Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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Experimental Study of Characteristics of Assist Gas in Laser Machining Using Supersonic Rectangular Nozzle

초음속 사각노즐을 이용하는 레이저 가공 보조가스의 특성에 관한 실험적 연구

  • Son, Sang-Hyuk (School of Aerospace and Mechanical Engineering, Korea Aerospace University) ;
  • Jun, Dong-Yeon (M&S System Corporation) ;
  • Lee, Yeol (School of Aerospace and Mechanical Engineering, Korea Aerospace University)
  • 손상혁 (한국항공대학교 항공우주 및 기계공학부) ;
  • 전동연 ((주)엠앤에스시스템) ;
  • 이열 (한국항공대학교 항공우주 및 기계공학부)
  • Received : 2011.06.20
  • Accepted : 2011.12.16
  • Published : 2012.03.01
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Abstract

An experimental study to improve the impingement characteristics of the assist gas in laser cutting was carried out. For various assist-gas pressures, and locations and installation angles of the nozzle, the characteristics of the impingement of the jet from a supersonic rectangular nozzle were compared to those previously observed for typical circular nozzles. Schlieren flow visualizations and Pitot pressure measurements downstream of the kerf surface were utilized for this purpose. The present rectangular supersonic nozzle decreased the strength of the Mach disc occurring at the corner of the kerf surface, and thus, could weaken the separation of the assist gas on the kerf surface and increase the Pitot pressures downstream compared to conventional circular nozzles.

레이저 절단가공에서 사용되는 보조가스의 충돌특성을 개선하기 위한 실험적 연구가 진행되었다. 보조가스의 압력, 노즐의 위치 및 각도 등 다양한 관계변수의 변화에 대하여, 초음속 사각노즐에서 분출되는 보조가스의 절단면 충돌특성이 기존의 원형노즐 경우와 비교 관찰되었다. 이를 위하여 쉴러린 유동가시화 및 절단면 하단에서의 피토압 측정이 진행되었다. 본 연구에서 응용된 사각노즐은 절단면 모서리에서 발생하는 마하디스크의 강도를 줄이고, 이를 통하여 기존의 원형노즐에 비하여 절단면을 따라 흐르는 보조가스의 박리현상을 약화시키고 보조가스 후방의 피토압력을 증가시킬 수 있음이 확인되었다.

Keywords

References

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