Home
학과소식
세미나
기존 세미나
기존 세미나
[기계]On the Mechanisms of Laser-Material Interaction in Microsecond Laser Ablation for high aspect
1. 제 목 : On the Mechanisms of Laser-Material Interaction in Microsecond Laser Ablation for high aspect ratio micro-hole drilling
2. 연 사 : Professor Jay F. Tu(Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC.)
3. 일 시 : 2008년 3월 27일 (목요일) 15:30~17:30
4. 장 소 : 301동 117호 세미나실
5. 내 용 :
Laser ablation with pulse durations in the microsecond range is a viable solution for high aspect ratio micro-hole drilling with very high material removal rate and moderate quality. The research objective of this investigation is to examine, both experimentally and theoretically, the laser-material interaction mechanisms during microsecond laser ablation using a 300 W, CW, single-mode fiber laser. The experimental portion of this investigation includes improved laser control and a blation tests. Several in-process monitoring experiments, such as photodiode measurements of the vapor inten-sity, high-speed photography, and spectroscopic plasma measurements were conducted. The theoretical portion consists of a thermo-hydrodynamic model that considers beam absorption due to multiple re-flections, vaporization-induced pressure, heat convection in the melt, and the free surface at the liquid-vapor interface. The results show that with one pulse of 1-3 micro-seconds, a microhole with 30 micron opening diameter, 15 micron mid-section diameter, and 180 micron depth can be created. This investigation quantifies the effects of adiabatic evaporation and ejection of fine droplets in the hole drilling process. From the analysis, a double-shot technique is developed which is capable of creating a micro hole with up to 300 micron depth and 15 micron mid-section diameter, i.e., an aspect ratio of 20.
6. 연사약력 :
<Education background>
Ph.D., Mechanical Engineering, December 1991, University of Michigan, Ann Arbor, MI.
M.S., Mechanical Engineering, May 1983, National Tsing-Hua University, Taiwan.
B.S., Mechanical Engineering, August 1977-May 1981, National Taiwan University, Taiwan.
<Professional experience>
- Professor, August 2005-Present, Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC.
- Associate Professor, August 2003-August 2005, Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC.
- Associate Professor, August 1998-August 2003, School of Industrial Engineering, Purdue University, West Lafayette, IN.
- Assistant Professor, August 1992-August 1998, School of Industrial Engineering, Purdue University West Lafayette, IN.
- Visiting Scholar, January 1999-December 1999, Intelligent Material Processing Laboratory, Department of Manufacturing Science, Osaka University, Osaka, Japan.
- Visiting Scientist, May 1993-August 1993, Livonia Transmission Plant, Ford Motor Company, Livonia, MI.
- R&D Supervisor, February 1992-August 1992, Micro Lithography, Inc., Sunnyvale, CA.
- Consulting Engineer, August 1991-December 1991, Ford Motor Company, Manufacturing Development Center, Detroit, MI.
- Summer Intern, July 1990-September 1990, Ford Motor Company, Manufacturing Development Center, Detroit, MI.
- Research Assistant, August 1988-July 1991Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI.
- Instructor, 1985-1987, National Taiwan Institute of Technology, Taipei, Taiwan.
7. 문 의 : 기계항공공학부 주종남 교수 (880-7136)
2. 연 사 : Professor Jay F. Tu(Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC.)
3. 일 시 : 2008년 3월 27일 (목요일) 15:30~17:30
4. 장 소 : 301동 117호 세미나실
5. 내 용 :
Laser ablation with pulse durations in the microsecond range is a viable solution for high aspect ratio micro-hole drilling with very high material removal rate and moderate quality. The research objective of this investigation is to examine, both experimentally and theoretically, the laser-material interaction mechanisms during microsecond laser ablation using a 300 W, CW, single-mode fiber laser. The experimental portion of this investigation includes improved laser control and a blation tests. Several in-process monitoring experiments, such as photodiode measurements of the vapor inten-sity, high-speed photography, and spectroscopic plasma measurements were conducted. The theoretical portion consists of a thermo-hydrodynamic model that considers beam absorption due to multiple re-flections, vaporization-induced pressure, heat convection in the melt, and the free surface at the liquid-vapor interface. The results show that with one pulse of 1-3 micro-seconds, a microhole with 30 micron opening diameter, 15 micron mid-section diameter, and 180 micron depth can be created. This investigation quantifies the effects of adiabatic evaporation and ejection of fine droplets in the hole drilling process. From the analysis, a double-shot technique is developed which is capable of creating a micro hole with up to 300 micron depth and 15 micron mid-section diameter, i.e., an aspect ratio of 20.
6. 연사약력 :
<Education background>
Ph.D., Mechanical Engineering, December 1991, University of Michigan, Ann Arbor, MI.
M.S., Mechanical Engineering, May 1983, National Tsing-Hua University, Taiwan.
B.S., Mechanical Engineering, August 1977-May 1981, National Taiwan University, Taiwan.
<Professional experience>
- Professor, August 2005-Present, Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC.
- Associate Professor, August 2003-August 2005, Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC.
- Associate Professor, August 1998-August 2003, School of Industrial Engineering, Purdue University, West Lafayette, IN.
- Assistant Professor, August 1992-August 1998, School of Industrial Engineering, Purdue University West Lafayette, IN.
- Visiting Scholar, January 1999-December 1999, Intelligent Material Processing Laboratory, Department of Manufacturing Science, Osaka University, Osaka, Japan.
- Visiting Scientist, May 1993-August 1993, Livonia Transmission Plant, Ford Motor Company, Livonia, MI.
- R&D Supervisor, February 1992-August 1992, Micro Lithography, Inc., Sunnyvale, CA.
- Consulting Engineer, August 1991-December 1991, Ford Motor Company, Manufacturing Development Center, Detroit, MI.
- Summer Intern, July 1990-September 1990, Ford Motor Company, Manufacturing Development Center, Detroit, MI.
- Research Assistant, August 1988-July 1991Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI.
- Instructor, 1985-1987, National Taiwan Institute of Technology, Taipei, Taiwan.
7. 문 의 : 기계항공공학부 주종남 교수 (880-7136)