• 한국기계가공학회지
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• 제18권7호
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• pp.90-96
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• 2019

Recently, friction stir welding of dissimilar materials are one of the biggest issues in terms of light-weight and eco-friendly technology of the automotive, aircraft and ship industry. In this study, friction stir welding of dissimilar materials is introduced with different tool rotational speed. Materials used in experimentation consist of A357 gravity cast aluminum alloy and FB590 high-strength steel plates. Dissimilar materials of plate type are fabricated with width of 150mm, length of 300mm and thickness of 3mm and welding is carried out by the lap joint method. The correlation between probe length and mechanical properties were investigated according to rotational speed and welding speed at tool tilt angle 0 degree. Consequently, feasibility of FSWed dissimilar materials were successfully presented in case of cast aluminum and high-strength steel at lap joint method.

• 항공우주시스템공학회지
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• 제17권2호
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• pp.16-25
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• 2023

항공업계의 외부 이물질(FOD)은 다양한 종류가 있으며 작업자가 분실한 공구는 항공기 제작, 운용, 정비 분야 전반에 걸쳐 위험 요소로 작용하고 있다. 작업자의 부주의에 의해 분실된 공구로 인한 사고는 항공산업 전반에 걸쳐 지속적으로 발생하고 있으며, FAA, EASA 등 항공 관련 기관에서는 FOD 발생 예방을 위해 공구 관리 규정을 제정하고 시스템을 구축하고 있다. 하지만, 국내의 경우 관련 규정 및 절차가 미흡한 수준이며, 항공기의 안정적인 제작 및 인증, 운용 및 정비를 위해서는 체계적이고 효과적인 공구 관리 시스템의 도입이 반드시 필요하다. 본 논문에서는 국내외 감항당국 및 항공산업 관련 단체의 공구 관리 규정 및 절차를 분석하고, 미국 국립 표준 협회를 통해 인증된 NAS 412의 Tool Control 규정을 바탕으로 국내 항공산업계 도입이 필요한 무선통신 기술 기반의 공구 관리 시스템을 제안하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.1051-1055
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• 1997

Hot forging is widely used in the manufacturing of automotive component. The mechanical, thermal load and thermal softening which is happened by the high temperature die in hot forging. Tool life of hot forging decreases considerably due to the softening of the surface layer of a tool caused by a high thermal load and long contact time between the tool and workpieces. The service life of tools in hot forging process is to a large extent limited by wear, heat crack, plastic deformation. These are one of the main factors affecting die accuracy and tool life. It is desired to predict tool life by developing life prediction method by FE-simulation. Lots of researches have been done into the life prediction of cold forming die, and the results of those researches were trustworthy, but there have been little applications of hot forming die. That is because hot forming process has many factors influencing tool life, and there was not accurate in-process data. In this research, life prediction of hot forming die by wear analysis and plastic deformation has been carried out. To predict tool life, by experiment of tempering of die, tempering curve was obtained and hardness express a function of main tempering curve.

• 한국기계가공학회지
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• 제12권3호
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• pp.28-35
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• 2013

Micro electrical discharge machining (EDM) as a non-contact machining process is very effective for micromachining with a thin electrode because of its low machining reaction force. The micro-electrode machining device has the advantage of maintaining high precision through the whole processes and uses a feeding wire in the thin electrode tool manufacturing process. This study describes the design and evaluation of a micro-electrode machining device using optical photo-interrupter. The electrode was fabricated by reverse electrical discharge machining. The performance of designed system was evaluated to measure tension force according to feed speed of wire. This system for micro electrode fabrication proves the feasibility in the micro-EDM process of the micro holes and parts for industrial applications.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.344-350
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• 2003

This Paper deals with the weight-lowering and the traits of NVH(Noise, Vibration and Harshness) by the development of tubular shaft replacing the existing solid Drive Shaft for the lighter and less-noisy automobiles. By the review of Swaging Process this study reveals the various forming traits of Swaging, one of the forming methods for tubular shafts. Furthermore, it showed the possibility of Drive Shaft manufacturing through designing & manufacturing of Swaging machine for tubular shaft, and the production ar analysis of the tubular shaft with the relevant process and tools. This study also shows that the forming by swaging not only makes the mass production of tubular Drive Shaft possible but also may be widely applied to other products with many advantages in review of dimensional precision, thickness change, hardness increase and surface roughness of the swaged products.

