• Korean Journal of Computational Design and Engineering
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• v.8 no.3
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• pp.150-156
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• 2003

Direct Metal Deposition (DMD) is a new additive process producing three-dimensional metal components or tools directly from CAD data, which aims to take mold making and metalworking in an entirely new direction. It is the blending of five common technologies: lasers, CAD, CAM, sensors and materials. In the resulting process, alternatively called laser cladding, an industrial laser is used to locally heat a spot on a tool-steel work piece or platform, forming a molten pool of metal. A small stream of powdered tool-steel metal is then injected into the metal pool to increase the size of the molten pool. By moving the laser beam back and forth, under CNC control, and tracing out a pattern determined by a computerized CAD design, the solid metal part is eventually built line-by-line, one layer at a time. DMD produces improved material properties in less time and at a lower cost than is possible with traditional fabrication technologies.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.5
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• pp.91-97
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• 2022

The Directed Energy Deposition (DED) is a representative metal additive manufacturing method. Owing to its strong point of repairment, its application is gradually spreading in aerospace applications, power generation, military components, and mold making. 5-axis cladding is needed to repair damage, such as wear and scratches on cylindrical surfaces to circular-shaped parts, including sleeves and liners. Furthermore, the condition of cladding on inclined parts must also be considered to prevent interference between the nozzle and the part. In this study, the effects of changes in scanning speed due to the 5-axis control system and differences from the height of laser beam irradiation due to inclination are evaluated among the items that should be additionally considered in 5-axis cladding compared to 3-axis cladding. Moreover, the trends of the width and height of the clad are identified by different tilting angles via single line cladding. Lastly, cladding methods on cylindrical surfaces at various angles are proposed to enhance the clad quality and post-processing efficacy. These results can be applied with 5-axis cladding on inclined surfaces, including cylindrical surfaces.

• Journal of Welding and Joining
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• v.18 no.2
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• pp.27-35
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• 2000

• Tribology and Lubricants
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• v.34 no.3
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• pp.84-92
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• 2018

Bearings are essential for reducing vibration and wear, in order to achieve high durability and increase longevity. White metal treatment of tilting pads via centrifugal casting method has the possibility of increasing durability. However, this manufacturing method has drawbacks such as long processing time, high defect rate, and harmful health effects. Laser cladding deposition technique is a powerful method that can address these issues by decreasing the processing time and providing good adhesion. In this study, we suggest optimum conditions for laser cladding deposition that can be used in industrial applications. We deposited a soft white metal layer on SCM440 that is primarily used in shafts to minimize wear of bearing pads. During the laser deposition process, we controlled factors such as laser power, powder feed rate, and laser head speed to determine the optimum conditions. In addition, we measured the hardness using micro Vickers, and performed field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, and friction tests to investigate the mechanical properties and surface characteristics for different parameters. Based on the experimental results, we suggest that laser power, powder feed rate, and laser head speed of 1.3 kW, 2.5 rpm, and 10 mm/s, respectively, constitute the optimum conditions for producing white metals using laser cladding.

• Proceedings of the KWS Conference
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• 2006.05a
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• pp.59-61
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• 2006

The $CO_2$ laser cladding was conducted on an AC2B alloy with feeding Fe-based powders. A powder feeding rate (PFR) and a travel velocity were related with the cracks adjacent to the Fe/Al interface. Preheating temperature was varied to study the interface crack. Preheating to $250^{\circ}C$ during the laser cladding suppressed the interface crack ratio (ICR). The ICR was limited for the single pass clad and the reciprocating test for the slide wear was conducted on an overlay cladding experiment. Comparing with no overlap overlay, the overlay clad with 50% overlap showed better wear resistance.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.279.2-279
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• 2001

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.4
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• pp.307-312
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• 2017

Laser cladding has some advantages compared to conventional cladding technologies such as arc welding and thermal spraying. Laser cladding produces a metallurgically well-bonded clad layer with a lower dilution ratio and few defects. Based on the characteristics of a 1-pass clad layer with many parameters, which were investigated in a previous report, it was found that it was essential to overlap a 1-pass clad layer when cladding a large area. In this study, the shape differences of multi-pass clad layers with various overlapping ratios were compared. Then, the alloying element distribution of cladding with a certain overlapping ratio was investigated using EDS and EPMA. As the overlapping ratio increased, the length of the clad decreased and its height increased. In addition, the height of the multi-pass cladding was higher than that of the 1-pass cladding under the same condition. The Fe content of the highly diluted first clad was found to be approximately 20 % in an element analysis. However in the area outside of the first clad, the Fe content was decreased to 10 % as a result of minimum dilution, and a uniform distribution of elements was found.

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.95-96
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• 2004

그동안 고출력 레이저에는 CO2 Laser, LPSSL, DPSSL 등이 주로 사용되어 왔다. 최근에는 Fiber Laser가 좋은 빔특성을 가지면서 10㎾이상의 고출력이 가능해 큰 주목을 받고 있다. 고출력 레이저는 매질의 냉각문제가 가장 큰 관건인데, Fiber Laser는 수백 $\mu\textrm{m}$의 지름을 가진 수십m 길이의 공진기 형태를 띠어 부피 대비 냉각면적이 가장 크다고 할 수 있다. EDFA 등 광통신을 위해 개발되었던 다이오드 레이저들이 Fiber Laser쪽으로 전용되고, Side Cladding pumping 방법의 실용화, 다이오드 페이저 펌핑 광과 광섬유사이의 커플링 방법이 개발되면서 고출력 Fiber Laser 개발이 급속히 이루어졌다. (중략)

• Proceedings of the KAIS Fall Conference
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• 2011.12b
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• pp.481-484
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• 2011

The increasing interest in the laser beam welding is placing stringent demands on the manufacturing techniques and performance requirements, and the manufacture employs the high quality and efficiency laser beam welding technology. This paper covers recent research trends of the laser beam welding technology including the laser beam surfacing and laser beam cladding technology.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.2
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• pp.30-37
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• 2020

We propose a practical method for increasing formability of a sheet metal plate using laser heat treatment (LHT) and cladding process. In this work, two kinds of process such as laser-induced heat treatment and cladding were utilized to evaluate the effect on formability of SUS316 sheets with different thickness of 1 and 3 mm. By using a vertically line-patterned tensile specimen that was LHTed or cladded on its surface, the process parameters of each surface treating method were studied and optimized. Through the basic test, we knew that the laser power of 900 W and scanning speed of 500 mm/min was the best condition for increase of formability. As the treatment results, ultimate tensile strength and elongation were increased as approximately 2.1 and 7.0%, respectively. To verify the usefulness of this work in industrial cases, we conducted a bulging test using with and without LHTed SUS316 sheet metal blanks. The results show that the bulging height of LHTed sheet was increased by 73% compared to that of the original one.