A Study on Pulsed Nd:YAG Laser Welding of Electron Gun in Braun Tubes (I) - Characteristics of Beam Output Energy and Optical Parameters -

브라운관 전자총 부품의 펄스 Nd:YAG레이저 용접에 관한 연구 (I) - 빔의 출력특성과 광학변수 -

  • 김종도 (한국해양대학교 기관시스템공학부) ;
  • 하승협 (부경대학교 대학원 생산가공공학과) ;
  • 조상명 (부경대학교 재료공학부 생산가공공학과)
  • Published : 2002.08.01


During laser spot welding of the braun tube electron gun, phenomena such as serious spattering and oxidative reaction, etc. were occurred. The spatter occurred from weld pool affects the braun tube, namely it blocks up a very small hole on the shadow mask and causes short circuit between two roles of the electron gun. We guessed that high power density and oxidative reaction are main sources of these problems. So, we studied to prevent and to reduce spatter occurring in spot welding of the braun tube electron gun using pulsed Nd:YAG laser. The characteristics of laser output power was estimated, and the loss of laser energy by optical parameter and spatter was measured by powermeter. The effects of welding parameters, laser defocused distance and incident angle, were investigated on the shape and penetration depth of the laser welded bead in flare and flange joints. From these results, the laser peak power was a major factor to control penetration depth and to occur spatter. It was found that the losses of laser energy by optic parameter and sticked spatter affect seriously laser weldability of thin sheets. The deepest penetration depth is gotten on focal position, and a "bead transition" occurred with a slight displacement of focal position relative to the workpiece surface and the absorption rate of the laser energy is affected by the shape factor of the workpiece. When we changed the incident angle of laser beam, the penetration depth was decreased a little with increasing of the incident angle, and the bead width was increased. The spattering was prevented by considering laser beam energy and incident angle.ent angle.



  1. Laser Advanced Materials Processing v.2 High power YAG Laser Welded Sleeving Technology for Steam Generator Tubes in Nuclear Power Plants T. Ishide;Y. Nagura(et al.)
  2. Journal of KWS v.18 no.3 Current Status of Tailored Blank Technology Jong-Bong Lee;Hee-Dong Park
  3. Journal of KWS v.18 no.4 The State of In-Process Quality Monitoring Technology in Laser Welding Jong-Do Kim;Young-Sik Kim
  4. Preprints of the national meeting of autumn in KWS v.36 Pulsed Laser Weldability of Electron Gun Parts in Braun Tubes(ReportⅠ) - Characteristics of Beam Output Energy and Optical Parameters - Seung-Hyup Ha;Woo-Young Yang;Myung-Do Kim;Jong-Do Kim;Snag-Myung Cho;Young-Sik Kim
  5. ICALEO'98 v.16 no.19 Recent Status of Laser Materials Processing in Japanese Industry Isumu Miyamoto
  6. ICALEO'98 v.16 no.19 Sub-micron and High Precision Micro-machining Using Nanosecond Lasers M.R.H. Knowles;G. Rutterford(et al.)
  7. Journal of America Welding Society Laser welding of Thin Sheet Steel with Surface Oxidation J. Xie;A. Kar
  8. Quarterly Journal of Japan Welding Society v.3 no.2 The Role of Assist Gas in CO₂Laser Welding-Laser Welding of Metal (Rept. 3)- Hiroshi Maruo;Isamu Miyamoto;Yoshiaki Arata https://doi.org/10.2207/qjjws.3.276
  9. ICALEO'95 Properties of keyhole plasma in CO₂Laser Welding Takuomi Maiwa;Isamu Miyamoto;Kiyokazu Mori
  10. ICALEO'96 v.81 Characteristics of Stable Induced Laser Plasma Susumu Tsukamoto;Kazuo Hiraoka;Yoshikazu Asai;Hirosada Irie
  11. Beam-plasma Coupling in Laser Material Processing R. Fabbro
  12. Laser Materials Processing Steen, W.M.
  13. Quarterly Journal of Japan Welding Society v.49 no.10 Laser Welding of Metal-Effect of Focussing Optics on Bead Form- Yoshiaki Arata;Hiroshi Maruo;Isamu Miyamoto;Fumimaru Kawabata https://doi.org/10.2207/qjjws1943.49.687
  14. ICALEO'97 Absorption in the Keyhole E.A. Metzbower
  15. Quarterly Journal of Japan Welding Society v.50 no.4 Laser Welding of Metal-Effect of Traveling Velocity on Bead Shape- Hiroshi Maruo;Isamu Miyamoto;Fumimaru Kawabata;Yoshiaki Arata https://doi.org/10.2207/qjjws1943.50.404