Functional WC Cemented Carbide by the Direct Selective Laser Forming

Abstract

Abstract Metal and polymer additive manufacturing is advancing on several applications. On the other hand, materials cermet such as WC/Co for functional structure molding by additive manufacturing are under studying. There are few reports for WC cemented carbide additive manufacturing process by forming with polymer binder then sintering. This indirect process has difficulties to make high precision functional parts due to shape control during additional sintering process. Direct forming is desired for high precision parts. However, factors and/or mechanism to achieve direct formed functional structure have been unclear in many aspects. In this study, the process conditions of the direct selective laser melting were investigated to achieve dense and hard WC cemented carbide mold parts. The optimization of laser melting conditions for WC/Co agglomerated and sintered powder was examined. In order to forming a dense and high hardness parts, the optimum conditions between powder preparation and laser energy density which related with laser power, scan speed and spot diameter were appeared by this experiments. Moldings more than 1500HV are achieved at low laser energy density. However, some of pores were observed in moldings. In addition, the dense molding could be obtained by high laser energy density. This means optimum dense functional WC cemented carbide molding is available by optimization of the molding condition. It is applicable for growing industries like automotive, aviation and cutting tool.