Here is what’s happening.
The Z motor has started to stall/skip several beats on a random basis and then work ok. It was a Dec 2009 replacement for a motor that had the same characteristics. For example, on the up cycle, it will stop moving, growl loudly, and may start moving again. I am using Mach3. To test, I swapped the Y -> Z and Z -> Y leads and both motors ran ok. Z was still loud. I swapped them back and Z ran (loudly), up and down, for a dozen cycles and then it would stall/growl again before continuing. I have tuned the steps accurately so I am tinkering with are the velocity and acceleration. The acceleration is set between 8-11 for all the motors. With the Z velocity set at 80, it will run for numerous cycles and then stall. I reduced the velocity downward in a series of steps all the way to 20. The most noticeable change was the motor growled louder as the velocity decreased. At a velocity of 26 it seemed to perform without stalling but was very loud. Has a lot of motor created vibration. It is the "quietest" and "smoothest" at around 80 where it will run for a while and then stall. Will run at 100 too, but stalls much faster. The error doesn’t seem repeatable in that it may run for an hour before skipping/stalling. Additionally, the missed beats seem to be on the up cycle which then drives the router into the wood on the next down cycle.
I am not sure it’s the motor although the motor removed from the machine is quite noisy and vibrates excessively. When I installed it last December, it ran quietly and would zip up and down smoothly. I have poured over the Mach3 documentation, their forums, this forum and tried numerous combinations of steps to isolate the problem. On Saturday it seemed to work ok and I was finally able to cut one simple house number sign. Yesterday, I was unable to successfully complete a single project. It would zip along, maybe 30-45 minutes, then miss/skip the up command only to drive itself into the wood on the next down command. Eat up a lot of cedar. Frustrating to say the least.
The hardware:
Dedicated computer and not connected to a network
Chinese CW250 Drivers
C10 Parallel Port Breakout
SKSP 500 28 power supply
5/8" 4TPI single start screws
KL23H286-20-8B motors
Kelinginc.com will replace the motor but before I declare the motor defective after 15-20 hrs, I want to ensure I have tried everything and eliminated any other possibilities. Looking to you guys for ideas. Have any?
Thanks
Dave Snellen