Design & Manufacturing

Korean Society of Die & Mold Engineering (한국금형공학회)
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Analysis of the effect of punch wear on shear surfaces in the piercing process

피어싱 공정에서의 펀치 마모가 전단면에 미치는 영향 분석

  • Jeon, Yong-Jun (Mold & Metal Forming R&D Department, Korea Institute of Industrial Technology) ;
  • Kim, Dong-Earn (Mold & Metal Forming R&D Department, Korea Institute of Industrial Technology)
  • 전용준 (한국생산기술연구원 금형성형연구부문) ;
  • 김동언 (한국생산기술연구원 금형성형연구부문)
  • Published : 2022.09.30
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Abstract

The recent increasing application rate of advanced high-strength steel(AHSS) for automotive parts makes it difficult to ensure the durability of forming tools. Significant load and friction generated during the piercing process of AHSS increase the wear rate and the damage degree to dies. These harsh process conditions also yield product failures, such as dimensional inconsistency of pierced holes and insufficient quality of hole's sheared edge. This study analyzed the effect of punch wear on the sheared surface of pierced parts and the forming load during the piercing process. Wear-shaped punches showed approximately 20% higher piercing load than normal-shaped punches, and the rollover ratio of the sheared surface also increased. It is considered that the dull edge of wear-shaped punches does not penetrate directly into the material but shears after tensioning it in a piercing direction. In addition, wear-shaped punches experienced compressive load even after completing the piercing process during the down-stroke and tensile load during the up-stroke. This load variation is related to the smaller diameter piercing holes produced by wear-shaped punches compared to normal-shaped punches. Thus, we demonstrated the predictability of the wear level of dies through a comparative analysis of the piercing load pattern.

Keywords

Acknowledgement

본 연구는 한국생산기술연구원 기관주요사업 "Add-on 모듈 탑재를 통한 지능형 뿌리 공정 기술개발(KITECH EO-22-0005)"의 지원으로 수행한 연구입니다.

References

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