Hi All,
Only just picked up the latest two posts so didnt try that out yet, but definately will.
Anyway, Ive spent this evening running a series of tests, checking over the electronics and also some mechnicals
Firstly, I have now stripped back all the electronics, such that I am now left with only the Z axis drive gear, the controller, and the power system. All other axis drivers have been disconnected and removed, the front panel connections have been removed etc.
So I thought I would start with a simply test, and that was to change the USB lead. I went and got a decent shielded USB lead and double checked the contiuity of the outer sheilding to the connector housing. Unforunately, this changed nothing.
I then went over all the remainging electrics, checking for any loose connections and tighting everything up to ensure all was so. I again ran a Z axis test and the same results.
Next, I took a look at the mechanical couplings from the motor to the ball screw. Ive checked these previously, but wanted to be doubly sure. I marke up a line between all the connections. I re-ran a test and the same result. Having checked the mechanical connection, the line was still intact along all connection points. So This rules out any slipage in the couplings.
So, out of ideas, I thought I would play around with the acc. and Vel. settings in mach 3. I started very very low and slowly worked back up. However, the test program I ran only moved the Z axis through a distance 70mm (reoccuring) so Im wondering if at the very low acceleration range if the motor every got up to the velocity?
Anyway, these are the results of those tests
Original Settings - Velocity: 6000, Acceleration: 300
Velocity: 500, Acceleration 20 - Good Result, Held Zero
Velocity: 2000, Acceleration 20 - Good Result, Held Zero
Velocity: 4000, Acceleration 50 - Bad Result, Lost Zero
Velocity: 4000, Acceleration 20 - Good Result, Held Zero
So it seems that if I slow the acceleration down to painfully slow, it stabilises. Im not sure this is a solution though, more an observation, as I know there are the same machines out there running fine at the orignal setting, but maybe this test can help to highlight some possible issue.
And Finally, an observation that I feel I need to mention, and Im very much wondering if this could lead us on right path to finding the issue. While I was messing with the Velocity and Acceleration settings, I forgot to compensate for this while jogging the Z axis downward. As such, I ended up crashing in to the workpiece. What I observed (which I assume is a common action) is that the motor and ball screw continued to rotate, and instead the slipping must have occured at what I think is called the Ball Nut.
What happened was that because the motor was still turning, Mach 3 thought the z axis was still travelling downward. Therefore, when retracted, the Z zero point had changed and was above the workpiece (same results).
Could this be a possible reason to whats happening durning a program run, could the Ball Nut be slipping?
The only thing I cant answer is how this would be happening on the X and Y axis as well, but concentraiting on the Z for now.
BVy the way, this is the signal from Pulse + pin
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