Bambulab P1S - Printing issues

Hi there,

So, I’ll get right to it. My prints are just not adhering to the bed. No matter what I try, it just doesn’t want to stick. The filament just balls up when the hotend is heating and ends up curling onto the nozzle and, as the hotend travels it just pulls it all up with it.

Filaments tested -

  • Raise3D Hyperspeed PLA 1.75mm
  • Bambu Official PLA 1.75mm
  • Overture Rock PLA 1.75mm (This is the main one I need to use)
  • Elegoo PLA 1.75mm
  • Generic HS Filament 1.75mm
  • PolyMaker PLA / PETG

Printer Information

  • Nozzle 0.4mm (Standard)
  • Tested with PEI and Cool Plate (Issue present on both)
  • Bambu P1S (Door open and closed attempted, same issue)

Things I’ve tried -

  1. I’ve levelled the bed according to the wiki.
  2. I’ve changed filament.
  3. All my filaments are dry as they’re kept in a drying and storage container (it’s like an oven type deal from Smart3D)
  4. This happens regardless if I print fast, slow or medium.
  5. I’ve attempted printing on each corner of the bed and of course central, but same issue occurs.
  6. I’ve attempted downgrading the firmware, same issue.
  7. Washed the bed thoroughly to remove any contaminant(s)
  8. Tried new SD Card (works on other printers no issue)
  9. Tried new version of Bambulab Studio, no change.
  10. Moved the printer closer to WiFi connection (no change).
  11. Tried on PC and Mobile app. Same issue.
  12. Room temperature is standard 22 degrees, as per normal. Until the last days, the printer was working great.

I’m at my wits end, I’ve got a job that needs almost 33 hours total time and, I’ve spent the best part of 2 days trying to resolve this issue. If I lose this client, it’s a big chunk of monthly income gone. Can anyone provide any possible things to try?

Thanks in advance!

General question asking stuff but you don’t say how you washed the build plate - could be important. If you don’t give details but are doing something wrong, saying you cleaned the build plate may cause some to discount build plate cleaning issues as a potential cause.

I’ve been doing a deep dive on filament drying and at least the Sunlu S2 I’ve been using is multiple shades of ineffective and hasn’t dried my filament at all so far. In fact it has added water to the filament. Much depends on the ambient humidity and the humidity you hit in your dry box with the filament in it. What humidity level is in your drybox? If you have a new roll of filament, you could try that if you haven’t already.

“Wet” filament can have issues sticking. Build plate temperature can matter. Are you using glue stick or glue to help adhesion and release? How you clean the build plate can matter. Filament should exit the nozzle cleanly and not curl up. Curling can be a sign of clogs or baked on filament grabbing and pulling the filament stream off to the side.

Photos can also help. Show what the defects look like and what your print head curl looks like. It all helps. Good luck!

1 Like

So I have a bunch of the “smooth” plates, which normally work great - for one of them I tested washing with just warm-ish water and a lint free cloth. No cleaning agent. Dried using a lint-free cloth and let sit for a couple hours in a dust free environment with a constant room humidity of about 15-20 percent. Temperature in this room is constant 22, never changes as I have air conditioning (along with dehumidifying).

The drybox is from Smart3D and claims to have filament dried completely and ready for use within 3 hours. Though my filaments essentially live in this thing and are usually dried for about a full day before use and, well, they’re bone dry. On all my other machines (Raise3D, Elegoo and so on) these rolls operate absolutely flawlessly. It seems to be only on the Bambu ones that have this issue present.

I have attempted printing with a brand new out of the bag roll too, and still, the same issue is present. I am really unsure what is causing this. The environment I print is and has no issue for other machines, and the Bambu even has an enclosure and normally prints absolutely flawlessly.

Sadly, I cannot provide images for NDA reasons.

Searching for an image - the issue is almost identical to this - though, without any layers adhered, just the “blobbing” part usually stuck on the nozzle itself. Note also the plate I’m using is not PEI but rather the smooth one.

