• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1996년도 추계학술대회 논문
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• pp.180-186
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• 1996

Using carbon steel or ceramic as a shaft material of monolithic and slited insert ring clamped on it. The fitting strengths of the sgrink fitted assemblies measured from room temperature to 30$0^{\circ}C$ and following conclusions were obtained as results of this investigation. 1) The fitting condition under which the shrink fitted assemble was stronger than that using simple fit in high temperature. 2) When both material of the 30mm-diameter shaft and 55mm-diameter boss are SM45C the clamping torque is increased 2.7times as the interference increases 3 times from 20${\mu}{\textrm}{m}$ at the contact length of 6mm monolithic fit. 3) When only the material of boss is changed to STS 304 the clamping torque is increased at the rate of 37.3N.m per 1mm increase of the contact length at the interference of 50${\mu}{\textrm}{m}$ monolithic fit.

• 한국공작기계학회논문집
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• 제11권6호
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• pp.68-74
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• 2002

This research covers the development of axi-symmetric plastic elements for injection molding with insert steel such as high stiffness Sabot. The functional requirements of sabot are concentricity and fracture resistance about vertical and horizontal forces. For these, an analysis of characteristics of PEI(polyetherimide) polymer is performed by standard test specimen with accordance of ASTM test guidance. Moldflow analysis and simulation of injection molding process are carried out in order not only to estimate of the warpage but also to predict the characteristics of residual stresses which both product and structure of mold may have. A new vertical side injection machine and transverse mold have been constructed. Results of the measuring concentricity and fracture test after molding of sabot are satisfied to design specification over Cp $ratio{\geq}1.33$. Finally, this technique needs more research application to others axi-symmetric elements having different radius with insert steel md structure analysis from now on.

• 한국공작기계학회논문집
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• 제17권2호
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• pp.38-44
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• 2008

Titanium and its alloys, due to their superior properties of high specific strength and excellent corrosion resistance, are increasingly used in living applications in the 21century. The applications in aerospace and medical industries demand machining process more frequently to obtain a desired product. But unfortunately, this material is one of the most difficult-to-cut. In the turning process of titanium alloys, the key point for successful work is to select proper tool materials and cutting conditions. This study suggests a guidance for selecting the tool materials and the cutting speeds to improve tool life and surface integrity in Ti-6Al-4V titanium turning process. The experiments investigate the change of surface roughnesses, cutting forces and flank wear with various cutting parameters of tool materials, depth of cuts and feeds. As the results, K10 type of insert tip was assured as the best for turning of Ti-6Al-4V titanium alloy.

• 한국산학기술학회논문지
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• 제13권5호
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• pp.2009-2014
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• 2012

기어의 파인 블랭킹에서 기능면으로 사용되는 전단면(잇 면)을 최대한 확보하기 위하여 다이 롤 높이(die roll height)의 최소화는 매우 중요하다. 본 논문에서는 파인 블랭킹 금형의 핵심 설계 요소인 V-링 위치와 다이 챔퍼(die chamfer) 형상에 따라 기어의 다이 롤 높이 변화를 고찰하기 위하여 V-링 거리와 다이 챔퍼 형상이 다른 여러가지 다이 편 및 가이드 플레이트 편으로 구성된 파인 블랭킹 금형 세트를 제작하여 실험하였다. 각 실험으로부터 시편을 채취하여 다이 롤 높이를 측정 분석한 결과 파인 블랭킹 기어의 다이 롤 높이는 각 모듈에서 다이 챔퍼 각도가 증가함에 따라 증가하고 V-링 거리가 증가함에 따라 증가됨을 알 수 있었다.

• 한국생산제조학회지
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• 제4권3호
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• pp.67-76
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• 1995

An experimental study of hot machining has performed to improve the machinability of Inconel718. This experiment used plasma are for heating materials and Whisker0reinforce aluminum oxide ceramic tool insert. An assembled plasma heating system are described and experimental results from both conventional and plasma hot machining of Inconel 718 are compared. The experiments with plasma heating demonstrated the following effectiveness. 1)The cutting force was reduced with increasing surface temperature of workpiece from 450$^{\circ}C$ up to 720$^{\circ}C$ as much as approximately from 20 to 40%. 2) Surface roughness(Ra) was improved by as much as a factor 2 in case of one pass cutting with new ceramic tool inserts.3) The depth of cut notch were at promary cutting tool was significantly reduced.

• 한국정밀공학회지
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• 제14권3호
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• pp.75-81
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• 1997

Automatic monitoring the cutting state is one of the important problems to increase the reliability of modern machining processes. In this study, cutting force signals were used in order to monitor the tool wear and fracture in the turning process. Turning experiments were performed using cemented carbide insert tools(K20) and STS304 steel as a workpiece. Cutting force signal characteristics and histogram analysis method were used to recognize the cutting states. It was found that tool wear and fracture can be diagnosed from the cutting force signal coefficient of variation(C.V.) and histogram analysis.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.1048-1051
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• 2001

This paper presents an analytical and experimental study of a cryogenic machining for precision hard turning. A cryogenic circulation system is designed and mounted on the top of the tool insert. The machining process used is facing operation on a CNC turning center with dry and cryogenic conditions. The tool temperature and cutting forces are measured by the K-type thermocouple and by a three-component Kistler dynamometer, respectively. Both data are fed into the data acquisition program through an A/D card. Surface roughness and form accuracy of the machined surface are measured by WYKO NT2000. It is also found that surface roughness and form accuracy with cryogenic cooling are better than those with no coolant.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.80-87
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• 1995

An experimental study of hot machining has performed to improve themachinability of Inconel 718. This experiment used plasma arc for heating materials and Whisker-reinforced aluminum oxide ceramic tool insert. An assembled plasma heating system are described and experimental results obtained from bothconventional and plasma hot machining of Iconel 718 are compared. Turning experiments with plasma heating demonstrated the following effectiveness. 1) The cutting force was reduced with increasing surface temperature of workpiece from 450 .deg. C up to 720 .deg. C as much as approximately from 20 to 40%. 2) Surface roughness(Ra) was improved by as much as a factor 2 in case of one pass cutting with new ceramic tool inserts. 3) The depth of cut notchwear at primarycutting tool was singificantly reduced.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.493-494
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• 2006

Chip breaker of cutting tool is an important feature to enhance cutting performance. Powder injection molding process was used to produce a triangular-shape cermet grooving insert which has three chip breakers. Attrition milled cermet powders were mixed with wax-based binder system in continuous twin screw extruder. Three-plate injection mold with slide cores was used to produce injection-molded parts. After molding, solvent and thermal debinding was carried out. Sintering was conducted in a batch furnace with a graphite heater. The sintered parts satisfy the requirements of dimensional tolerances and material properties.

• 한국정밀공학회지
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• 제16권11호
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• pp.74-80
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• 1999

In this study, a stereolithography apparatus (SLA) prototype is used as a master model to be transformed into the silicone pattern by vacuum tool forming. The tool for the first prototype is fabricated by using this silicone pattern. Following this procedure, a temporary tool with metal powder and epoxy for wax injection is prepared for the die set of quick change type which consists of upper and lower base die나 and an insert die. The die set of quick change type appears to be very effective in casting operation by changing tools rapidly. The original wax pattern is formed through the die set, and is made of lost-was. Finally the lost-wax pattern is applied to investment casting. The final casting product is checked regarding its dimensional accuracy.