[turmite]

I need help as I am basically at my wits end.

I have an old Digital Tool 902 router that uses rack and pinion gearing on all axis except the rotary 4th axis I added. This machine came originally with a Anaheim Automation 4 axis drive box, and four 200oz round stepper motors that were 6 wire that ran in full step mode. I bought the machine in 1991 and upgraded it in 1993 to triple stack 300oz round 6 wire motors and a new Anaheim drive system that was 1/2 step. The controller was a proprietary thing from Digital using LPT Indexer from Ability Systems. I soon changed that and went with a system from a young man in TX. This machine had/has extremely long motor cables that are 16ga 6 conductor and no shielding. The Y axis cable is approximately 25 ft long with the X and Z being about 22feet long. Fast forward to 2000 and my old machine took a dive on me. At that time, I made the decision to move to Mach control and Geckos for my drives. Everything ran very smoothly until 2008 when I shut my business down to take care of my wife who had breast cancer. I lost her to the cancer in Feb of 2011. I took most of 2012 off and started in Jan of 2013 to rebuild my business and get back to work. What I discovered though, was a machine that just did not seem to work like it did before. I lost a few thousand $$ in ruined parts because the problem was intermittent and I honestly did not spend enough time tearing the machine down for a complete maintenance rebuild. That said, I did discover that at least one of my round motors was demagnetized and had zero holding torque. So at that time I decided to make an equipment change and bought new 1200oz high torque hybrid motors from Homeshopcnc in California. I also went with the Ethernet Smooth Stepper and a new breakout board from Bob Campbell of Campbell Designs. Got everything installed and still had problems, and all the problems were on the Y axis and have remained on the Y axis.

So after installing the ESS and new high torque steppers, here is a quick rundown of what I have found and fixed.

1. Broken pinion on the y axis gantry opposite side from the motor (Digital Tool used a shaft connected between the two rails and racks on the Y axis to sync both
sides of the machine)
2. Bad motor cable for the y axis, I replaced it and have tested it with two different cables, so I know that was part of it.
3. Found and replaced a frayed timing belt on the Y axis
4. Found and repaired a loose limit switch connection on the Y axis
5. What I did not fix was the Gecko drive I fried while doing something stupid that I just never do......leave the power on when I am working on the wiring on the
motors.......yep....I shorted the ground and power and discovered there is a lot of smoke in one of those little boxes.

I have the old Gecko 201 drives and Mariss himself spent time on the ph with me to get them set to my old stepper motors. According to the spec sheet from the old motors and the new motors, they are essentially the same specs as far as voltage and amperage is concerned.

Here is what I discovered this am. I decide to start the day by trying to run new parts with my ESS system. I turned everthing on, referenced the machine set my starting position, and proceeded to run 4 perfect parts. This program is a little snap together bird house and comprised of 7 parts that have either tabs or slots for the tabs in all pieces. Material is .146" and I am using a .096" cutter making two passes. Sand the fuzz off of them and they snap together perfectly.

After the 4th run, I had loaded a new blank in the machine and I was watching it as it cut the little slots. About 2/3 through the slots portion of the code, the machine made a growling noise, not like sound of a stalling motor, but it did stall. I had never heard it before.

So, I turned everything off, moved all my cables except the ESS cable to the old computer and went to Mach2 and a parallel port. To my surprise, the condition followed the computer swap so that told me it was not my ESS, or anything about the new system. I tried jogging the machine and noticed something strange.

It was like the motor was trying to move both directions at the same time, and the stalling sound was like the growling I describe before. I took one of my gearing belts off the Y axis to separate the motor from the axis, without turning it off, and to my surprise again, it was still with the motor. I could take my finger and shove the very large x axis gantry most of the 144" length. There was basically no resistance so I knew then that it was within the motor or the first two stages of the gearing steps. I took the motor loose from the coupling and removed it from the machine. I sat it on the y axis carriage and then jogged it via my keyboard. I then could physically see the shaft trying to reverse itself while being jogged in only one direction. This was still with the older Mach 2 system. So, now I think I have it narrowed to the y axis motor or the y axis step driver, but that was checked earlier. It can't be the parallel port because it is present with both systems, and therefore that also rules out both of the computers.

I have been on the phone with Rick from Homeshopcnc this afternoon, and he thinks the problem is the long unshielded motor cables.......but.....that said, I want to remind you before we start this that the problem is only on the Y axis, and worked flawlessly for years until I let the machine sit unused for that nearly 5 years. It was there with an old 300oz round motor and has been there with three different new 1200oz hybrid motors. The drive has been swapped out, the cable has been swapped out, control systems have been swapped back and forth and I am totally at a loss. Any help would certainly be appreciated.

Thank you in advance for you input.....

Mike

[James Newton]

Use a torque wrench to check for mechanical binding on the Y axis?

[ger21]

Measure the voltage on the Y axis direction pin while jogging. Measure it at the parallel port, breakout board and drive.
It should be a steady 0V in one direction, and 5V in the other direction.

[turmite]

Thanks for the replies guys. James, I can take my finger and freely move the y axis with almost no resistance. Where would I check for binding with a torque wrench?

Gerry, this is not just when using the old Mach 2 and a parallel port. I get the same thing when using my Ethernet Smooth Stepper as well.

I worked on it again today and just to be sure, I wired the motor to the z axis cable and sat it up with a piece of paper as a flag so I could see rotation. When jogging the z axis, the motor did not reverse itself once. I then swapped out the z axis gecko with the y axis driver and repeated the test with the motor not mounted on the y axis, again with a flag so I could see rotation. It reversed itself again, and it seemed to be keyboard related, so I changed keyboards to a brand new one. Problem still there. I then double checked the step and direction connections and found a loose connection on the direction wire. Eureka, right? Well, I thought so until I jogged the axis again, and I could see the motor reverse still. So, I began a wire by wire inspection and to my surprise, I found I had put the a axis direction wire into the y axis drive when I had originally swapped them out. Corrected that and just knew I had finally found it. I tested it before mounting the motor and all seemed well. I then mounted the motor, and tried the jog the axis only to have the reversing thing still there.

I have had no sleep in almost 48 hrs and have to rest, but will check the step and dir voltages in the morning. If you or anyone can think of anything else to try please let me know.

Mike