Insight into the limitation of the Beer–Lambert law in stereolithography ceramic 3D printing: a study on irradiance parameters and slurry curing

Stereolithography is a promising technique for fabricating ceramic components with complex geometries. Its development has advanced the understanding of curing behaviour, with the Beer–Lambert law commonly used to model the curing process. However, its accuracy in ceramic stereolithography requires further validation. This study examines the response of ceramic slurries to varying irradiance parameters within the Beer–Lambert framework. The fitted results deviate from the model’s predictions when the same slurry is exposed to different irradiation parameters. For slurry S1, the fitted penetration depth values under different parameters (laser power, hatching space, and scanning speed) are 76.2, 113.1, and 85.9 μm, with corresponding critical energy dose values of 14.3, 55.0, and 23.3 mJ/cm², respectively. For ceramic slurry S2, increasing hatching space raises the energy dose required to reach a 200 μm curing depth from 4.8 to 51.1 mJ/cm², while increasing scanning speed raises it from 5.7 to 37.2 mJ/cm². FTIR analysis confirms that higher energy delivery rates reduce polymer conversion. Single-layer tests reveal that a larger hatching space compromises curing uniformity, and faster scanning speeds tend to reduce dimensional stability. These findings highlight the limitations of the Beer–Lambert law and offer insights for process optimisation in ceramic stereolithography.