Z axis stalls out

[Tlempicke]

For the past month I have been having a problem with my Z axis. I am trying to cut a table leg with the rotary axis and what will happen is that the Z axis, sometime during the program, will stop moving, give a 4 blink yellow code and the other moving axis which is the X axis will ruin the piece.

Here is what I have done in an attempt to fix the problem;

Installed 1K ohm shunt resistors in the X Y and Z axis as shown in the Clearpath owners manual.
Replaced the original Z Gearbox with a new one, as it seemed that the one installed had a “stiff Spot”.
Checked the 24 volt supply, and it is right on the money under load.
Used a different post processor
Finally I have swapped the two motor/gearbox units on the Z and X axis. I did a fresh training for the z axis before I swapped over and I recorded all three axis and installed them in the proper position after the motor swap.

Since the problem has appeared in the Z position with two different Motor/gearbox combinations I am thinking it is not the motor.

I am including a fresh report, the Clearpath equivalent of a report on both the X and Z motors and a copy of the tool path that I am trying to run. (Warning it is pretty long)

Does anyone have ANY idea what to do next?

[Gary Campbell]

Tom...
No real answers here, but questions that I would use to find the issue.

1) Have you checked for mechanical binds on the Z axis or crud in the rack? Those SB enclosed roller setups were famous for that
2) Do you have an air counterbalance on the Z? The OEM springs are OK in the middle, too light at the top and too heavy near the bottom. Works ok for steppers, but servos are more sensitive to loads beyond what they are tuned for.
3) You mention the 24v voltage, which does little or nothing for the motor, what is the Teknic IPC-5 voltage to the motor when running?
4) You say the blink code is 4. I assume yellow, have you connected to the motor while the fault exists and read the exception on the top right of the MSP window? You can also press (I think) CTRL + G and get a list of previous exceptions.
5) The 4 options are: a) Speed too high b)Tracking Error Limit c) RMS Torque Exceeded d) Excessive bus current Each of these will have drastically different solutions
6) Was motor autotune on the Z axis done more than one time in more than one place, or at least over the full range of motion?

The others are relevant, but #1 & #4 will most likely provide the answer. Little or no info can be gleaned from a long 3d rotary cutting file, its best to take a minute long video and upload it to YouTube

[ShawnM]

As Gary mentioned, what is the voltage at the IPC5 power supply? I cant see this being the issue as I have 4 Clearpath NEMA 34 motors on one IPC5 supply. And that it's always the z axis tells me is not a voltage issue. My guess is a mechanical binding somewhere. You stated you added 1k resistors, The Clearpath/Acorn official diagram from Acorn is a 100 ohm, 1/2 watt or more pull up resistor. I doubt this is the issues as the other axis are working correctly. I'd check for binding, install a good counter balance and retune the motor.

[Tlempicke]

Gary
The Tecknic manual talks about the 24 V supply and says that the motor will fault out below 18V. The very first things I did were to clean the rack and tracks and put fresh grease on. Another autotune is a good idea. I will do that. I put about a 3 pound weight on the axis last time I id it, what would you recommend?

Shawn
I have two IPC5's. I don't recall which motors are on which supply, one has two and the other has one on it. I will swap cables around and see if that changes anything.

Thanks guys. I am at my wits end with these things. This machine has worked absolutely perfectly since the Acorn conversion three yeas ago.

[Gary Campbell]

Again...unless you have a power hub installed and you wish to use it's features, the 24v power is irrelevant to your issues as long as it keeps the Acorn board powered.

Now the real question, which should give you the answer to your problems:. Which exception condition of the 4 does the motor report? These motors are smart. They will tell you what went wrong if you take the time to look

[ShawnM]

I think you are misreading the manual. It does state that the motors will operate from 24 volts up to 75 volts and will drop out if the voltage drops below 18. Regardless of that, you stated you have not one but two IPC5 power supplies. Those are 75 volt power supplies for the motor power. Your voltage is not dropping below 18 volts at the motor.

That said, if the voltage ever drops below 18 volts the LED on the motors turns off and does not even display blink codes. So the mere fact you see blink codes when the motor faults tell me it's not a voltage issue.

You should plug the motor into your laptop and see what is happening. See page 159 of the users manual. Since 4 blinks can be 4 different errors, the only way to know exactly what happened is to plug the motor into your laptop and run the MSP software. When you plug it in and open the software look in the "exceptions" field.

Once again, as Gary stated, these are very smart motors and they will tell you exactly what is happening if you take the time and look using the MSP software.

Find out what is going on mechanically with the axis, get that sorted out and retune the motor. I would not add any additional weight to the axis like you said you did before. Tune it just as you run it.

[Tlempicke]

After reading your posts I realized that a part of the Z track was impossible to clean without taking the whole thing apart. I have removed the Z axis from the machine and taken it apart. Wow, what a dirty mess! I have high hopes for this!