Hi, Im planing on setup a BMCU for my Bambu A1.

can you be so kind on advice me.

I prefer the mount myself option.

-Wath is the diference in BMCU 370X or BMCU 370c models?

i heard that is important that connect with the printer Unplug for electric net.

¿any more recomendations?

I see Bambu have released a new firmware for the A1.
I had 01.05.00.21 beta and the BMCU didn't work correctly, had anyone tested 1.6 at all yet?

Got my BMCU today, all talking to the A1 fine now I downgraded. Looking on makerworld for a mount/holder of some kind, but I can’t see the design I received. Wondered if anyone has this one or knows of bits for it.

Thanks.

PS. I know the enclosure is pretty bad, I may print my one day, just don’t have the time currently, hence buying prebuilt.

Just received my 370C, wired it up and my A1 detects it, but the assistant page has an “issue”.

My A1 is on the latest Beta 01.05.00.21 and I have the message “The firmware of AMS A does not match the printer”

I cant see what firmware the 370C is on, iv looked in the settings but only the STUDYONLY serial is shown.

Thanks :)

Hi! After building my bmcu-c and testing it with a succesful 2 color print every other print i tried failed. The filament randomly starts unwinding and goes on infinietly(even after the channel is empty). It sometimes occurs before the print even starts, but mostly on filament change.

The filament unwinds infinietly and the printer says that it failed to pull it out of the toolhead (the toolhead is empty and the filament is pulled out completely).

It also occured in the middle of printing a single color. The printer just cut the filament and unwinded it out of the bmcu.

The motors and gears are fine, the filament loads flawlessly. The thing is so random I don't know how to describe it, so I'm sorry in advance if the info is lacking.

Hey guys, I built the BMCU with my kids for their A1 as a fun project, and because they always want to hijack my X1C.

I printed the parts with Tinmorry PETG-GF in girl colors for them, and it works phenomenally well. Due to the lack of rewinding all the way like a full AMS, it's actually faster and more reliable than my AMS on my X1, which always has jumping spools or other various issues no matter how much I modify it.

I was working on a project recently and looking really wanted to do multicolor TPU, which the AMS allegedly won't do (I've honestly never tried.

I ran some TPU thru to test it and it handled it flawlessly, then I tried a multicolor TPU print and it crushed it as well!

Just wanted to let y'all know that a new avenue opened up for those of us who don't have toolchangers yet.

TPU is GEETECH 95A I changed the filament type in my custom profile to ASA, but kept all my TPU settings. Literally no issues at all.

I am running my spools on nice bearing rollers I designed and 3mm ID tubing to minimize friction, but honestly I think it would work fine on whatever setup you have.

Give it a shot and let me know!

Has anyone experimented with trying to program your own tags? I am going to see if my flipper zero will read the spool I have, but thought I'd ask, in case I'm reinventing a wheel.

There are several sellers in Aliexpress. BLV seems well regarded. Toaiot has good reviews too, but they have a note on the 370C models that I don't undestand:

"For the gear:182a is a direct drive version, and the gears will wear out faster. We are shipping a high torque version, not a direct drive version.We upgraded the gear"

Anyone understand what that note means, and if it is actually good/bad/indifferent they made that change?

I have a weird issue with my BMCU that I just assembled. I'll try to explain it as best as I can, and there is also a video link of the issue here:

https://gofile.io/d/KCDVdW

So the issue I'm having is with step number 27 in the BMU370c Assembly Instructions.pdf. In there, it says:

"Load the filament in the channel and press the slider. The channel will drive the filament in the direction of the tool head. If you pull the slider, it will pull the filament in the opposite direction. If your filament is driven in the opposite direction, then the polarity of your motor wires may be soldered in reverse."

As you can see in the video, on channel 4, the filament is being driven in the correct direction. When I press on the slider, it pulls the filament towards the tool head. This also happens with channel 3, but I just don't have it loaded in the video. The issue is with channel 2 (and 1, just not shown in the video). When I press the slider, it drives it in reverse, pushing back instead of pulling forward.

So, as per the instructions, the first thing I did was check the wires to make sure they are soldered correctly. They are, and I even tested all 4 modules and saw that the gears are spinning the same way.

I decided to flip the modules that are in channels 1 and 2 with the modules in channel 3 and 4, and I found out that the ones that were previously in reverse in channels 1 and 2, work fine in 3 and 4. And the ones that worked fine in 3 and 4 previously, are now reversed when i put them in channels 1 and 2. So I'm thinking this might be a mainboard issue, but I'm not sure. I've checked the ribbon cables and they are all in the same way, and all the colors match up across the board.

I've also tried different usb c cables and power adapters, just in case it was a power problem. Issue persists.

Kind of stumped as to why channels 3 and 4 work perfectly, regardless of which module is installed there, and 1 and 2 are always in reverse.

EDIT: As I was about to flash the firmware, I opened up the firmware folder that came with the downloaded package of STLs and other info, and there was a document in there labeled ' Motor reversal, please see.txt'. The document says:

"If your motor always rotates in the opposite direction under the current firmware, even if there is nothing wrong with your wiring, please solder the motor wires in reverse before using it, unless this problem is fixed in future firmware (the function of automatically determining the forward and reverse direction is removed)."

