Print size does not match stl file measurements
I am using an Original Prusa mk2 which is about 14 months old with firmware 3.1.0 and Slic3r 1.39.1 😀
when i generate g code for a test square and print the square the measurements are correct.
when I generate g code for a complex object with internal circles etc., the external measurements are correct but the internal circles etc. are small by about 0.20mm.
I noticed this when printing the "x-carriage-back.stl" for my MK2 to MK2.5 upgrade.
Is this a firmware error or a Slic3r error or something I am doing?
usually I do not notice such small errors, especially with internal sizes but in this case I am afraid the parts might not fit when I try to assemble the hot end and bolts.
Re: Print size does not match stl file measurements
.2 isn't so bad.
people print endless calibration cubes and adjust extrusion multipliers (don't do this) to try and "calibrate" dimensional accuracy or whatever...bottom line is that the ONLY way you'll ever get perfect dimensions with FDM is good old-fashioned sanding and reaming.
For holes I'd go smaller and ream them out, for surfaces I'd rather be thicker and sand to fit. Sometimes if you're only worried measurement in one direction you can just add a bit of dimensional scale to that axis in your slicer.
Re: Print size does not match stl file measurements
it is a small amount but how about when I put in the extruder? This is a large object and needs to be accurately placed. Also, it is just not the holes it is the groves nut traps etc.
Re: Print size does not match stl file measurements
Check out the Slic3r setting:
Print Settings -> Advanced -> Other -> XY Size Compensation
That is designed for fine tuning hole sizes.
That said, I think curtis.c2 is correct in general.
Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…
Re: Print size does not match stl file measurements
Even NON-FDM manufacturing uses tolerances when making parts. Plastic shrinks when cooled and other things. the mk2s is fairly decent and when i add a 0.1-0.2 tolerance to holes they come out perfect. unlike in other machines it an be hit or miss without good tuning.
i would try tuning linear advance as it could make a minor difference with holes (holes have seams usually). however for absolute perfection i would just make tiny holes as guides for just drilling them out so they're 100%.
Re: Print size does not match stl file measurements
if you are printing a Prusa extruder housing there is every probability that they will have added a tolerance to the dimensions anyway
I make sunshades for telescopes, I want them to be a snug fit over the body so I typically model the part to be approx 0.2mm oversize on the internal dimension, then do a test print on the first 20mm or so, to ensure that the chamfer on the end takes care of the elephants foot and the main body gives me the fit I require
adjusting dimensions as required
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK