Mirror Surface Grinding Research Articles

ELID Mirror Surface Grinding for Concave Molds by Conductive Elastic Wheel Containing Carbon Black

Elastic grinding wheels have previously been adopted for the development of the mirror surface finishing method for concave spheres. In this study, new conductive elastic grinding wheels, to which electrolytic in-process dressing (ELID) can be applied, are developed; the aim of the study is to address the challenge of maintaining a constant removal rate for rubber bond wheels. When ELID grinding is performed using a non-diene (isobutane isoprene rubber, IIR)-based wheel, a larger removal amount is achieved, and a higher-quality surface is also achieved compared to a diene (acrylonitrile-butadiene rubber, NBR)-based wheel. In addition, to investigate the effect of grinding wheel bond hardness on the removal amount and ground shape accuracy, grinding wheels with various levels of hardness are prepared by controlling the amount of carbon black contained in them, and grinding experiments are conducted. Thus, a larger removal amount is achieved using a harder grinding wheel, but the roughness of the ground surfaces deteriorates. Therefore, in practice, it is necessary to select an appropriate grinding wheel that can achieve both productivity and surface quality. Finally, to obtain a high-quality mirror finish on a concave spherical surface, ELID grinding is performed on the workpieces as is done for spherical lens molds. Thus, high-quality mirror surfaces with roughness Ra < 10 nm were generated. When the work pieces are ground using a grinding wheel of the same radius, excessive removal occurs at the edge of the concave spherical profile, decreasing the form accuracy. Numerical simulation demonstrates that chamfering of the grinding wheel is effective for improving the shape accuracy. The results of this study are expected to contribute to automation and cost reduction in the mirror-finishing process for concave molds.

Removal mechanism of ultrasonic vibration and ELID composite plane grinding based on ultrasonic vibration of nano-ceramic workpiece

To realize the high efficiency mirror surface grinding of hard brittle materials (such as nano-ceramic material), this work firstly constructs an experimental platform for workpiece ultrasonic vibration and ELID combined plane grinding according to the processing mechanism of ultrasonic vibration assisted grinding and ELID grinding; then, based on the removal mechanism of hard brittle material, this work analyzes the kinematics of single abrasive grit with workpiece ultrasonic vibration plane grinding, and studies the effect of ELID plane grinding on the grinding depth; finally, based on the above work, this work proposes the mathematical model of material removal rate for the workpiece ultrasonic vibration and ELID combined plane grinding. Experimental results show that the material removal rate of combined plane grinding increases with the increase of the cutting depth and workpiece speed, the material removal rate of ultrasonic vibration and ELID combined grinding is higher than that of ELID grinding under the same conditions.

Basic study on mirror surface grinding of CVD-SiC material

Basic study on mirror surface grinding of CVD-SiC material

Mirror surface grinding of sapphire by coarse grain size diamond wheels

This paper discusses the grinding of sapphire for mirror surfaces by coarse grain size diamond wheels. Sapphire is a hard-to-machine material because it has excellent mechanical properties and indentation hardness. Since it is effective for hard materials to use metal-bonded diamond wheels, the authors had two experiments to investigate mirror surface grinding by coarse grain size diamond wheels. The 1st experiment was investigating appropriate grinding conditions, and the 2nd experiment was investigating protrusion height of abrasive grains. Although the conventional methods could not acquire mirror surface, the results of the experiments show that mirror surface (Ra: 5 nm <) were obtained by the #270 and #325 mesh size wheels. These results indicate the possibility of decreasing grinding processes by coarse grain size diamond wheels.

Research on the error analysis and compensation for the precision grinding of large aspheric mirror surface

The purpose of this paper is to propose a compensation grinding method for large aspheric mirror surface. Because the tradition grinding is not suitable for large aspheric mirror surface, in this paper, a grate parallel grinding in 3-axis and an on-machine measurement system are applied. Based on that, it presents the errors that mainly affect the form accuracy and technology of compensation grinding. An experiment of compensation grinding was carried out for large aspheric mirror surface. With the separation of decentering, wheel arc, and residual grinding system error, the PV value further decreased comparing to tradition compensation. These results indicated that this compensation can improve the form accuracy significantly in large aspheric mirror surface grinding.

Finite Element Analysis for Critical Components of Ultra-Precision Grinding Machine Tool

The ensemble static stiffness of machine tool is its ability to maintain smooth working condition and resist a variety of loads. As the dispensable part of ensemble static stiffness, critical components stiffness plays a significant role in the performance of the ultra-precision grinding machine tool. In this paper, a three-axis CNC grinding machine tool for the ultra-precision mirror surface grinding of advanced materials such as ceramics and other hard and brittle materials has been designed. And the stiffness and modal parameters of the grinding machine tool are discussed using finite element software. The results are presented and discussed thoroughly. This in turn can help to revise design defects and reduce research and develop costs.

