Dimensional accuracy is a critical challenge across many additive manufacturing (AM) technologies, directly impacting the assembly of 3D-printed parts. This study investigates these deviations for stereolithography (SLA) on a desktop printer. To analyse the influence of part geometry and the key process parameter of layer thickness, 54 specimens featuring cylindrical protrusions and holes (5, 10, and 20 mm nominal diameters) were produced with three distinct thickness values (25, 50, and 100 µm). A Coordinate Measuring Machine (CMM) was used to measure dimensional and geometric characteristics, and Analysis of Variance (ANOVA) was performed for statistical analysis. The results revealed a systematic deviation trend: protrusions were consistently oversized (up to +195 µm), while holes were consistently undersized (down to ‒250 µm). Both diameter and layer thickness were found to be statistically significant parameters influencing these deviations. Based on these findings, a compensation strategy was developed to correct CAD models by accounting for mean deviation and process variability. The strategy was successfully verified through a practical example, demonstrating its effectiveness in achieving a controlled clearance fit (26 µm). This approach provides a practical methodology for improving the functional accuracy of SLA parts, crucial for a wide range of engineering applications where precise component assembly is required, including the production of functional prototypes and custom spare parts.
Kačmarčik et al. (Sun,) studied this question.