• 한국정보통신학회논문지
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• 제18권2호
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• pp.276-281
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• 2014

본 논문은 산업용 로봇을 위한 힘 피드백 제어는 사람의 감각을 기반으로 한 작업을 대체하여 구현하기에 적합한 연마 시스템을 제안하였다. 기존 연마작업의 표면 연마, 비드처리, 기계 가공 디버링 등의 공정은 그 복잡성에서 자동화가 가장 곤란하다고 인식되어 주로 인력에 의존 해왔다. 본 연구에서는 연마 공구를 파지시킨 힘 제어 로봇에 의한 자동 연마 시스템의 구축과 힘 센서로부터 신호 피드백 제어 방식의 특성 파악과 연마 공정에 적응성을 검증했다. 또한 실용화를 목적을 위한 선박의 바닥 및 측면 연마에의 응용을 진행했다. 따라서 자체 제작한 연마로봇을 활용 한 표면 연마작업을 통하여 실험결과를 검증하였다.

• 대한금속재료학회지
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• 제50권5호
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• pp.375-381
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• 2012

Magnesium prepared by mechanical grinding under $H_2$ (reactive mechanical grinding) with transition elements or oxides showed relatively high hydriding and dehydriding rates when the content of additives was about 20 wt%. Ni was chosen as a transition element to be added. $Fe_2O_3$ was selected as an oxide to be added. Ti was also selected since it was considered to increase the hydriding and dehydriding rates by forming Ti hydride. A sample $Mg-14Ni-3Fe_2O_3-3Ti$ was prepared by reactive mechanical grinding, and its hydrogen storage properties were examined. This sample absorbs 4.02 wt% H for 5 min, and 4.15 wt% H for 10 min, and 4.42 wt% H for 60 min at n = 2. It desorbs 2.46 wt% H for 10 min, 3.98 wt% H for 30 min, and 4.20 wt% H for 60 min at n = 2. The effects of the Ni, $3Fe_2O_3$, and Ti addition, and hydriding-dehydriding cycling were discussed.

• 대한치과기공학회지
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• 제38권3호
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• pp.157-163
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• 2016

Purpose: It is to compare and evaluate the change of the wear rate and phase variation of the Zirconia before and after the sintering after the grinding by a high speed equipment manufactured for the Zirconia. Methods: The specimen of the sintered Zirconia was manufactured as size of $15mm{\times}15mm{\times}2mm$. The grinding has been applied to each of all pieces of each test groups for a minute fit for each condition at same speed of 50,000 rpm by a diamond bur at high speed handpiece with injection of the air and water. For the observation of the surface before and after the sintering of the each test piece, the cross section of it was observed as 100 magnification by a scanning electron microscope after it was coated by PT, and the diffraction analysis was performed by XDR to compare the crystal phase of the Zirconia. The average surface roughness value of all specimens were evaluated. The wear test was performed at room temperature by applying a load of 1kg for 120,000 cycles for the chewing period 6 months. Wear was analyzed for the enamel cusps by measurement of the vertical substance loss with a laser scanner. Conclusion: The phase variation from the tetragonal phase to the monoclinic phase was confirmed in the test group of the pre-sintered Zirconia after the grinding, and the value of the surface roughness and the wear rate was increased in experimental group.

• 한국강구조학회 논문집
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• 제12권6호
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• pp.701-713
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• 2000