ELID法による鏡面研削効果と特性

ELID法による鏡面研削効果と特性

단결정 사파이어 광학소자의 ELID 경면연삭 가공 특성

This study has been focused on application of ELID mirror-surface grinding technology for manufacturing single crystal optic sapphire. Single crystal sapphire is a superior material with optic properties of high performance as light transmission, thermal conductivity, hardness and so on. Mirror-surface machining technology is necessary to use sapphire as optic parts. The ELID grinding system has been set up for machining of the sapphire material. According to the ELID experimental results, it shows that the surface of sapphire can be eliminated by metal bonded wheel with micron abrasives and the surface roughness of 60nmRa can be gotten using grinding wheel of 2,000 mesh in 4.5um, depth of cut. In this study, the chemical experiments after ELID grinding also has been conducted to check chemical reaction between workpiece and grinding wheel on ELID grinding process. It shows that the chemical reaction has not happened as the results of the chemical experiments.

금속기지 세라믹 복합소재의 경면연삭 가공 특성

This study has been focused on properties of mirror surface grinding technology by ELID(Electrolytic In-process Dressing) for metal matrix ceramic composites using in high precision mirror for optics. The experimental studies have been carried out to get mirror surface by grinding for composites, Al-SiC, Al-graphite and Mg-SiC. Grinding process is carried out with varying abrasive mesh type, depth of cut and feed rate using diamond wheel. The machining result of the surface roughness and condition of ground surface, have been analyzed by use of surface roughness tester and SEM measurement system. ELID grinding technology could be applied successfully for the mirror-surface manufacturing processes in spite of ductility of metal matrix material. As the results of experiments, surface roughness of Al-SiC(45 wt%) has been the most superior in these experimental work-pieces as 0.021 μm Ra.

다이아몬드 지립을 이용한 구조세라믹스의 경면가공 특성

This study has been focused on properties of mirror surface grinding technology by ELID(Electrolytic In-process Dressing) for structural ceramics using in high precision structural parts as like semi-conductor manufacturing processes. The experimental studies have been carried out to get mirror surface for grinding of structural ceramics, SiC, Al₂O₃ and AlN. Grinding process of the ceramics is carried out with varying mesh type, depth of cut and feed rate using diamond wheel. The machining result of the surface roughness and condition of ground surface, have been analyzed by use of surface roughness tester, SEM, AFM and three dimensional surface profiler measurement system.

Development of a Desktop Machine Tool for Mirror Surface Grinding

This paper is a report on the process of developing a desktop machine tool to be used in “Micro Workshops.” It incorporates emerging technologies for the production of “micro parts and components” as a newMonotsukuriThe resultant desktop machine tool was developed after designing structures which simultaneously meet both requirements of lighter weight and sufficient rigidity and which prove to be capable of producing mirror quality finish using the electrolytic in-process dressing (ELID) grinding .system.In order to verify the successful achievement of mirror surface grinding, a fine grain (#8000) abrasive grinding wheel used in the ELID grinding system was employed to generate an aspherical surface by cross grinding technique after completion of development on the aforementioned simultaneous achievement of lightness and rigidity for mainframe structure of the machine.The grinding wheels used in this experiment were a grinding wheel of #1200 diamond abrasive grain bonded with cast iron and another type of grinding wheel of #8000 cerium oxide abrasive grain bonded with metal resin.As the basic experiment, a silica-glass workpiece was ground and finished using the cross-grinding technique. The result showed that stable grinding and finishing operations can be achieved without burning during grinding even by using a very fine abrasive grain of #8000 or higher.

Nano-precision combined process of electrolytic in-process dressing grinding and magnetic assisted polishing on optics glass material

This study is focused on the application of an effective fabrication method combining electrolytic in-process dressing(ELID) grinding and magnetic assisted polishing(MAP) to nano-precision mirror surface grinding on the optics glass-ceramic named Zerodure that is commonly used in precision optics components. The results show the variation of surface roughness after MAP processes utilizing Fe+CeO 2, Fe+CeO 2+diamond paste and Fe+diamond paste are applied to ELID ground surfaces. The MAP surface roughnesses for ELID ground surface roughnesses( R a) of 52.1, 39.8 and 51.1 nm using #1200 grinding wheel are improved to 6.1, 4.6 and 1.9 nm, respectively. The surface roughness of MAP process using Fe+CeO 2+diamond paste is superior to that using other processes. Moreover, it takes less than 10 min to conduct the MAP processes. The combined method suggested effectively reduces the working time to get the required surface qualities.

