What Supports Do
Support structures play an integral role in printing parts on the Formlabs SLA 3D printers. They allow for a wide variety of complex and detailed parts to be printed.
PreForm offers basic and advanced support settings. This segment of our video series explains best practices for using PreForm to create support structures and the theory of supporting upside-down geometries.
Support Structure Overview
Support structures can be thought of as scaffolding; they allow for construction of parts and are removed afterwards. They consist of two core components: a flat base and vertical shafts. The flat base ensures that the part adheres well to the build platform. The shafts emerge from the base and connect to the part through small touch-points (also referred to as “teeth”) which can be removed by hand or with flush cutters when the part is finished.
To make removing a freshly-printed model from the build platform easier, the support base includes an angled edge and handy quick release tabs — small notches on the side of your model’s base that help it lift easily off the build platform. Learn more about part removal during the finishing process.
Overhangs and Shallow Angles
Using 3D printers to make parts without support structures severely limits the part geometries that will print successfully. Because 3D printing is an additive process, in which each layer is consecutively added to the previous layer, there must exist some material on which each layer can build. Accordingly, each layer can only be slightly larger than the previous layer without sagging. From a macroscopic perspective, parts must have steep angles in order to print properly without supports.
The support structures allow for parts to be printed at shallow angles. By touching the part via the touch-points along the shallow slope, the support structure gives it added strength, preventing unwanted twisting or other deformations. Additionally, the support structures can accommodate overhangs that would otherwise be unable to print.
Air Pocket Relief
Without supports, printing parts with a flat surface and holes in the geometry may create air bubbles. As the part prints, these air pockets can cause voids in the model. The support structures, in this case, create pathways through which the air bubbles could escape.
Red Shading on Models
When support structures are generated, “supportedness” coloring is also added to the model, by shading red portions of the model that are unsupported. If a part of the model is a deep red, that portion of the model is unsupported and will most likely not print well. If a part of the model is a lighter shade of red, that portion of the model is less-well supported and may have structural defects.
Typically a very unsupported region (deep red) is caused by an internal overhang or a feature too thin to be supported. In these cases, it is best to activate internal supports or try rotating the part to a different orientation. Auto-orient maximizes part supportedness and can be very helpful for parts with unusual overhangs.
The example part shown here is unsupported and the top of the top arm will fail.
A lighter shade of red is less of a cause for concern. Very often, parts will print well despite the coloring. This light red serves only as a warning that there may be issues with the part orientation. The sphere shown with a faint red ring will likely print just fine.
A fully-supported part will show no red. Make sure to examine your models closely, to identify any odd regions of un-supportedness. Try re-orienting the part and generating new supports to find the ideal configuration.
Generate Selected vs. Generate All
When you have positioned multiple .STL files in PreForm, you can generate supports for all those pieces at once, or individually for each part.
Generate the same type of supports at once for all parts on the build platform by pressing “Generate All”. Unless you have changed the Advanced Support Settings, this will use the default support settings.
In the case where you might wish to vary the advanced support settings for each of these parts, and thus generate slightly different supports, you can generate a set of supports one part at a time using “Generate Selected”.