Transactions of Materials Processing (소성∙가공)

The Korean Society for Technology of Plasticity and materials processing (한국소성∙가공학회)
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Study on the Evaluation and Prediction of Micro-Defects in the Hemming Process

헤밍 공정에서의 미세 결함 평가 및 예측에 관한 연구

  • 정헌철 (강원대학교 대학원 기계 메카트로닉스공학부) ;
  • 임재규 (춘천기능대학 컴퓨터응용기계과) ;
  • 김형종 (강원대학교 기계 메카트로닉스공학부)
  • Published : 2005.09.01
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Abstract

The hemming process, composed of flanging, pre-hemming and main hemming, is the last one of a series of forming processes conducted on the automotive panels, having greater influence on the outward appearance of cars rather than on their performance. The hem quality can be quantitatively defined by the hemming defects including turn-down/up, warp and roll-in/out. However, it is difficult to evaluate and predict the hem quality through an experimental measurement or a numerical calculation since the size of defects is very small. This study aims to precisely evaluate the hemming defects, especially turn-down and roll-in, through numerical and experimental approaches and to investigate the influence of process parameters on the hem quality, focused on how to simulate the same conditions as in the experiment by the finite element analysis (FEA). The FEA results on the turn-down and roll-in obtained from a model composed of the optimum-sized elements, including a spring element linked to the flanging pad, and given the double master contact condition between the inner and outer panels, had a good correlation with the experimental data. It is thought possible to make an early estimate of the hem quality in a practical automotive design by applying the methodology proposed in this study.

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References

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Cited by

  1. Numerical Evaluation of Hemming Defects Found on Automotive Door Panels vol.24, pp.4, 2015, https://doi.org/10.5228/KSTP.24.4.280