Design & Manufacturing

Korean Society of Die & Mold Engineering (한국금형공학회)
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A study on surface roughness depending on cutting direction and cutting fluid type during micro-milling on STAVAX steel

STAVAX 강의 마이크로 밀링 중 가공 방향 및 절삭유체 분사형태에 따른 표면 거칠기 경향에 관한 연구

  • Dong-Won Lee (Korea Institute of Industrial Technology, Research Institute of Advanced manufacturing & materials Technology) ;
  • Hyeon-Hwa Lee (Korea Institute of Industrial Technology, Research Institute of Advanced manufacturing & materials Technology) ;
  • Jin Soo Kim (Korea Institute of Industrial Technology, Research Institute of Advanced manufacturing & materials Technology) ;
  • Jong-Su Kim (Korea Institute of Industrial Technology, Research Institute of Advanced manufacturing & materials Technology)
  • 이동원 (한국생산기술연구원 뿌리기술연구소) ;
  • 이현화 (한국생산기술연구원 뿌리기술연구소) ;
  • 김진수 (한국생산기술연구원 뿌리기술연구소) ;
  • 김종수 (한국생산기술연구원 뿌리기술연구소)
  • Received : 2023.06.20
  • Accepted : 2023.06.30
  • Published : 2023.06.30
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Abstract

As Light-Emitting Diodes(LEDs) continue to advance in performance, their application in automotive lamps is increasing. Automotive LEDs utilize light guides not only for aesthetics but also to control light quantity and direction. Light guides employ patterns of a few hundred micrometers(㎛) to regulate the light, and the surface roughness(Ra) of these patterns can reach tens of nanometers(nm). Given that these light guides are produced through injection molding, mold processing technology with high surface quality micro-patterns is required. This study serves as a preliminary investigation into the development of high surface quality micro-pattern processing technology. It examines the surface roughness of the workpiece based on the cutting direction of the pattern and the cutting fluid type when cutting micro-patterns on STAVAX steel using cubic Boron Nitride(cBN) tools. The experiments involved machining a step-shaped micro-pattern with a height of 60 ㎛ and a pitch of 400 ㎛ in a 22×22 mm area under identical cutting conditions, with only the cutting direction and cutting fluid type being varied. The machining results of four cases were compared, encompassing two cases of cutting direction(parallel to the pattern, orthogonal to the pattern) and two cases of cutting fluid type (flood, mist). Consequently, the Ra value was found to be the highest(Ra 128.33 nm) when machining with the flood type in parallel to the pattern, while it was the lowest(Ra 95.22 nm) when machining with the mist type orthogonal to the pattern. These findings confirm that there is a difference of up to 25.8 % in the Ra value depending on the cutting direction and cutting fluid type.

Keywords

Acknowledgement

본 연구는 한국생산기술연구원 및 산업통상자원부의 소재부품산업기술개발기반구축사업의 '글로벌 시장진출을 위한 차세대 자동차용 R100㎛, Ra20nm급 디지털 라이트닝 초미세 Light Guide 모듈 금형성형기술 개발(KM230100, 20019131)'과제의 지원을 받아 수행되었다.

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