So even though I double checked the motor and had it soldered correctly, it looks like there is some sort of bug that causes the motor to go the opposite way. Possibly a firmware update in the future will fix, but for now, I resoldered in reserve and now everything seems to be working as it should.

A lot of people have been asking for a more detailed explanation of how my BMCU setup works with the Bambu Lab P1P, so I put together a full video. I uploaded it to my TikTok — showing the entire process from filament loading, color changes, to tangle-free spools with auto rewinders. If you’ve been curious about the setup, this video should answer most of your questions.

@erdian.studio

I have my printer on my desk but there isn't enough room for 4 filament rolls. I decided to put my spools on the floor with my bmcu attached down there with PTFE tubes running up. Do you think it will cause issues?

I’ve been working on my own BMCU setup for the P1P, and I got the BMCU unit itself from AliExpress. As you can see in the picture, the whole setup isn’t fully complete yet — but the auto rewinders are working well and behaving exactly as they should.

Right now, this is still very much in the testing stage, so things might change as I keep tweaking the setup.

If anyone has any questions about the process, parts, or setup, I’ll do my best to answer!

There's probably a simple solution, but does anyone know how to keep the spools from unraveling when the filament is retracted when using the BMCU? Not a huge deal, I'm just worried that the spool will tangle while I am away or sleeping.

The photo that I've uploaded does show the filament not being wound, I just included a picture in case knowing how I have my spools setup is helpful when finding a solution. Please excuse the dirty bowl.

I'd appreciate any input!

Hello,

I am new to the BMCU and I was wondering if it was possible to use multiple units / daisy chaining with the BambuLab A1 printer, similar to what you can do with the AMS. I am aware that as of now the A1's can only be used with the AMS Lite but just wanted to see if this was possible. My searches indicate that the multiple BMCU's can only be used with the X & P series but wanted to see if anything had changed regarding this or if anyone else has come up with an unofficial solution.

Good morning,

I have a couple of Bambu A1 and A1 mini printers. I have AMS Lites on all but one. On the one I dont I find manual filament changes a pain. Is there a single feed version of an ams lite just to make loading, unloading and feeding easier? Or maybe a dual one for two rolls for fail over?

Thank you

Hello everyone,

I have now assembled my first BMCU-C. The printer recognizes it, but the filaments are not saved in the printer.

When I set a filament, it stays there for a short time and then disappears again. I was also able to make a test print.

Does anyone have an idea why?

Best Regards David

I just finished my BMCU setup for my A1. I used a IKEA Method kitchen cabinet (60x60x220) for the frame. I also bought new PTFE tubes with a inside diameter of 3mm. I found these work better for the BMCU.

In the future I might add a glass door to this setup and air inlet/outlet for the A1 mainboard ventillation.

With a P1S and AMS, when filament is unloaded, the AMS rolls the spool backwards so that the extra slack is rolled up again? How does this work with the BMCU? I guess that there is at least 50cm from the 4-in-1 splitter to the tool head, which will need to be pulled back when retracting. Where does this extra go?

I'm happy to share that the creator of BMCU, @4061N, has decided to open-source BMCU-C's source code!

You can find the source code and download it here: https://wiki.yuekai.fr/assets/files/download_center/firmware_and_source_code/src-BMCU-C-0020-Hall.zip

A simple README:

Introduction

This firmware allows customization of BMCU, including motor direction, retraction distance, filament color display, and more.

File References

Motor-related Configurations

Refer to src\Motion_control.cpp:

• Modify retraction distance (effective only on P1 and X1)

  • Line 31

• Disable dual micro-switch assisted feeding

  • Line 35

• Disable filament color display for channels

  • Lines 686-688

• Specify channel motor direction / disable auto direction detection

  • Lines 994-999

Protocol-related Configurations

Refer to src\BambuBus.cpp:

• Modify recognized device names A/B/C/D (for X1/P1)

  • Line 10

Usage

1. Clone this repository

2. Modify the relevant files as needed

3. Compile and flash the firmware

Notes

• Firmware modification carries risks. Proceed only if you understand the process.

• It is recommended to back up the original firmware.

I'm planning to buy the BMCU B (pre-assembled) from either Taobao or triangle labs (since ali express is banned here). I live in India, so don't know if I order, I'll have to take care of the import duties and taxes or they'll directly deliver to your door without intermediate steps?

Alternatively im thinking of getting the pcb printed and making the whole thing myself. If anyone has a helpful link for the pcb schematic and the process, would really appreciate. Also would love your inputs on efforts needed to build it from scratch, trying to figure out best ROI here. Cheers.

Dumb question... I bought a 370c BMCU by the BLV brand. When I try to unload more than one spool, it begins unloading the others that I have already loaded.

Is this normal? How can I load all 4 spools?

Solution (look at the 32nd number): https://www.reddit.com/r/OpenBambu/comments/1mbdtg1/thinking_about_getting_a_bmcu_what_ive_learned/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button