Intermittent movement in Z axis.

[Skip45]

The servo motor operates but varies Z movement. Wrecked to good project pieces and figured I programmed settings differently. I currently think my servo motor is not pausing correctly. Could it something other then the motor ???

[Bob]

OK John,
A couple things to check:
1. Check the tightness of the screws holding the coupler on the stepper motor to the Z drive screw. These become loose. Check also to make sure that the set screws on the coupler are engaged with the flat areas on the motor and the drive screw.
2. Check the coupler itself. They do break. If you have been using your machine for a few years, it's a good thing to check.
3. Clean and lubricate the guides and drive screw. Gunk gets built up after a lot of use.
4. Check your safe Z distance. Are you hitting the limits of travel? The the gantry?
5. Is the bit plunging too deep, or too shallow when a project is ruined?
6. Are there unusual sounds during Z operation? Can you describe them if any?
7. Has anything like this happened before?
8.You can also go here: https://nextwaveautomation.zendesk.com/ ... cYQAvD_BwE
Let me know what you find out.
Bob

[Skip45]

Here is what I now know:
I did go to your recommended trouble shooting Shark site. Changed Y and Z cables to control. Motors work fine as I was jogging the two axises. Put cables back to original position. Then I ran an op and with program in control had same Z problem. The tech support said it might be a driver card not working correctly. I did double check screws as they are allen head cap screws. The exposed one is tight on shaft. The other one of the collar screws is not loose and is the same height. Therefore, they are tight and I won’t have to take the motor off. I will call the company on Monday and see if they agree with my hypothesis about motor control card.

[Bob]

Thank you for the update. My suggestions are based upon the experiences of many others who use this forum, so I wouldn't be too surprised if there's another solution.
Please keep us updated. Your experience will probably help others with similar challenges.
Bob

[Skip45]

Bob,
Called next Wave and over a few days my HD 3.0 is 98% better. I did purchase a Z axes card and replaced the old the old one. Then check Z axes connection to lead-screw. Found the motor screw still tight and reassembled motor. The new board operation made Z movement very quite when operating. Next, the fellow helping me on line wanted me to run a distance test on my machine, take a picture of the machined board and send it back to him. My Y axes was slightly off according to the picture. He requested me to pull the Y axes and check the tightness of the set screws on motor and lead-screw. Well, I was surprised to find the motor was loose and needed to be tightened. Then I ran the distance test again and found a slight improvement. There is no easy way to get at the motor screws. I could hardly fit my chubby arms between the table and the carriage slide. Finally the motor was tight, but couldn’t pull the Y axes because the lead-screw was attached opposite of the motor. Gee, what if I pull the shaft out to check collar set screws and could not press it back in? Well, this morning Matt wrote back and said the bearing is a skate bearing and the lead-screw will just slide back in. I will do this check or repair in a few weeks to bring my cnc router to 100%. Thank you Bob. You wrote back with questions and suggestions and started me on the right path.
Skip45

[Bob]

Skip45,
Thank you for the update. This information could prove to be very helpful for others with similar problems in the future.
Bob