This is just an idea at the moment and would like to hear your thoughts on this.

Instead of a toolchanger that goes to a designated spot, releases a hotend and picks up another one, would it be feasible to have two independently moving X rails? I mean two sliders on the Y axis that each have their own independent toolhead mounted on it.

To 3D print using two materials you could have rail 1 move out of the way so that rail 2 can move to the object and resume printing. I suppose this could be done with a pause command followed by executing gcode with different stepper motors.

This obviously only makes sense on a 3D printer that is large enough. I would say rails of at least 500mm in X and Y direction and a bed that supports that.

Does this make any sense over a dedicated toolchanger? I suppose the complexity is much lower and it’s less likely to fail.

I also believe there is a benefit for printing multiple objects simultaneously but at some point it might as well be two separate printers.