Wash using plain dish soap and warm water. You need something that will cut finger oils and other residues. I dry with plain white paper towels. You don’t want to use anything that could have its own lotion or moisturizing oils. Just plain white paper towels to dry. Then handle outside the printing area.

You didn’t mention anything about glue. The Bambu cold plate seems to love glue stick. Others use liquid glue on the textured PEI plate. Not sure but I’d bet the smooth PEI as well. On PEI you can increase the bed temperature a little to help with adhesion.

You don’t give humidity numbers but bone dry could be anything as I’m betting you don’t mean 0% relative humidity. If you aren’t measuring the humidity in the dry box it really could be anything. If you are using desiccant, the filament is also a desiccant of sorts and a “dry box” can actually add water to the filament instead of remove it. It’s an equilibrium process if you are using desiccant that can be regenerated. Without RH% numbers you are flying blind.

As to NDA, unless you work in a facility that doesn’t allow cameras, photos of your nozzle could reveal issues with stuck filament that might be a cause. You can also print a non-NDA part to troubleshoot since this is bed adhesion. The issue should present itself right away or not.

And last, it could be the slicer. When positioning a part in Studio, if you don’t happen to put a face square down on the build plate but instead get it at a slight angle, that can also cause plate adhesion issues.


Thinking soap and water along with recalibration.

1 Like

As for washing, I have also used dish soap as a test and it’s also present. I’ve also washed with iso, and PLM to see if there is a difference. There is none in the resulting issue. The “blob” still occurs and “flakes up” on the bed.

As for glue, I’ve not used glue since I’ve printed almost 2,500 parts in the past 3 months and not needed any extra adhesives - this is the first time this has occurred, specifically with this machine.

As for the drybox, this is the information provided on the manufacturers site -

Internal humidity is going to be of course lower than external, and the room itself is extremely dry overall. We don’t even bring in bottled water or open drink containers to ensure there is no possibility of excessive moisture. (This room is also housing numerous resin machines and facilities). Though they’re about 15m away in the opposite direction in a glass walled container.

We’re printing in lab like conditions with very strict measures on humidity and regulation of such things. I’ve mentioned the humidity earlier, and inside the box - when it’s running, it’s pretty warm inside and as stated prior, it dries in under 3 hours. But we let the rolls sit for a lot longer before using for those “just in case” moments.

As for NDA, no devices are permitted with cameras on the inside of the working environment.

As for slicing, the part is angled correctly and prints on other machines just fine. I would print it on another machine but, since our client requested we use specifically this machine for the layer height (since the others are all dialed in and rolling out almost 10,000 parts for this quarter), I’m unable to use anything else.

I will try drying the filament again and see if that resolves it. If it doesn’t, I will just stop using the Bambu and resort to something else since I am losing a lot of time here. Apologies if my comments come off harsh, I’m trying my hardest to get this thing to just print and it’s becoming more and more of a hassle than anything else.

Maybe layer height is part of the issue. Maybe try reprinting something that used to work to see if it still does. If so maybe it is something with this print.

Maybe someone else can help you.

I would try literally any print - but the first layer is the main issue here, it just doesn’t stick at all. It performs the “line wipe” and then the hotend sits at the back of the printer for about 20 seconds before starting the print itself, in this time - filament has gone and curled up onto the nozzle - by the time the nozzle touches down - it “blobs” onto the bed and pulls everything it previously attempted to lay down along with it.

I’m really unsure what the issue is, perhaps it’s a bad batch of filament? But it works on other machines with no issue. In either case, I’m going to dry it for a further 3 hours and check back. I really can’t think of what else it could be.

Thanks for your input either way :wink:

Issue has been found…

Heating the nozzle, poking it with the acupuncture needle set something inside of the nozzle free, it looks metallic/hard so I think this might have been the cause. I will try to print now and see if there is any issue present.

Fingers crossed.


I’ll say this.

I appreciate the time you put in to trying to help. I’m stressed and, taking it out on you is not called for. I do sincerely mean that.

