of truing and dressing changed by kinds of filler. In addition, Young's modulus and bending strength of the grain layer of a resinoid bond diamond wheel was measured by three point bending test and ultrasonic pulse method. In the results, it checked that the mechanical properties such as bending strength and Young's modulus of a grain layer changed by kinds of filler. And, the modulus of rupture was calculated from the Young's modulus and bending strength.The result of having compared the modulus of rupture with the critical grain holding power, it was found that the modulus of rupture and the critical grain holding power have good correlation. Namely, the critical grain holding power of a resinoid bond diamond wheel can be evaluated by the modulus of rupture. Furthermore, it was shown that the grinding performance may be able to be predicted by the modulus of rupture of a grain layer of a resinoid bond diamond wheel.

Abstract: This paper describes on the experimental results of diamond wheel wear in groove grinding of cemented carbide. The speed ratio of grinding was widely changed. Square grooves and 90 degree V-grooves were ground. The square grooves were ground by using a resin-bonded diamond wheel and the V-grooves were by a vitrified diamond wheel. At first, a water-based coolant was used, but afterward, to investigate a possibility of nitrogen to suppress the wear of wheel, nitrogen gas was dissolved into the water-based coolant. The main results obtained are as follows, (1) The wheel wear increases as the speed ratio decreases, (2) The average grinding forces is almost independent from the grinding conditions but those at the lowest speed ratio are fairly large, (3) The influence of nitrogen gas dissolved coolant is small, but in a case of V-shape grinding at a middle speed ratio there found a considerable decrease of wheel wear.

Abstract: The wafer grinding by use of fixed abrasive diamond wheels is required to create a high-quality wafer surface in a short time. In general, it is known that the grinding performance of diamond wheel is mainly dependent on grinding wheel specifications and grinding conditions. The cutting edge distribution or abrasive protrusion height in depth-wise of a specified wheel is one of the most important factors to determine the finishing surface roughness and the grinding force, which in turn determine the surface and subsurface quality of ground wafers. The overall purpose of this study is to understand the dynamic behavior of each diamond abrasive via modeling an actual diamond wheel and simulating of wafer grinding. In previous report [1], we have theoretically analyzed three-dimensional cutting edge distribution on the working surface of diamond wheels. This paper reports our recent achievements in the evaluation of 3-D cutting edge distribution in depth-wise of a specified wheel via the bearing ratio of its topography.

Abstract: Glass panels are one of core components in liquid crystal displays (LCDs). Grinding is an essential edge chamfering process in the preparation of LCD glass panel. With the size of glass panel increasing, both high productivity and high quality are required in the edge chamfering process. However, surface and subsurface defects are usually introduced to the chamfered glass edge under high-efficiency grinding conditions. In this work, we explored to develop crack-free grinding process while maintaining high chamfering efficiency with two designed diamond wheels for the chamfering of LCD glass edges. The grinding performance was compared and analyzed in terms of surface roughness and morphology. Normal and tangential grinding forces were measured to characterize the material removal characteristics. It was found that crack-free grinding/chamfering of LCD glass edge was achieved under high-efficiency grinding conditions i.e. wheel speed of 52.3 m/s, feed rate of 10 m/min, depth of cut of 50 μm. The developed grinding process is potential to reduce subsequent polishing time and cost or even replace subsequent polishing process for the preparation of LCD glass edge.

Abstract: Grinding experiments were carried out in wet, with MQL, in dry, with a spray of dry ice particles and various gases to examine influence of grinding atmospheres on the grinding performance in the combination surface grinding of steel and WC with a diamond wheel. From the experimental results, it was found that the grinding with inert gas injection which reduces an oxygen concentration at the grinding point would proceed a processing at more stable grinding force, resulting in less wear of the diamond abrasives.

Abstract: The deep narrow groove of the coupling plate and side with WC-CO coating was grinded by diamond wheel with metal bond and vitrified bond. The side of the deep trench flatness error was less than 0.02 mm, the bottom of the tank around the corner radius was less than 0.3mm. The type of porosity, particle sizes, surface roughness were measured by experiments, the data for the selection of the grinding wheel bond varieties. The experimental results show that grinding wheel with vitrified bond was suitable for parts of small coating porosity, fine particle size, surface roughness, and others were suitable for the grinding wheel with metal binder.