Application of Back-Up Ring in Fine-Blanking Process

2010 ◽  
Vol 443 ◽  
pp. 140-145 ◽  
Author(s):  
Suthep Yiemchaiyaphum ◽  
Masahiko Jin ◽  
Sutasn Thipprakmas

Considering the advantages of the fine-blanking process, the smooth-cut surface without further operation could be fabricated. However, one of the major problems of the fine-blanking is the occurrence of the die-roll formation. This problem is the main factor which affects the quality of the fine-blanked parts. In this study, to reduce the amount of die-roll formation, the application of back-up ring was proposed. The finite element method (FEM) was used to investigate the effects of back-up ring. In addition, the effects of bridge width were also investigated. The FEM simulation results illustrated that the mechanism of back-up ring and the effects of bridge width could be theoretically clarified base on the material flow analysis. The FEM simulation and experimental results showed the good agreement with each other. Therefore, the application of back-up ring could reduce the amount of die-roll formation on the fine-blanked parts. In this study, the amount of die-roll formation increased as the bridge width increase and it was constant at the bridge width of over 15 mm.

2010 ◽  
Vol 443 ◽  
pp. 219-224 ◽  
Author(s):  
Suthep Yiemchaiyaphum ◽  
Masahiko Jin ◽  
Sutasn Thipprakmas

The hole quality on sheet metal parts is directly dependent on the die design and process parameters. In conventional piercing process, the secondary operations such as shaving, reaming and grinding are needed for manufacturing the precise-dimensioned holed parts without any cracks, resulting in the increase of both production time and costs. The fine-piercing process, referenced to the fine-blanking principle, is used to produce the precise-dimensioned holed parts with smooth-cut surfaces over the whole material thickness in a single operation. However, it is difficult to achieve the suitable die design and process parameters for meeting the part requirements. In this study, the die design by chamfering punch cutting edge was investigated on both the experiments and the finite-element method (FEM). The results were compared with the results obtained when the conventional die design with the punch cutting-edge radius was used. The FEM-simulation results showed the amount of die-roll, smooth-cut surface, and cracks agreed well with the experimental results. The results showed that an application of punch cutting-edge chamfer results in a superior fine-pierced hole surface could be achieved. Furthermore, the mechanism and effects of the punch cutting-edge chamfer have been theoretically clarified on basis of the material-flow analysis and stress distribution.


2011 ◽  
Vol 473 ◽  
pp. 290-297 ◽  
Author(s):  
Wojciech Wieckowski ◽  
Piotr Lacki ◽  
Janina Adamus

The required technological quality of the blanked products can be achieved through operations of fine blanking. This allows for obtaining products with improved dimensional accuracy and good quality cut-surface. In order to cut products from soft materials, including aluminium and its alloys, the methods of fine blanking with upsetting and fine blanking with reduced clearance are typically employed. The study presents the results of numerical modelling of the fine blanking process for a disk made of 1-millimetre sheet aluminium EN AW-1070A. The goal of the numerical simulations was to evaluate the effect of clearance between blanking die and the punch, and the impact of V-ring indenter on stress and strain distribution in the shearing zone.


2009 ◽  
Vol 410-411 ◽  
pp. 305-312 ◽  
Author(s):  
Sutasn Thipprakmas ◽  
Masahiko Jin

The V-ring indenter geometry (angle, height and position) was investigated by using the finite element method (FEM) to theoretically clarify the mechanism and its action in the fine-blanking process. The FEM simulation results indicate that very small or very large V-ring indenter angles, heights, and positions cause difficulty in the rotation of the material-flow and that the hydrostatic pressure is generated with great difficulty in the blanked material; therefore, crack formation occurs easily. The application of a suitable V-ring indenter angle, height, and position significantly suppresses the formation of rotating flow, which results in increased hydrostatic pressure, and crack formation is consequently prevented.


2010 ◽  
Vol 443 ◽  
pp. 201-206 ◽  
Author(s):  
Sutasn Thipprakmas ◽  
Wiriyakorn Phanitwong ◽  
Mutjarin Chinwithee ◽  
Thanaporn Morkprom

Burrs are unwanted materials remaining not only after the machining operation but also after the sheet metal cutting operation. Burr formations decrease the part accuracy and increase the cost for the deburring operation. In this study, the reciprocating shaving process was proposed to eliminate crack and burr formations in the pressed parts. The finite element method (FEM) was used as a tool to investigate the possibility of this process and its working process parameters as well. The FEM simulation results showed the effects of clearance in shearing operation, shaving allowance, and half-shaving direction on the shaved surface. These results were validated by laboratory experiments, and they showed a good agreement with each other. The FEM simulation could be used as a tool for prediction of the cut surface in the reciprocating shaving process. The results revealed that the reciprocating shaving process could be applied for eliminating crack and burr formations in pressed parts using suitable working process parameters.


Author(s):  
Y C Leung ◽  
L C Chan ◽  
C H Cheng ◽  
T C Lee

An excellent quality of shearing edge implies that a smooth cutting edge without tearing will be observed on the whole edge surface. This is one of the most significant features of the fine-blanking process. To achieve this good blanking edge quality in fine-blanking, quite a large number of factors need to be considered simultaneously during the operation, such as blanking speed, processing material, product shape, lubrication and tool geometry. Thus, the objective of this paper is mainly to study the influence of tool geometry change in fine-blanking for different materials. This is because the nose radius usually seriously deteriorates with increasing service period in mass production, which eventually causes the entire loss of the specific features of the fine-blanking process. Therefore, a tailor-made experimental study was carried out to investigate the relationship between the punch nose radius and the shearing edge quality, such as the shearing edge surface finish, burr height and die-roll height, during fine-blanking for different types of materials. Consequently, findings show that an increase in the punch nose radius produces a higher percentage of fracture of the blanked edge and increases the amount of burr height.


2008 ◽  
Vol 575-578 ◽  
pp. 316-321 ◽  
Author(s):  
H. Du ◽  
S.M. Ding

This paper puts forward a negative clearance fine-blanking theory and its technique process, and introduces the technical processing of fine-blanking which can be used on ordinary punching machines. In this paper, computer simulation and the experimental study of negative clearance fine-blanking process are carried out. Thus the parameters of the force of blanking, the value of negative clearance are determined. The effect of fine-blanking quality was obtained, and the perfect rate of the blanking fracture achieves 90%. By comparing negative clearance precise blanking with conventional blanking, the following conclusions are drawn: 1. Blanking quality of negative clearance blanking is increased by 57% than that of conventional blanking. 2. The down surface of the work-pieces obtained by the conventional blanking processing have 0.2 - 0.5 mm longitudinal burrs, while the work-pieces obtained by the negative clearance blanking have no burrs. Thus the processing of clear away the burrs could be spared. And the manpower, the material, energy and the equipment investment are saved. The researching result provides theoretic reference and the experimental data for the engineering practice. It has instructive significance and reference value to engineering manufacturing.


2013 ◽  
Vol 721 ◽  
pp. 397-401
Author(s):  
Li Min Wen ◽  
Qing Li ◽  
Yi Min Wang

A numerical model research of fine-blanking has been built up. The fine-blanking process of parts with pressure is 0KN20 KN40 KN60 KN respectively , thickness of plate 2.9mm and diameter 16mm,of steel 45, has been simulated. Through simulation, the study gets the material distribution situation of mean-stress fields in the progress of fine-blanking, and analyzes the relation between mean-stress fields and the crack of shearing zone. And get the pressure optimization value.


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