3d Printer resolution?

I am trying to print a rod end bearing on my ender 5. I started with a sphere inside and a matching surface with different clearances between them. I printed .2mm, .5mm, and 1mm clearance. The 1mm was too loose, the .2mm ended up fusing together so it would not rotate and .5mm was decent but still too loose. I am going to experiment further with different clearances and diameters to see if I can find the sweet spot.

Is there some kind of rule of thumb to go by on FDM 3d printers on what resolution they are capable of, or what is the minimum clearance before things fuse together? I am sure there is lots of variables to this, nozzle size, stepper motor resolution and reduction ratio. Would a smaller nozzle be the way to go on this or is it the printers resolution that determines how this will work?

I think it is something that is pretty dependent on your calibration. If you have any over extrusion, it is all going to end up in that gap. If you have any backlash in X or Y, it will end up making that gap stretch and shrink.

The smaller tolerances will only be achievable with finely tuned printers.

I feel justified saying this because there are a lot of models with joints like this and they often come with multiple tolerance versions.

Just spit balling here, but you could try making one surface textured, so there is less area in contact. Then it would be easier to break the fused sections and grind down to a good tolerance.

Or maybe the outside could be a ring with a small break, and a screw to adjust the size to just right.

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Makers muse has a tolerance test something like this part. I believe he says 0.3 is really good for most printers.

So I would shoot for that but it is printer, filament, slicer dependent.

One more thing I can add is that most reasons for material ending up in the gap will be magnified with smaller later heights. So if the model and printer can handle it, sometimes just increasing layer thickness can tame those unfortunate nuggets a bit.

Thank you. That tolerance test will save me time finding what works for my printer.

No one said nozzle size will make a difference. Is that anything you think I should experiment with? I only have the one nozzle right now.

I don’t think the nozzle size would effect it much. Shooting for smooth walls and no stringing or blobs. I would do an extrusion calibration on the filament you are using and an extrusion thickness test. Both are pretty quick and easy. Those are, extrude 100mm to make sure your steps are spot on, and print a single wall box to make sure it is doing what you tell it.

Both are here, https://teachingtechyt.github.io/index.html

One more detail I don’t quite understand about this. To get the best accuracy from model to print would you stick with making changes to the model size in increments of a nozzle widths, or does the slicer do something to adjust for this?

The slicer takes care of it.

Work through the Teaching Tech series of videos and tests and you should end up with a very well calibrated machine.

Some of the settings are for the overall machine, so once you’ve got them they’ll be good pretty much forever. This includes micro-stepping and steps per MM for the axes, and the PID tuning for extruder and bed heaters.

Then there are some elements (temperature, extrusion multiplier, retraction, linear advance, etc.) which will need to be tuned per filament. Most people expect to use different settings for different classes of plastic (e.g. PLA vs PETG), but you may also get better results with slightly different temperature and retraction settings for different colors or manufacturers of a single kind of plastic.

The Teaching Tech videos work through all of this in a logical sequence, and he does a great job explaining where settings might have interactions with one another.

Thank you, I do like the teaching tech calibration aids. I have done all of them except for things like linear advance which my my stock firmware ender does not support. Id like to get a new board / firmware to take advantage of all of the things you can do to improve calibration.