3D Printing Supports: Overhanging Features in a Design

3D printing Supports are tools meant to hold cantilevered section of meshes. Their shape depends on the material and technology used.

A part with 3D printing supports generated using meshmixer.jpg A part with 3D printing supports generated using meshmixer

Material Support

In this case, a part is printed on a bed dense enough so that cantilevered section do not fall as they are printed. Material support needs to be more dense than the printed part. This is mostly the case of jet modeling and SLS . In case of jet modeling two types of resins are used, one for the part and another specifically for the material support. In the case of SLS it is the unsintered powder that acts as material support preventing parts to fall, this is not possible in the case of metal printing as the sintered part is too dense and would "sink" in the metal powder.

Printed Support

In the case where there is no structure to hold the part, which is common case, with FDM and SLA , supports must be added to the part in order to make it self sustaining, The image shows the area where they are needed in order to print the part. Those supports will be printed along with the part. The connection to the model must be made as thin as possible in order to allow removal. In the case of metal printing removing the supporting structure will require machining tools.

Analysing a part using meshmixer to find cantilevered section.jpg Analysing a part using meshmixer to find cantilevered section

Batch fabrication

In the case of SLS printing the absence of added supporting structure allows the manufacturer to optimize his batches. The fabrication process therefore includes a nesting phase where models are clustered together. The goal is to reduce the printing volume, which  will result in a faster printing and less wasted powder. Heuristic algorithms are used to find optimal spatial arrangement of meshes. This optimization ultimately allows Sculpteo to offer more competitive prices which the reasoning behind the batch control tool.