• Design & Manufacturing
• /
• 제15권1호
• /
• pp.41-47
• /
• 2021

The Fine Blanking process is an effective precision shearing process that can obtain a smooth cutting surface and high product precision through a single blanking process. It is widely used in various manufacturing fields. However, shearing through this fine blanking process is only intended to minimize burrs, die rolls and fracture surfaces and does not completely remove them. Therefore, it is necessary to study the minimization of burrs, die rolls and fracture surfaces in the fine blanking process. In this study, a study was conducted on the relationship between the fracture surface and process conditions that occurred during product production using the fine blanking process. For this purpose, the shape of the V-ring indenter, the distance to the punch, and the pressure force, clearance, shear rate, and physical properties of the material were selected as process and design variables, and the relationship with the fracture surface according to each process and design condition was tested. It was analyzed through the Experimental Design Method.

• 암석학회지
• /
• 제18권4호
• /
• pp.293-305
• /
• 2009

경상분지 영양지괴와 의성지괴가 접하는 길안-청송 지역은 선캠브리아기 변성암류, 트라이아스기 청송 화강암, 백악기 퇴적암류(일직층, 후평동층, 점곡층), 그리고 백악기 화성암류(안산암, 석영반암, 규장암) 등으로 구성되어 있으며, (서)북서, 북북서, 동북동, 남북, (북)북동 등 경상분지를 대표하는 다양한 방향의 단층들이 발달한다. 본 연구는 이들 단층의 발달사 및 운동성을 조사하기 위해 길안-청송 지역에 발달하는 단열계의 기하학적 운동학적 특성을 파악하였다. 그 결과, 연구지역내 발달하는 단층들의 운동성은 대부분 주향이 동성으로 인지되며, 방향성별 단열조의 출현빈도는 동북동, 북북서, (서)북서, (북)북동, 남북 등의 방향 순으로 높게 나타난다. 방향성별 단열조의 연장성은 (서)북서, 북북서, 동북동, (북)북동, 남북 등의 방향 순으로 우세하게 나타나고, 이러한 우세 방향성은 단층들의 연장성과 거의 일치한다. 방향성별 단열조의 발달사 및 운동성은 (1) (서)북서 방향 단열조의 우수향 전단단열운동 $\rightarrow$ (2) (서)북서 방향과 북북서 방향 단열조의 공액성 전단단열운동(전자: 우수향, 후자: 좌수향) $\rightarrow$ (3) 북북서 방향 단열조의 우수향 전단단열운동 $\rightarrow$ (4) (서) 북서 방향 단열조의 좌수향 전단단열운동 $\rightarrow$ (5) 동북동 방향 단열조의 우수향 전단단열운동 $\rightarrow$ (6) 동북동 방향과 남북 방향 단열조의 공액성 전단단열운동(전자: 좌수향, 후자: 우수향) $\rightarrow$ (7) (북)북동 방향 단열조의 좌수향 전단단열운동 등으로 요약되고, 이러한 연구결과는 길안-청송 지역에 발달하는 단층들의 발달사 및 운동성과 밀접한 관련성 있다.

• 한국정밀공학회지
• /
• 제16권1호통권94호
• /
• pp.182-190
• /
• 1999

The objective of this study is to develop an analysis scheme in order to predict regrinding due to tool wear in shearing process. The analysis of material now and fracture in shearing process should precede the prediction of tool wear. Thus the developed FE-program to analyze shearing process is used. In order to predict tool wear, the wear model is reformulated as an incremental form and then the wear depth of tool is calculated at each deformation path. Because the regrinding of shearing tool is determined on the basis of allowable size of burr, the analysis of shearing process is iteratively performed using the worn profile of tool. To show the effectiveness of the scheme the simulation result is compared with experimental one.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 춘계학술대회 논문집
• /
• pp.747-752
• /
• 2000

Rotary shearing using of rotating and locally shear force has been studied. It is possible to be obtained in any case for requested blank diameters. In this paper, different local forming zones, that are clearances between upper roller and vertically taped low roller, were investigated. Required shearing force is calculated by undecided coefficient method for clearances and strokes of upper roller. Rotary shearing is completed undergoing some processes composed of pressing steps and standing steps. The reason for using these processes is to avoid jamming or tearing of blank by means of upper roller during shearing.

• 대한금속재료학회지
• /
• 제47권9호
• /
• pp.580-585
• /
• 2009

The effects of shear speed and tip height on the high speed shear test of Sn-3.0wt.%Ag-0.5wt.%Cu ball joints were investigated. Solder balls of $450{\mu}m$ in diameter were reflowed at $245^{\circ}C$ on a FR4 PCB (Printed Circuit Board) in order to obtain a sample for the high-speed shear test. The UBM was comprised of Cu/Ni/Au, and the shear speed and tip height varied from 0.5 to 3.0 m/s, and from 10 to $135{\mu}m$, respectively. According to the experimental results, faster shear speed enhanced the shear strength of the solder joints, regardless of the tip height. The fraction of ductile (solder) fracture decreased when the shearing speed was raised from 0.5 to 3.0 m/s. With an increasing tip height from 10 to 50 and $135{\mu}m$, the fracture mode changed from pad lift to mixed (ductile and brittle) and ductile fracture, respectively, while the shearing energy also increased in the same order. The shear energy had a proportional relationship with the fraction of the solder fracture.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2010년도 춘계학술대회 논문집
• /
• pp.269-270
• /
• 2010

