Design Guidelines

3D Printing & Additive Manufacturing 

The following information outlines guidelines and limitations for the 3D printing services we offer.  Unless otherwise instructed, Forge Labs prints 3D models as they are provided to us. Typically, we are able to notify our clients of potential problem areas and alert them before production begins. However, it is not always possible to check every feature, and therefore Forge Labs cannot be held responsible for failed prints, or fragile parts that break during post processing if they do not meet the minimum standards laid out in the guidelines below. 

design guidelines for 3d printing
FDM Icon
Fused Deposition Modeling (FDM):

Download Design Guidelines (Adobe Acrobat PDF)


  • FDM accuracy is approximately ± 0.127 mm (± 0.005 in.), or ± 0.0015 mm/mm (± 0.002 in/in), whichever is greater. The larger the part is the looser the tolerance – if you need a specific tolerance on a part, please ask


  • Maximum build size is 914 x 609 x 914 mm (36 x 24 x 36 inches).
  • The layer resolution ranges from 125 – 330 microns, depending on the settings specified. Standard layer height is 254 microns (0.010″) unless otherwise stated.
  • Minimum wall thickness is 1 mm. Thicknesses that are achievable in the real world depend on the design of the part, and walls built to the minimum thickness may be fragile when cleaned and finished.
  • Extruded text must have a wall thickness of at least 1.5 mm (0.059 inches) when printed flat, and 2 mm (0.079 inches) when printed in the Z-axis.
  • Minimum resolvable feature size, including text, is at least 1mm, or greater.
  • Depending on orientation, circular holes can flatten out to ovals – if higher accuracy is required, printing the hole smaller and then drilling it out is recommended.
  • Pins should be at least 5 mm (0.197 inches) in diameter.
  • Clearance for moving parts, hinges, joints, etc, is 0.5mm on all sides.


  • Our Fortus FDM printers print using soluble support for most materials- meaning that support material can typically be washed off without leaving visible ‘marks’ from where it contacted the model.
  • Hollow walls and enclosures will be filled with support material, and must be designed with drain holes so that the support can be dissolved and removed during cleaning.
  • Parts can either be printed in ‘solid fill’ or ‘sparse fill’.  By default, all parts will be printed with solid fill unless otherwise specified.  ‘Sparse fill’ prints large volumes with a honeycomb structure instead of solid plastic to lower material costs.

Surface finish:

  • Note that FDM has visible layer lines, especially on curved surfaces.
  • 3D models cannot have overlapping geometry – they must be water-tight