EFFECTS OF MSLA PRINTING PARAMETERS ON THE MECHANICAL AND ACOUSTIC PROPERTIES OF 3D-PRINTED RESIN FOR ULTRASONIC WEDGES

Abstract

Additive manufacturing offers new opportunities to fabricate customized ultrasonic wedges for Non-Destructive Testing (NDT). However, the relationship between Stereolithography (SLA) printing parameters and the resulting mechanical and acoustic performance of printed wedges remains insufficiently understood. In this study, the effects of Layer Height (LH), Exposure Time (ET), and Light-off Delay (LD) on the mechanical and ultrasonic properties of SLA-printed polymer specimens were investigated using Response Surface Methodology (RSM) with a Central Composite Design (CCD). The compressive strength of the printed specimens ranged from 22 MPa to 79 MPa, indicating a strong dependence on the printing parameters. Ultrasonic attenuation ranged from 0.04 dB/mm to 0.17 dB/mm and generally increased with mechanical strength, suggesting a trade-off between mechanical integrity and acoustic transmission. A scatter-based mechanical–acoustic analysis further revealed that parameter conditions that produce higher compressive strength tend to result in slightly higher ultrasonic attenuation, due to increased polymer cross-link density and internal scattering mechanisms. The ultrasonic wave velocity exhibited a relatively small variation across the investigated parameter space, ranging from approximately 1970 m/s to 2150 m/s (≈ ±4% variation). A stepwise regression model based on LH and LD was developed to estimate ultrasonic velocity, which may serve as an initial estimator for wedge calibration prior to final experimental adjustment. Overall, the results demonstrate that SLA printing parameters can be optimized primarily based on mechanical–acoustic performance, while ultrasonic velocity remains relatively stable and can be calibrated within a narrow range. These findings provide practical guidance for the design and fabrication of SLA-printed ultrasonic wedges for NDT applications.