Hollow cavities will trap liquid resin so escape holes are needed in order for us to completely clean excess resin from a part.
1.3 mm diameter (or thinnest dimension if not circular)
Sprues are wires that hold several parts together and tend to be removed by the customer after receiving the model. Sprues need to be connected to at least two sides of the parts and the support material generated for sprues should not interfere with the models' structures. If sprues are placed above parts will result in rougher surfaces from excess support material than would not be necessary if the parts were printed separately without sprues. Since sprues often support larger masses relative to their size, the sprue thickness should be greater than a standard wire. See "Wires" for more details.
Print Lines or "Stepping"
Although SLA technology can create very smooth surfaces, a "staircase" effect, or print lines, can occur on the surface of your print, and is more pronounced on curved and angled surfaces.
Making your design more stiff (increasing torsional rigidity) will reduce the risk of warping. Longer walls need to be thicker than short ones.
Stereolithography only prints one material at a time. Therefore support structures are printed in the same material as the part and need to be removed when parts are removed from the build plate. Support structures may adhere to the part in several locations depending on part geometry and orientation. After removing the supports, there may still be small nubs or artifacts on the surface of the part from where the supports were previously connected.
Our production team does their best to evaluate your product and orient it to optimize either dimensionally accuracy or aesthetics depending on the application. Support material can leave small markings after removal so aesthetic features will be oriented to limit support contact.
We cannot clean holes that are too small relative to their depth. Additionally, tubes with corners can be difficult to reach and we may not be able to fully clean your model.
We recommend creating multiple access points to holes and small tubes so that we can properly clean your model.