3D Tolerances

3d printing design guide

Just as CNC milling requires undercut and tool path considerations, or injection molded parts require draft angles and ejector points, there are a number of fundamental elements elements that are relavent to 3D printing. Detailed design information discussing how to achieve successful 3D printed parts with our FDM technology can be found below. 

FDM is able to produce walls down to 0.8 mm. As a general design rule of thumb it is good to make wall thickness a multiple of the nozzle diameter (if this is known). The most common nozzle diameter for FDM is 0.4 mm.

Overhang features less than 45° relative to the horizontal plane require support material to print accurately.

All embossed and debossed (engraved) details prduced by FDM should be no smaller than 0.6 mm wide and 2.0 mm high (if they are to be readable).

Unsupported horizontal bridges produced by FDM should have a span no greater than 10 mm to avoid cracking.

FDM can sometimes produce holes that have slightly undersized diamter. If accurate holes are required drilling after priniting is reccomended. Holes smaller than 2.0 mm in diameter should be avoided.

When clearance is required between parts, a spacing of 0.5 mm should be used. This can be varied based upon the type of fit that is required.

The minimum feature size when printing with FDM is 2.0 mm

Vertical pins created using FDM should be no smaller than 3.0 mm in diameter, if they are functional. Most of the issues relating to minimum pin size center around cooling. Off the shelf pins, inserted into a drilled hole, are the best solution if functional pins are required in a design.

Unsupported edges will begin to lose quality and fail to print if they are too long. Unsupported edges should be no longer than 3.0 mm.