It's begun....

[Washout]

Hi All,

A bit of an update and hopefully if I can work it out a vid to follow:

Its fun to be back on the learning curve and earlier in the week I retrofitted my second X Axis ballscrew. The ballscrew itself was not much of an issue, but I had some "fun" getting the pulley onto the back of the stepper motor and not wobbling about.


Anyway after doing that it was obvious I have some slack in my drive belt, which needs taking up so just for testing purposes I found something "suitable" to take some of the slack out it (see pic). I then ran a few full speed jogs around the table and all seemed well, but there's a few things I need to do:


1. Add some support to the 2nd ballscrew where it extends to the same length as the stepper motor (there's some flex in there when the axis changes direction) - a suitable bearing has been ordered.
2. Add a proper 3rd pulley to provide belt tension rather than the hasty affair you can see in the pic, although I'm not sure how much play should be in the belt - parts ordered anyway


After that I decided to push my luck, being an impatient bugger, and run a short job "cutting air", just to see how it goes. That ran OK from start to finish, which was nice although you'll hear that the belt (or maybe ballscrew alignment) is out if I can get the vid posted. The job is a 3D roughing operation from Cut3D that took ~15 minutes and I also ran the other "side" of it, which also completed OK (~15 minutes).


Flush with success I loaded up a longer job (50+ minutes) and ran that. Again all was well for 20 minutes or so, but I noticed that heat was building up in the X Axis stepper motor. Then all of a sudden during a longish X Axis run (@1200 mm/min) the stepper made what can only be described as a "graunching" sound, like it had met sudden resistance and I hit the feedhold and then the estop. After that I checked that the x axis could be moved by hand (as the motors were no longer "holding position" in the e-stop state) and it could.


I'm assuming therefore that my gantry hadn't crabbed and bound up due to the ballscrews getting out of sync, but I could be wrong as hitting the estop could have "relaxed" the binding. Also I noticed that the stepper motor was hot to the touch i.e. hot radiator temps, but I'm not sure what behaviour an over heating stepper usually exhibits and whether the stepper (3Nm SY60 Nema 23) is maybe not man enough to drive 2 ballscrews?


Anyway once I get the other parts I'll tidy up the belt and pulley arrangement and then work out next steps, which I guess might mean getting and then trying to fit a larger stepper on that axis (the other two axis motors were cold/barely warm)? Perhaps Nema 34?


Later


Chris