• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.06a
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• pp.191-198
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• 1994

A practical example of the axisymmetric deep drawing process is simulated by the elastic-plastic finite element analysis using updated Lagrangian approach considering the large deformation. An approach is suggested to solve the problem of the ductile fracture that may encounter during the deep drawing process. The result can be applied to the design of the die for the axisymmetric deep drawing.

• Transactions of Materials Processing
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• v.9 no.3
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• pp.304-312
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• 2000

An inverse finite element approach is employed to efficiently design the optimum blank shape and intermediate shapes from the desired final shape in multi-stage elliptic cup drawing processes. The multi-stage deep-drawing process is difficult to design with the conventional finite element analysis since the process is very complicate with the conventional finite element analysis since the process is very complicated with intermediate shapes and the numerical analysis undergoes the convergence problem even with tremendous computing time. The elliptic cup drawing process needs much effort to design sine it requires full three-dimensional analysis. The inverse analysis is able to omit all complicated and tedious analysis procedures for the optimum process design. In this paper, the finite element inverse analysis provides the thickness strain distribution of each intermediate shape through the multi-stage analysis. The multi-stage analysis deals with the convergence among intermediate shapes and the corresponding sliding constraint surfaces that are described by the analytic function of merged-arc type surfaces.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.10a
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• pp.166-171
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• 2001

Copper bus-bar is made by drawing process and used in many part of industry. When design drawing die for copper bus-bar, design factor is focused on the deformation of die-land by drawing force and shrink fit. In this paper, to determine shrink fit value is analyzed by automatic shrink fit analysis program, APDL/UIDL language in a commercial FEM package, ANSYS, has been developed that enables optimal design of the dies taking into account the elastic deflections generated in shrink fitting the die inserts and that caused by the stresses generated in the process and by using DEFORM software for drawing process analysis. This data can be processed as load input data for a finite element die-stress analysis. Process simulation and stress analysis are thus combined during the drawing die design. The stress analysis of the dies is used to determine optimized dimension of die-land.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.4
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• pp.123-129
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• 2018

A rotational drawing die which can form a long tube with spiral grooves on the surface is presented. The main feature of the proposed die is a rotation insert that is embedded into the die container for the die to freely rotate with respect to the drawing centerline as the materials are drawn. We employed a three-dimensional finite element model to investigate the effects of the rotational die on the material filling of spiral grooves. The material used in the finite element analysis was stainless 304. We also performed a pilot drawing test to verify the usefulness of the proposed rotational drawing die. Results reveal that the material filling of spiral grooves by the proposed rotational drawing die was in good agreement for both the finite element analysis and the drawing test. We found that the underfill in a conventional drawing die was reduced in the proposed rotational drawing die.

• Transactions of Materials Processing
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• v.12 no.7
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• pp.647-653
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• 2003

A systematic approach for the process design in deep drawing is necessary to improve the quality of drawn cups. This study concentrates mainly on the influence of process design strategy on the product quality. Different types of process design were chosen from initial blank of 100mm in diameter to make final cup of 50mm in diameter. In order to make this cup, we used 2-stage deep drawing. Forming analyses are carried out to find out better design in terms of drawing force. It is proposed that the process design, in which maximum drawing forces during successive operations are equal, is a more desirable one. Through experiment, it is found that the proposed case shows equivalent values in terms of maximum drawing force during successive operations in real process and can achieve the best product quality in terms of dimensional accuracy. Thus, it is shown that proposed design is very effective in the improvement of quality in drawn cups and may be extended to deep drawing with more stages.

• Transactions of Materials Processing
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• v.18 no.7
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• pp.550-555
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• 2009

In the multi-pass shape drawing process, the pass schedule that includes the determination of reduction ratio and intermediate die shape is very important. This study used the equal reduction, equal load, and electric field analysis method for pass schedule of the multi-pass shape drawing. The reduction ratio was calculated by the equal reduction and equal load method. And the intermediate die shape was determined by the result of the electric field analysis and the calculated reduction ratio. The proposed pass schedule method was applied to a shape drawing for producing cross roller guide. Finally, FE-analysis and shape drawing experiment were performed to verify the effectiveness of the proposed method.

