Any advice how to tune your printer for dimensional accuracy? (within reason, of course)
I know it’s not a CNC machine, but I printed a test print which is 100mm on X and Y plant and 10mm on Z plane.
Why these numbers?
I want to deal with X and Y first, and I’m printing parts that are about this size.
My test print was measured with digital calipers very carefully.
X=99.71
Y=99.69
There is not currently a way to do this - the biggest obstacle is the inability to determine what the current step values are. I’ll comment that flow ratio has a noticeable effect on the level of accuracy you’re looking for, and your three-nines desire may be unattainable at this price point. That said, everything I have printed on my X1C where dimensions matter has been functionally spot-on.
Expecting the precision of CNC with a FDM printer is a mistake. Even if the steppers have 0.0001% resolution. The filament extrusion process itself has limitations, but the biggest issue is that the plastic changes size as a function of its temperature. That doesn’t just matter for the finished print. It’s changing size while you’re printing, so particularly for taller objects you can get some “shift” as the mid layers cool and pull on the still warmer upper layers (the build plate keeps the lowest layers hot, but that doesn’t guarantee the part won’t still pull on and deform those lowest layers as you’re printing it. It’s what causes warping).
Measuring ~99.7 on a 100mm dimension is excellent. IMO you’ll be hard pressed to do much better. You might get it tuned better for today, and find it’ll be a little off again in the future. Ambient conditions matter.
You really need to design for some additional tolerance stack up, or if you have the tools, do what I do - print the surfaces that need to be accurate slightly oversized and then cut them down on a CNC.
But more often i just resize the object after first print, when really is needed found that was the easiest for me
Also sometimes adjusting line width and layer height helps
The main problem i have seen is from the shrinkage , and very slow cooling after the print reduces the problem
but then the cooling profile changes the percentage as well , so use the same cooling profile
As others mentioned very difficult to get to a good accuracy , but i have done it to sub 0.05mm, on 70mm object but too much hustle
Can’t you use the old method of finding out with a couple of calibration cubes the % you"ll need to input to scale up each axis of the model in the slicer to get an accurate printed size?
I know it’s annoying because you should do it for each type of filament and have to remembeer to do it each time you are printing somenthing and not always gives you perfect results with big models
Hey,
I just received my X1C two weeks ago and got similar issues.
PETG is off by 0,2 to 0,3mm at 100mm part size.
Also X and Y are not “off the same” the deviation on the Y axis is bigger.
Maybe the settings for steps are not correct?
Tested with a calibration cube and an L-shaped object.
Also circles behave strange, the outside diameter is way off (17,8mm / should be 18mm)
But inner diameters are spot on. (10mm in that case)
I tried the L-shaped part also in PLA.
X is bang on (99,99 to 100,03 - printed multiple parts)
Y again is smaller at around 99,89mm
Manual flow calibration did not help with the XY dimension.
Any Idea how to improve on that?
Regarding “CNC” quality - nah. 0,1mm around the measurement is what to expect from an 1,5k€ machine, when my Ender 3 holds these tolerances all day long.
I tried playing around with different number of walls, infill and infill pattern.
(Trying to check if more material == more deviation)
No siginificant change.
I also tried placing my L-shaped part at 45° hoping the errors would ease out, as the printer has to move the head 45° with both axis at the same time.
It did not change much.
One leg is still 0,1 under dimension (okay I guess)
The other one is 0,2 under. (not okay.)
yes that is a good part to get a lot of measurements.
Anyway, I think the real problem is not to find how far we are off, but to find a way to copmpensate for it.
So far I am using the scaling option within the slicer with good results, but I still have to check for parts of different dimensions. (Big parts, small parts)
Even if this will work out it is more of a workaround than a solution in my mind.
A proper solution would be to be able to change E-Steps on the printer and/or allow an option, where we can bind the scaling value to the filament settings. (shrinkage)
If i was bulding something where 0.1mm difference between the left and right legs mattered, I would put in some kind of adjustment mechanism to level the machine.
But you’re correct to complain abotut the dimensional accueracy of your printer. It should really be adjustable. Perhaps there will be firmware later, either from Bambu or a 3rd party.
I came from the DIY days of building and calibrating your own printers. Getting accuracy of 0.1mm in any dimension is quite routine. After buying 2 A1s, I discovered that Bambu Lab printers aren’t that good in dimensional accuracy and also repeatability across printers.
I’m going thread on this statement gently… most people who probably started with a Bambu Lab printer probably doesn’t know that it is quite possible although tedious to get your printer to achieve about 0.1mm accuracy if you are able to calibrate the ESteps.
I’ve managed to get my printers to match by using the archaic method of dimensional transformation before each print.
Honestly this would actually suffice if we can save this setting into individual printers.
Same here, my ender 3 is tuned to a very high accuracy +/-0.01 on XY. I put ball screws on the Z and it has about the same accuracy with no backlash. Just did a cal cube on my X1 and I am 19.9. Would love to figure out how to pull that Z closer to .99
Same for me, my A1 has really bad accuracy.
Out of the box I get with the cross calibration test :
149,3 mm instead of 150 mm
4.83 mm instead of 5 mm
19.81 mm instead of 20 mm and more…
Very bad result, with my Anet A6 I have less than 0.1 mm and the same with my own personal DIY printer.
I have tried to modify estep and get these error :
150,25 mm instead of 150 and 19.81 mm instead of 20 mm in same print !
No way to solve that.
Very disappointing printer.
