• Journal of Welding and Joining
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• v.34 no.2
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• pp.36-45
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• 2016

Recent developing tendency for technologies of high efficient brazing are studied by searching of NDSL, Science Direct, KIPRIS, PCT and so on. Active metal brazing, arc brazing, fluxless brazing, brazing with low melting point, reactive air brazing, laser brazing, laser droplet brazing are investigated. By optimal selecting of the above mentioned technologies, it needs to investigate an economical metallurgical design and the advanced brazing methods. To improve the embrittlement of intermetallic compound at brazing interface, it must be studied the inexpensive variant metals including nonmetals and the heat sources(MIG, TIG, Laser) by hybrid techniques.

• Advances in materials Research
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• v.1 no.3
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• pp.183-190
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• 2012

Brazing Mo using Ti and Ti-15-3 foils has been investigated in the experiment. For traditional furnace brazing, solidification shrinkage voids cannot be completely removed from the joint even the brazing temperature increased to 2013 K and 160 ${\mu}m$ thick Ti foil applied in brazing. Similar results are observed from the joint using Ti-15-3 filler. In contrast, the quality of laser brazed joint is much better than that of furnace brazed joint. A sound joint is achieved after laser brazing. Tensile strengths of 418 and 373 MPa are obtained from laser brazed joints at the power of 800W and travel speed of 5 mm/s using Ti and Ti-15-3 fillers, respectively. All laser brazed joints are fractured at the brazed zone and cleavage dominated fractures are widely observed from their fractographs. The Ti base fillers show potential in laser brazing Mo substrate.

• Proceedings of the KAIS Fall Conference
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• 2011.12b
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• pp.475-477
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• 2011

The increasing interest in the laser brazing is placing stringent demands on the manufacturing techniques and performance requirements, and the manufacture employs the high quality and efficiency laser brazing technology. This paper covers recent research trends of the laser brazing technology including the SCI-E analysis of published papers, research subjects and research institute analysis.

• Proceedings of the KWS Conference
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• 2003.05a
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• pp.228-230
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• 2003

Recently, lots of joining methods of thin metal sheets are being developed in order to improve joint quality and productivity in manufacturing area. Current existing welding methods are continuously challenged as new materials and smaller thickness of metal sheets are required. In this study, laser plug brazing process was investigated as a new joining method of thin metal sheets. A CO2 laser system with automatic feeding of filler metal wire and flux was developed, and laser plug brazing experiments were conducted. The brazed joints were analyzed using various methods.

• Journal of Welding and Joining
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• v.13 no.3
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• pp.96-105
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• 1995

An advantage offered by brazing over fusion welding is that strong joints may be produced at relatively low heat input. To minimize the thermal effects and maintain the desired dimension of assemblies. the CO$_{2}$ laser beam can be applied to the brazed joint of pin and plate as a micro heat source. This paper presents a analysis model of the laser brazing process considering the laser beam mode and heat flow in brazed parts by using the finite element method. The simulation results were compared with the experimental results obtained from the infrared temperature sensing system. Based on these results, the proper process parameters were investigated to get a good joining quality. The influence of the beam mode change was examined with respect to the temperature distribution and joint quality.

• Laser Solutions
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• v.17 no.1
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• pp.7-12
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• 2014

The dissimilar welding between magnesium alloy and steel sheet was required in automobile industry to increase the strength of the dissimilar joints. Laser brazing is one of the good joining processes for Mg- steel dissimilar joint. In this study, AZ31 magnesium alloy and Zn coated steel dissimilar joint was brazed using diode direct laser with Mg600 filler wire and Superior #21 flux. The wetting of Mg filler wire on Zn coating was very good because of the formation of eutectic phase with low melting temperature. The strength of the brazed joint between AZ31 magnesium alloy and Zn coated steel was 131.3N/mm. The fracture occurred at brazement.

• Journal of Welding and Joining
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• v.31 no.4
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• pp.7-12
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• 2013

The dissimilar welding between magnesium alloy and steel sheet was required in automobile industry to increase the strength of the dissimilar joints. Laser brazing is one of the good joining processes for Mgsteel dissimilar joint. In this study, the effect of coating materials was evaluated on the laser brazing for the dissimilar joint between AZ31 and coated steels such as Zn, Sn and Ni. Diode direct laser was used to braze the lap-edge joint with Mg600 filler wire and Superior #21 flux. The wettability was best on Zn coated steel. The interlayer was formed at the interface between brazement and steel for all coating materials. The strengths of brazed specimen were 146.5N/mm, 204.6N/mm and 101.6N/mm for Zn, Sn and Ni coated steel respectively.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.402-407
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• 2002

Laminate tooling process is a fast and simple method to make metal tools directly for various molding processes such as injection molding in rapid prototyping field. Metal sheets are usually cut, stacked, aligned and joined with brazing or soldering. Through the joining process, all of the metal sheet layers should be rigidly joined. When joining process parameters are not appropriate, there would be defects in the layers. Among various types of defects, non-bonded gaps of the tool surface are of great importance, because they directly affect the surface quality and dimensional accuracy of the final products. If a laminate tool with defects has to be abandoned, it could lead to great loss of time and cost. Therefore a repair method for non-bonded gaps of the surface is essential and has important meaning for rapid prototyping. In this study, a rapid laminate tooling system composed of a CO2 laser, a furnace, and a milling machine was developed. Metal sheets were joined by furnace brazing, dip soldering and adhesive bonding. Joined laminate tools were machined by a high-speed milling machine to improve surface quality. Also, repair brazing and soldering methods of the laminates using the $CO_2$ laser system have been investigated. ill laser repair process, the beam duration, beam power and beam profile were of great importance, and their effects were simulated by [mite element methods. The simulation results were compared with the experimental ones, and optimal parameters for laser repair process were investigated.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2003.05a
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• pp.9-13
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• 2003

• Journal of the Korean Society for Precision Engineering
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• v.10 no.3
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• pp.231-238
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• 1993

Mold-marking industries currently demands to reduce the tooling costs and time in mold making and to improve the productivity and quality in injection molding process. These problems can be easily solved by the laminated injection mold which is made by laser cutting metal sheets and bonding them by the brazing. Comparing with the conventional mold making technology which mainly depends on the machining, the new thchnology enables an arvitary design of cooling circuit whithout any restrictions of geometry. Therefore, it will offer high production tata of the injection molding processes. This paper evaluates the conventional and laminated injection mold making processes with a simple molding geometry, and also the cooling efficienty of the kinds of mold with the filling and cooling analyses. The results show that the laminated injection mold process takes much shorter time in tooling and cooling, and distributes temperatures more uniformly than the conventional one.