Influence of layer thickness and exposure on mechanical properties of additively manufactured polymer-derived SiOC ceramics

Abstract

One significant hurdle in additively manufacturing polymer-derived ceramics lies in reconciling the lower mechanical properties of additively manufactured parts compared to traditionally manufactured ceramics and PDCs. Here, a methodology is presented for evaluating the influence of layer thickness and exposure on polymer-derived ceramics within the constraints of commercially available software and hardware. Maximizing exposure within printable limitation of DLP processes, produced green bodies with the highest conversion, and resulted in improved pyrolysis outcomes, manufacturability, and most importantly ceramic strengths comparable to traditionally manufactured SiOC PDCs. Decreasing layer thickness and increasing total dwell time had a dramatic impact on mechanical properties, increasing flexural strength by more than 6x from 18 MPa at 100 μm layer thickness to 111 MPa at 10 μm layer thickness. Density of resultant ceramic also increased from 1.62 ± 0.03 g/cc to 2.3 ± 0.05 g/cc. This represented a large increase in mechanical strengths of PDCs produced via DLP in literature.

Keywords

• Additive manufacturing
• Polymer-derived ceramics
• Digital light projection
• Vat photopolymerization