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Lee S.W.,Nano Convergence and Manufacturing Systems Research Division | Yeom H.K.,DONG Energy | Lee H.K.,Inha University
International Journal of Precision Engineering and Manufacturing | Year: 2011

In keeping with the development of machine tools with higher speed, more axes, and a greater degree of sophistication, thermal deformation is becoming an important factor in the precision of machine tools. It has been found that thermal error accounts for about 70% of the total error in machine tools. As such, oil coolers which absorb heat from heat generating parts with cold oil are being used to reduce the error caused by thermal deformation. The gas bypass type oil coolers used in ultra-precision (temperature accuracy within ±0.1°C) machine tools are simple in structure and precise in terms of their temperature control performance; however, they have a limitation as regards temperature control due to the instability of their performance under light load conditions. In this study, an oil cooler system equipped with dual electronic valves was developed to solve the problems of the single electronic valve system and achieve more precise temperature control. To verify the performance of the developed system, its performance under the operating conditions of rated load, DIN 8602 standard, and ISO/DIS 230-3 operational mode was compared and analyzed. The proposed oil cooler system is applicable to semiconductor equipment, ultra-precision injection molds, and ultra-precision machine tools, and improves the quality of the products. © KSPE and Springer 2011. Source


Park C.,Nano Convergence and Manufacturing Systems Research Division | Kyung J.H.,Nano Convergence and Manufacturing Systems Research Division | Park D.I.,Nano Convergence and Manufacturing Systems Research Division
ICCAS 2010 - International Conference on Control, Automation and Systems | Year: 2010

An industrial manipulator for the easy and safe human-robot cooperation is under development and the research results will be introduced in this paper. Until now, it is difficult to operate the industrial robot manipulators for not-trained worker for the manipulator operation. Moreover, most of the industrial robot manipulators are used in the separated environments because it can harm the operator near the robot systems. For this reason, the final target of the research of this paper is to develop the industrial manipulator which can be easily operated by the not-trained workers for the manipulator operation and is safe even when the manipulator is operating near the operators. In this paper, the structural details of the manipulator under development will be introduced and the intuitive teaching method - direct teaching method - for the developed manipulator will be introduced also. ©ICROS. Source


Kim K.-S.,Nano Convergence and Manufacturing Systems Research Division | Lee H.-J.,Nano Convergence and Manufacturing Systems Research Division | Kim H.-Y.,BIO-NEMS | Kim J.-H.,Nano Convergence and Manufacturing Systems Research Division | Hyun S.,Nano Convergence and Manufacturing Systems Research Division
Transactions of the Korean Society of Mechanical Engineers, A | Year: 2010

Four-point bending tests were performed to investigate the interfacial adhesion of Cu-Cu bonding fabricated by thermo-compression process for three dimensional packaging. A pair of Cu-coated Si wafers was bonded under a pressure of 15 kN at 350 °C for 1 h, followed by post annealing at 350 °C for 1 h. The bonded wafers were diced into 30 mm × 3 mm pieces for the test Each specimen had a 400-μm-deep notch along the center. An optical inspection module was installed in the testing apparatus to observe crack initiation at the notch and crack propagation over the weak interface. The tests were performed under a fixed loading speed, and the corresponding load was measured. The measured interfacial adhesion energy of the Cu-to-Cu bonding was 9.75 J/m 2, and the delaminated interfaces were analyzed after the test The surface analysis shows that the delamination occurred in the interface between SiO2 and Ti. Source


Choi K.-B.,Nano Convergence and Manufacturing Systems Research Division | Lee J.J.,Nano Convergence and Manufacturing Systems Research Division | Kim G.H.,Nano Convergence and Manufacturing Systems Research Division | Lim H.J.,Nano Convergence and Manufacturing Systems Research Division
International Journal of Precision Engineering and Manufacturing | Year: 2012

A compliant parallel mechanism for two translations is proposed and applied to a XY fine motion stage driven by piezo actuators. Four flexure-based prismatic-prismatic joint chains are arranged in four sides of a target platform to implement the compliant parallel mechanism. Among others, two are passive joint chains for only motion guidance, and the others are active joint chains for motion guidance merging the function of the displacement amplification of a piezo actuator. Due to the active joint chains, the proposed mechanism has more compact structure than the others which have the separated mechanisms of the motion guidance and the displacement amplification. In addition, the compliant mechanism has a monolithic structure not to be assembled. The compliant mechanism is designed, verified to satisfy some design constraints using Finite element Analysis, and then combined with piezo actuators and capacitance sensors. The characteristics and the performance of the piezo-driven compliant parallel mechanism are demonstrated by experiments. © KSPE and Springer 2012. Source

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