Proper Measurements for Fitting Pieces Together

Hello,

I'm new to the forums and still a beginner with 3D modeling/printing. What I would like to know is if I am fitting an object inside another for a 3D model, should i make it slightly smaller or the same size. For example, if I have a hollow cylinder with an inside radius of 4mm and want to have a solid cylinder inside of it that can slide freely, should I make the solid cylinder have a radius of 4mm as well, or will this not allow for free movement. Is there a recommended size shrinkage? Again I'm new to the forum so if there is a previous thread you can point me to I would appreciate it.

Thanks

You'd need to leave some clearance between the parts you want to have print separately, especially if you're printing them in place, since otherwise they'll be permanently stuck together. The exact amount of clearance you'll need depends on what sort of fit you want, and the characteristics of the printer you're using. You'll have better control of this if you print them separately and assemble them later.

Andrew Werby
www.computersculpture.com

Same size will never work even if printed separately. Best to print a test cube (or similar) and get the calipers out to check. I have found it could be 0.1mm thicker than modelled in one direction of print (squeeze effect) but bang on in another. The other aspect is design clearance, tight fit that is permanent, tight that will loosen with time (wear) or loose fit from day one. Experiment, there is no hand book on this :)