Mechanical isotropy and postcure shrinkage of polydimethylsiloxane printed with digital light processing

Abstract

Purpose This paper aims to investigate the printability of photocurable PDMS with digital light processing (DLP) in terms of dimensional accuracy, mechanical properties, isotropy and postcure shrinkage. Design/methodology/approach The photocurable PDMS was made from methacrylated PDMS-macromer and 2,4,6-Trimethylbenzoyldi-Phenylphosphinate (TPO-L) photoinitiator. The PDMS was printed using different orientations, sizes and post-exposure conditions and then evaluated by tensile test and microscope to determine the printability. Findings Printed parts show good accuracy and low shrinkage, but high directionality in modulus, ductility and strength. The dimensional error is less than 2% and the shrinkage rates are less than 0.52%. In contrast, the modulus varies between 0.87 and 0.96 MPa depending on print orientation, elongation varies from 34.7% to 66.4% and strength varies from 0.23 to 0.49 MPa. Originality/value This study quantitatively characterizes the printability of photo curable PDMS with DLP, which has not been reported elsewhere. This paper also discusses the challenges of PDMS printing for future advancement.