First off, I would like to say hello to everyone. I have been away for a while. Spring projects, spring cleaning, yard sales, and ripping out everything in my master closet (I mean everything, lights, wire shelving, base boards, and carpet.) On top of that my girls have dance and violin recitals this next week. I have been busy but I love it all. The little free time I have had has been spent playing with my new MMU2 on the prusa. Love it!
Anyway. Onto the main topic. I have been watching how the Prusa i3 Mk3 with the MMU2 work. I have some theories and ideas. I wanted to share them in case any of you wanted to … copy those ideas?
Idea #1. I think I have figured out how they are able to do their homing without end stops. The printer doesn’t do this but the MMU does. The way they home is by using a low current and crashing the motors into the walls for a couple seconds. Then they assume that is Home. Cleaver. The low current makes it so the motor doesn’t damage anything. It just clicks weakly for a few seconds. If they don’t have that firmware source code available to the public then I am sure that piece shouldn’t be too difficult to repeat.
Idea #2. They level the Z axis on the printer by raising the z axis all the way up to the top then crashing both the motors into the top. That way they know the two are level. Sooo… That got me thinking. We could auto square the MPCNC the same way even if with serial motors. Move X axis all the way to the left and crash both motors into the sides then you know it is square. OR… wire up X min switches in series or parallel. So they trigger when the motors crash into the sides. That way one of the motors might crash first and trigger the first switch. The second will crash and trigger the second switch. Then we know they are square. The first motor might stutter a little while the second one finishes up its movement. (hopefully without damaging anything.)
There is more but I’ll end there for now. I’ll cover the other ideas later in this same thread. I am not planning to take this idea any further. But I wanted to share it in case someone else was interested. Dual End stops already works so its not like we would be trying to solve something new.