Additive manufacturing has been recognized as an innovative technology with the potential for fabricating complex parts with less material waste. Among the various metal-based additive manufacturing technologies, Laser Powder Bed Fusion has been recognized for its precision and full densification. However, it has been reported that the technology is difficult to handle with powders. Similarly, Bound Metal Deposition and extrusion-based metal printing technologies have been recognized for their material efficiency. However, the technologies have been reported to undergo debinding and sintering operations. The debinding and sintering operations result in shrinkage, inaccuracy in dimension, and a long processing time.

The current research aims to design a hybrid additive manufacturing machine that combines the extrusion-based green layer deposition with the in-situ laser melting technique using the EOSINT M 270 machine. The research aims to replace the debinding and sintering operations with the laser melting technique. Various binders were tested for the additive manufacturing machine. The binders included a cornstarch-based aqueous binder system, a wax-based thermoplastic binder system, and a polyvinyl alcohol-based aqueous binder system. The research focused on optimizing the rheological properties of the binders for the extrusion-based additive manufacturing machine.

Green layers were built using the Z-Morph VX and Desktop Metal systems, followed by laser exposure under controlled parameters. The range of power used was from 110 W to 170 W, with a constant speed to check the consolidation of layers of varying thickness. The surface morphology, build height, and melt pool were analyzed visually as well as using Scanning Electron Microscopy (SEM). The elemental composition was analyzed using Energy Dispersive Spectroscopy (EDS), whereas the surface roughness was analyzed using optical profilometry with Alicona. Vickers microhardness tests (HV 0.5) were performed for the build height to check the variation of mechanical properties.

The results showed that there is an optimal energy window for the consolidation process. For the green layer thickness of 0.8 mm, the most balanced melt pool behavior and lowest surface roughness (Ra = 4.63 μm) were observed at 130 W. Increasing the laser power was found to improve the vertical build-up for thicker green layers (1.2 mm), although excessive energy input caused instability in the melt pool leading to surface irregularities. The hardness results showed that there was a spatial variation along the height of the build, which was lower near the substrate due to thermal history effects. The results from the SEM-EDS analysis showed that metallic consolidation was improved at optimal levels of laser power, while lower levels showed incomplete fusion and binder-rich material.

The results showed that hybrid extrusion-laser consolidation is possible if the binder material composition, green density, and laser energy input are balanced. This study is a step towards the development of a more efficient and sustainable metal 3D printing technology by minimizing the need for powder spreading and furnace sintering.