Print Quality Issue, Overhangs, X1 Carbon, PLA

I tried that and it didn’t do anything for the overhang quality. I also tried dropping all the speeds down to 30mm/s, there was some improvement but then it’s so slow I may as well just use my Prusa, which has zero overhang issues. I think it’s something else. My best guess is the filament is too hot for overhangs but needs to be hot for the fast parts and/or the cooling fan/shroud isn’t up to the task.

So… :face_with_peeking_eye:
My issue has been resolved :partying_face:
Shout out to @BambuLab for getting back to me overnight.
I’m still testing and need a bit of time before I talk about it.
I understand that might be frustrating but before I make a lengthy post and recommendations I need to verify them.
I’m not here to give anyone bad advice.

Also @azCubs76, thank you for your settings! I know I didn’t share my results yet but they did help allot and I will be using them in the foreseeable future! Unfortunately they were not the “fix” BUT in real world they have a huge impact on model quality. 100% can recommend @azCubs76 settings, think of them as extra insurance lol Great job man! Thank you for sharing.

Chat soon everyone


Hey there, this seems pretty interesting. I will do some tests too. What I know right now is, that using 0.16 layer height will result in way better overhangs as lower heights, which should not be the case.

Maybe its because of the geometry or because the nozzle is made of steel which leads to colder extrusion. One of the problems could be the longer meltzone heating the material intensive while the nozzle itself is rapidly cooling down the filament… Im running another thread precised on cooling issues.

Also I’ve ordered an aftermarket nozzle. Its 2mm longer and I hope brass will conduct the heat more even. Lets test the hell out of the machine to eliminate this once and for all :slightly_smiling_face:

Ok, lets talk about it.

Quick recap:
I came to the forums seeking help with an issue I was having with overhangs and surface quality. I had multiple failed prints, the largest being the alien hand featured in my first post. I was using the default 0.12mm profile in Bambu Studio on my X1 Carbon with AMS, only changes made to the profile were to infill.
The issue presented in overhangs, blobbing, poor surface quality on the outer layers.
I knew this model was able to be printed without supports, I had printed it before but not on this machine.

My X1 Carbon had less then 100 hours of print time, was only a week old. When I purchased and setup the unit I followed the instruction and was up and printing within the hour. Great experience out of box aside from some frustrating issues with the AMS and cardboard spools. Carboard spools you say? Thats a topic for another thread :stuck_out_tongue_winking_eye: Lets keep on track.

Yes, my problem is solved. I have been running my X1 for over a day now and can confirm the issue is gone.
Well… its complicated.
I will outline the steps I took and the instructions bambu sent me. There were multiple “fixes” I performed and I did them all at once so i’m not exactly 100% sure which one caused the issue although I have my theories.

  1. Hardware
    Maintenance the machine.
    When I contacted bambu they immediately instructed me to perform maintenance on my carbon rods and belt tensioner. They provided me with a lengthy and somewhat intimidating guide for cleaning the rods and adjusting the belt tension on my unit.

Step 1: Use IPA to clean your carbon rods.
My rods were filthy, bambu instructed me to clean the rods until no more black was rubbing off on my paper towel.
To do this I first loosened my belt tensioner screws on the back of the unit, 2 on each side.
Remove the top glass then carefully move the tool head to the centre and begin cleaning.
Make sure to use allot of IPA, bambu instructed I move the tool head over the wet rods so the IPA could get inside and clean the bearings. Don’t spray the toolhead, only the rods, be patient and let the IPA work slowly. I found soaking my paper towel was better then spraying, That was the method I used.
It took about 5 minutes, multiple paper towels until my towel remained clean.

Step 2: Belts
This one was tricky, the instructions bambu sent me were a little intimidating but once I took a moment to poke around back there I figured it out quickly. I’m mechanically inclined, im comfortable tinkering so this part went smooth for me. Before I loosed the bolts in step 1 I did check my belts, Y was allot looser then X but regardless both were way too loose.
The way I did was using a bed scraper to apply even pressure to the little tabs.

