Study on the indirect selective laser sintering (SLS) of WC-Co/PA12 powders for the manufacturing of cemented carbide parts

Abstract

A new approach for the manufacturing of cemented carbide parts with a high degree of complexity via indirect selective laser sintering (SLS), using commercial WC-12Co with different amounts of polyamide (PA12) and using low-cost standard equipment is proposed. After debinding, vacuum sintering and sinter-HIP at 1400 °C with 50 bar Ar of the green specimens, the samples showed low relative densities in the range of 60–66%, while the shrinkage after sintering ranged between 35% and 42%, being constant within the volume. This method enables the production of complex shape parts which retained their shape even with respect to the cooling channels after sintering, showing good surface quality and geometry definition. The 3D scan of a WC-12Co end mill sample with 20% PA12 showed low dimensional deviation compared to the 3D model (.stl), proving the capability of the SLS to manufacture near-net-shape cemented carbide parts. The obtained results are indicating that, by adopting a better suited WC-Co powder, indirect SLS followed by Sinter-HIP, can become an interesting method for the Additive Manufacturing of complex cemented carbide parts.