Key techniques of selective laser melting rapid prototyping system

The key points of the three main subsystems of selective laser melting (SLM) rapid prototyping system such as the laser, the powder delivering and the scanning systems, are studied through calculation of the needed laser energy during SLM processing. The selection of laser to be used is confirmed. It is found that the accuracy of the cylinder movement, the eccentricity and interval in the radial run-out of the roller have important influences on the control of minimal layer thickness. Combined with an experiment of selective melting of metal powder at varying scanning speeds, the scanning performance is analyzed, and the result shows that fast scanning speed and proper scanning strategy should be used during SLM processing to avoid thermal deformation. Based on above research work, an experiment for producing metal part using Cu-based powder is carried out. The result shows the part is metallurgical bonded entity with density of 95%, dimension precision of ± 0.5 mm, and the microstructure of the part is composed of equiaxed and dendritic crystal. The cross section and the shape of the SLM part, the processing parameters such as layer thickness and scanning speed, demonstrate the key points of SLM technique.