• Transactions of Materials Processing
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• v.10 no.6
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• pp.456-464
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• 2001

Deep drawing and ironing are tile major process today in manufacturing of aluminum alloy battery case used in cellular phone. Most of these process require multi-stage ironing following the deep drawing and redrawing processes. The practical aspects of this technology are well known and gained through extensive experiment and production know-how. However, the fundamental aspects of these processes are relatively less known. Thus, it is expected that process analysis using FEM techniques would provide additional detailed information that could be utilized to improve the process condition. This paper illustrates the application of process modeling to deep drawing and redrawing operations. To verify the simulation results, the experimental investigations were also carried out on a real industrial product. The numerical analysis by FEM shows good agreement with the experimental results in view of the deformation shape of the product. A commercially available finite element code LS-DYNA3D was used to simulate deep drawing and redrawing operations.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.9
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• pp.126-134
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• 2003

This paper investigates the multi-pass wet wire drawing process considering the slip between the wire and the capstan. The production of fine wire through multi-pass wet wire drawing process would be impossible without backtension. The backtension is affected by many process parameters, such as slip, dies reduction, coiling number of wire at the capstan, machine reduction, characteristic of lubricant etc. Up to date, die design and dies pass schedule of multi-pass wet wire drawing process have been performed by trial and error of expert in the industrial field. In this study, an analysis program which can perform the analysis and considering the effect of slip at each capstan was developed. The effects of many important parameters (drawing force, backtension force, needed power, slip rate, slip velocity rate etc.) on multi-pass wet wire drawing process can be predicted by this developed program. It is possible to obtain the important basic data which can be used in the pass schedule of multi-pass wet wire drawing process by using this developed program.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.3
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• pp.198-204
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• 1993

The study is concerned with finite element analysis and design of axisymmetric deep drawing by local heating. When the bottom shape of a cup is not flat but in complex-shaped, i.e., hemispherical, the cup cannot be drawn in one or two processes in the conventional deep drawing process and the limit drawing ratio is limited as well. By introducing local heating selectively with regards to the heating position, the formability of the sheet metal can be greatly increased with the reduced number of processes. In the Process analysisthe rigid- viscoplastic finite element method is employed and the temperature effect is incorporated. Bishop's step-wise decoupled method is employed to analyze the thermomechanical interaction between deformation and heat transfer. Axisymmetric deep drawing of a hemisphere-bottomed cup has been analyzed for various combinations of heat application in the punch and the die. At the first stage of deep drawing stretch forming is practically carried out by firmly pressing the blankholder with the punch and the die heated at various levels of temperature. Then at the second stage the same cup is drawn for the saame or different combination of temperature. From the computation, it has thus been shown that the fromability of a cup is greatly increased in two-stage deep drawing with increased limet drawing ratio.

• Journal of Korean Society for Quality Management
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• v.48 no.3
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• pp.381-393
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• 2020

Purpose: The purpose of this study was to find useful solutions by analyzing causes and results about defects on mechanical drawing notes and provide an automated tool with solutions to mechanical engineers. Methods: The collected data for defects on mechanical drawing notes were from ongoing development and mass production projects. Various measurement methods were used based on the Lean 6 Sigma analysis such as Process analysis, C&E diagram and some statistical analysis. Results: The results of this study are as follows; The results of the Lean 6 Sigma analysis, the validity of the selected indicators for improving drawing notes quality was verified through the verification of cause variables. The strategy established to improve the mechanical drawing notes was reflected as an automated program, and the defects were within a manageable range and achieved target Sigma level. Conclusion: Through the application of the "Mechanical drawing notes automation tool", it is expected to resolve the "Voice of Customer, VOC" and "Voice of Business, VOB".