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자동차 차체 품질 및 생산성 향상을 위한 용접ㆍ접합 신기술
조용준(Yongjoon Cho),김인준(In-June Kim),이희범(Heui Bom Lee),장인성(In-Sung Chang),도성섭(Sung-Sup Do) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Even though Resistance Spot Welding (RSW) and Gas Metal Arc Welding (GMAW) have been the most popular joining processes, there are still various quality issues in auto body assembly process. New high strength steel and light weight materials make the process more complicated resulting in new challenges for welding and joining. In this presentation, various approaches to solve conventional challenges are introduced. Intelligent current regulation in RSW helps to control welding current and time more stable. Cold Metal Transfer (CMT) machine for GMAW process reduces the amount of spatters and avoids manufacturing downtime. Adhesive bonding is another outstanding way of increasing body strength without any extra materials or panel thickness change. Various implementation results and benefits of the processes are also discussed.
조용준(Yongjoon Cho),장인성(In Sung Chang),이희범(Heui Bom Lee) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6
RSW(Resistance Spot Welding) have been the most successful sheet metal joining process in automotive industry for many decades. However, there are certain limitations due to the access of welding gun and electrodes. Laser welding or arc welding is used to weld a closed section and hydro-formed parts where resistance spot welding is hard to apply. In this research, an automated single-sided spot welding system is introduced to overcome typical RSW issues and its applications to automotive body assembly are presented. This new welding machine is designed to make a weld by singled-sided access with low electrode force. Weldability lobe curves were developed to find applicable operating conditions and found that relatively low welding current was possible to make a reasonable size of weld nugget. Various applications for Body-In-White were investigated. Hydro-formed side member parts and brackets were welded together and got successful result. Large floor panels were joined together with small-sized single-sided welding gun. Although a few limitations and challenges have to be considered to maintain good-quality weld, this technique can be a great alternative to hard-to-spotweld applications on automotive body assembly.
정성훈(Sung Hoon Jeong),김광희(Kwang-Hee Kim),육성민(Sung Min Yook),이희범(Heui Bom Lee),도성섭(Sung Sup Do) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
In this paper, a press-fit machine using a robot with servo press is proposed to change an existing press-fit machine for flexible manufacturing line. The existing machine carries out a process at a station but the new developed machine can conduct two processes and is more flexible by using a Robot because positions where parts are pressed can be freely changed. To develop this machine, centering device is used for correcting centers of the parts. The centering device has a function of locking to prevent the oscillation of the parts during moving. The locking function can prevent the extension of cycle time. Also, frame for supporting tons of repulsive force during pressing-fit is used. The frame is a plate made of steel and contact with the bracket of servo press and transfer the repulsive force to base plate fixed at floor. As a test result, the quality of press fit with bearing race and dowel pin is very good. The flexible press fit machine can be applied to parts such as plug, steel ball in engine assembly line..
박홍석(Hong-seok Park),최흥원(Hung-won Choi),강무진(Mu-jin Kang),이희범(Heui-bom Lee),장인성(In-sung Chang),이현동(Hyeoun-dong Lee),최병욱(Byung-wook Choi) 한국자동차공학회 2003 한국자동차공학회 지부 학술대회 논문집 Vol.2003 No.10
Nowaday, the increasing global competition put much pressure on increasing the efficiency and quality at all stage in the life cycle of manufacturing systems e.g., (re)design, implementation and operation. To increase efficiency, there is need to minimize the time and cost for development and operation of a manufacturing systems. Therefore, it becomes more and more to important to analysis and test a manufacturing system before a large investment.<br/> In this paper, we introduce procedure for digital manufacturing and OLP for high efficiency. And. according to these procedures, we implement a virtual laser welding cell using IGRIP and CATIA V5 as an example.
정성훈(Sunghoon Jeong),류성희(Sung Hee Yoo),정대현(Dae Hyeon Joung),이희범(Heui Bom Lee) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11
The quenched and tempered steel is usually treated by heat treatment. But micro-alloyed steel including alloying elements such as vanadium, boron and so on is applied without overall heat treatment. The surface of crankshaft made with micro-alloyed steel is locally processed by induction hardening. The process can cause a crack on grinded surfaces when residual tensile stress is higher than strength of the material. Therefore crack inspection is required. Various inspection methods such as magnetic testing and eddy current testing have been used for detecting surface defects of shaft in automobile engine and transmission. Magnetic testing is to see fluorescent lines by condensed magnetic particles on defects and can have an error because of worker’s subjective judgment. Eddy current testing is difficult to be flexible because it should have many sensors to detect surface defects. Also, it has limitation in detection ability because the higher sensor sensitivity is the more noise is included. The eddy current sensor can detect cracks above a depth of 0.1mm. In this paper, it is investigated that vision inspection method is valid in ability of detection, classification, measurement of surface defects such as crack, contamination, scratch, and pores.
양주석(Ju-Seok Yang),민경호(Kyung Ho Min),우승걸(Seung-Geol Woo),이희범(Heui Bom Lee) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
High pressure die casting is used in manufacture of the various auto parts due to its excellent productivity compared to any other casting processes. However, it has disadvantage which is difficult to form parts having complex inner shape or under-cut shape by its metal mold. To solve this problem, collapsible cores, which can withstand high pressure and speed of the melt flow on casting and easily be removed after casting, have recently been developed. There are three types of them; sand, salt, and plastic core. The purpose of this study is to develop the sand core which is excellent with respect to productivity, cost, and applicability. In this study, cerabeads was used as core sand and its particle size and resin contents were modified to improve shear strength. In addition, two coating agents were applied to the core and their concentration was adjusted. As the results, the core whose shear strength is above 110kgf/㎠ was obtained, and practical high pressure die casting test using it was performed to verify its applicability.