The re-usability of heat-exposed poly (ethylene terephthalate) powder for laser sintering

• Published in: Additive manufacturing Vol. 28; pp. 194 - 204
• Main Authors: Gu, Hao, Bashir, Zahir, Yang, Lanti
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2019
• Subjects: Additive manufacturing; PET; Powder; Recycling; Selective laser sintering; Selective laser sintering; Additive manufacturing; Recycling; Powder; PET
• ISSN: 2214-8604; 2214-7810
• DOI: 10.1016/j.addma.2019.05.004

Selective laser sintering, also called laser sintering (LS), is an additive manufacturing process that requires micronized plastic powder. Recently, we showed poly (ethylene terephthalate (PET) powder is a suitable material for LS, with a comparable printing performance as the current front-runner, polyamide 12 (PA12). However, the LS process, by its nature, leaves unused powder that has been exposed to heat for prolonged time, and this powder may not be fully re-usable due to degradation. In this work, the re-use potential of heat-exposed PET powder is established. This is a matter of crucial importance as powders suitable for LS are very expensive, and the powder left after a building episode has to be re-used. Heat-exposed PA12 has to be blended or refreshed with virgin powder, to avoid printing defects. In contrast, heat-exposed PET powder, after 96 h at 210 °C, could be used, without refreshing with a portion of virgin powder. The printed articles from heat-exposed powders were as good as those from the fresh powder. There was no cross-linking and there was only a minor increase in the molecular weight of the powder after 96 h, at 210 °C.