• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.937-940
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• 2010

본 연구는 fine blanking 프레스로부터 기능면으로 사용되는 100% clean cut 전단면을 얻는 fine blanking 공정에서 die roll을 최소화하기 위한 목적으로 성형 해석 및 실험적 방법을 통해 die chamfer 형상에 따라 성형되는 제품의 die roll size 변화를 검토한 것이다. fine blanking 과정을 묘사하기 위하여 deform 2D를 이용하여 성형 해석을 수행하여 die roll size를 예측하였으며, 실제 die chamfer가 다른 die insert를 제작하여 fine blanking 실험을 실시하여 die chamfer 형상에 따른 die roll size에 대한 해석 data와 실험 data를 비교 분석하여 die roll 길이 방향 size의 경향을 파악할 수 있었다. 이 연구 결과는 fine blanking 판재 성형에서 die roll을 최소화하기 위한 die chamfer 설계에 유용하게 적용될 것으로 판단된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.565-570
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• 2011

There is always die roll in fine blanking parts which is able to have 100% clean shear surface. In this paper the change of die roll size was studied by fine blanking tryout in order to minimize die roll size. Various die inserts with different die chamfer were machined, fine blanking die was manufactured and tested. The die roll sizes of fine blanking samples were measured and the tendency of thickness directional die roll size was comprehended. This result will be used on the design of die chamfer in order to minimize thickness directional die roll size of fine blanking parts

• Transactions of Materials Processing
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• v.25 no.6
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• pp.390-395
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• 2016

GDI fuel rail is component of GDI system which directly fuel with high pressure in the engine combustion chamber. And it is required to high strength and dimensional accuracy. Multi roll-die drawing process consists of the idle roll-die and drawing die in tandem. In the course of drawing with roll-die, deformation takes place between the idle roller pair or pairs. The friction force decreases with the idle roll-die, enabling the reductions to be risen in one step. In this study, the caliber of 4-roll was designed into pass schedule that made the draw force at the exit of the drawing die be equal. In order to compensate for over-filling area, the roll caliber was modified using the result of FE-analysis. The results of FE-analysis and experiment show that the proposed design method can be used to effectively design the multi roll-die process, leading to an accurate shape and correct dimensions of the final within an allowable tolerance of ${\pm}0.08mm$. Furthermore, the productivity was evaluated by comparing with multi roll-die drawing process and conventional multi shape drawing process. The result was confirmed that it has an efficiency of about 2 times than conventional process in terms of time.

• Design & Manufacturing
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• v.17 no.3
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• pp.15-20
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• 2023

In the fine blanking process, which is a press operation known for producing parts with narrow clearances and high precision through the application of high pressure, die roll often occurs during the shearing process when the punch penetrates the material. This die roll phenomenon can significantly reduce the functional surface of the parts, leading to decreased product performance, strength, and fatigue life. In this research, we conducted an in-depth analysis of the factors influencing die roll in the curvature area of the fine blanking process and identified its root causes. Subsequently, we designed and experimentally verified a die roll reduction process specifically tailored for the door latch manufacturing process. Our findings indicate that die roll tends to increase as the curvature radius decreases, primarily due to the heightened bending moment resulting from reduced shape width-length. Additionally, die roll is triggered by the absorption of initial punch energy by scrap material during the early shearing phase, resulting in lower speed compared to the product area. To mitigate the occurrence of die roll, we strategically selected the Shaving process and carefully determined the shaving direction and clearance area length. Our experiments demonstrated a promising trend of up to 75% reduction in die roll when applying the Shaving process in the opposite direction of pre-cutting, with the minimum die roll observed at a clearance area length of 0.2 mm. Furthermore, we successfully implemented this approach in the production of door latch products, confirming a significant reduction in die roll. This research contributes valuable insights and practical solutions for addressing die roll issues in fine blanking processes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2009-2014
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• 2012

It is very important to minimize the die roll height of gear, in order to maximize the shear cutting surface(tooth surface) of fine blanking. In this paper, the fine blanking tool sets were manufactured in order to study the die roll height according to V-ring position and die chamfer shape. They were constituted of the various die inserts and guide plate inserts with different die chamfer shape and different V-ring distance. The fine blanking experiment was conducted with the fine blanking tool sets and the die roll height of the gear samples was measured. It should be noted that die roll height on the fine blanked gear increased with increasing the V-ring distance and die chamfer angle.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.40-44
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• 1999