Instead of writing my own instructions Ill post what bambu sent me, to keep things consistent.

Here is a snip from out conversion.

1.Make sure the belt tensioners work as seen in the first 30 seconds in the video, after loosening the screws and turning the power off.

2: If the functionality of the belts is like in the video, not only clean the rods but make sure that the IPA will reach the bearings in the tool head by moving it over the IPA repeatedly. After this, clean the rods make them wet with IPA again, and move the Tool Head over the IPA and clean the rods again. Continue to do this until there is no more black residue. At that point, you are sure the bearings are clean and the self-lubricating function works.

3: Please move the gantry fully backwards and keep pushing the gantry to the back while re-tensioning the tensioners screws

Step 3:
This one was interesting. Previously I had my printers on a shelf build to save space. It wasn’t the most ridged shelf neither. The X1 is allot heavier then my previous printers and accelerations throw them around like crazy, creating allot of vibrations and flexing of the shelf. This is bad for 3d printers, the x1 likes a solid surface.
I know many of us struggle with space, its not easy to find a rock solid surface to put your printer. But… its kind of a must with these machines.
I spent the next hour or two back and forth in the shop cutting wood and reinforcing my self. By the end of it i could stand on them lol solid as a rock.
I see allot of people buying cheap walmart end tables or maybe ikea, these are not strong or stable enough for the x1. Now since were bordering opinions here ill leave surface topic at that, this is just what i did, you do you.

Step 4
Once your printer is back in its place, all hooked back up its time to calibrate it. Dont skip this step, the cleaning of the rods and re-tensioning of the belts changes how the printer mechanic behave with eachother, they need to be recalibrated.
To do this on you x1, using the printer screen go to Settings-Utilities-Calibration and ensure all 3 boxes are checked then hit strat calibration.
At this point walk away. Dont touch, dont open the door, dont lean on your wobbly table :crazy_face:
You get the drift.

And that’s it for hardware.
Personally, I think this issue was a hardware issue. My rods were dirty, my belts were loose, my shelf was wobbly. The combination of all 3 caused my poor quality print surface and overhang issues. Below ill post my results.

These are very acceptable prints, fantastic quality at full speed, default profiles. Exactly as I expected.

I spoke to bambu about my results, I believe this happened because like most new users I expected the printer to be fully calibrated and ready to go out of box. With under 100 print hours it was obvious to me the printer should of been inspected before I began using it. I suggested bambu change their setup guide to include the rod cleaning and belt tensioning in the initial setup faze. Yes its not as sexy as “yank it outa the box, plug it in and go” but it could of saved me allot of time AND taught me how to maintain my machine for the future right outa the box. This is important knowledge, your going to do this allot through the life of your printer. I don’t think this is a quality control issue on bambu side. My printer worked fine for the first couple days of printing. This isn’t something they would of caught in QC, and who knows what kind of journey my printer took across the ocean to my doorstep. In short, bambu if your listening please consider instructing new users to perform these tasks upon initial setup. Much love :kissing_heart:

Now… Im not done yet lol

  1. Software
    During my experiments trying to correct the issue in software I learned allot about the slicer.

Step 1
Downgrade Bambu Studio to
Yes, beta means broken. Never rely on beta software, never, never, always treat it as a test and expect it to fail.
I knew this… lol and stupidly ignored my own advice. Throughout allot of my testing I was using bambu latest build of bambu studio known as softfevers build and it is NOT ready for prime time lol
Sorry new P1S users, remember this thread is about the X1, I know you don’t have an option right now. I’m sure bambu will fix this as soon as they can.

So whats the problem in the latest bambu studio build?
No clue.
I noticed they changed the default profiles around for the x1, mainly the Arachne wall generator.
Im not going to get too deep into this, maybe switching it back to classic solves the surface quality issue, maybe it makes it worse. Just dont use beta software… lol Thats my answer. If your relying on this printer for commercial use, let others who are just playing around be the guinea pigs, stick with the basics.

