• 한국정밀공학회지
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• 제29권2호
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• pp.156-160
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• 2012

Recently, the demands of the large scale machine tools gradually increase to machine the large parts, such as large scale crankshaft, yaw and pitch bearings for the wind power generator and the vehicle or aircraft components. But the high technology is necessary in order to develop the huge machine tools. Furthermore, the global market of it has been monopolized by a few companies. So, we need to develop the large scale machine tools and study its core technology to rush into the increasing market. In this study, we carried out the researches for the important core technology of a multi-tasking, machine tool; a large scale 5-axis machine tool of gantry type for multi-task machining. This study is focused on the design of large size gantry type multi-axis machine. In the case of large size of machine the cross rail deflection in the X-axis is significant. To reduce the deflection due to the eccentric spindle head, a special hollow type design in the cross rail with outside ram is adapted in this study. Also, the Zig-Zag motion in the Y-axis is inevitable with the gantry geometry, which is by the un-balancing, different motion at the left and the right columns moving. We tried to reduce the influence of Zig-Zag motion using FEM with different loading conditions at the left and the right side column.

• 한국생산제조학회지
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• 제20권3호
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• pp.357-360
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• 2011

Machine tools of Gantry type have been performing machine work as a moving machinery. In a large machine tools, the machinery is moving with bed and it is structurally unstable. When the objects are processed, machine tools gets loads in the direction of Z-axis. In other words, the machine tools which become bigger was performed by the trend of complexation. It made that the increased machine weight can't be passed over. In order to enhance manufacturing precision, it needs to compensate Z-axis deflection of weight for machine tools. In this paper, Machine tools of Gantry type were miniaturized and deflection was measured by LVDT sensors. When deflection was measured, block mass weighted 50kg is moving on particular distance. Then, the displacement of fixed point and moving point is measured by recording telemeter.

• 대한기계학회논문집A
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• 제39권2호
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• pp.157-162
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• 2015

대형 5축 문형공작기계는 Gantry가 bed를 따라 절삭, 급송 이송하면서 가공을 수행 한다. 가공을 수행하는 중에 발생하는 오차(Zig-Zag)원인으로써 1) 양쪽 X축 이송모터의 위치오차 제어차이 2) 양쪽 Column의 무게차이에 의해 발생하는 마찰력에 대한 오차 3) spindle 회전력에 따른 오차 3가지의 원인이 있다. 3가지 오차원인을 분석하여 문형공작기계성능을 향상시키기 위해 연구를 진행 하였다. 연구결과로는 첫 번째로 양쪽 Column이 동일한 무게를 갖는 Gantry 구조에서 한쪽 축의 무게를 변경함으로써 마찰력이 미치는 영향을 확인하였다. 두 번째로 우리는 스핀들 회전이 미치는 영향을 해석 및 실험하였다. 그리고 우리는 스핀들 회전이 Gantry이송에 미치는 영향을 확인하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1469-1474
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• 2007

In recent years, research to machine large-surface micro-features has become important because of the light guide panel of a large-scale liquid crystal display and the bipolar plate of a high-capacity proton exchange membrane fuel cell. In this study, in order to realize the systematic design technology and performance improvements of an ultra-precision machine for machining the large-surface micro-features, a structural characteristic analysis was performed using its virtual prototype. The prototype consisted of gantry-type frame, hydrostatic feed mechanisms, linear motors, brushless DC servo motor, counterbalance mechanism, and so on. The loop stiffness was estimated from the relative displacement between the tool post and C-axis table, which was caused by a cutting force. Especially, the causes of structural stiffness deterioration were identified through the structural deformation analysis of sub-models.

• 대한기계학회논문집A
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• 제31권12호
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• pp.1173-1179
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• 2007

In recent years, research to machine large-surface micro-features has become important because of the light guide panel of a large-scale liquid crystal display and the bipolar plate of a high-capacity proton exchange membrane fuel cell. In this study, in order to realize the systematic design technology and performance improvements of an ultra-precision machine for machining the large-surface micro-features, a structural characteristic analysis was performed using its virtual prototype. The prototype consisted of gantry-type frame, hydrostatic feed mechanisms, linear motors, brushless DC servo motor, counterbalance mechanism, and so on. The loop stiffness was estimated from the relative displacement between the tool post and C-axis table, which was caused by a cutting force. Especially, the causes of structural stiffness deterioration were identified through the structural deformation analysis of sub-models.

• 한국정밀공학회지
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• 제29권2호
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• pp.129-138
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• 2012

In this study, three types of large scale multi-tasking machine tools together with core technologies involved have been developed and introduced; a multi-tasking machine tool for large scale marine engine crankshafts, a multi-tasking vertical lathe for windmill parts, and a large scale 5-axis machine tool of gantry type. Several special purpose devices has been necessarily developed for the purpose of handling and machining big and heavy workpieces accurately, such as PTD (Pin Turning Device) with revolving ring spindle for machining eccentric crankshaft pins, hydrostatic rotary table and steady rest for supporting and resting heavy workpieces, and 2-axis automatic swiveling head for high-quality free surface machining. Core technologies have been also developed and adopted on their detail design stage; 1) structural design optimization with FEM structural analysis, 2) theoretical hydrostatic analysis for the PTD and rotary table bearings, 3) box-in-box type cross-rail and octagonal ram design to secure machine rigidity and accuracy, 4) constant spindle rpm control against gravitational torque due to unbalanced workpiece.

• 전기전자학회논문지
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• 제23권4호
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• pp.1387-1392
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• 2019

비구면 거울은 구형 거울보다 무게가 가볍고 성능이 우수하지만, 그 형상을 가공하고 가공 정밀도를 측정하는 것이 어렵다. 특히 위성에 사용되는 대형 조리개 비구면 미러는 높은 정밀도가 필요하고 처리하는 데 시간이 오래 걸린다. 기존의 연마 공정에는 갠트리 구조를 갖는 컴퓨터 수치 제어 공작기계가 사용되고 있으나, 자유도가 부족하여 복잡한 형상을 처리하기 어렵다는 단점이 있다. 이러한 문제를 극복하기 위해 다관절 산업용 로봇을 사용하는 연마 시스템을 개발하였다. 개발된 시스템은 공구 경로 생성 프로그램, 실시간 로봇 모니터링 및 제어 프로그램으로 구성되며, 시뮬레이션 소프트웨어와 실제 로봇 작동을 통해 개발된 시스템의 성능을 검증하였다.