• 한국공작기계학회논문집
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• 제18권2호
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• pp.178-186
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• 2009

Most of automotive plastic parts are injection molding products. Inspection of total product is impossible, because number of product to inspect is too many and various. Condition-based Monitoring was proposed to decrease cost and time for inspecting. In this research, a system that predicts quality of part at fabrication point of time, and confirms informations through the internet was developed. Cavity sensors were installed inside of mold, and gathered signals as measuring, and through this process Sensor-based Monitoring system can be observed manufacturing of a part. Monitoring system transmits signals to client through the internet, and finally developed system provides manufacturing informations and predictions of quality as web-based monitoring.

• 대한기계학회논문집A
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• 제37권1호
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• pp.61-66
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• 2013

적층조형 방법의 개발로 열전도성 금형 혹은 형상적응형 냉각회로를 구비한 금형의 제작이 가능하게 되었다. 금형의 재질로 치수변화가 적은 P21 툴 스틸이 널리 사용되고 있지만, 열전도율이 낮기 때문에 냉각효율은 높지 않다. 이러한 점에서 열전달 효율을 극대화 시킬 수 있는 방법으로 P21 스틸과 구리(Cu)를 기능적으로 혼합한 기능성 경사 복합재(FGM)를 사용하는 방법이 검토되고 있다. 본 논문에서는 FGM 구조를 가지는 금형의 적층조형을 위한 예비연구로 P21-Cu 간의 1 차원 FGM 을 DMT 장비를 이용하여 제작하고, 열전달 관련 물성치를 평가하였다.

• 한국기계가공학회지
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• 제16권2호
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• pp.28-33
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• 2017

Recently, the operation of precision pocket machining has been studied for the high speed and accuracy in industry to increase production and quality. Moreover, the demand for products with complex 3D free-curved surface shapes has increasing rapidly in the development of computer systems, CNC machining, and CAM software in various manufacturing fields, especially in automotive engineering. The type of aluminum (Al6061) that is widely used in aerospace fields was used in this study, and end-mill down cutting was conducted in fillet cutting at a corner with end-mill tools for various process conditions. The experimental results may demonstrate that the end mill cutter with four blades is more advantageous than that of the two blades on shape forming in the same condition precise machining conditions. It was also found that cutting forces and tool deformation increased as the cutting speed increased. When the tool was located at $45^{\circ}$ (four locations), the corner was found to conduct the maximum cutting force rather than the start point of the workpiece. The experimental research is expected to increase efficiency when the economical precision machining methods are required for various cutting conditions in industry.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.108-113
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• 1997

In these days, customers require high-quality, high-performance, high-ride comfort for Automobile and then the automotive manufacturers concentrated on study of electrical, high-performance, low-cost of parts and sub-parts. In this paper, for ride comfort estimation PSD(Power Spectral Density) of acceleration at eight test point are measured, and then are calculated with new index of ride comfort. The new index of ride comfort developed for optimal design, real test, applied the actual. It can apply for various fields.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.573-578
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• 2000

Recently, Tailor Welded Blanks(TWB) is widely used in automotive industry since the transformation characteristics of its material can be changed. However, clearance between welding surface becomes the important factor which affect the quality of the laser weld, causing difficulties in preparing the sheet. The objective of this paper is to systematically evaluate the effects of previously presented fracture criterion and shearing condition on precise mechanical shearing simulation result. Also predict the optimum shearing condition, effect of shearing condition such as clearance and punch radius on the shear plane shape was evaluated.