Hefei Zhongjian 3D Technology files patent for cleaner multi-resin SLA printing

Hefei Zhongjian 3D Technology Co., Ltd. has filed a Chinese patent (CN122210937A, published 16 June 2026) for a multi-material light-curing 3D printer and method designed to reduce cross-contamination during resin changes. The design uses multiple resin boxes mounted on a moving platform, with a build plate that rotates 90 degrees after each layer to drain excess resin back into the original vat. A vibration generator then shakes the plate along a horizontal guide, followed by an air knife that blows residual resin off the part. C-shaped shields with grooves and raised edges around each resin box capture splatter and guide it back into the corresponding vat, aiming to enable fully unattended multi-resin printing without liquid wash steps.

This patent addresses a persistent operational barrier in vat photopolymerization (SLA/DLP): the difficulty of switching between different photopolymers mid-print without contaminating subsequent layers. While multi-material resin printing has been demonstrated in research and a few commercial systems (e.g., Stratasys PolyJet, which uses inkjet deposition rather than vat switching), the cleaning step has remained a bottleneck for production use. Hefei Zhongjian's approach - combining mechanical rotation, vibration, and air knife cleaning with passive splash containment - is notable for its relative mechanical simplicity compared to solvent-based wash stations. If the method proves effective at removing enough resin to prevent functional or aesthetic defects in gradient or multi-material parts, it could lower the barrier for applications requiring soft/rigid zones, color changes, or localized performance differences in fields such as medical-dental, consumer goods, and industrial tooling. However, the patent does not specify quantitative cleaning efficacy, and the added mechanical complexity (motors, gears, rails, air knife, shields) will increase machine cost and maintenance requirements.

The practical question is whether this cleaning sequence - lift, rotate, drain, vibrate, blow, reposition, switch vats - can be executed fast enough to be economical for production runs, especially when material changes are frequent. The patent describes a plausible engineering path, but the gap between a patent filing and a reliable production machine remains wide. For buyers evaluating multi-material resin systems, the key metric will be cycle time per material change and residual contamination levels in deep holes, thin gaps, and textured surfaces. Hefei Zhongjian will need to demonstrate repeatable part quality across multiple material transitions before this moves from concept to commercial offering.