• 한국기계가공학회지
• /
• 제14권4호
• /
• pp.134-139
• /
• 2015

PolyJet technology is an additive manufacturing (AM) technology commonly used for modeling, prototyping, and production applications. It is one of the techniques used for 3D printing. The PolyJet technique is a process that joins materials to fabricate a product from 3D CAD data in a layer-by-layer manner. The orientation of a layer can affect the mechanical properties of the product manufactured by the PolyJet technique because of its anisotropy. In this paper, tensile and shearing tests of specimens were developed with the PolyJet technique in order to study the mechanical properties according to the orientation of a layer. The mechanical properties of the specimens were determined on the basis of true stress-strain curves from tensile and shearing tests. In addition, the tensile and shearing tests were simulated under the same conditions as those of experiment, and the experiment and simulated results were compared. Through this study, the fracture criteria could be established.

• 소성∙가공
• /
• 제21권5호
• /
• pp.298-304
• /
• 2012

The shielded slot plates for a molten carbonate fuel cell(MCFC) have a sheared corrugated trapezoidal pattern. In the FEM simulations for the production of the shielded slot plate, the user material subroutine VUMAT in the commercial FEM software ABAQUS was used to implement a ductile fracture criterion. The critical damage value for the ductile fracture criterion was determined by comparing the experimental results of the shearing process with the simulation results. Using the ductile fracture criterion, the FEM simulation of the three-dimensional forming process of the shielded slot plate was conducted. The effects of the shearing process on the forming process were examined through FEM simulation and experiments. The forming simulation of nine unit cells was conducted. Using the simulation results of the forming process, the deformed shape after springback was calculated. The experimental result shows good agreement with the simulation.

• 대한금속재료학회지
• /
• 제49권3호
• /
• pp.237-242
• /
• 2011

The effect of shearing speed on the shear force and energy of Sn-0Ag-0.5Cu solder ball was investigated. Various UBM (under bump metallurgy)'s on Cu pads were used such as ENEPIG (Electroless Nickel, Electroless Palladium, Immersion Gold; Ni/Pd/Au), ENIG (Electroless Nickel, Immersion Gold; Ni/Au), OSP (Organic Solderability Preservative). To fabricate a shear test specimen, a solder ball, $300{\mu}m$ in diameter, was soldered on a pad of FR4 PCB (printed circuit board) by a reflow soldering machine at $245^{\circ}C$. The solder bump on the PCB was shear tested by changing the shearing speed from 0.01 m/s to 3.0 m/s. As experimental results, the shear force increased with a shearing speed of up to 0.6 m/s for the ENIG and the OSP pads, and up to 0 m/s for the ENEPIG pad. The shear energy increased with a shearing speed up to 0.3 m/s for the ENIG and the OSP pads, and up to 0.6 m/s for the ENEPIG pad. With a high shear speed of over 0 m/s, the ENEPIG showed a higher shear force and energy than those of the ENIG and OSP. The fracture surfaces of the shear tested specimens were analyzed, and the fracture modes were found to have closer relationship with the shear energy than the shear force.

• 마이크로전자및패키징학회지
• /
• 제18권1호
• /
• pp.35-39
• /
• 2011

고속전단시힘의 표준화를 위한 기초 연구의 일부로 Sn-3.0wt%Ag-0.5wt%Cu 솔더 볼의 고속전단특성에 대한 연구를 수행 하였다. 고속전단 시험편 제작을 위해 직경 450 ${\mu}m$의 솔더 볼을 FR4 PCB (Printed Circuit Board) 위에 장착한 후 $245^{\circ}C$ 온도에서 리플로 솔더링을 행하였다. PCB 상의 금속 패드로는 ENIG (Electroless Nickel/mmersion Gold, i.e Cu/Ni/Au)와 OSP (Organic Solderability Preservative, Cu 패드)를 사용하였다. 고속전단 속도는 0.5~3.0 m/s 범위, 전단 팁의 높이는 10~135 ${\mu}m$ 범위에서 변화시켰다. 실험결과로서, OSP 패드의 경우 전단 팁 높이 증가에 따라 연성 파괴가 증가하였으며, 전단속도 증가에 따라 연성파괴는 감소되었다. ENIG 패드의 경우에도 전단 팁 높이 증가에 따라 연성 파괴가 증가하였다. 전단 팁 높이 10 ${\mu}m$(볼 직경의 2%)는 패드 박리 파괴가 대부분이어서 전단파면 관찰에는 부적절한 높이였다. 고속전단에너지는 OSP 및 ENIG 패드 모두 전단 팁 높이 증가에 따라 증가하는 경향을 보였다.