back it up a few seconds. He says if you can’t change your firmware like on the new bambu machines or the prusas…
Right, but now instructions of what to actually do.
Hello,
new here, running Mk3 for some time and recently X1C carbon. On X1C also having troubles with dimensional accuracy, tracked it down to skew:
- Califlower calibration test show => skew -0,19° (pretty bad for my needs)
Based on good discussion in this thread I see 3 possible skew remedies:
- manually distort print model (step) to compensate for printer skew prior slicing – not easy, not convenient, but seems feasible
- Boneyard labs video recommend to shim-out the x/y skew – based on my tests, this seems to work in short term. But I actually don’t fully understand the core XY kinematics & belt system and I am a bit concerned this may cause some undesired effect/belt tension/wear in long term?
- CNC kitchen Stefan’s video seems to indicate GoSkew G-code postprocessor - I don’t have any experience with such technique and was not able to find any reference/discussion anybody using it for Bambu or Orcaslicer
Does anybody here have relevant experience to share which of the solutions actually work and is most reliable/robust/convenient in long term please?
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Belt tension comes to mind as a 4th point. But you have probably already done that.
Goskew gives directions on what to do and how to do it:
In case you didn’t see it, have a look at:
Progress!
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Thank you pointing me to this! This is definitely significant and I agree it should just be in the official wiki. I’m still waiting to hear back from support, but it will be interesting if they suggest this same thing.
Just to a little add to this. I’m coming from 30 years mechanical engineering and 10 years of personal CNC. Quite a noobie in 3D printing at 2 month.
When having prototype parts made, you give a model the machinist who will adjust offset based on the material for materials. (at prototype you may use a different material for cost) This similar to filament types.
Many times in subtractive the cutting tools are measured to 4 decimal points and that dimension is put into the CNC machining equipment.
Lastly for threads, if they were designed and made exactly the same (line to line) they would thread together, some clearance is necessary. Same goes for mating part with slots.
Steve.
The problem you describe seems to be related to the printer not calibrating the printer correctly in steps per millimeter along the X and Y axes. Adjusting the hole and contour compensation settings in the cutter may temporarily correct this problem, but will not completely solve it, especially for round and square shapes.
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As already mentioned further up, the printer mechanics and electronics are rarely the root cause for too small parts. So adjusting steps/mm does not solve the root cause. Instead, you should look out for shrinking of the material when cooling down. Accordingly, that should be compensated in a material profile, separately for each material you use.
Skew is a different story, where calibration of the machine absolutely makes sense.
Going to give a try to this firmware fix, seems almost too good to be truth! 
To provide update:
“mechanical” tape fix is difficult to fine tune and does not seem to be fully stable over time (probbably change in belt tesion?).
Spend quite some time getting GoSkew integrating in Orca Slicer - finally got it to work in terms of “skewing” the g-code but also generates weird artefacts in the gcode trajectories.
Next step - give to try to firmware enabled fix as pointed out by NeverDie!
Thanks, and yep, just belt tension re-set did not help.
Have you see this post about the skew compensation built into Bambu firmware?
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That does indeed look odd. Maybe the model you’re working with is too “coarse”? How was it created?
In the past I would “print” my fusion360 CAD model to a .stl file. When doing that, I could specify the degree of “refinement” in the output file. Default was “medium”.
Is that how you’re making your model? If so, maybe try the “High” setting or something custom that’s more refined. The goal would be to export a mesh that has, say, 10x as many triangles in it.
Anyhow, I no longer do it that way myself. Now I export .step files, because I’ve heard it is more geometrically precise. More like vector graphics than pixel graphics, if I’m getting the gist of it right. So, maybe try a .step file.
Unfortunately, I’m out of my depth and these are both just wild guesses, but it seems somewhat plausible and very easy to try, so maybe you want to see if it makes any difference.
Did you use values from the Califlower or Calilantern? I’m trying to figure out what values to use with goskew.
Opened a brand new X1C today to find the same issue. 115mm length off by half a mm. 100mm gives 99.75. Skew test is 114.56 vs 114.72. 10mm cylinders undersized by 0.2mm. Most dimensions small by about 1%, sometimes more, but never the correct size. I printed at all wall speeds 60mm/s and nothing changed.
This is the included Bambu filament that was calibrated using a flow cube, 2x 0.42 walls gave 0.84. I also let the lidar autocalibrate and got even smaller parts. Orca slicer, tried the fitment test and the 6mm hex was 5.9mm
I’m glad to see this conversation has gotten back on track but it’s insane that $1500 flagship printers are coming out of the box with worse dimensional accuracy than my ender 3 from 5 years ago and there’s no fix.
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Honest question. If you’re so unhappy with the dimensional accuracy of these printers why on earth would you buy another one?
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It would be nice if the printer could do an auto calibration for shrinkage using all the built in sensors it has on the X1C… Their engineers should be able to program the machines to calibrate using some kind of multi ring calibration print to measure the movement increments and then compare that to the data captured by the lasers, lidar, and nozzle camera for each ring of the print. Larger the ring, the more shrinkage where it could measure the difference and automatically compensate per filament… But what do I know, I am just some idiot on the internet.
If they cant do that for us, they should at least implement the shrinkage feature like OrcaSlicer has. Having to manually scale the size of the model or change the hole and contour compensation settings in BambuStudio every time I print something is not going to work for me. I bought the X1C so I could have a workhorse printer that I can trust while I have my other printers to tinker with and I not expect them to be at the level of the X1C, but I find myself using my custom CoreXY just to print parts that I need to be accurate.
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Please read the entire thread. The root cause is not in the printer but in the natural shrinking of the filament when it cools down. Those shrinkage numbers are perfectly in the expected range. In my experience, PLA typically shrinks by around 0,3%, PETG by 0,4 … 0,5%.
Of course one can mistune the printer to compensate shrinking of one material and achieve perfect dimensions with e.g. PLA. You would probably get good enough results with PETG too. As soon as you use material with a different shrinking rate like ABS, Nylon, … you again have “wrong dimensions”.
So the proper way is to let the printer move the correct distance (which doesn’t need calibration) and compensate the filament shrinkage in the filament profile.
Regarding flagship printers: In my opinion this is not a high spec printer but a consumer printer with an extremely rich feature set at a budget price. At work we have an Ultimaker S5 that was like 6000€ (AMS not included) with far less bells and whistles that is really frustrating in many regards compared to the X1C.
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