I've been looking for this for a while, and it looks like no one has tried it before.
Does anyone know if there is a way to link an Arduino Mega with RAMPS as master, with an Arduino Uno with a CNC Shield as slave, and get it to work on Marlin firmware?
Why do I want to do this? I'm planning to build a DIY heavy duty 3d printer that will use a lot more stepper motors than the typical prusa style machines, and I want to use Arduino to control it instead of custom CNC/stepper/3d printer controller boards.
so points to that case:
- how are you going to sync master/slave?
- adding more steppers to master (even only for pushing control to slave) will limit speed in the whole system (this is mainly one of the reasons why we shall go to 32-bit platforms to print faster).
As marlin will give you a good grasp to convert g-code into steppers movement, then if you are willing to double or triple steppers number per axis, you can grab
step signal and forward it to other steppers drivers without the mess of syncing movement in time and board. If you are going to add a special tooling - then you shall add your mods to firmware as well.