X-Axis got tired

[brucemoore]

It seems that my X-Axis motor is giving me some problems on my HS-1. I was cutting a little sign today and the X-Axis started to drift in the negative direction during the cut. I started playing with it and found that the X motor just doesn't have any power. I wouldn't normally do this but after finding that it was easy to stop the X travel I found that I could simply grab the wheel on the motor and hold it from turning with my fingers.

With all power off the X-travel is smooth with no binds any place. I checked out all of the connections in the tray and all looks OK. Ohm'ing out the A-B and CD phases from the driver board, I get about 1.8 ohms on each leg. Thats equal to the Z axis motor and double the Y as I would expect.

Not sure what to check next. Any suggestions.

Anyway. Just getting this puppy fired back up after being shelved for almost a year. A couple of knee replacements and moving into a new house can take a lot of your time away for the fun things. But winter over, the shop is warmed up and here we go.

[romaxxcnc]

Hey Bruce.

We can go up on the current set resistor, it's under terminals 11 and 12 on each drive. Check the color code and go up by one amp. It probably has a 36k in it, you can go up to 62k.

If that doesn't rectify it. Check it out by swapping a drive. Power down the machine, wait 5 minutes and lift the header off of X and put it over on Z drive. Leave the X drive disconnected just as a test. Z jog will now be X axis. It will tell us if it is the drive or the motor. Make sure the header is all the way down before you power up. The header is the terminal strip on the front of the drive, it just lifts off. A stepper or servo motor can weaken over time, but it takes a long time.

-Ron

[brucemoore]

Well Ron,

I got home this evening and started doing what you suggested. I pulled the plugs on the X driver and got to thinking that I'm not doing this right, I should really fire the thing up first and get a good reference of where I'm starting from. So I plugged them back in and turned it all on. I jogged all three of the axis and made sure they were moving... fine. Then I jogged the X while trying to hold the router back like yesterday. Easy to do yesterday. Today the entire machine would have moved off of the table before I could have held it back with my hand. Sure glad I didn't have hold of the motor shaft to test it like yesterday. I'd be probably be typing this through some band aids. Anyway, I put it all back together and it works fine now.

I'm not sure if this is a good thing or a bad thing. Would have been nice to have something to fix so I don't have a potential intermittent problem. On the other had maybe it was simply a loose or dirty connection and it got fixed for free (short of a little aggravation).

Any ideas, suggestions, etc.

[romaxxcnc]

The terminal strips on the drivers have a history of less than perfect connections where they slide down on the pins. I would say this was the case as well here. It probably won't do it again.

-Ron

[brucemoore]

Running again. Did a quick test cut tonight and all works well.

Attachments:

[mattgatten]

Nice sign! I work on computers all the times. Contacts oxidize all the time and re-seating them often fixes things. A pencil eraser is awesome for cleaning contacts too.

[brucemoore]

The story continues. I had another problem with the X-Axis yesterday.

A wood chip got caught in the rollers on the Y-Axis, jamming it up for a second. As a result, everything was off of where it was supposed to be. After that the X-Axis stopped working. No movement, no response....

I did all the usual checking again. Signals were getting to the drive but no output. I figured that I would go for a complete reset by powering down before I got too excited. I waited an hour with the machine unplugged and tried again, no luck. So I started over. I started monitoring the power levels and watched the voltage drop. After a few hours, I still had 2 volts on the power lines. I disconnected the connectors on the drive to see if that would at least get the voltage down closer to 0 on drive power pins of the drive. After 4 hours the drive still showed 1.5 volts. This morning I was down to less than .1 volts so I put it all back together and it works fine.

So my guess is that the drives can be driven into a state that leaves them not working and it takes a power down to zero to reset them. When it started working during the tired X-Axis problem, there was a period of over 24 hours that it sat when it started working, so the voltage would have been down to close to zero also.

When it got stuck yesterday it looks like the X was driven into trying to make a real deep cut that it shouldn't have. With the last problem (Tired X-Axis), I don't recall any bind ups like this. So Ron, do you think this is an indication of a flaky drive or is it just a really bad set of things stacking up to cause these problems.

[romaxxcnc]

Bruce,

Where is the voltage that is being measured?

If this is just the X axis acting up, Swap that drive with another and see if it now moves to the axis you swapped with, that will tell us what it is.

Ron

[brucemoore]

When I refer to measuring the power lines, it's the system voltage going to all of the drives. I measure at the voltage input of the drives when the plugs connected. In the case of the plugs being pulled above the drive voltage was measured on the power + and gnd of the pins of the drive.

Swapping. Good Plan. Does it matter which other one gets swapped with the X.

By the way. Ran it about 3 hours today and all worked well.

[kwoe]

THis sounds a lot like my problem tonight. I had another CNC router and the drive started failing. Not a gecko though. Will check the connections as suggested above. Maybe I need a new drive chip?