3D Printing Tolerances & Fits

If you are reading this, then there is a greater than 90% chance you are an engineer or designer interested in 3D printing functional parts. 


Like any manufacturing process, in 3D printing it is important to understand the tolerances of the process so that you can properly design parts to fit together and function.

While each printer and technology has specific tolerances that can be achieved, we find that the following designed-in clearances will allow your parts to fit together and function as intended:

Desired Fit Clearance Gap (in) Clearance Gap (mm)
Press Fit Line to Line Line to Line
Tight Fit 0.005 0.127
Normal Fit 0.010 0.254
Loose Fit 0.020 0.508

 

And don't forget...holes in 3D printed parts are ALWAYS undersized.  This is because of the STL file format that is used for 3D printing...we are building a circle from the straight edges of triangles...think circumscribed circle. 

 

Good news is that holes can easily be reamed out by a handy-dandy drill bit

 


Need some more guidance? 

No worries, 3DChimera is here to help.  Don't hesitate to reach out to alex@3dchimera.com with any specific questions for your application. 

 


2 comments

  • Question. When you speak of the gap, and the situation is a peg in a hole, do you need to reduce the peg by double the gap values you stated? For example a tight fit would have .127mm reduction on both sides, or .254mm reduction in diameter? Or are you meaning that there would be a .127mm reduction in diameter? Thanks!

    Chris
  • Thanks for this.

    Chris

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