Warped bed :( seems like a common QC issue

WELL THEN!!!

That right there may be the ticket if you can access the screws without removing the OEM BL sticker on the aluminum. Shim between the aluminum and the base at the screws, or just remove the screws, add some thread sealant (or blue locktite) to the screw and then insert the screw and tighten until the deviation starts. IIRC there is another bed - Voron maybe that this is the procedure for getting the bed flat by adjusting the mounting screws.

I know there are pictures in this mile long thread of the build plate but I don’t have time in the mornings to research it.

Somebody try this please.

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Introducing FullMetal™ plate: which provides 8mm more metal than legacy Bambu PlasticSides plate :rofl:. I made a 256x256mm 1mm thick aluminum plate with holes for mounting screws (not traming screws which are now embedded inside) and glued it with epoxy glue to original hot plate while pre-tensioned on steel frame. Trying to make super thin glue layer I screwed up a bit. I run the heater to make glue more liquid and it worked well. The problem was that the moment it hardened while hot was very rapid while I was still moving it back and forth to get excess glue out. So I misaligned it by about 1mm on one side and somewhat screwed up flatness on one corner too which I later fixed by bending the plate in glued state and scraping the surface. Got it down to about 0.05mm flatness when cold and hot, it changes shape a little bit when heating but stays within this figure.Then when I put on Trianglelab magnetic sticker it screwed up flatness which became about 0.15mm along right edge and 0.1mm overall. This garbage is somewhat thicker along the edges. Also it’s 254.3x254.5m instead of claimed 255x255mm. Should have bought larger sticker and cut it myself. Still much better flatness than originally but I’m thinking about getting a different magnetic sticker. This construction is just 0.4mm higher than original bed, so build plate alignment ribs still work. Also as it’s lightweight there are no sensor warnings.
BTW Bambu sent me a new bed which should arrive in a few days.

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My replacement bed have arrived and it’s warped. It’s better than original one, but still far from perfect.
I’d like to measure it cold and heated, but I’d prefer to heat it up outside the printer, before even trying to replace it.
Have anyone tried to heat the bed by connecting mains power directly to the heating element? What is the power drawn from it? What is the duty cycle needed to keep it at let’s say 70-80 degC?
I measured it’s DC resistance, it’s around 51.6 Ohm. My DC PSU can give 30V, the bed takes about 0.58 A at that voltage, that’s too little power to warm it more than somewhere at human body temperature.

I ran it from autotransformer. Did not make exact experiments but I think it needed about 80-90V to keep it at such temperature after it reached it at higher voltage. This is equal to about 10% duty cycle if you run it from switched 230V. I don’t suggest running it from mains voltage for more than half a minute without interruption. It’s important to measure temperature to avoid overheating as there is 130°C thermal fuse. If you have ~120V version, divide voltages I wrote by 2.

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Good point, thanks for warning me, I didn’t know that.

I figured out my PSU has two truly independent outputs, so I can double the voltage by putting them in series, which makes 60V DC, that should deliver about 70W of heating power, I’ll try that before doing experiments with mains voltage.

Today I received a new V3 bed from Bambu. Same Banana garbage, 0.4 mm cave in X direction, mostly flat in Y direction except area near to calibration board. However I expect it to be much worse when hot but did not try running its heater yet. So I was right to not wait for Bambu and modding original bed with FullMetal™ plate. Printed a few things yesterday evening and today and results were simply godlike compared with printing on banana garbage.

Wow, I just checked bed flatness again on my modified plate, and stupid 0.1mm thicker edges on magnetic sticker have miraculously disappeared. So now bed is perfectly flat. No wonder my prints were flawless in this regard. :sunglasses:

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Hi all,
I have bought 2 Babmulab X1 Carbon Combo printers form the EU store (first one on 14.January.2023, second one received today).
Both of them have super flat beds - I don’t see any issues even when I shine light under the ruler (when heated up thay are perfectly fine too !)
Im 3d printing for over 10 years now and I have seen a lot of printers that had much worse heated bed flatness.
Even in my RAPTOR XLS 360 printer which I’ve built a few years ago the bed is not that flat across the whole surface when heated up (Heated bed was made from special and expensive CNC milled Gleich aluminium plates that have superior flatness across the whole surface - the cost of the alu plate was around 200$ and it is 8 mm thick ! )

See photos below:


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Good for you. BL must have put some leftover Kickstarter beds in yours. They then switched contractors and stiffed the rest of us with garbage banana beds, and now are doubling down.

Absolute garbage.

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But did you check flatness when hot? On mine bed was almost flat when cold but warped when heated.

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Yes I have heated both of them to 100 deg. C (I have waited for 10 min for temp to stabilize) and they are still flat :slight_smile:

EDIT:
Even the auto bed leveling is not correcting for any flatness issues - after calibration the Z axis is not moving at all when moving the X/Y axis across the bed :slight_smile:

Interresting MQTT seems to give ABL results :

Unforunatly I am more able to connect to MQTT using mosquitto_sub :confused:

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So I have disassembled my replacement bed and figured out that the warp is the matter of aluminium heating element only. Plastic wrapping is actually there only to cover electric parts, no other mechanical role, it’s soft and thin.
Aluminium plate is warped around 0.3mm in X and 0.1mm in Y.
I’m going to get new glass plate, this time it will be tempered glass 257x257x4mm with fillet edges and round corners (radius is 6mm). I’ll glue it directly on aluminium plate using neutral silicone in the corners and I’ll fill the gap between the glass and aluminium using thermal paste for better heat conductivity.
Then magnetic sticker and new PTFE coating, because I’m experiencing significant mechanical degradation when magnetic sticker is left unprotected.

Edges of magnetic rubber sit on plastic so plastic can easily lift them up. On mine it was both aluminum plate warping and plastic lifting the edges.

True, but the reason is the edges are not aligned with the aluminium bed. I will have to use some washers as underlay for the bed, so the glass doesn’t sit on plastic edges at all.
In my case the plastic edges are 0.2mm higher than heatbed, so I’ll use something about 0.3mm to get 0.1mm clearance.

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Or you file them down - like I did. The plastic is very soft and you need only a couple of minutes. But use a vac. while filing ^^ its a mess :rofl:

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i dont understand why they dont use 8mm MIC6 …??

Because it’s heavy, expensive and requires a separate heater rather than being just an aluminum PCB made in mass production process at PCB fab.

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“It’s within Spec” - 1.7mm off. Bambu better hope my next printer isn’t this jacked up. That’s a USA Quarter. This part is 128x73mm in size, printed in the middle of the bed.

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Hello everyone.

I think I earned myself a spot in the warped bed community. Seeing all the troubles you guys have getting your warped bed replaced, I’d like to ask a few questions if you’re kind enough to reply to those.

From left to right, and considering leads screws have a 8mm pitch, I can see the ABL trying to compensate around 1/8 of a turn very close to the edges. I can infer this translates to roughly 1 mm. Moreover, I can see that my prints are warped ; I’m going to print with ASA and this will cause an issue.

  • Should I try to open a ticket and get a replacement bed, or is the game not worth the candle as I may get a warped bed as well, and it will only get here in a few weeks? I have a V3 heatbed.
  • In the meantime, I’d like to go the “tape” way. Has anyone wrote a gcode to facilitate putting down tape and checking the results quickly? Do you have advices on this procedure? Any brands someone would like to recommend?
  • Any other alternatives?

I’d like to avoid goodplate as it’s causing the heatbed sensors to “overload” as some people have experienced.

Thanks.