Abstract: Harder workpiece materials and increased efficiency requirements for grinding processes make the use of super abrasive grinding wheels indispensable. This paper presents newly developed processes for the dressing of super abrasive grinding wheels. The different bond systems of grinding wheels require distinct dressing process. In this paper, dressing processes for metal and vitrified bonded grinding wheels are investigated. It introduces the method of electro contact discharge dressing for the conditioning of metal-bonded, fine-grained multilayer grinding wheels. A description of the essential correlation between dressing parameters and the material removal rate of the bond material is presented. The considered parameters are the dressing voltage, the limitation of the dressing current and the feed as well as the infeed of the electrode. For the grinding of functional microgroove structures, multiroof profiles with microscopic tip geometries are dressed onto the grinding wheel. For this, a profile roller in combination with a special shifting strategy is applied on finegrained vitrified bonded grinding wheels.
Abstract: In this paper, the characteristics of high speed grinding of advanced ceramics, including alumina, alumina-titania, zirconia, silicon nitride and silicon carbide, were reviewed. The associated material removal mechanisms were discussed. Pragmatic technologies for the high speed grinding of advanced ceramics were also presented.
Abstract: Lapping is an important material-removal process for manufacturing of substrate wafers. Objectives of lapping include removing subsurface damage in sliced wafers, thinning wafers to target thickness, and achieving a high degree of parallelism and flatness of wafer surfaces. This paper reviews the literature on lapping of substrate wafers. It presents reported experimental results on effects of input parameters (lapping pressure, plate rotation speed, abrasive grain size, slurry concentration, and slurry flow rate) on material removal rate and surface roughness.
Abstract: Increasing the performance of the abrasive waterjet (AWJ) cutting technology for engineering materials is the ultimate aim of research in this field. This paper presents a review on the studies using a controlled nozzle oscillation technique to increase the cutting performance of the AWJ cutting technology and the associated mechanisms primarily based on the work in the author’s laboratory. Primary attention is paid to the discussions of the depth of cut, the effect and selection of process parameters and the advantages by using this technique in both single- and multi-pass cutting modes.
Abstract: ELID Grinding, since its introduction over two decades ago, has helped in material removal of hard and difficult-to-cut engineering materials. A gist of the important research milestones on the process has been organized in this report. The hybrid process of ELID Grinding has a simultaneous electrolytic reaction and grinding action. Electrolysis takes place between the conductive anodic wheel and highly conductive cathode in presence of a special electrolyte. The resulting anodic oxide wears off easily to allow efficient grinding. The different parameters involved in electrolysis complicate the mechanism of grinding and makes it significantly different from conventional grinding. Different variants of the process have also been reported, though the basic philosophy of operation is the same as basic ELID. Several authors have also suggested mathematical explanations, among other fundamental studies, that provide further insight. The basic components of the process, machine tool, power supply, grinding wheel, electrode and electrolytes, have also undergone several modifications and developments to deliver better results and suit specific purposes. The process has been successfully applied in stock removal operations for hard and brittle ceramic materials with low grinding forces compared to conventional grinding. Fine finishing of almost all kinds of hard and brittle materials, ranging from hardened steels, BK7 glass, mono-crystalline silicon, silicon carbide, aluminum nitride, silicon nitride etc, has been successfully carried out, to provide high quality surfaces with low sub-surface damage. Finally, discussions on the different stages of evolution of the process have been put forward as a conclusion to the report.
Abstract: The delivery of grinding fluid to the contact zone is generally achieved via a nozzle. The nozzle geometry influences the fluid velocity and flow pattern on exit from the nozzle orifice. It is important to the efficiency of the process and to the performance of the operation that the fluid is delivered in a manner that ensures the desired jet velocity has adequate coverage of the contact zone. Often, assumptions about adequate coverage are based on visual inspections of the jet coherence. This paper provides new insight into the internal nozzle flows and the coherent length of a wide range of nozzle designs. The work presents a new analytical model to predict coherent length which is shown to correlate well with measured data from experiment. Recommendations are given to guide a user to optimal design of nozzles to ensure adequate fluid supply to the contact zone.
Abstract: Progress of new dental materials such as biocompatible metal, ceramics is being accelerated because of aging society and sophistication of medical treatment. In addition, the demand for dental implant treatment is increasing. Currently, dental implant crowns (superstructures) are formed by cutting semi-sintered ceramics and then sintering the ceramics at a high temperature. So, there is some concern that to maintain the form accuracy of the workpiece is difficult. Meanwhile, it is usually difficult to machine sintered ceramics with high precision and high efficiency. In this paper, we tried to apply grinding with metal bonded superabrasive wheels, and investigated the grinding and surface characteristics of an alumina and zirconia ceramics for dental implant superstructure due to lack of such data. As a result of experiments, sintered dental ceramics can be ground with high precision and Fe, it has harmful effect to human body, was not detected in sintered dental ceramics.
Abstract: The effect of cutting-edge truncation on the grinding mechanism of quartz glass as a hard and brittle material was investigated. From computer-aided grinding simulations and experiments on surface plunge grinding it was found that cutting-edge truncation decreases the ground-surface roughness and the maximum grain depth of cut; however, the maximum grain depth of cut approaches a constant value depending on the grinding wheel specifications. The alternative means of making the maximum grain depth of cut much smaller than this constant value is to increase the speed ratio. Cutting-edge truncation should be terminated at the optimum truncation depth to avoid the high grinding forces resulting from the flattening of cutting edges.
Abstract: This article reviews the state-of-the-art techniques for polishing diamond and polycrystalline diamond composites. A focus is on their material removal mechanisms and features. It concludes that while each of them has its advantages and drawbacks, the technique by dynamic friction has a promising potential for polishing production.