Papers by Keyword: Diamond Tool

Abstract: A tool for fabricating micro/nanopatterns was utilized in space optics, virtual reality, augmented reality, and semiconductor industry. Nowadays, demand of manufacturing technique for ultra-precision is continuously increasing virtual reality and augmented reality industry across the board and core technique for manufacturing next generation lens is cutting tool fabricating technique with nanoscale. In particular, tools of micro/nanosize for ultra-precision machining was made by using an ultra-precision grinding, but it was difficult to fabricate tools which have under micro scale. Recently, results of studies with many researchers were pulsed laser ablation, electric discharge machining and precision grinding. However, previous studies are unsuitable in making tools of micro/nanoscale. Due to unique physical properties of diamond, it can be easily controlled by using focused ion beam. The surface properties of the diamond layer are affected because of the amorphous damage caused by the FIB gallium ions collision, implantation and these effects can make to be able to control the geometry of cutting tool. In this study, we carried out in fabricating diamond tools under micro scale by using FIB milling through various process studies and determined in order to optimize the length of unstable tool.

Abstract: Contact lens manufacture requires high accuracy and surface integrity. Surface roughness an important response because it has direct influence toward the part performance and the production cost. Hence, choosing optimal cutting parameters will not only improve the quality measure but also the productivity. This research work is therefore aimed at developing a predictive surface roughness model and investigate a finish cutting conditions of ONSI-56 contact lens polymer with a monocrystalline diamond cutting tool. In this work, a novel surface roughness prediction model, in which the feed rate, cutting speed and depth of cut are considered is developed. This combined process was successfully modeled using a Box–Behnken design (BBD) with response surface methodology (RSM). The effects of feed rate, cutting speed and depth of cut were investigated. Analysis of variance (ANOVA) showed that the proposed quadratic model effectively interpreted the experimental data with coefficients of determination of R² = 0.89 and adjusted R² = 0.84. The worse surface value was obtained at high feedrate and low spindle speed.

Abstract: Recently, high efficiency and performance have become necessary attributes of information equipment such as laser printers. Thus, demand has increased for optical scanning parts that reduce optical aberration, scatter, and diffraction are required in laser printers. Polygon mirrors are manufactured by polishing a plating or glassy material to a mirror finish. In this study, we shortened the manufacturing process to improve the productivity and ultra-precision cutting technology of polygon mirrors made of aluminum. Thus, we had to reduce the geometric surface roughness achieved by mirror-cutting Al-Mg alloy and remove tear-out and scratch marks that occur during the cutting process. We investigated the cutting edge shape by using a straight diamond tool to decrease the surface defects produced during the ultra-precision cutting of Al-Mg alloy. We examined the mechanism for the occurrence of scratch marks and a method to reduce them. First, we measured the shape of the scratch marks and the cross-section with a scanning electron microscope. We found the tool collides with crystallization to produce small pieces, which then cause scratch marks. We developed a triple-facet tool with a double-facet at the end cutting edge to remove scratch marks and investigated the influence of surface defects. We clarified that using the triple-facet for a tool setting angle of 0° to 0.04° could achieve a good-quality machined surface without tear-out and scratch marks. In addition, the undeformed chip thickness was less than 80 nm

Abstract: One research objective for generating gear grinding is to increase economic efficiency and productivity of the process. Furthermore, the gear quality must be equal or higher compared to the non optimised process. In addition to the grinding process and the grinding tools, the dressing process can be suitable to lead to an increase of efficiency of generating gear grinding. Due to the variety of dressing tool specifications process users have the problem of selecting the best fitting dressing tool for their demands. Therefore, it is necessary to know the interactions of dressing tool specification and dressing tool wear. But the influence of the dressing tool specification onto dressing tool wear has yet not been sufficiently investigated for generating gear grinding.

Abstract: The paper presents a review on the current situation of diamond tool ultrasonic vibration cutting ferrous metal. The key technology of diamond tool ultrasonic vibration cutting ferrous metals is presented in this paper and the influence of the processing environment of the presence of carbon atoms protective gas, the presence of carbon particles coolant of temperature control technology, ultrasonic vibration, workpiece material surface pretreatment or without on diamond tool wear rate and workpiece surface quality, the relationship between diamond tool wear rate, the workpiece surface quality and the ultrasonic vibration technology, processing environment, workpiece material surface pretreatment technology factors is given. Propose research direction and research emphasis on reducing diamond tool wear rate and improve workpiece surface quality.

