Study of the selective laser sintering of polycarbonate and postprocess for parts reinforcement

Abstract

Polycarbonate (PC) powder, a common and low-cost amorphous polymer, can be moulded easily by the process of selective laser sintering (SLS). However, the sintered parts cannot be used as functional parts because of their poor mechanical properties. In this article, epoxy resin was applied to improve the mechanical properties of PC SLS parts. Specimens for testing dimensional accuracy, tensibility, flexibility, and impact strength were made by SLS with 75-100 mm PC powder. Some of the specimens were posttreated with two types of epoxy resins. Dimensional accuracy and mechanical properties of the specimens were measured. Microstructures of tensile fracture were observed by scanning electron microscopy. The result shows that the mechanical properties of the specimens are reinforced greatly after the epoxy resin has been infiltrated. Extent of the reinforcement depends on curing agents of epoxy resins. For example, with curing agent W, it is increased to 13.82, 8.00, and 3.69 times, respectively, in tensile, flexural, and impact strength and with curing agent Y, it is increased to 19.87, 7.43, and 1.55 times, respectively, in the same properties. The reinforcement in mechanical properties of PC SLS parts can be improved a step further by means of optimizing the epoxy resin system. Therefore, the PC SLS parts reinforced by epoxy resin can be used as functional parts, if the requirement on mechanical properties is not very high.

Fracture mechanics of laser sintered cracked polyamide for a new method to induce cracks by additive manufacturing

“…Similar results have been found by Shi et al [7], who post-treated polycarbonate (PC) specimens infiltrated with epoxy resin, showing great enhancement of mechanical properties. At the same time, they found that the average dimensional error of PC SLS specimens is not satisfactory, ranging from 6.67 to 13.6 per cent.…”

Experimental analysis of selective laser sintering of polyamide powders: an energy perspective

“…While [13] optimises the SLS parameters to build polyester lattice structures. Also experimentally, [14] and [15] examine the effect of preheating and respectively of part porosity and postprocessing on the mechanical properties of polyether and polycarbonate. Although complex and impractical, two-and three-dimensional analytical models still show severe limitations for direct quantitative predictions.…”

Investigation into the Differences in the Selective Laser Sintering between Amorphous and Semi-crystalline Polymers

“…Therefore, thermal properties of materials are of particular important factors determining the SLS processing parameters and part properties. Several amorphous polymers have been successfully used as SLS materials, such as polycarbonate (PC) (Childs et al, 1999;Ho et al, 1999;2002;Fan et al, 2005;Shi et al, 2007), polystyrene (PS) (Shi et al, 2004;Zheng et al, 2006), high impact polystyrene (HIPS) (Shi et al, 2008;Yang et al, 2009) and styrene-acrylonitrile copolymer (Yan et al, 2010). Ho et al (1999;2002;) did many works in exploring to make PC function plastic parts via SLS.…”

“…They investigated the effect of laser energy density on the morphologies, densities and tensile strengths of PC SLS parts, attempting to make high density and strength parts by increasing laser energy density. Shi et al (2007) discussed the possibility of making PC functional parts via SLS from another angle. The green PC SLS parts with high dimensional accuracy and low strength were first fabricated, and then infiltrated with epoxy resin so that the mechanical properties were greatly enhanced.…”