Step 2: Don’t over-complicate your profiles.
Bambu develops and provides the default profiles for a reason. They work. Years of testing went into these machines and its safe to say the engineers over at bambu know best. Listen to them.
Don’t get me wrong tho, tweaking profiles is great as seen in the example from @azCubs76 and his custom overhang speed settings. I’m now using these settings in my default profiles, the theory to them and why they make sense + verifying = great success. Thanks again for your input!
It comes down to experience and the type of models and materials your printing.

I spoke about temperature, speed in a previous post.
Looking back at that now… I kind of regret bringing it up. I tend to think and overthink out loud lol circling back why would bambu include the speeds and temperatures they do in their default profiles if they were bad. No the x1 speed is not a party trick, it can and does print at its advertised speeds just fine.
If your really really concerned about filament temperatures I would first check with your filament manufacturer or better yet check your spool and see what they recommend as the max temp, most of my PLA suggests a print temp of 190-220c.
The generic PLA profile is within that range, and im leaving mine at the default 220c.
The test prints or results i posted above were all printed at 220c, standard mode, no tweaking to the profiles. Results speak for themselves.

Final thoughts.
Here we are, at the end of my crazy long post. I now have a working X1 that producing amazing prints in record time and I couldn’t be happier.
I hope this post helps anyone reading it. Never assume, verify! Be diligent, dont rush and enjoy it for what it is.
Please note that while these steps corrected my issue, it doesn’t mean it’ll correct yours. Reach out to bambu if the steps above don’t solve your issue, be polite and provide them with as much information as you can. Include a link to this threat, explain you tried all the steps listed and still have poor results. They can guide you forward.
Remember this post was never about getting perfect overhangs to 80% and above. I have been 3d printing for many years and most printers can achieve similar to the x1. Its the name of the game, use supports when needed, assume supports are probably needed and you’ll do fine. Allot of it comes from experience, trial and error. Years later im still learning and so will you.

Good luck everyone! I hoped this help. See you in the next tread :thinking:


Pretty nice to know, but thats not acceptable for my wish of getting 70° degree overhangs like on a V400. :grinning:

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Ive made some progress. Look at this link to stay updated.

65° clean with standart 0.12 settings are possible. Reducing the temp and go slower and/or using aux fan will give even better results.

I will upload the file soon.

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Taking a look at your print, my X1C can produce that same print almost flawless using the default 0.2mm layer height. I believe I posted pictures. Regardless. Your machine has an issue. I already outlined in great detail what those issues are possibly. Did you try to tighten your belts? Or clean your carbon rods? Make sure your printer is on a rock solid surface? And if you did then you need to reach out to Bambu. Add a link to this forum and politely tell them the tasks you’ve performed. They can assist you further. The model your printing is a stress test. It will never print perfect, that’s the whole point of the model. Even my x1c has ugly under hangs because it’s literally printing in mid air. No printer can print in mid air. I wasn’t even going to comment because of your last post claiming your other printer can do better… honestly that’s not what these forums are for, if you want to compare one to another make a different threat. This threat is here to help people who had the issue I had. My issue is fixed and so can your be if you just follow the guide. And if you have then you need to reach out to Bambu. Playing with slicer settings, speed, fan speed. It’s just an unnecessary rabbit hole. The default profiles are some of the best profiles made by the engineers who built the printer. Most people shouldn’t muck with them, they should be a base and modified slightly per model as needed but only if needed.
I hope that helps. This isn’t the threat for bad cooling theories. In fact I think the x1 has some of the best cooling out there. The aux fan works great. Most of the material I print “petg” I don’t even use cooling, or very little. Again it works just fine.

Instead of throwing this big text at me, you should have read mine thread … Nevermind I wont argue under such circumstances :wave:

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Your post was off topic, and I have flagged it as such.
I have seen your thread and I am not interested.
I have nothing against you, I wish you all the best.

