• Journal of the Korean Society for Precision Engineering
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• v.18 no.7
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• pp.106-111
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• 2001

This study reports the grinding characteristics of quartz. Grinding experiments were performed at various grinding conditions including wheel mesh, table speed and depth of cut. The grinding forces and specific grinding energies were measured. Surface roughness was also measured with tracer and the ground surfaces were observed with SEM. A new parameter SDR(Surface roughness Direction Ratio) is proposed to characterize the grinding mechanisms of quartz. A set of experiments was performed to verify the effectiveness of the suggested parameter. The experimental results indicate that the ductile mode is the dominant material removal mode at the grinding conditions which show the higher value of SDR whereas the material is removed by brittle fracture in a lower value of SDR value increases with wheel mesh size.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.5
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• pp.493-498
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• 2013

The present study treats the optimization process for a non-linear grinding system with dual time delay, mainly from the energetic viewpoint. To this end, the stability of the grinding system is investigated first with regard to the grinding wheel rotation speed. The concept of grinding energy density is newly proposed as the primary figure of merit and this quantity is evaluated at various stable and limit cycle conditions. The computational results show that simple monotonic trend in energy density is observed under stable conditions, whilst rather complicated behaviors can appear when the conditions are associated with limit cycle oscillations. Finally, the relations between the vibration amplitude and the energy density and their implications on the engineering decision/compromise are discussed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.459-464
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• 2000

In this paper, it verifies the relationships between wheel velocity and surface roughness with the mirror surface grinding using electrolytic in-process dressing (ELID). In the general, as wheel velocity is high, surface roughness is better on the base of grinding theory. However, the relationships between wheel velocity and surface roughness is undefined due to the effect of electro-chemical dressing and the characteristics of materials. According to above relationships, ELID grinding experiment is carried out by following the change of wheel velocity. As the result of this study, it is found that surface roughness is not better as linearly as the increase of wheel velocity, but the limit of wheel velocity exists according to the characteristics of materials. Also, in contradiction to the present trend of high wheel velocity of manufacturing system for high surface integrity, it is able to expected to the base on the development of new ultra precision grinding method with the practicality of mirror surface grinding using ELID grinding method.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.1
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• pp.16-22
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• 2018

Silicon carbide (SiC) is used in various semiconductor processes because it has superior thermal, mechanical, and electrical characteristics as well as higher chemical and corrosion resistance than existing materials. Due to these characteristics, various manufacturing technologies have been developed for SiC. A recent development among these technologies is Chemical Vapor Deposition SiC (CVD-SiC). Many studies have been carried out on the processing and manufacturing of CVD-SiC due to its different material characteristics compared to existing materials like RB-SiC or Sintered-SiC. CVD-SiC is physically stable and has excellent chemical and corrosion resistance. However, there is a problem with increasing the thickness, because it is manufactured through a deposition process. Additionally, due to its high strength and hardness, it is difficult to subject to machining.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.5
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• pp.40-46
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• 2017

A plasma gas control apparatus for semiconductor plasma etching processes securely holds a cathode for forming a plasma, confines the plasma during the plasma etching process, and discharges gas after etching. It is a key part of the etching process. With the advancement of semiconductor technology, there is increasing interest in parts for semiconductor manufacturing that directly affect wafers. Accordingly, in order to replace the plasma gas control device with a CVD-SiC material superior in mechanical properties to existing SiCs (Sintered-SiC, RB-SiC), a study on the grinding characteristics of CVD-SiC was carried out. It is confirmed that the optimal grinding condition was obtained when the result table feed rate was 2 m/min and the infeed depth was $5{\mu}m$.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.801-802
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• 2013

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.10
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• pp.81-86
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• 2020

A ceramic vacuum chamber feedthrough ceramic insulator is made of Al2O3; the manufacturing process involves filling alumina powder into a urethane mold and pressing it with a rubber press to produce a molded body. Thereafter, manufacturing is completed through primary shape processing, sintering, and secondary shape processing in the green body, which is a pressurized molding body, This work is intended to prevent defects in the first shape processing by improving the ceramic insulator in the green body, and to improve the productivity of the ceramic insulator by determining the optimal processing conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.880-883
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• 2000

Temperature generated in the workpiece during grinding process can cause thermal damages. Therefore it is important to understand surface temperature generated during grinding process. In this paper, a theoretical and experimental investigation were performed for the grinding temperature. Grinding experiments were performed in machining center using vitrified bonded CBN cup-type wheel. The surface temperature was measured using thermocouple and calculated through a model of the partition of energy between wheel and workpiece. The residual stress and hardness of ground surface were measured. The experimental results indicate that the surface temperature was in good agreement with theoretical ones. Residual stress and hardness of ground surface were more affected by the change of table speed than the depth of cut.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.12
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• pp.66-72
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• 1997

This paper aims at reviewing the possibility application over normal or abnormal, detection used by AE and the wear characteristics of grinding process. In this study, when diamond bur in dentistry with chosen grinding conditions were tuned at grinding. The variation of grinding resistance and AE signal is detected by the use of AE measuring system. The tests are carried out in accordance with diamond burs and workpiece: arcyl and bovine. According to the experiment results, the following can be expected: AE has the possibility to detect the state normality and abnormality. Hpwever, the grinding resistance measuring can find it difficult to detect it. It can be accurately excepted from AE occurrence pattern in contact start point of diamond bur and bovine, grinding condition and derailment point. It is known that AErms is well compatible with grinding resistance. According to the increase of the material removal rate, the specific energy of the diamond bur is inclined to dectease and the grinding resistance has a tendency to increase.