What is the best way to calibrate for dimensional accuracy. I’m using Bambu Matte PLA.
I recently printed a bunch of parts, which I’ve had no issues with in the past, but this new batch was off about a one mm making them completely useless.
Hoping to prevent this in the future.
Thank you.
Proper filament calibration is where I would start.
How big was the part and in which direction was it off?
Search for “FDM print accuracy” and you will find you can reasonably expect a dimensional tolerance of ± 0.15% and a lower limit of ± 0.2 mm. It may require some tuning to reach those limits.
For consistent results with any filament, start by calibrating nozzle temp, flow rate, and pressure advance. OrcaSlicer has those tests (and more) in one convenient spot.
You can make X_Y and Z shrinkage adjustments in the OrcaSlicer filament settings. These changes will apply to all models using that filament preset.
Studio and OrcaSlicer can both provide X-Y hole (interior) compensation and X-Y (exterior) compensation. I find that using these Quality:Precision settings usually requires several prints to get right and need to be repeated for each project and filament. Orca’s filament shrinkage factor seems to work better for multiple projects using the same filament.
i always use this one after i have tuned flow and pa
p*intables.c o m/model/683647-calibration/comments
It would still be interesting, how much the model is off relative to its size to rule out any defects.
I would recommend to choose a model for calibration, that uses inside and outside measurements, so that any deviations due to linewidth cancel out. this excellent video from CNC-Kitchen explains why: https://youtu.be/H7OsnMLDIMw?si=zSDVzIGjP2CMlPOt
He suggests to use the Califlower by Vector3D. It is a payed download unfortunately.
I have created my own model that also uses less material and uploaded it to makerworld, but I didn’t post the updated version yet. Anyway you can find the old version here: Another Shrinkage Compensation Model by Alex_vG - MakerWorld
What’s with the cryptic post? We aren’t sharing nuclear launch codes here? 
My client emailed me and said nine parts are off, they’re simple parts, but relatively large? I can get four on a build plate.
He sent me pictures but it’s hard to tell. Unfortunately I’m traveling so I won’t be able to look at them for about two weeks.
Honestly I’ve had a fair amount of issues with dimensional accuracy on this printer. I recently sold my Markforged because they discontinued it, but that was spot on every time to 0.1mm, crazy accurate.
I just need to be more on top of checking the dimensions.
As @JonRaymond pointed out. First start with dialing-in filament calibration to the best of your ability. Orca Slicer is better for this over Bambu Studio since it has calibration tools Bambu Studio does not have.
When it comes to calibration, there’s a lot of overthinking out there—probably a relic from the days when folks built their own machines and every aspect of the X,Y and Z coordinate system could be adjusted. But with Bambu, despite my critiques, the hardware precision is undeniably top-notch, and credit’s due where it’s due.
I’m someone who’s been accused of OCD, so trust me—I tried to “dial in” the perfect calibration early on. Forget those elaborate calibration models on Printables; you can get results faster and simpler on your own.
First, ask yourself why dimensional accuracy matters in your design and how precise you really need it to be. If it’s just for the satisfaction of hitting “11” on the dial (hello, Spinal Tap 
), here’s a quick guide to get you there.
The good news is that you really only have two parameters to adjust so it really narrows down your options which makes it simpler.
Remember, there is:
So ditch the fancy Printables models, and follow these straightforward steps:
Print, measure, and adjust as follows:
BTW: Did I mention to not overthink it? 
There are two parts of this story which don’t add up. Those are PLA and customer dimensionally accurate parts. If were doing this as a business, I’d never sign up for producing dimensionally accurate PLA parts. I’d insist on a tolerance spec or make one on my own and then I would specify only with a precision filament like PC or CF variants, I definitely would not sign up for a dimensional guarantee based on PLA.
If it’s for a client then going forward I would suggest that you require that they provide a toleranced drawing. Then you can print go/no go gauges (or they can provide) for the critical dimensions to check your parts. The tighter the dimensions they require the more the part should cost them.
No two spools of filament should be trusted, I’ve just recently scored a lovely bunch of ABS (brand I normally use) heavily discounted because they were defective. I’m using them for utility prints around the home and the first half spool was fine, the second was grinding the nozzle and giving me all sorts of ick print quality. Still ok in the grand scheme of things, the defects aren’t an issue but not for public use.
As a business level its different, you know a customer will complain no matter the price. Cheap out on material or design isn’t always profitable as one glitch will haunt you.
As above, calibration is going to help but don’t overthink it. Good habits like drying and calibrating don’t take long but will save you scrapping prints for minor blips like this.
I’ve not tried this, but did bookmark a recent post by @RocketSled:
Possibly this M290.2 code is being used by OrcaSlicer to provide shrinkage compensation for X-Y and Z?
I think, Orca simply rescales the objects accordingly before slicing.
In general, if a part deviates more than a few layers in Z direction like in the linked topic, something is wrong with the printer. It might be a modified parameter or something mechanical.
In X-Y each material shrinks a certain amount when cooling down. For PLA, I mostly measured values around 0.3 to 0.4 %. For PETG, it is more like 0.5%. Other materials like ABS or Nylon shrink even more. Materials with fibers typically shrink much less. If you see deviations of more than 1% for PLA, then I think there’s something wrong.
For really accurate parts, you should use Orca instead of BambuStudio because it allows compensation, measure the shrinking for each material you use and enter the value in a material profile.
Alternatively, in BambuStudio, you could manually rescale each model on X&Y according to the measured shrinking.
I wouldn’t mess with the printer configuration. That should only be used to correct the mechanics, not the material shrinking.
I don’t know what Markforged are doing to cancel shrinking. Maybe a default compensation is baked into the printer? Or they have included compensation in their slicer?
was not allowed to insert links, so i thought maybe other than Bambu is not allowed here. I saw it too often in other forums, that’s why i wrote it like this.
Ran into an issue with this the other day. Printed parts are about 99.5% height of expected. No problem when printing small objects, but if your model is 250mm, the shrinkage compensation will cause the slicer to think the model will exceed z height. Had to scale this in CAD, then import with no shrinkage value. Annoying workflow since it’s filament dependent and my CAD software doesn’t differentiate that way.