ABS for me shrinks in all axis, maybe this is why bambu has not added softfever’s shrinkage yet. I found a 70mm tall object comes out around 0.5mm shorter, so I scale the whole model. I’ve also had PETG shrink 1mm on a 180mm long part on my other printers.
Thank you! Yes, that is super helpful. Thank you for pointing that out.
My skew measurements came out similar to yours:
The one person who had replied to that thread had given me reasons as to why I couldn’t hope for better, and to leave it alone, but now, after reading some of the comments here, I’m starting to think that improvement might be possible after all.
All of which raises a worthwhile question: just how good can we realistically aim for, and at what point can we do no better and should just leave it alone?
At least to me, the CaliLantern required a fairly large number of tedious measurements. It’s not something I would want to do very often.
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That’s an excellent question and my off-the-cuff answer is: It should be as good as, if not better, than any open source printer. We are paying a premium for the BL printers and since they are closed, they are basically saying “we know what we are doing, trust us.” The stuff I’m printing is being printed by several other people on everything from Enders to Prusas, and they are getting tighter tolerances and results than what I’m getting. So, BL needs to either let us tweak to the FW as needed, or perform better quality control at the outset to ensure 0° skew since we can’t make the adjustments that need to be made.
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I like your answer. The BL prints a lot faster than the Prusa, though, so I wonder whether expecting the same or better level of accuracy at higher speed is fair or not. On the other hand, the BL can certainly print slower if you ask it to. I haven’t tried that. Does it make any difference? Anyone know? Or is this a foolish question?
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No idea, but I feel like they should be able to leverage the LiDaR to true up the skew just like they do the flow. It could draw a large box around the perimeter of the parts and then scan the corners for 90°. No idea how to check the Z axis though.
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I obtain prints with around 0.2mm of shrinking when I use a layer height of 0.2mm. If I use the 0.16 High Quality profile, I achieve around 0.05mm of dimensional accuracy. Very curious…
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Maybe that has to do with the height of the model? The slicer can only divide it into an whole number of layers. So with 0,2mm layers, one more layer might be just above the model’s height, so the print is almost a whole layer shorter, while with 0,16mm layers it might work out much better.
Resonance Compensation / Input Shaping is prone to alter dimensions (especially if it is not done perfectly but I assume Bambu has that handled). So yes tehoretically Printing slower would get you better dimensional accuracy.
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It only affects the XY dimensions. The Z dimension remains the same.
Sounds like we need a new theory. 
What Do you mean? What theory?
Has anyone found an improvement regarding this issue?
I tried everything that came to my mind, but I am out of ideas now.
The only thing that helped to improve accuracy a little was the “belt tightening” method.
Anyway an 100mm L-shaped object is still constant off -0,1mm on one axis and 0,2mm on the other.
This thread echoes other Bambu Lab specific forums, being reddit, FB etc. The general tone of responses seem to be an attack on an OP for asking a question or proposes anything but perfection from one of these machines. Followed by a slew of upvotes/likes for non-helpful comments. The OP is simply pointing out a performance issue with his machine. On a support forum. He’s not asking how you feel about his question. He appears to be looking for a solution.
This seems to be an unfortunate trend for Bambu. I’m not going to analyze why but I haven’t seen this in forums for machines that don’t market a plug-n-play solution.
Instead of trying to prove the OP wrong the right approach could be a non-emotional “That’s an interesting find. Thanks for sharing your findings. I don’t know why this is happening. Let’s look into this and figure it out.”
That being said I’ll be following this thread as I’d like to see a method to calibrate / control these tolerances in an measurable and repeatable way. I do understand Bambu’s hesitance to open up too much control as it complicates their ability provide support. And self-calibration is one of their selling points. Perhaps they can add this as a option which can be switched on and off for their troubleshooting purposes. I’ve always been anal and thorough, measuring steps-per-unit then adjusting these numbers when building a Marlin firmware. My Mono-price, Enders, Cr-10s have been accurate and repeatable.
TL;DR: It’s not up to us to decide if OP needs to calibrate to his acceptable tolerances.
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I suppose you’re right: 95 posts, and nothing got solved, did it?
Hi together,
I just stumbled over this video here: (YouTube)
Within the video the creator explains how the belts are slightly missaligned and how on his printer also the squareness between the reference-points is off.
And how to fix it.
As CoreXY systems are pretty picky when it comes to belt tension and alignment I could imagine that this is a possible solution to get at least some of the issues sorted out. (Espacially my issue with different deviation in X and Y axis).
I will give this a shot in the next couple of days.
If someone finds the time to try it earlier: please share the results.
BR
/Kevin
All well put. I wish i could have said it this well.
@adminmat Also a perfect statement. This is why i barely ever post anymore.
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The carbon rods are only specced to ±0.1mm for straightness and the bushings have almost half of that too in running clearance, you’re not going to get much closer than that without getting very lucky with the tolerance stack up on the carbon rod/bush motion system, unfortunately. It’s why you’re always going to have different deviation in the Y vs X axis.
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I tried this because I don’t like the ripples when printing petg. Diagonally, the printer had a difference of 2 mm. I compared everything using calibrated gauges. No result. Only now the waves are cleaner. It seems that some inaccuracy and curling is probably a standard feature.
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I’ve found that compensation for shrinkage by entering a calculated shrinkage factor into the material profile is pretty much the silver bullet for my accuracy problems. I believe only Orca supports this though.
I use a model and spreadsheet from Thingiverse to calculate it for each filament:
https://www.thingiverse.com/thing:1982686
And also make sure to zero out the values in X-Y hole compensation and X-Y contour compensation before running the print.
Here’s some of them:
Inland PLA-CF Black: 99.638%
Hello 3d Silk Gold PLA: 101.131%
eSun ABS+ Black: 99.118%
Inland ABS Black: 100.762%
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