How do you design for assembly and functionality in stereolithography?

1 Orientation and supports

The orientation of your part affects the quality, accuracy, and strength of the final print. You should avoid placing large flat surfaces parallel to the build platform, as this can cause warping and curling. You should also minimize the number of supports needed to hold your part during printing, as they can leave marks and require post-processing. You can use software tools to optimize the orientation and supports for your part, or manually adjust them according to your design goals.

2 Wall thickness and hollowing

The wall thickness of your part determines its durability and stability. You should avoid making your walls too thin or too thick, as this can cause cracking, deformation, or resin trapping. A general rule of thumb is to keep your walls between 0.4 mm and 5 mm thick, depending on the size and shape of your part. You can also hollow out your part to save material and reduce printing time, but you should add drainage holes and internal supports to prevent resin accumulation and collapse.

3 Overhangs and bridges

Overhangs and bridges are features that extend beyond the support of the previous layer. They can create aesthetic and functional effects, but they also require careful design and printing parameters. You should avoid making your overhangs and bridges too long or too steep, as this can cause sagging, drooping, or breaking. A general guideline is to keep your overhangs and bridges below 45 degrees and shorter than 5 mm. You can also add chamfers, fillets, or support structures to improve the printability and strength of these features.

4 Tolerances and clearances

Tolerances and clearances are the gaps and fits between parts that are meant to move or connect. They are essential for ensuring the functionality and assembly of your SLA design. You should account for the shrinkage, expansion, and deformation of the resin during and after printing, as well as the accuracy and resolution of the printer. You should also test and measure your parts before and after curing, and adjust your design accordingly. A general recommendation is to leave at least 0.2 mm of clearance for moving parts, and 0.5 mm for snap-fits.

5 Finishing and post-processing

Finishing and post-processing are the steps that improve the appearance and performance of your SLA part. They include washing, curing, sanding, polishing, painting, and coating. You should follow the instructions and safety precautions of your resin and printer manufacturer, and use the appropriate tools and materials. You should also consider the impact of finishing and post-processing on your design, such as the removal of supports, the smoothing of surfaces, and the application of colors and textures.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?