A 100 W blue diode laser with an optical fiber having core diameter of 100 μm was developed and installed into blue diode laser metal deposition system (B-LMD), achieving at the laser intensity of 7.58 ×104 W/cm2, four times higher than that of previous B-LMD system. Pure copper has been widely applied for various industrial components such as heat exchangers, heat pipes, electro circuits and motors because of having excellent properties such as thermal conductivity and electrical conductivity. Besides the copper, expected to be used for handrails, doorknobs, and other parts, are touched by a large number of people in order to prevent from infectious diseases, because of having the excellent properties such as an antibacterial property and a virus inactivation property. However, copper is low strength to only about 40% as strong as stainless steel. In order to add a new function of virus inactivation property to the surface keeping the strength, it is necessary to develop a coating technology to form a pure copper layer on the surface. Thus, we have developed a multi-beam type laser metal deposition method with a high intensity blue diode laser which newly developed with an output power of 200W and with 100 μm core diameter of optical fiber. As a result, the power intensity reached 7.5 × 105 W/cm2, and a pure copper layer with a thickness of about 24 μm was formed at a processing speed of 200 mm/s.
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