Unusual dual head printer - looking for advice

Basic Information:

Printer Model: Dual-headed printer
MCU / Printerboard: RAMPS plus others

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Describe your issue:

I am just about to start transitioning one of my printers from Repetier Firmware to Klipper. This printer is unusual in many respects and I am hoping that somebody can give suggestions about configurations for similar printers that I can use as starting points. I have just completed an installation of Klipper on a Delta printer but that was quite straightforward: I don’t expect this other printer to be nearly so easy.

This printer, known as Biceps, has two print heads with a quick change mechanism and nozzle cleaning on each change. The first problem is that the swap from one nozzle to the other is under the control of a microcontroller driving a small stepper motor with a single input line to command a change and an output line signaling either a successful swap or failure to accurately home.

Another problem is that the bed leveling and bed meshing is performed by two separate sensors; a single underbed sensor to set the reference height of the nozzle by bed contact, and a touch sensor to carry out the mesh scan. This last is also a piezo sensor but works in a similar manner to a BLTouch. The MCU conditioning boards for both of these sensors report a nozzle or touch sensor contact but also report if the contact was clean or if there was contamination, whether hot or cold plastic or other detritus.

The head swap can be seen on YouTube at Biceps dual headed 3D printer Toggle mechanism and bed sensor tests - YouTube
Please note that the right-hand nozzle was dummy probing when this video was taken- hence the heavy jounce when the right-hand nozzle hits the bed.

Any thoughts, suggestions, or pointers will be gratefully received.


Uh wow, interesting printer design. Your own build?

I predict you will have a hell of a time to get it klipperized :sweat_smile:

There is too few information to really help you. From the first look:

Hi Sineos,
It is my own design though based loosely on a 3D printer I saw several years ago at TCT. The general idea is to have the printing heads moving only in the Z direction - this allowed heavyweight items like multiple printer heads, milling attachments, etc. to be more rigid.

Mostly the outputs needed will just be pin toggling with just 5V or 3V logic inputs. The possibility exists for serial IO from the RAMPS or Raspberry Pi to my various boards as the pin selection on the MCUs has been done with flexible IO in mind.

It does seem likely that the way to go is with macros as this is pretty much what I use in Repetier. The difference is that Repetier is small enough that there was pretty much one right way to toggle pins or check the status of a pin. Klipper seems to have many ways of doing such things

Example of this printer configured for some light milling on YouTube at Making a vacuum hold down plate for a 3D printer - YouTube