A finite element analysis has been performed to investigate the effect of die clearance on shear planes in the fine blanking of a part of automobile safety belt. For the analysis S45$^{\circ}C$ is selected as an material which is used in manufacturing the part of automobile safety belt and Cockcroft-Latham fracture criterion is applied, Effect of die clearance on die-roll width die-roll depth burnish zone and fracture zone has been concentrately investigated in the finite element analysis. From the analytical results it has been found that die-roll width and depth of the shear plane increase with increasing die clearance. And the burnish zone has been concentrately investigated in the finite element analysis. From the analytical results it has been found that die-roll width and depth of the shear plane increase with increasing die clearance. and the burnish zone decreases with increasing die clearance but the variation of fracture zone is opposite to that of burnish zone because the increase in die clearance requires less fracture energy Theoretical predictions are compared with experimental results, There is a good agreement between theory and experiment

• Transactions of Materials Processing
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• v.9 no.2
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• pp.152-158
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• 2000

A finite element analysis has been performed to investigate the effect of die clearance on shear planes in the fine blanking of a part of automobile safety belt. For the analysis, S45C is selected as an material, which is used in manufacturing the part of automobile safety belt, and Cockcroft-Latham fracture criterion is applied. Effect of die Clearance on die-roll width, die-roll depth, burnish zone, and fracture zone has been investigated in the finite element analysis by a rigid-plastic FEM code, DEFORM-2D. From the analysis, it has been found that die-roll depth and depth of the shear plane increase with increasing die clearance. And the burnish zone decreases with increasing die clearance, but the variation of fracture zone is opposite to that of burnish zone because the increase in die clearance requires less fracture energy. Theoretical predictions are compared with experimental results. There is a good agreement between theory and experiment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6060-6065
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• 2013

Minimizing the height of the die roll is very important for maximizing the size of effective shear planes. In this study, the die roll change was investigated for the change in the amounts and clearance of the V-ring indentation. Shear analysis and experiments were conducted with the V-ring distance fixed to 2mm. Fine blanking die was applied to the die insert with different clearances. Several specimens were analyzed about the height of the die roll. As a result, the pressure of V-ring effectively inhibited the flow of materials. And the height of the die roll was lowest when the clearance between the die and punch was 1% of the material thickness.

• Design & Manufacturing
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• v.11 no.3
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• pp.46-50
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• 2017

Press processing is one of the best machining methods capable of mass production, satisfying dimensional, shape and quality among the methods of processing a metal plate. Among them, Fine blanking is a method of obtaining a precise cross-section such as machining of the shear surface shape. In this research, Using SCP-1 and SHP-1 materials. The deformation behaviors of the material flow affecting the die height of the shear section in accordance with the position of the V-ring in the Fine blanking were compared and analyzed. Result of interpretation, It was confirmed that the force acts on the position where the material flow direction accurately forms the die roll that the material of SCP-1 is at a position of 1.5 mm and the material of SHP-1 is at 2.0 mm. As a result, it was confirmed that the state of fo1111ing the shear surface by the V-ring was excellent. Using analysis results, In the experiment, the height of the die roll was considered by applying The position of the V-ring was 1.5 mm in SCP-1 and 2.0 mm in SHP-1. As a result of comparing the height of the die rolls, the height values of the die rolls were different from each other, It has been considered that the tendency of the die rolls to coincide with each other. It is considered that the difference of the die roll height is caused by the pressure input of the V-ring. In this study, the deformation behavior of the material(In addition to the position of the V-ring, the flow direction of the material depends on the shape of the V-ring and the Indentation amount) is considered to be an important factor in determining die roll height.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.2
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• pp.159-166
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• 2015

Slot-die coating is well known technique to guarantee a uniformly coated layer and is compatible with roll-to-roll process. In actual roll-to-roll slot-die coating process, the lateral difference of coated layer thickness is observed. An experimental study was performed to improve the coating quality. Coating speed and coating gap were selected as the experimental factors. A full factorial, statistical method was conducted to optimize the process conditions. Based on the results of repeated experiment, the lowest deviation of lateral thickness (700 nm, <10%) was achieved at 10 m/min coating speed and $300{\mu}m$ coating gap. This result has significance because such optimized process guideline can be utilized with all process improvement in various coating applications.