Is there a way to calibrate or adjust the printers? I have 2 A1s and they are slightly off in dimensional accuracy. That means I cannot print parts that fit across the 2 printers unless I compensate the sizes individually.
There are calibration shapes that you can use to correct for inaccuracies, but it depends on the materials and type of things that you do. CNC Kitchen has a new video on YouTube that is quite comprehensive on how to do this well: https://www.youtube.com/watch?v=H7OsnMLDIMw
2 Likes
There isn’t a way to adjust dimensions on the Bambus - traditional methods setting X, Y and Z steps don’t work on a CoreXY design, and Bambu doesn’t give you a way to see what current values are.
I’m a bit surprised at differences between printers of the same model. Are you using the exact same filament and print settings? On my X1C, dimensional accuracy has been outstanding.
1 Like
Exact everything, same setting, same batch of filament etc…as I bought 2xA1 just to run a small production of parts.
I used to build my own printers and I’m familiar with the pains of calibration but at least my parts fits if I print them across my printers.
Bambu needs to have an option of calibrate their printers.
How off is “slightly off”?
1 Like
Hi.
I need to print parts with precision, and I have noticed that, for example, when printing a patterned ring with an outer diameter of ø50mm, inner diameter of ø30mm, and a thickness of 8mm, I obtain measurements of approximately ø49.75mm, ø29.8mm, and 8.02mm, respectively. I have tried using the “X-Y compensation” options, but they cause problems during slicing, resulting in the loss of contours. Another option has been scaling the models, but it is tedious and prone to errors. How do you address this issue? Are deviations of 0.25mm considered normal?
Thank you.
There is already a long thread about similar questions that you can find here: Dimensionally Inaccurate Parts Being Produced by X1C - #54 by jrovito
But in short: yes, a 0.25mm deviation on a 30-50mm part is an inaccuracy of 0.5-0.8%, which is as good as you will probably get on a consumer machine, especially one using FDM.
The best solution is to scale the models, by calculating a scaling offset for each material that you are printing. CNC Kitchen has a recent, comprehensive video on this that you can find in my earlier post in this thread.
For example, in the Trent900 Jet Engine, I need some accuracy to adjust the bearings correctly. Scaling all parts is impractical. 
Maybe the best solution is to add a cylinder or a ring to the parts where the bearings need adjustment, and then adjust the scale for these added parts only.
In Orca Slicer, there is an option in the filament parameters called Shrinkage. Does it work? Perhaps it would be a good idea to implement this in BambuStudio as well.
About 0.5mm error at 120mm.
Better than 0.5%. In my experience, that’s pretty close to if not better than the level of accuracy you can expect from a FDM printer. It’s not just a function of the steps/mm of the motion stage. The plastic has a large coefficient of thermal expansion. ABS shrinks by as much as 7-8% when it cools (which is why it is so prone to warping in the printer). Two prints in succession from the same printer might show this level of variation if the environmental conditions change between prints.
When I design for FDM parts, I make a lot of allowances for the tolerance stackup and I don’t expect to get really precise fits. I use SLA for parts that need precision, and/or I print with FDM and then machine the features that need to be accurate on my CNC. Gave up trying to print high tolerance parts with FDM long ago.
2 Likes
If you can do your own calibration, it is quite common and easy to get your printers to 0.1mm accuracy. Even crappy printers.
3 Likes
That’s a big “If” - on Bambus, you can’t. At least the A-series, being bed-slingers, make it possible to adjust X and Y steps, but Bambu doesn’t provide a way to see what the current steps are so that you can issue Gcode commands to change them (and that’s assuming that the firmware would respond to G92). The CoreXY designs are more complex in this regard, though I assume there is some corresponding tweak you can make.
Regardless, you have no visibility into the steps settings and no obvious way to change them.
1 Like
hi there
did u solve the problem ?
I also have the same problem with my A1 printer, and as the part size increases, the dimensional discrepancies become even more pronounced. I’ve tried everything, but I still haven’t found a solution
yeah i had a similar issue need at least 0.1mm precision. I used the califlower model and got it to within that range comfortably. But important you do that when you already have done bed levelling, flow calibration, pressure advance etc.
There isn’t a way to automatically add in the x and y offsets in bambu or orca. Doing x and y can be ok but they’ll likely be different so individually scaling them (making sure that they have the same orientation as the build plate, if not you can arrange them then export and reimport them so they have a orientation like the bed). then just scale them and print.
Awkward but orca or bambu dont allow pre slicing scripting, and adjusting the sizes after slicing would mess with pressure advance etc.
Not easy but if you need it you need it.
This is something I miss from Klipper - being able to add skew correction easily.
I just started needing to mix parts printed on my Bambu A1 mini and my super old modded Cr-10s Pro v1 and ran into this issue. Parts printed on my CR-10s Pro were a good amount tighter when trying to fit two parts together that I had previously tested on my A1 mini. Started measuring a bunch of prints and realized the mini is pretty off and that my CR-10s Pro is almost dead on. I have klipper running on it and have done the Califlower sku calibrations a year or two ago. Now I have the issue that I designed all of my tolerances based on the mini and they are way off when printed on more accurate printers. I should not have assumed the mini was going to be very accurate right off the bat.
A wall thickness that is 2.145mm in cad is 2.15 on my CR10s-Pro with a .5mm nozzle and on my mini it is 2.01mm with a .4mm nozzle. The width of the same part is 12.1mm in cad and Cr-10s Pro is 12.11mm and the mini is 11.95mm. Printed in Bambu PETG HF on the mini and 3DO ASA GF on my Cr-10s Pro. Now to go down the rabbit hole of trying to make the A1 mini more accurate and fix all of my designs.