I am going to continue trying to find a resolution here, I’m on the verge of breaking down mentally as I’m now at the building over 14 hours today alone and I cannot figure this out. If you do wish to continue helping me, I’d be forever grateful - if not, I’d totally understand given my previous behavior here.



Since this is a production printer, if it has any high temperature filament left in the print head it can cause stringing. If that could be an issue do a cold pull. It’s in the Bambu wiki but simple to do.

If you print something else that worked before and it works now using the same build plate and filament, you can probably eliminate the printer and filament.

You said this print was on this printer because the client wanted thin layers. Thin layers can have issues with adhesion. You could try printing with thicker layers and see if that changes behavior. Since it’s build plate adhesion you can stop as soon as you decide if you made a change that helped or not. If it’s the issue I believe you can set up the first layer different from the rest of the model so almost all of it could still have the thin layers.

Sometimes it’s not actually build plate adhesion but instead an overhang causing issues. If edges have fillets instead of chamfers, it could be the strands don’t have enough overlap with the previous layer to stick well. One recent user thought they were seeing 1st layer adhesion issues but it was 2nd layer overhang.

Sometimes on concave curves the tension on the filament can pull it back off the previous layer or the build plate. Not much experience with that but maybe higher extrusion temperature. Brims can also help anchor the first layer.

Upping temperature 2-5C on PEI build plates can help with adhesion. Glues are as much for separation as they are for adhesion. If there isn’t a reason to not use glue, it could possibly help. I get using textured PEI but if using PLA, why not use the cold plate instead of smooth PEI?

The Bambu cold plate works great for me but I use glue stick. Things stick great during the print but separate easily after.

We’ve had discussions here of build plate temperature issues. At least one person made a thermal image of their build plate and for whatever reason had a cold area in their build plate that was causing them adhesion issues directly over it. If you have access to a thermal imager you can see if your build plate is more uniform. I checked mine and had about 2C variation from center to edge. Their variation was much bigger and the cold spot was obvious. Bambu is replacing it under warranty for them.

I don’t know how common for Bambu printers but some use tape or a spray of hairspray to help hold/release models. Those would be other things you can try if you can’t find a root cause.

I would do what I could to narrow the cause down. Printing something simple with the filament would let you start being able to say what is good and narrow down what is left to test. Tests should be fairly quick since you really only need to get past the first layer at least at first.

Thanks for replying,

So I managed to get one layer to sort of go down - it’s a HUGE improvement over before - I also managed to sneak a picture of the print, with nothing visible so… There’s that.

I’m now seeing “some” adhesion, which is better - to achieve this I tried a freshly washed bed with dish soap, dried the filament for a further 6 hours and a very light coating of 3DLac spray.

So bed adhesion was improved greatly with the help of adhesives, and increasing the layer thickness. The print image shown is a non-NDA print, so it’s fine to show it.

I think it’s the right direction - and I’m thankful as hell that you’re still replying here.

I tried in the meantime another filament - but sadly had the same result.

Edit - the finger printing in the middle is from me just now before taking the picture.

I’m out of my experience so this may be bad advice but it looks like maybe the filament isn’t pulling back like it should or as much as it should leading to that stringing. There’s a setting for retraction in the setup in Studio. The problem is those strings harden up and then the print nozzle can hit them and break the model loose.

But with the photos others may be able to help more.

One last thing is it’s looking close to printing properly with whatever you’ve done to now. There is another way to get rid of those strands but it introduces its own issues. If you pause the print the print head will go park and you can go in with edge nippers/cutters (wire cutters with a flat ground side that let you cut with essentially zero clearance) and gently trim those back to get rid of the bumps. You have to be careful because any torque on the cutters can also lift up the layer and you’ll be cramped by close quarters as you do it. You can lower the build plate to get better access but if you do that, maybe just use the big steps (easier to count to put the build plate back exactly where it was before resuming). I sometimes get tiny versions of those strands and cutting them away lets the print continue and has saved some for me.

