• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
• /
• pp.507-513
• /
• 1998

In surface grinding, the conditions of the grinding wheel has much more significant effect on the machined workpiece as compared to other metal removal processes. The contact between the grinding wheel and the workpiece introduce heat and resistance, which restrict the self-dressing of the grits and result in burrs cracks on the workpiece. Therefore, before or during the grinding operation, it is necessary to self-dressing the grinding wheel for more accurate performance. In general, however, the choice of the dressing time has made by the operator's own decision or the condition of the workpiece. In this paper, a new method for finding the optimal dressing time of the grinding wheel is proposed. In order to develop a more sophisticated methodology, a non-contacting in-process optical measurement method using a laser beam has been introduced to find the glazing, loading, and spilling of the grinding wheel Simultaneously, a three-dimensional computer simulation of the grinding operation has been attempted based on the contact mechanism between the grinding wheel and the workpiece. The grains of the grinding wheel are simulated and the optimal dressing time is determined based on the amount of grain wear and work surface roughness.

• 한국정밀공학회지
• /
• 제19권2호
• /
• pp.58-64
• /
• 2002

In these days, according to increasing the technical development, the dimension of a product goes up for ultra-precision. For the net shape manufacturing, grinding is a important process that influences directly the accuracy and the integrity of produced products. In this study, an experimental evaluation was carried out. Workpiece materials were used STD11, SUS304, and STB2 in accordance with varing condition of feedrate and depth of cut. From measuring the grinding force and the surface roughness, material characteristics of grinding by using CBN wheel were examined.

• Journal of Mechanical Science and Technology
• /
• 제15권9호
• /
• pp.1268-1273
• /
• 2001

To successfully establish the ELID-grinding, it is important to properly select the electrolytic condition according to grinding conditions. Currently, the selection of electrolytic condition is mainly dependent on the operators experience, which is one of difficulties preventing the successful application of ELID technique. In this study, an in-process measurement system of the insulating layer using two gap sensors-a capacitance type and an eddy current type-are developed and the change of the thickness of insulating layer during ELID grinding is detected. Evaluation experiments show the possibility to control the electrolytic condition through the in-process measurement of the layer status.

• 대한기계학회논문집A
• /
• 제29권4호
• /
• pp.614-623
• /
• 2005

This study aims to perform the characteristic evaluation of surface grinding for the STD11 material with experimental and analytic techniques based on the response surface model. The grinding force acting on the workpiece and the ground surface roughness were measured according to the change of grain size, table speed and depth of cut. The effect of spark-out on the grinding force and the surface roughness was also characterized. The frictional coefficient between workpiece and grinding wheel could be determined by the analysis of spark-out effect. From the experimental data, the second-order response surface models were developed to predict the grinding force and the surface roughness. Validation of the developed model was examined.

• 한국기계가공학회지
• /
• 제12권5호
• /
• pp.36-41
• /
• 2013

One of the problems in grinding process using a machining center(MC) with a small diametric wheels is machining error due to decrease of the quill diameter. In this study, side-cut grinding is performed with a vitrified bonded CBN wheel on the machining center. Grinding experiments are performed at various grinding conditions including quill length, quill diameter and depth of cut. The effect on the grinding force, machining error and surface roughness due to the change of the quill rigidity are investigated experimentally. The slenderness ratio of the quill is significant factor to analyse the change of the grinding force and machining error.

• 대한기계학회논문집A
• /
• 제21권8호
• /
• pp.1298-1310
• /
• 1997

In recent years, grinding techniques for precision machining of brittle materials used in electric, optical and magnetic parts have been improved by using superabrasive wheel and precision grinding machine. The completion of optimum dressing of superabrasive wheel makes possible the effective precision grinding of brittle materials. However, the present dressing system cannot have control of optimum dressing of the superabrasive wheel. In this study, a new system and the grinding mechanism of optimum in-process electrolytic dressing were proposed. This system can carry out optimum in-process dressing of superabrasive wheel, and give very effective control according to unstable current and gap increase. Therefore, the optimum in-process electrolytic dressing is a good method to obtain the efficiency and mirror-like grinding of brittle materials.

• 한국정밀공학회지
• /
• 제31권5호
• /
• pp.367-373
• /
• 2014

Surface texturing is a machining process on the surface to give engineering functions. The representative process of the surface texturing is lotus effect to give hydrophobic property by the lithography and chemical etching, which is the bio mimic from the nature. Surface texturing can be manufactured by a lot of processes, in particular using mechanical method such as a precise diamond turning, grinding, rolling, embossing, vibrorolling, and abrasive jet machining (AJM). Among them, the grinding process is notable in terms of the wide range of texturing area and fast processing time. The patterning by grinding is done by the grooved grinding wheel on the work piece. In this case, the pattern shape is determined by the grinding conditions as well as the wheel dressing conditions. In this paper, experimental study on the pattern shapes were done and provide the feasibility in use for the large area patterning.

• 한국기계가공학회지
• /
• 제21권6호
• /
• pp.36-43
• /
• 2022

Automobile brake discs are a major part of automobiles that are directly related to driver safety, and prevention of judder and squall noise is very important. This phenomenon occurs for complex reasons such as the precision and assembly of the brake module, and the material of the brake disc. The purpose of this study is to analyze the effect of the grinding wheel's grain size on the grinding conditions when machining cast iron, the material of the brake disc, and to derive the optimal grinding conditions through this.

• 한국정밀공학회지
• /
• 제19권6호
• /
• pp.145-154
• /
• 2002

CMP (Chemical mechanical polishing) process was used to control the fine grinding process induced mechanical damage of Cz Silicon wafer. Characterization of mechanical damage was carried out using Nomarski microscope, magic mirror and also using angle lapping and lifetime scanner evaluation after heat treatment. Magic mirror and lifetime scanner were very useful for the residual damage pattern characterization and CMP process was effective on the reduction of fine grinding induced mechanical damage.

• 한국생산제조학회지
• /
• 제25권6호
• /
• pp.440-444
• /
• 2016

Owing to the introduction of various IT devices with emphasis on portability and design, the TFT (thin film transistor liquid crystal display) panel applied to IT devices has the same shape as the product, and the portability requirement of IT devices has resulted in a need for panels with higher rigidity. In this study, the effect of grinding conditions such as the feed rate and edge speed of edge grinding on the surface roughness and chipping of the machined surface is investigated using a metal bond wheel. During edge grinding of alkari-free glass, weak mechanical property of glass results in big chipping owing to generation of tensile stress at the end of grining operation. The results of this study show that the grinding characteristics of alkali-free glass are obtained and meet industry requirements.