본 연구에서는 하중비전달형 필렛용접부를 대상으로 순수휨 상태에서 그라인딩 처리 및 TIG 처리에 따른 피로강도 향상정도 및 피로특성을 정량적으로 평가하기 위해서 일련의 4점 휨실험을 실시하였다. 피로실험결과 그라인딩 처리한 경우와 TIG 처리한 경우 $2{\times}106$회 피로강도가 한등급 향상되는 것을 알 수 있었으며, 국내 외의 피로설계기준에서 규정하고 있는 피로강도등급을 대체로 만족하고 있음을 알 수 있었다. 용접지단부의 기하학적 형상에 대한 매개변수해석결과 하중비전달형 필렛용접부에서 응력집중계수에 영향을 미치는 인자는 곡률반경과 비드접선각도임을 알 수 있었다. 한편 파괴역학적 해석 결과 피로균열 발생초기에는 균열보정계수에 가장 큰 영향을 미치는 인자는 기하학적 형상 보정계수임을 알 수 있었으며, 상대깊이가 0.4 이상이 되면 기하학적 형상보정계수 보다는 유한판 보정계수가 보다 큰 영향을 미치는 것을 알 수 있었다. 또한 유한요소해석결과로부터 산정한 응력확대계수범위와 피로균열성장속도의 관계식으로부터 하중비전달형 필렛용접부의 피로수명을 비교적 정확하게 산정할 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.235-236
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• 2011

• Design & Manufacturing
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• 제8권1호
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• pp.27-30
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• 2014

Alloy tool steel such as SKD11 and SKD61 or high speed tool like SKH51 are used as materials for semiconductor dies. Cavities, curl blocks, pot blocks and housings are made from those materials. To make those parts from alloy tool steel or high speed tool, one utilizes discharge machining, and mechanical machining including machining center, milling, drilling, forming grinding and others. In the process of cutting machining and polishing, the die materials become unsuitable for machining owing to bubbles and foreign substances in them, which hinders production process. Therefore, this study focuses on die material selection criteria, and on analysis and comparison of material characteristics to help companies to solve their problems, make die manufacture less burdensome and extend die life.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.508-511
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• 2002

With increasing the needs for micro and precision parts, micro machining technology using micro tools has been studied to fabricate a small part with high density such as electronics, optics, communications, and medicine industry more than before. Though these micro tools have developed rapidly, it is difficult to apply them to micro fabrication technologies, because of the inherent manufacturing. In this study, micro tools(wc) to produce micro structures and parts were manufactured by cylindrical grinding machine employing ELID(Electrolytic In-process Dressing) technique and good dimensional accuracy was achieved. Furthermore we researched the characteristics of machining on the micro drilling using micro drills and manufactured micro tools. Finally it is confirmed that manufactured micro tools can be used for micro machining.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.96-99
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• 2005

Fiber optic connector, ferrule, is a device to connect and align fiber optics cable on fiber-optic communication system. In this paper, Structural analysis was performed to analyze bed and frame structure of co-axial grinding machine. Deformation and modal analysis for natural frequency was performed using ANSYS Designspace program to analyze structural characteristics. New improved model of bed and frame structure was proposed based on initial basic model.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.962-967
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• 2003

Recently, environmental pollution has become a serious problem in industry, and many researches have been done in order to preserve the environment. The coolant, which promotes lubrication, cooling and penetration, contains chlorine, sulfur and phosphorus to improve the machining efficiency. These additives, which move around into the air during machining, pollute working. Therefore, many researches on how to reduce the amount of coolant during machining have been carried out. However, to reduce even small amount of coolant causes high temperature of a workpiece and it brings thermal defects. In this study, the experiments of wet & dry grinding using cooling methods (using coolant only, mist and compressed cold air only) are performed to solve the problem of environmental contamination and to get a better surface integrity of a workpiece by comparing surface roughness, roundness and residual stress.

• 한국정밀공학회지
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• 제19권12호
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• pp.171-178
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• 2002

With increasing the needs for micro and precision parts, micro machining technology using micro tools has been studied to fabricate a small part with high density such as electronics, optics, communications, and medicine industry more than before. Though these micro tools have developed rapidly, it is difficult to apply them to micro fabrication technologies, because of the inherent manufacturing. In this study, micro tools (WC) to produce micro structures and parts were manufactured by cylindrical grinding machine employing ELID (Electrolytic In-process Dressing) technique and the micro tools are fabricated as square shape with the dimension less than 100${\mu}{\textrm}{m}$. With the micro tools on the same machine, characteristics of micro grooving and drilling are evaluated. Also we compare normal micro machining with ultrasonic micro machining on the vibration table. It is confirmed that the developed micro tools are fully applicable to micro grooving, micro drilling and free form cutting.