I don’t know if the printer automatically returns the bed where printing was paused or not. I may not have ever lowered and returned the bed. I have managed to get my hands in the printer to cut those strands without lowering the bed and usually do that.

The problem comes in that while you’re doing all that the print head is hot and some filament may ooze out. It tries to knock any extrusion off but may drag a bit with a fine strand across the print. I have canned air to try to blow those kinds of things away but it can possibly ruin the print while saving it if it gets dragged into the print. It could be just before you resume you can manually knock or pull whatever has dripped from the print head while parked.

I think that’s everything I know. Hopefully someone else recognizes the stringing issue and has some other tips.

1 Like

I increased retraction and set the travel speed a little higher and now it’s printing flawlessly.



I think you may still have a number of issues but glad you are getting a good start on a new print.

The curling of filament as it exits the nozzle still points to some kind of nozzle issue - old higher temp filament still stringing out or burnt filament on the nozzle surface. It could even be wearing out. Abrasive filaments can slowly eat out the inner surface and cause print issues. It could be you need a new (hardened?) nozzle or hot end assembly depending on what is actually causing it?

PEI is normally pretty good about holding prints down while printing but has issues with oils and maybe even plastic deposits from previous prints. Depending on what (if anything) is happening with the build plates, dish soap cuts a lot of oils. Isopropyl alcohol has its own issues but can help with deposits. You can use IPA but you need to make sure to flood away the contaminated IPA or you risk just moving contaminants around. Increasing build plate temperature helps PEI hold onto prints. If it works too well and the print gets difficult to remove, some report models popping off after putting plate and model in a freezer for a bit to use the different thermal expansion to stress the interface.

Some have mentioned using stronger solvents here so might want to search back and see what they are saying. IIRC it was acetone to rejuvenate the PEI surface but don’t do it unless you find and verify what they were talking about or someone else remembers and mentions it. Some solvents will probably destroy the PEI surface.

It may not have anything to do with the issues you are seeing with stringing, but moisture in filament can cause that. I know you said things were dry but I’ve personally seen water/oil traps in air lines not properly maintained and completely full. No idea what your setup looks like but what it should be and what it is might need a spot check just to make sure all is ok.

There was an issue with some filament Bambu was shipping where new filament fresh from desiccated bags was carrying excess water and causing print issues. You are apparently using some kind of special filament for this IIRC and if it sat for a while before you got it, or if it was manufactured under less than ideal conditions, maybe it is part of the issue still even though you are able to compensate.

These kinds of problems can be difficult to all get sorted but plate adhesion on PEI has only been an issue so far when I’ve used “wet” filament. Normally it all works fine for me but I use mostly PLA while branching into some ASA. My experience is fairly limited.

Very glad extra retraction got you past the stringing though.

Hey there,

So now it’s adhering to the plate - but I’m seeing this happening now -

I am not sure what is causing this, it does absolutely look like moisture present… Should I just abandon this roll and use some alternate? I’m so close, yet so far.

Have you tried cleaning your nozzle or changed the nozzle for a new nozzle? You may have some residue build up in your nozzle and their is also another possibility, if you have many prints with this nozzle in place the thermal paste between the heat pad and nozzle could of gone hard and is no longer heating your nozzle consistently. You can check this after doing a hot pull on your nozzle, remove the nozzle and disconnect the heat pad from the nozzle, clean it down properly and put some new heat paste prior to re-assemble. This procedures for the hot pull and removing of the heat pad are all in the Bambu Lab Wiki.

I don’t know what causes that and sometimes get that too. Subsequent layers tend to cover that kind of thing up but it still can leave scars. Might be moisture in the filament but I can’t say for sure.

If you haven’t got it sorted yet I’d suggest reposting the last images as a new thread. The problem is now different so you’ll get more eyes if you start fresh. Hopefully someone has some suggestions. I’d be interested too.

I’ve never had luck printing PLA with the bed temp at 35. I increased my bed temp to 55 and haven’t had any problems since.

1 Like