Note: This topic has been solved

Only reply here if:

  • You have additional details
  • The solution doesn’t work for you

If you have an unrelated issue, please [start a new topic] (Bambu Lab Community Forum) instead.

Might be related to this one

From time to time have been having issues with overhangs but never critical but worse than Prusa and today 3dsurfr reported an issue and tried to check it on my machine from curiosity and yes it is an issue and finally discovered what is the actual problem slicing . Googled and found this thread
Have found a couple of work arounds but not happy with the solutions . Changing the layer height on some models helps , but working with 0.2 is the common , I know that 0.12 and 0.08 most of the time solves it , also orca slicer has a nice feature as well which i think works always

Any one found a solution of the slicing in the air when the angle is above 65degress some times less with 0.2 layer height ?

My temperature profiles and filaments are very well tunned , so not related to fan, temperature for filament tuning , and pretty sure that 3dsurfr is an expert in that area as well.

Didnt adjust a single setting for these. My overhangs sucked before the dual fan. Also very dry and calibrated filament.Notice the last pic is better on the right side thn the left. The duct that the guy designed for the right side has a better spread. Covers the whole build plate. The first pic shows bridging across nearly the whole build surface.Both were printed fast.
I also have real filtration for asa and abs now. Just ran a switch to the original aux fan so it can be turned off while using the bento box on the right.

Not sure where the fuzzies came from. This pink pla does it to me every time. And only the pink.


Do you have a link for that last test model?

If you read below on that link, he has a couple other interesting overhang tests linked


Good news your printer is working.
But i don’t understand people using high tech printers which need accelerometer Sensors for movement compensation, and put it on a wobbly stand.
My printer was placed on the ground. I never received problems like this even using default profiles and bambu materials. After printing several thousand of hours pla, petg, and cf materials i didn’t cleaned the rods or adjusted belt tension. I plan to do now thanks for the good explanation.

I bet your problem 100% based on wobbly table.

Hi I have come across your post i am new to the 3d printing world and having the same issues as yourself so frustrating I don’t have any cleaning alcohol on my so I have ordered some, in time being I have done the belts like you I had a spare 0.4 nozzle changed that too done a calibration and still having issues from the 50* mark going to clean the rods once the alcohol turns up if no luck will have to contact Bambu directly.

it prints flat objects fine try to print one of the usb cable tidy spools and it has failed 3 times on the hangover grrrr…

im a total noob, just got my 3d printer 2 days ago… i also think i ran into this issue…whole print is fine just the bottom parts are horrible… i tried with a couple different support styles and they all didnt helped… it tried 0,08 layer height and 1,5 and 2 …still all the same…

i think i might try cleaning it but i doubt this will fix it… i think the wobble on my desk may be a bigger factor… i will stand it on the floor so its totally fixed, for a test print…

ok i have been checking out the printer and most of my prints work out perfect…
only things i cant manage to get right , with or without support are the overhangs…

idk i saw mutliple pics and videos online with perfect overhangs…
i get the feeling its not my fault!!!

i probably printed this figure about 20 times… tried everythign possible and alwas get similiar results… i start to belive something in the printer isnt straight! maybe something warped from shipping…

Overhang capability is theoretically only a function of layer width to layer height ratio, but in reality many other factors affect it: temperature/cooling, speed, outer/inner wall order, filament type/brand/humidity - you name it. That head and cap visor doesn’t look trivial to print without supports but it’s hard to judge from the pictures. Is that a free model somewhere that we could look at to judge it? What filament and presets are you using?

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hi thanks for the answer, i tried everything u named… best result was with 0,08 layer height and very slow and all fans on 100…
but still looked bad… allso supports dident helped tried a ton of variations… with petg, etc…

i have a similar model i had the same problem… i basically have them on all overhangs…
if u want u can cut the boddie then u just have the head and it s faster for testing.

  • dont mind there are no supoprts on the colar thats my fault lol…
    but i would be happy if the head /chin at least would be smooth

So your problems are basically with supports, as opposed to unsupported overhangs? Did you do any kind of calibration of your filament?