• 소성∙가공
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• 제30권4호
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• pp.179-185
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• 2021

Lithium ion batteries are generally manufactured by laser and etching using aluminum thin sheet. These processes are relatively expensive and have low productivity. In this study, blanking process of aluminum thin sheet for lithium ion battery was employed to replace laser cutting and etching process, all to reduce the production cost and improve productivity. Mechanical properties for aluminum and coating were determined by experimental results and rule of mixture for FE analysis of blanking process. Normalized Cockcroft-Latham criteria was also applied to describe shear behavior and critical damage values were determined by comparison of analytical and experimental result. We performed FE analysis to investigate the effects of clearance and punch-die radius on sheared surface of aluminum thin sheet and to determine optimal process condition. We manufactured the die set using the determined optimal process and conducted an experiment to confirm the feasibility of blanking process. The sheared surface of manufactured product was observed by optical microscope. As a results, the proposed process conditions successfully achieved the dimensional requirement in production of lithium ion battery parts.

• 대한기계학회논문집B
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• 제36권3호
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• pp.233-240
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• 2012

레이저 절단가공에서 사용되는 보조가스의 충돌특성을 개선하기 위한 실험적 연구가 진행되었다. 보조가스의 압력, 노즐의 위치 및 각도 등 다양한 관계변수의 변화에 대하여, 초음속 사각노즐에서 분출되는 보조가스의 절단면 충돌특성이 기존의 원형노즐 경우와 비교 관찰되었다. 이를 위하여 쉴러린 유동가시화 및 절단면 하단에서의 피토압 측정이 진행되었다. 본 연구에서 응용된 사각노즐은 절단면 모서리에서 발생하는 마하디스크의 강도를 줄이고, 이를 통하여 기존의 원형노즐에 비하여 절단면을 따라 흐르는 보조가스의 박리현상을 약화시키고 보조가스 후방의 피토압력을 증가시킬 수 있음이 확인되었다.

• 소성∙가공
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• 제32권2호
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• pp.81-86
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• 2023

The hot stamping process is widely used for high strength of vehicle parts, with heating 900 ℃ or higher in a furnace and in-die quenching to achieve strength above 1.5 GPa of the quenchable boron alloyed steel 22MnB5. First of all, the hot stamping process consisted of heating, forming, quenching and trimming. In the trimming process case, the laser method has been conventionally adopted. For laser trimming process, it has the problems pertaining to low productivity and high cost while the hot stamping process, accordingly the trimming process need to investigate the research for alternative method. In order to overcome these issues, many research groups have studied the mechanical trim solution on the hot stamped parts at high temperature. In this study, the mechanical piercing was performed during the hot stamping process at the high temperature for overcome the disadvantages of laser cutting. Also, the process parameters such as piercing time after die closing, clearances of between die and punch were controlled for obtaining the reasonable shear characteristics.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권2호
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• pp.55-59
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• 2004

Throughout manufacturing processes, pulse shaping is required for material processing and it is regarded as an important (actor according to the specific characteristics of materials. Therefore, this study suggests a highly appropriate pulse shaping technique using a multi-switching method. This is a pulse superposition method in which one flash lamp can consecutively turn on by the double switching of the discharging system. It is possible to construct a variety of pulse shapes and pulse widths by the consecutive trigger of the silicon-controlled rectifiers (SCR) of a PIC (program integrated circuit) one-chip microprocessor. The use of this technique can provide a number of advantages to people who require suitable pulse shaping for particular applications such as welding, cutting, and drilling.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.44.1-44.1
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• 2010

레이저 가공기술은 공정 적용이 용이하고 응용 분야가 넓어 산업 전반에 걸쳐 널리 사용되고 있다. 특히, 태양전지 제조공정에서는 cutting, grooving, doping, ablation등의 분야에 활발하게 적용되고 있으며 최근에는 다양한 종류의 레이저를 기술을 이용하여 효율 향상과 원가 절감을 위해 많은 기관에서 활발하게 연구를 진행하고 있다. 본 연구에서는 실리콘웨이퍼에 특정 파장의 레이저를 조사하여 실리콘웨이퍼 표면의 용융과 고상화를 통해 구조적, 전기적 특성 변화를 확인하였다. Si wafer의 표면은 레이저 조사 조건에 의해 다결정화 하며 레이저의 power와 frequency, scan speed등을 조절하여 다결정 실리콘 영역의 형성 깊이를 조절 할 수 있다. 다결정화 된 부분의 구조적 특성은 SED과 XRD를 이용하여 측정하였으며, 전기적 특성은 면저항 측정을 통하여 실시하였다. 또한 이러한 특성을 이용하여 태양전지 제조 공정의 적용가능성을 평가하였다.

