• Laser Solutions
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• v.16 no.3
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• pp.1-10
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• 2013

In this study, Al-Si coated boron steel(1.2 mm) were laser welded by $CO_2$ laser and hot-stamping was applied to the laser joints. Tensile properties and microstructures of the joints were investigated before and after hot-stamping. Tensile and yield strengths of the as welded specimen similar with base metal and fracture occurred base metal of boron steel. Although, in case of heat treated specimen, fracture occurred fusion zone that Al segregated zone near the bond line. These could be explained by the existence of ferrite, in the Al segregated zone near the bond line and base metal of boron steel. Before hot-stamping, hardness of base metal is lower than fusion zone and heat affected zone in spite of exist Al segregation zone($Fe_3$(Al,Si)). So fracture occurred base metal. Although, after hot-stamping, microstructure of base metal and welds zone transformed to martensite and bainite except in Al segregation zone near the bond line that $Fe_3$(Al,Si) transformed to a-ferrite. So fracture occurred Al segregation zone near the bond line.

• Journal of Welding and Joining
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• v.18 no.2
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• pp.43-48
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• 2000

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1493-1498
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• 2007

Silicon Nitride ($Si_3N_4$), which is widely used in a variety of applications, is hard-to-machine due to its high hardness. At high temperature (e.g. above $1000^{\circ}C$), however, the machinability can be greatly improved. In this work, we used a $CO_2$ laser with a high absorptivity to $Si_3N_4$ of 0.9 to preheat the surface of a rothting $Si_3N_4$ rod. Preheating and turning of $Si_3N_4$ was executed at the same time. The result of machining was MRR of $8.0mm^3/s$ that is four times faster than normal grinding. Continuous chip formation was observed by a microscope.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2001.05a
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• pp.31-34
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• 2001

Laser cladding Processing allows rapid transfer of heat to the material being minimum conduction into base metal. The effects of CO$_2$ laser cladding with high powder were investigated. High viscosity bronze powder consists of bronze powder used at a high temperature. The material has a high viscosity So that it can be substrate. Therefore. Laser cladding can be processed on a curved or slope surface. CO$_2$ laser cladding was designed It consists of the high viscosity bronze powder the shielding gas system and the preheating system The high viscosity powder properly at 0.3g/s and 0.50g/s. Because of the metallic bond between bronze per the hardness of dilution layer was suddenly increased. Experimental as results viscosity mixed powder can be a useful cladding material.

• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.563-567
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• 2009

This study compared the instrument performance and tissue healing of a steel scalpel with a $CO_2$ laser in an animal uterine surgery model. Five Landrace and Yorkshire mixed breed pigs were used. Two symmetrical incisions were made in the uterine of each pig. One incision was made on the left side of the uterine horn using a steel scalpel, while the other incision was performed on the right side using a $CO_2$ laser with an 8W output power. Each instrument was evaluated clinically for speed, ease of incision, and extent of bleeding. An ovariohysterectomy was performed at 21 days after the surgical procedure for a histological examination. The scalpel was an easier instrument to use in the confines of the uterine tissue, compared with the laser. However, there is no significant difference between the two groups. The amount of bleeding was less in the laser group but the time of the incisions was shorter with the scalpel. Postoperative uterus adhesion in the $CO_2$ laser incisions was lower than the scalpel incisions. Scalpel incisions showed complete restoration of the epithelium and endometrial gland. On the other hand, the laser incisions showed incomplete restoration of the epithelium and endometrial gland. Although the scalpel produced less damage to the uterine tissue and was easier to handle than the $CO_2$ laser, it did not provide hemostasis that was helpful for use on highly vascular tissue. The $CO_2$ laser provided good hemostasis but delayed wound healing.

• The Optical Journal
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• s.100
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• pp.26-29
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• 2005

레이저 가공기 세계시장은 2010년에 약 70억 달러 이상의 규모가 예상되고 고출력 CW 고체 레이저 시장은 2010년까지 매년 약 30%의 성장이, 펄스레이저 시스템 및 레이저마킹기 시장는 연간 10% 이상의 성장을 예상하고 있다. 반면, 세계 레이저 발진기의 시장에서 CO2 레이저의 경우 시장의 규모가 작아져서 2004년에 약 4억 달러의 규모가 2010년에는 약 2.3억 달러 수준으로 하향할 것으로 예상되고 있다. 고체 레이저에서 특기할 사항은 2010년에 Lamp Pumped CW Nd;YAG 레이저의 경우 약 74백만 달러로 규모가 축소됨에 비해 고출력 DPSSL(Diode Pumped Solid State laser) 시장규모는 약 17억 달러로 급성장하며 레이저 마킹 및 미세 정밀 가공용 저출력 DPSSL의 시장 규모가 약 13억 달러로 고속 성장할 것으로 예측이 된다.

• Proceedings of the Optical Society of Korea Conference
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• 1990.07a
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• pp.40-44
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• 1990

• The Optical Journal
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• v.14 no.4 s.80
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• pp.65-68
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• 2002

• Journal of Welding and Joining
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• v.22 no.1
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• pp.38-41
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• 2004

• Proceedings of the Optical Society of Korea Conference
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• 1989.06a
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• pp.1-4
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• 1989