How to get your 3D prints to fit together

Learn how to make your own 3D printable blocks in tinkercad.
Link to Full Course: learningportal.makeshiftedtec...

[@KevinLevy]

Instead of looking through an object by making it a "hole" is to hit "t" when selecting the object to make it simply appear transparent.

[@BeastBishop]

When calculating tolerances for my printer, I look at layer height and nozzle size. If you have a 0.2 mm layer height, any object that doesn't divide by 0.2 will be taller or shorter than expected. I have a nozzle of 0.4, so I try to make sure my dimensions also divide by 0.4mm. If your printer follows the outline of the object without compensation for nozzle thickness, this would cause the object to be thicker by 0.2 to 0.4. Extrusion rate can also cause excess filament to be extruded causing the walls to be slightly thicker. Calibration is important, though even professional products include tolerances that vary depending on the production process used.

[@GoatZilla]

starting rule of thumb: add nozzle radius to perimeter of concave (arc compensation) surfaces, fillet outer edges in case of sharp edges, counter-hole inner straight edges.

[@raugust6786]

I learned about tolerances the hard way trying to fit magnets! Great lesson. Thanks!

[@asdf0019]

I watched some video about 3D print bolt and nut. They create a bolt first, duplicate it and turn it to "hole" and create a nut from it. I always wonder how it work without putting any tolerance. Thanks for the explanation in your video and support me that tolerance should be taken in fitting two pieces in 3D printing.

[@danko6582]

Tolerance required depends on Slicer settings and printer condition. I use 0.2mm in Prusa Slicer and Cura. Also sharp outside corners on inserted parts should ideally be rounded.

[@PatJones82]

That's a good tip to make the top block a hole temporarily to see how it is fitting inside. Thanks!

[@makeshiftedtech]

Glad it was helpful!

[@jacquesalphonso3636]

You can also hit t on your keyboard to make it transparent. And you can even see better than making it a hole. Try it out.

[@PatJones82]

@@jacquesalphonso3636 Didn't know that. Good tip. Thanks!

[@jacquesalphonso3636]

@@PatJones82 Glad it help. I found out about this in Tinkercad, there's a place were you can save all the shortcuts in a pdf form and print them out as a reminder. Pretty useful information.

[@arthurtorricer4544]

New Subscriber.. thank you for these lessons with Tinkercad.

[@arthurtorricer4544]

I'm also using shapr3d.. wish tinkercad could import things from shapr3d STL..

[@littlefrank90]

So basically "give it a little space" also "trial and error". Nice.

[@bigboomer1013]

What can you do when you scale the whole model? The gap will become alot bigger, so i wonder if there is a mathimatical way to change the size of the gap depending on the scaling persentage in a printing slicer program. For example, im trying to make an action fuigure of different sizes. I have the design of the joints that have been cut out for a 6inch fuigure. But if i want to make the same fuigure scsled up to 10 inches, what persentage do i put in for scaling up tje model to that size and how much bigger by percent should i scale down the "male" pin to make the peices fit snug and keep the gap at .2 mm? Do i have to remake the joint. Also asking because im trying to make a boolean key joint and i worry about constantly making new ones instead of editing the thickness of the gap

[@makeshiftedtech]

This is definitely a challenge with scaling shapes in programs like Tinkercad. This where parametric design programs such as Fusion 360 or OnShape come in hand. That way you can set a variable for your tolerances and object size so everything updates accordingly and you don't have to worry about scale. This is a different way of modeling though.

[@3DJapan]

Even if your print was perfect you'd still have to deal with friction.

[@makeshiftedtech]

Good Point. Always important to remember there is no friction in the digital world. Thanks.

[@zc33s_sport75]

Horizontal expansion will fix this very easily 👌

[@soundspark]

Do so to calibrate your printer, not the part.

[@daliasprints9798]

From the thumbnail screenshot, your printer does not have linear advance calibrated. Those are some giant bulging corners. This is probably the main cause of your dimensional inaccuracy.

[@darrennew8211]

THE FOLLOWING INFO ABOUT WHERE THE WALLS ARE IS OBJECTIVELY WRONG. IGNORE ME. :-) The idea of using teflon tape is still good tho. The slicer generally runs the print head around the border of the STL, so the walls are going to be about half the nozzle width on each side. So make the hole to nub difference a bit more than the width of your nozzle. For big prints, it's helpful to put it in the slicer, add enough negative space to chop out everything but your holes or bumps, and see how things fit, before printing a large chunk of plastic. If the bits are bigger (tens of mm across) you can print the hole significantly bigger and then wrap the peg with a bit of teflon tape to make the fit very snug.

[@mates1627]

The teflon tape approach is a good idea, but I don't think, that slicers run the print head around the border, but actually on the inside of the border, so that the part is as close to the real dimension as can be. When I print pieces, that are supposed to fit together snuggly, I leave out a 0,1mm space on each side, so that's 0,2 mm gap, with 0,4 mm nozzle. That accounts for the tolerance of the printer and any imperfections are accounted for.

[@daliasprints9798]

This is just false. All slicers inset the toolpath correctly accounting for line width.

[@darrennew8211]

@@daliasprints9798 I'm pretty sure Cura gives you the choice, at least. I'll have to see what PrusaSlicer does. You might be right, and I might have gotten bad information.

[@darrennew8211]

@@daliasprints9798 It looks like this is true for external permiters in PrusaSlicer, but internal holes are a little funkier, with explicitly rounded corners and slightly longer travels than the sides of the model subtracted out. (I made a one-layer cube and subtracted out a smaller cube and did the math in the g-code.) Weird, but I think you're primarily correct, which makes sense given the concept of calibration cubes. Thanks for the correction!

[@daliasprints9798]

@@darrennew8211 You could explicitly make it wrong by setting horizontal offset to + half nozzle width, but otherwise that's not happening. I had a question whether slicers did thos right years ago when I was new to 3DP, and yes I think it's a natural one, but anyone who's ever printed small parts or parts with small features knows they get this right already. +0.2 mm offset everywhere would make anything small or mechanical completely unusable.