On my diy cnc, I would like to mount a double limit switch on the double y axis..so that it can automatically straighten to squareness..I have two mainboard controllers available..STB5100 USB Motion Card and mks tinybee... thanks for the reply Josip
Isn't it possible that in an axis with two steppers, driven by two separate drivers, the steppers can get out of sync and will need to be reset, hence the autosquaring?
Of course there are valid reasons. But far too often people try to fix a badly built machine using that
I have always wondered how a person doing this knows that the switches are exactly in the right place on both sides to know it will be square, and also are the switches precise enough to ensure the machine is square? I know my machine frame is square via physical measuring of it, so if I want to ensure the gantry is square I just run it all the way up to the front frame member and ensure both sides are touching.
100% correct and I do mention that in my other post I shared above. Way easier to use a hard reference (square base, jog into end of travel lol)
Yes, but things are going badly wrong if that is happening on a regular basis. I've "squared up" my Y gantries three times in five years - one broken cable connection, one crashing into an obstacle and one rebuild when I upgraded to linear rails. Alex. Four times if you count when I first built it.
Help = using experience to guide people away from bad ideas. Have a read through the provided info before you dismiss it
My way of squaring the Y-Axis: After homing the machine, I take a ruler and measure the distance between the gantry plate and the end of the C-Beam on both sides. If the distances are not same, I turn off the PSU, rotate one of the lead screws until the distances are same, and turn on the PSU.
I have auto-squaring on my machine, but as the others say, it is no substitute for getting the machine square in the first place. The auto-squaring on my Y axis is just a 'safety net' as it is only when I have done something stupid that it goes out of square, like leave my screwdriver on one Y arm in a way that jams the arm when I start to move the machine...... I have done it more than once which is the frustrating part! My machine also has a dual-Z and that has auto squaring too. On the Z it is more important as the spindle is heavy and when the machine is powered off, if I forget and lean on the X axis gantry for some reason, it can rotate a Z motor by a few steps as the stepper detent torque when powered off is not huge. Using good quality (i.e. repeatable) sensors does become important as others have mentioned as you now rely on the sensor repeatability to set the overall accuracy. I have inductive sensors, and cheap ones can be really quite inaccurate. With the inductive sensors, they are a threaded rod design, so tweaking the in/out length to get the machine square in the first place is actually really easy. Some other mounting types, and especially micro switches, may not be as easy to adjust (I had microswitches before).
fluidnc (unsupported) and grblHAL (supported in CONTROL) supports auto squaring nicely and using it is valid, it doesnt necessarily mean its a substitute not to build it as square as possible initially but there are many reasons that an axis can lose its initial alignment and the auto square is a nice feature to have when used properly