Abstract: In this study, we investigated ultra-precision cutting technology of aluminum alloys for polygon mirrors made of Al-Mg Alloys. It is necessary to improve the geometric surface roughness achieved in the mirror cutting of Al-Mg alloys and remove tear-out marks and scratch marks that occur during the cutting process. Therefore, we investigated the cutting edge shape using 2 types of straight diamond tools and 2 types of round tools to decrease the surface defects in the ultra-precision cutting of Al-Mg alloys. As a result, a double-facet tool can achieved a good machined surface roughness and reduce the cutting force and the scratch marks compared with other tools.

Abstract: The use of hard and brittle materials for manufacturing optical parts, such as dies and molds are required in order to extend mold life. Although, cobalt-free tungsten carbide is one of the hardest materials, micro-cutting is very difficult due to its hardness and its brittleness. This paper investigates face turning of cobalt-free tungsten carbide using a nanopolycrystalline diamond [NPD] tool and Zinc dialkyldithiophosphate (ZnDTP) fluid. Surface roughness of the cobalt-free tungsten carbide achieved was 22nmRz, which is far larger than the theoretical value. That is, traditional cutting theory does not directly apply for face turning of cobalt-free tungsten carbide using NPD tool and ZnDTP fluid.

Abstract: Recently, increasingly high efficiency and high performance have become to be required of information equipment. As a result, optical scanning parts that reduce optical aberrations, scatter, and diffraction are required in laser printers. It is therefore necessary to improve the geometric surface roughness achieved in mirror cutting of Al alloys and eliminate tear-out marks and scratch marks that can be created during the cutting process. In this study, we investigated the effect of tool wear on the occurrence of surface discontinuities in ultra-precision cutting of Al alloys. In our previous studies, a crystal orientation of {110} plane was adopted in cutting an Al-Si alloy (AHS material, 11wt% Si) and Al-Mg alloy (A5186 material, 4.5wt% Mg) using a straight diamond tool. The cutting edge recession that occurs when cutting AHS material has been reported to be approximately 5 times greater than that which occurs when cutting A5186 material. Therefore, we cut the AHS material for accelerated wear and investigated the cutting edge recession, the surface roughness and the cutting force. We found that the cutting edge recession decreases as the tool wear angle γ increase. For example, at a tool wear angle γ = 40°, the cutting edge recession is approximately 7 times greater than that which occurs at a tool wear angle γ = 12°. As the tool wear angle increases, the cutting distance increase, which produces a mirror like surface. In addition, we were able to obtain a good machined surface using a positive tool setting angle because side cutting edge produces residual stock of removal 0.1 μm when the cutting edge recession is 0.3 μm or more and when it is cut by following end cutting edge.

Abstract: This paper makes the experimental experiment on adding rare earth elements cerium doped in diamond matrix composites. Based on the doping of rare earth in metal powders including tungsten carbide, iron and nickel, the cobalt in diamond matrix is entirely with iron and the process route of rare earth doping is indicated. The performance of matrix composites with rare earth elements and free of rare earth elements is measured and the results obtained show that the flexural strength, the hardness and the impact ductility of matrix composites with rare earth elements are improved and the flexural strength increases by 10~62% over that of the composites free of rare earth elements, and the impact ductility by about 5% correspondently. We have successfully studied out the rare-earth diamond tool matrix composites replacing Co with Fe, bearing good practical service performance and low price, and have made corresponding diamond bit.

Abstract: Diamond tools are fabricated by brazing and used to machine dental ceramics in this paper. The morphology, grinding ratio, wear and grinding force of the brazed tools are investigated in comparison with that of the electroplated ones. The results show that the brazed alloy forms a hill-like structure around the diamond grits, and the protrusion of the brazed diamond grits is higher than that of the electroplated one. The grinding ratio of the brazed diamond tool is higher than the electroplated one. Many fall-off diamond pits of the electroplated tool and only few micro-crack diamond grits of the brazed tool are observed after grinding, and the brazed one remains well process capability. The grinding force of the electroplated tool is larger than that of the brazed one.