What Post-Processing Steps are Required for SLA Prototypes?

Essential Post-Print Support Removal and Cleaning

The post-processing of SLA (Stereolithography) prototypes is a critical, multi-stage workflow to transform the raw print into a functional, stable, and high-quality part. The first step is Support Removal. After printing, the prototype, attached to the build platform with support structures, is carefully detached. Supports are manually removed using snipping tools and fine pliers. This must be done delicately to avoid marring the part's surface, especially for intricate geometries common in prototypes for medical and healthcare or detailed visual models.

Critical Washing and Uncured Resin Removal

The most crucial SLA-specific step is Thorough Washing. The part is saturated with uncured, liquid resin. It must be immersed in a solvent bath—typically isopropyl alcohol (IPA) or a specialized detergent—within an ultrasonic cleaner or wash station. Agitation is key to dissolving all residual resin from the surface and cavities. Inadequate washing results in a permanently tacky surface and poor curing. For parts with complex internal channels, like those used in aerospace and aviation fluid testing, pressurized flushing may be required. After washing, the part is air-dried in a clean environment.

Post-Curing for Final Polymerization

Post-Curing is the transformative step that achieves the part's final mechanical properties. The washed and dried part is placed in a UV curing chamber or under a UV light source. This controlled exposure completes the polymerization reaction, hardening the resin throughout. The duration and intensity of curing are calibrated to the specific photopolymer resin chemistry. Proper curing ensures maximum tensile strength, thermal resistance, and long-term stability, which is essential for functional prototypes undergoing material testing and analysis.

Surface Finishing and Assembly Preparation

After curing, the part enters the Finishing Phase. This includes sanding with progressively finer grits to eliminate support marks and achieve the desired surface smoothness. For a glossy, injection-molded-like finish, polishing compounds can be applied. Priming and painting are common for aesthetic prototypes or to apply specific colors. For parts requiring high dimensional accuracy on certain features, local CNC machining or drilling may be performed. Finally, components intended for assemblies may undergo post process steps like tapping threads or adhesive bonding preparation.