Effect of resin composition on cure depth, dimensional accuracy, and surface roughness in Al2O3 stereolithographic 3D printing

Abstract

The choice of resin for ceramic stereolithographic 3D printing has a critical impact on printed ceramic preforms. In this study, we focused on the correlation between resin composition and parameters such as cure depth, surface morphology, lateral dimension, apparent layer height, and surface roughness. Special emphasis was placed on the addition of an oligomer and a plasticizing agent to a monomer-based suspension. Four suspensions were studied: a 100% monomer (ethoxylated trimethylolpropane triacrylate) only suspension (M100), a suspension with 25% by weight plasticizing agent (polyethylene glycol) (PEG25), and two different suspensions with oligomer (urethane methacrylate) added at 25% (O25) and 50% (O50) by weight. Constant energy and printing parameters were used between suspensions. Adding a plasticizing agent (PEG25) was found to increase the cure depth and projected image of the samples, while additional oligomer with both amounts (O25 and O50) resulted in a decrease in the same parameters. The suspensions with oligomer were found to have increased surface roughness measured using the average deviation from the profile height mean line (R_a), with O25 at 13.47 µm and O50 at 11.47 µm. All suspensions had negative values of skewness (R_sk) in the range –0.4 to –1.2. PEG25 had the surface most distinct from a normally distributed surface with an R_sk of –1.12 and a kurtosis (R_ku) value of 4.49. The use of the average length of a profile element (R_Sm) as a layer height estimation tool was explored and it was found that the R_Sm was within 10 µm of the printed layer height in all suspensions studied except for PEG25. This study highlights the importance of resin composition in ceramic stereolithographic 3D printing. Modulating the inclusion of a plasticizing agent and oligomer in the resin has significant effects on printed sample parameters such as cure depth and surface roughness.