Experimental Investigation on Friction Behavior of Selective Laser Sintering Processed Parts

Selective laser sintering (SLS) is a powder bed fusion additive manufacturing process that uses polymer powders to produce functional parts directly from digital 3D models. SLS supports small- to medium-batch fabrication of customized products for various end-use applications. These parts can be used as tooling to support conventional manufacturing and inspection where mechanical and tribological behaviors are important. This article evaluates the friction behavior of parts fabricated by SLS polyamide (PA12) and glass bead-filled polyamide (PA-GF) materials. Pin-on-Disk tribometer was used to characterize the behavior in dry sliding conditions with part build orientation, load, and speed as factors. Taguchi's approach and analysis of variance are used to quantify the influence of these factors on the friction coefficient. Both materials show reduction in friction coefficient with the increase in load; on the other hand, an increase in speed affects adversely. However, the influence of part orientation is comparatively lesser than the other two factors considered in this study. The debris, pin, and disk wear surfaces were examined to learn wear mechanisms. It is observed that surface porosity resulting from the fabrication process plays a significant role in friction behavior. The glass beads in PA-GF material function as reinforcement against load and influences the friction behavior. Low friction and wear characteristics make both materials as a prospective contender for tooling application.