Development of Mirror Surface Grinding with ELID

Development of Mirror Surface Grinding with ELID

Nanoprecision Micromechanical Fabrication

ELID grinding is a method that realizes high quality mirror surface grinding in the nanometer order by use of electrolytic dressing metal bonded wheels consisting of fine abrasives. Currently, ELID grinding is increasingly being applied as an ultraprecision grinding method to achieve desired surface roughness, high surface accuracy, high surface quality, and high grinding performance. This paper introduces the ELID grinding and discusses some applications of ELID grinding to mirror surface grinding. For ultraprecision optical components, ultra fine smooth surface quality of sub-nanometer or sub-angstrom in Ra may be required. To satisfy these requirements, ultraprecision on machine measurement system had been developed. Synergistic the nano precision mechanical method, nano precision measurement method with nano resolution machine, the ultraprecision components can successful to fabricate.

Study on mirror surface grinding of die steel by using ultrasonically assisted diamond tools

This paper describes Ultrasonically Assisted Grinding (USG) to obtain a glossy surface quickly and precisely. In this research, diamond electroplated tools perform grinding experiments on a 3D milling machine equipped with an ultrasonic spindle system. Generally, diamond tools cannot cut ferrous materials because of the terrible wear due to diffusion of carbon into the bulk and chips. In USG temperature rising of tool abrasive is prevented due to discontinuous contact between tool and workpiece by periodical vibration. So, ultrasonically assisted diamond grinding can make fine surface (roughness Rz is 0.4-0.84 µm) of die steel, without severe tool wear. Effects of tool feed rate, radial depth of cut and axial depth of cut on the ground surface were investigated.

Functionalization of stainless steel surface through mirror-quality finish grinding

In this study, a stainless steel mirror-finished surface obtained by a high-precision grinding process was investigated in detail using some advanced surface analyzing techniques. We found that the mirror-surface grinding process produced a stable oxide layer on the workpiece surface, and also that the abrasive elements of the grinding wheel penetrated and diffused into the substrate. Compared with surfaces that had been polished, surfaces that had been mirror-finished by grinding process exhibited superior surface properties including hardness, tribological and fatigue properties, corrosion and high-temperature oxidation resistances, and adhesive strength with coating films. In addition, varying the processing conditions offers the possibility of controlling the electrical potential characteristics and hydrophilicity of the surfaces.

3609 マイクロハードディスク用超精密フラット・チャンファリングシステムの研究開発(G13 生産加工・工作機械,G13 生産加工・工作機械)

Recently, a demand for micro hard disk is on the increase. Along with it, it is necessary to machine micro hard disk with smoother surface (ultra precision flat) and sharper edge (ultra precision chamfer). In this research, we developed the ultra precision flat/chamfer machining system for micro hard disk, and we investigated a characteristic of this machining system. This machining system has control part, mirror surface grinding part with ELID unit, processing arm part and standby part for glass hard disk. As a result using this machining system, when a SD#8,000 wheel and #8,000 particles of CeO_2 were used, finished roughness was Ra 5.2nm and 2.8nm.

Study on mirror surface grinding of die steels by using ultrasonically assisted diamond tool(Grinding technology)

This paper describes ultrasonically assisted grinding for injection die steel using diamond abrasive tools. In this study, a 3D positioning machine equipped with an ultrasonic spindle carried out grinding experiments. Generally, diamond tools cannot grind steel because of the terrible wear due to chemical reaction between diamond and steel. However, ultrasonically assisted grinding can make fine surface (roughness Rz is 0.4〜0.84μm) of die steel, without severe tool wear. Effects of tool feed rate, radial depth of cut and axial depth of cut were investigated.

2916 ELID 研削によるシリコンウエハの超薄厚加工

For grinding the ultra thin wafer, an ELID-grinder for substrates had developed. In this study, the authors thus attempted the mirror surface grinding of thin silicon wafer by the electrolytic in-process dressing (ELID) grinding method, which has been successfully used to obtain efficient and high quality ground surfaces of brittle materials. In the experiments, #2000 and #4000 cast bonded diamond wheels were used to investigate the ELID grinding characteristics of silicon. The results of the experiments showed that the ground surface roughness improves as the abrasive diameter becomes smaller, and a high quality-grinding surface of 7.0 nm Ra can be achieved with the #4000 wheel, and good surface flatness can be obtain.

Mirror surface grinding of steel bonded carbides

Mirror surface grinding of steel bonded carbides