I currently have a cnc router where the Y-axis is controlled by two separate stepper motors and drivers. These are driven through linear rails and lead ball screws, having some give in them so I am having to manually square the axis every time I turn on the machine. Is there some way that I can wire in either proximity/mechanical limit switches to square the axis. I have looked through the forums but since I am using a DDCS V3 controller I cannot really code in a way to do this. I was thinking something like wiring the switches in series so that the controller wouldn't show the axis as home without both being triggered. Problem is that it wouldn't stop the specific motor that reached home first. Anyone got any ideas?
it is possible but it is a pain in the butt. much more effective to use a home limit switch on one side backed up by hardlimits. you can mount a screw on each side giving you some adjustment so that when the gantry it up against the screws, it is square. (only turn the leadscrews by hand when power is off!) once it is square, it should stay square and ordinary homing with preserve that. This is how I do my machine, the frame is square so just pushing the gantry up against the ends is enough to square it and it stays square until I manage to dumpthumb it into some sort of hard crash (-:
My current method is affixing a square to the frame and manually adjusting the lead screws so that the router bit lines up square to the frame. I'm not overly confident in pushing up against a hard point given that my gantry arms are made of laminated acrylic to an inch thick and have some give, not helped by the fact that a dust barrier got caught in between one of them and expanded that give a bit more. I see what your saying though. I have an idea of how I might use components to do what i'm asking I just don't know how to implement it. I could potentially use relays to turn off the stepper that reached home first while causing both sensors to have to be activated to turn off the home command, but I've never used a relay before and am not certain of the wiring as I don't want to accidently kill my controller.
Y gantry squaring is a compile option in grblHAL, no need for external hardware, but if you are placing 2 accurately positioned limit switches you might as well just place 2 adjustable hard stops, but as I said, once it is square only a crash will change that unless there is some serious out of alignment forces trying to skew it so that it shifts the moment power is removed. manually bumping against acrylic will not be a problem, you just be gentle (-:
