Additive manufacturing process combines powder and resin printing

Shown is a 3D-printed sample with an inner cylindrical region composed of TPU powder and an outer region of SLA resin. The print has 30 layers. a) Upper view of the inner and outer region. b) Profile view of the nested cylinder. c) Sliced sample profile view.

Researchers have developed a method that allows printing components from SLS (selective laser sintering) powders and SLA (stereolithography) resins, according to a research paper posted to the Science Direct website.

The dual-material approach allows users to couple the strength of SLS parts with the surface finish of SLA components, write the researchers, Columbia University PhD candidate John Whitehead and Columbia professor Hod Lipson.

The paper, “Multi-Process Printing Combining Powder and Resin Based Additive Manufacturing,” explains that SLA and SLS are both laser-based technologies. However, liquid resins are used for the SLA process while SLS processes build parts from fused material particles, including metal alloys and some polymers.

The new process could be used, for example, to print conductive metal channels into a nonconductive resin part.

“Traditionally, users have been forced to select a single AM machine that uses a single printing process with a single type of material to produce a given part and then make adjustments to the printed object with a secondary material through postprocessing,” the authors write. “This can be imprecise or time-consuming, depending on the adjustment method used.”