scholarly journals Optimum Clearance in the Microblanking of Thin Foil of Austenitic Stainless Steel JIS SUS304 Studied from Shear Cut Surface and Punch Load

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 678 ◽  
Author(s):  
Yohei Suzuki ◽  
Ming Yang ◽  
Masao Murakawa

An extrusion-type fine blanking with a negative clearance was proposed by the authors instead of standard fine blanking for creating a full-sheared surface in the micro blanking process. In this study, micro blanking experiments and finite element analyses with narrow, zero and negative clearances are carried out for the optimizing the clearance at which a shear cut surface can be finished with a full-sheared surface with the minimized punch load. Fracture criterion, hydrostatic stress and maximum punch stress for the conditions with various clearances are investigated. As a result, it was clarified that the clearance at which the cut surface does not fracture and minimization of the punch load is achieved is gained by the use of clearance −4 μm.

2009 ◽  
Vol 16-19 ◽  
pp. 495-499 ◽  
Author(s):  
Si Ji Qin ◽  
Li Yang ◽  
Jia Geng Peng

The fine blanking process with a stepped-edge punch was researched by finite element method (FEM) and experiment investigation. Finite element analysis showed that the hydrostatic stress of the blank around the edges changes a little during fine blanking process using a stepped-edge punch with negative clearance. The burnish zone of sheared surface increases with the increase of the relative negative clearance. The reasonable forming parameters were presented by a lot of experiment investigations. Parts of three kinds of materials, Q235 steel, copper and industrial aluminum, were formed using fine blanking process with a stepped-edge punch. Full burnish zone were obsearved for all the parts.


2012 ◽  
Vol 229-231 ◽  
pp. 105-108
Author(s):  
H. Du ◽  
F. Li ◽  
H. Zhang

The stainless steels are used more and more in blanking process. To further enhance the quality of blanking fracture surface, this paper made the related experiments of fine-blanking with negative clearance in stainless steel. Through the comparison analysis between the fine-blanking microstructure and common blanking one with stainless steel, the result points out that the fine-blanking with negative clearance inhibit the warping in common blanking, make the work-hardening of material fracture surface improves, and which can have a more positive effect for the fine-blanking with negative clearance. Meanwhile, the work-hardening capacity of two blanking methods was different, and it can enhance the punching section entire strength commendably by fine blanking with negative clearance.


2002 ◽  
Vol 124 (2) ◽  
pp. 416-419 ◽  
Author(s):  
A. M. Goijaerts ◽  
L. E. Govaert ◽  
F. P. T. Baaijens

In a previous work a numerical tool was presented which accurately predicted both process force and fracture initiation for blanking of a ferritic stainless steel in various blanking geometries. This approach was based on the finite element method, employing a rate-independent elasto-plastic constitutive model combined with a fracture criterion which accounts for the complete loading history. In the present investigation this work is extended with respect to rate-dependence by employing an elasto-viscoplastic constitutive model in combination with the previously postulated fracture criterion for ferritic stainless steel. Numerical predictions are compared to experimental data over a large range of process speeds. The rate-dependence of the process force is significant and accurately captured by the numerical simulations at speeds ranging from 0.001 to 10 mm/s. Both experiments and numerical simulations show no influence of punch velocity on fracture initiation.


2021 ◽  
Author(s):  
Huajie Mao ◽  
Han Chen ◽  
Yanxiong Liu ◽  
Kaisheng Ji

Abstract Fine blanking is a kind of metal forming process with the advantages of high precision, good surface quality and low cost. Influenced by the concept of lightweight, a large number of metal materials with high strength are widely used in various fields. High strength materials are prone to be cracked during plastic deformation due to their poor plasticity, which limits the application range of them. This paper proposed a force variation fine blanking process for high-strength and low-plasticity materials. At the same time, a method to find the curve of forming force for this novel process was presented. A 2D finite element fine blanking model was established for the TC4 material. Combining genetic algorithm and neural network methods, a model was built up to find the optimal forming force loading curve. The parts fabricated by force variation loading and constant loading fine blanking process were compared through experiments. The mechanism of force variation fine blanking is also revealed. The forming force mainly affects the length of clean cutting surface by affecting hydrostatic stress. According to the ultimate optimal loading curve, the forming force should be kept at a low level in the early stage of blanking stroke, and increased gradually in the ending stage. In the application of force variation fine blanking, the part with long length of clean cutting surface can be obtained with lower die load.