• 한국디지털건축인테리어학회논문집
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• 제12권1호
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• pp.25-33
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• 2012

Ever since the local interior and architecture design industry adopted Digital fabrication modeling tool for its design operation in early 1990's, working environment has been changing. The Purpose of study is to analyze the digital Architecture fabrication modeling for digital design education in academy course. Digital Design Tools, Digital Space and Form, Digital Materiality and Digital Production. The Digital fabrication modeling is and important role in a traditional design process and digital design process. It is comprised of digital input devices(3D digitizer, 3D design tools) and digital output devices(cutting plotters, laser cut, CNC machines, 3D printers). Digital input devices can be shift a traditional design process to digital design process. Digital output devices are the principle of digital fabrication by CAD/CAM. Also, the result of this study provide the fundamental data for physical resources and digital design curriculum in KAAB.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1993년도 춘계학술대회 논문집
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• pp.323-327
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• 1993

Mold-making industry demands currently to reduce the tooling costs and time in mold making, and to improve the productivity and quality in injection molding process. These problems can be easily removed by laminated injection mold which is made with metal sheets prepared by laser cutting and bonded by brazing. Comparing withthe conventional mold making technology which mainly depends on the machining, this new technologyenables an arbitary design of cooling circuit without anyrestrictions of geometry. So it brings about high production rates of the injection molding processes. This paper estimate the conventional and laminated injection mold making process with a simple molding, and also the cooling efficiencyof thoes two kinds of mold with the filling and cooling analysis. The results show that the laminated injectionmold has much shorter tooling time, uniform mold temperature, and shorter cooling time in injection molding process.

• 한국기계가공학회지
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• 제6권4호
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• pp.36-43
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• 2007

Dieless CNC forming is an innovative technology which can form various materials with complex shape by numerically controlled incremental forming process. In order to apply the technology to industrial parts, however, many problems such as spring-back, rising of material, and trimming difficulty must be solved. In this paper a new dieless CNC forming method to improve forming quality is proposed, which consists of how to modify its original shape in CAD and how to generate its CNC tool path in CAM. The effectiveness of the proposed procedures is tested with a brake dust shield of a vehicle. The results shows that the method proposed enhances the forming quality up to 48% compared to traditional method.

• 한국초전도ㆍ저온공학회논문지
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• 제15권2호
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• pp.44-47
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• 2013

Large AC loss from the second generation (2G) high temperature superconducting (HTS) wires has been one of the major bottlenecks in power applications with HTS materials. Moreover, the large power applications also require the large current capacity from the HTS wires, which makes them produce larger AC losses. In order to reduce the AC loss from the HTS conductors with large current capacity, an HTS compact cable with some striations on the superconducting layers has been proposed. In this paper, we prepared some sample HTS compact conductors with striations, and measured their magnetization loss from the external magnetic field. We also made some slits on the superconducting layer of the HTS wire by laser cutting to reduce the aspect ratio of the superconducting layers. It would make the low eddy current loss and magnetic decoupling. Finally, the magnetization losses of the sample HTS compact conductors were measured and analyzed.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.367-372
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• 2000

Accuracy of a machined component is determined by the relative motion between the cutting tool and the workpiece. One of the important factors which affects the accuracy of this relative motion is the geometric error of machine tools. In this study, geometric error is modeled using form shaping motion of machine tool, where a form shaping function is derived from the homogeneous transformation matrix. Geometric errors are measured by laser interferometer. After that, the local positioning error can be estimated from the form shaping model and geometric error data base. From this information, we can remodel the part by shifting the design surface to the amount of positional error. By generating tool path to the redesigned surface, we can reduce the machining error.