High-Speed and High-Resolution Polygon Mirror-Based Industrial Stereolithography With Advanced Active Error Compensation

A high-speed and high-resolution polygon mirror (PM)-based industrial stereolithography apparatus (SLA) is designed and integrated with advanced active error compensation (AEC). The designed PM-based scanner provides extremely high laser beam scanning speeds but suffers from wobble errors caused by facet tilts, compromising its print quality. The advanced AEC is proposed to reduce the wobble error, where laser beams are deflected according to a precomputed compensation trajectory using a fast-steering mirror with iterative learning control. By exploiting the repetitiveness of the compensation trajectory, the advanced AEC yields a substantial 27-fold reduction in the wobble error and achieves a printing precision of $5 \,{\upmu}\mathrm{m}$ in standard deviation, enabling the industrial SLA with $22 \,{\upmu}\mathrm{m}$ optical resolution in a $460 \,\mathrm{m}\mathrm{m}$ print range with a print speed of $230 \,\mathrm{m}/\mathrm{s}$. The achieved printing performance is demonstrated by printed samples using photosensitive resin.