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.


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.


2016 ◽  
Vol 716 ◽  
pp. 762-769 ◽  
Author(s):  
Fei Zhou ◽  
Hua Jie Mao ◽  
Yan Xiong Liu ◽  
Lin Hua

This paper proposes a new blankholder to fine blanking process. V-ring indenter has been widely applied in fine blanking to produce clean cut parts, however, it is difficult to be manufactured, the machining accuracy of which is hard to ensure and the cost is very high. In this approach, the fine blanking process combined with discontinuous dot indenter was put forward and the parameters design for workpiece with different thickness was studied with the finite element simulation and the orthogonal experiment methods. The larger burnished surface zone can be obtained by optimizing discontinuous dot indenter parameters. In addition, the relationship between the discontinuous dot indenter parameters and the workpiece thickness was got from data processing. Finally, applying this relationship to fine blank workpiece with different thickness, nearly full clean cut surface part was obtained.


2011 ◽  
Vol 52 (3) ◽  
pp. 447-451 ◽  
Author(s):  
Toru Tanaka ◽  
Seiya Hagihara ◽  
Yuichi Tadano ◽  
Shuuhei Yoshimura ◽  
Takuma Inada ◽  
...  

2011 ◽  
Vol 291-294 ◽  
pp. 440-443 ◽  
Author(s):  
Chun Dong Zhu ◽  
Fu Tao Li ◽  
Zhi Qiang Gu

Due to the limitation of 2D simulation in fine blanking, finite element software DEFORM-3D was used to simulate the 3D model of Back Plate. In this article the Normalized Cockroft&Latham fracture criterion was chosen to simulate the blanking process. The distribution and developing trend of the hydrostatic stress, equivalent stress in the fine blanking process are predicted. When the die radii are between 0.4mm and 0.6mm, burnished surface improves. It shows that the ideal blanking clearance value is 0.6% of the material thickness. The results indicate that FE numerical simulation could effectively optimize fine blanking process and offer basis for quality improvement.


2004 ◽  
Vol 261-263 ◽  
pp. 1665-1670 ◽  
Author(s):  
Y.H. Seo ◽  
Byoung Kee Kim ◽  
H.D. Son

Wire cutting(EDM) or blanking is used to made workpieces from sheet metal. Wire EDM provides a relatively simple method for making holes of any desired cross section in material. But EDM requires a lot of working time and the high unit cost of production. In conventional blanking, for the production of precision devices or assemblies, it is always necessary that at least two, but generally more, secondary operations are required per piece part. Using the fine blanking process, a precise finished part with inner and outer forms clearly sheared over the whole material thickness are produced in one single operation. In this study an attempt is made to manufacture a sprocket with fine blanking process. The sprocket is parts for the tape feeder of surface mount system in electronic parts. First, a change of the existing design is made in a sprocket. The materials selected are three kinds of stainless steel, SUS304, SUS316 and SUS430. And the mechanical properties are investigated through the tensile test. After fine blanking, hardness and precision are examined with hardness test and 3-dimensional coordinate measuring for samples. The results of investigations of fine-blanking process with the help of FEM code, DEFORM 2D, are presented. For the simulation, SUS304 and SUS316 are used as materials. The damage model of Cockroft and Latham is used to calculate damage. Die-roll height, die-roll width, burnish zone and fracture zone from the fine blanking simulation are investigated in comparison with them of samples. And the applied force at each part of fine-blanking die is estimated with load-stroke diagram.


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