Support material in 3D printing
In Fused Deposition Modeling (FDM) technology 3D printed objects are built by extruding molten filament layer by layer on top of the previous layer until the print is complete. At 45 degrees, the newly printed layer is supported by 50% of the last layer which is sufficient to build upon. Above 45 degrees, support is required to ensure that the newly printed layer does not bulge down.
To sum it up when a feature is printed with an overhang beyond 45°, it can sag and requires support material beneath it to hold it up.
Bridging occurs when the printer is required to print a horizontal part between two anchor points mid-air (without support material). If the distance between the points is less than 10mm support generally is not necessary. Letter “H” is an excellent example for bridges if the center bridge between the two columns is under 10mm, it can be printed without support.
Removing support material
Support is manually removed in post-processing and can create in marks or damage to the surface in contact with the support. It can also be difficult to remove support from small, intricate features without breaking the print.
Furthermore, support requires additional filament and it adds more work, therefore, increases the total cost of the print job.
In order notes, you can request to leave support intact so that you can remove it yourself. In this case, you agree to be responsible if the print becomes damaged in the process of cleaning it up yourself.