• 소성∙가공
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• 제22권6호
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• pp.317-322
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• 2013

A radio frequency(R/F) switch connector is widely used in wireless devices such as mobile phone and navigator to check defects of the circuit board of product. The R/F switch connector shell plays a role in protecting the switch connector. Previously, this part was machined using a turning, which is time-consuming and has poor material utilization. Furthermore, the workpiece material of brass containing lead that has excellent machinability has environmentally regulated during recent years. The purpose of the current study was to develop the connector shell by forming through progressive dies including embossing, burring and forging process in order to achieve higher productivity and dimensional accuracy without tool failure. To accomplish this objective, a strip layout was designed and finite element (FE) analysis was performed for each step in the process. Try-out for the connector shell was conducted using progressive die design based on FE-analysis results. Dimensional accuracy of developed part was investigated by scanning electron microscopy. The result of the investigation for the dimensions of the formed connector shell showed that the required dimensional accuracy was satisfied. Moreover, productivity using the progressive die increased four times compared to previous machining process.

• Design & Manufacturing
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• 제12권1호
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• pp.13-17
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• 2018

It was analyzed and experimented on the change of the material thickness according to the size of the "R" of the punch and die corners using the material of SCP-1 0.25mm As a result, the following conclusions were obtained. Tensile strength analysis and safety analysis of materials are very important process for each process in strip layout, and Through this, the Influx of material and the deformation of the material were found. As a result of safety analysis and tensile thickness analysis, when the corner R of the punch was 0.3 mm and the edge R of the die was 1.0 mm The inflow of the material was not smooth, and the thickness of the corner part became 0.2 mm, causing cracks. when the corner R of the punch was 0.5 mm and the edge R of the die was 1.5 mm The inflow of the material was smooth, The thickness of the corners of the product is 0.21mm and It was considered that cracks do not occur when the thickness of the bottom surface and the body part becomes thin. The results obtained by applying the results obtained from the analysis, In Experimental Condition 1, a crack occurred in the same part of the analysis In Experimental Condition 2, the flow of the material was smooth and the drawing processing could be performed without generating cracks.

• 한국지반공학회논문집
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• 제27권6호
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• pp.39-48
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• 2011

본 논문에서는 모형실험과 수치해석을 수행하여 유한한 두께의 모래지반 위에 놓인 얕은 띠기초의 지지력 평가방법을 제안하였다. 모형실험은 현장에서 채취한 모래시료를 사용하여 모래지반의 상대밀도와 대상 기초폭(B) 에 대한 모래층 두께(H)의 비(H/B)를 변화시키면서 1g와 20g 중력수준의 원심모형실험을 실시하였다. 실험결과, H/B가 감소함에 따라 지지력은 증가하고 침하는 감소하는 경향을 보였으며, 상대밀도 증가에 따라 지지력이 증가하는 경향도 나타났다. 강성지반 위 두께가 얇은 모래층의 지지력 평가방법을 제안하기 위하여 실험 결과 얻은 지지력 계수를 H/B의 영향을 고려한 Mandel & Salencon(1972)의 수정지지력계수와 비교 분석하였다. H/B에 따른 지지력계수비 관계를 제안하여 보수적인 설계에 적용할 수 있도록 하였다. 기초 제원, 사질토 상대밀도, H/B를 변화시킨 수치해석을 실시한 결과, 제시된 관계식과 유사한 경향성을 확인하였다.