Movie About the Z-axis Skipping

[Chazz]

I'm not seeing anything unusual in the video that you posted.

I think it is on the fourth pass from left to right (just before I stopped the cut). On the previous passes you will see that I ramp it up towards the end of the run. On the last left to right pass, you can see that it starts to ramp up; but that an additional sound can be heard and the router does not climb but rather kind of stutters but remains basically level. Then the cut starts the right to left swing and cuts deeper and basically chops up the test wood.

With regards to the hold-downs. I have evolved over the years. This test material has been bolted down for I guess about a month as I have shifted my attention to life issues. To boot, the part happens to be over one of my first spoiler board damaging mistakes -- yes, this is my original spoiler board. There was a small amount of gap even when it was over an inch thick; but the time did cause it to curl up a touch. The flexing that you see didn't happen on the original cutting.

I like the idea of trying to manually run it up and down with pressure on it in each direction. I wish I had a scale to measure the actual pull in any given direction. Do you have any ballpark weight that should be considered "good"?

Chazz

[Chazz]

Test results....

I did my best to drive the head up and stop it with my hand, it seemed to have sufficient upward strength. I was reaching arms length to press and hold; but it was enough to overcome any of these small issues.

I decided to run the modified file that changed the 3D Ramp to 150 next. It started skipping on the FIRST pass.

Then I tried to change the movement speed to 1 (from 2). The router couldn't even raise itself for the initial pass.

Then I went back to just using the keypad to move it -- it refused.

Then I turned it off and tried to move it by hand -- it moved fine.... fairly easy for both up and down.

Lastly, I made another video (https://youtu.be/ldaJcONznN4) showing the last two.

Thoughts?
Chazz

[Brady Watson]

...spoiler board damaging mistakes -- yes, this is my original spoiler board.

A spoiler board might be found on the back of a jacked up Camaro... I think you wanted to say, spoilboard.

Thoughts?

Yes. There are 3 possibilities off the top of my head.

First, check the 4 wires that run from the Z motor all the way back to the driver. If they are pinched or 2 or more of the wires are frayed, it is very possible for them to short out one of the coils in the motor. If the wires are not properly strain relieved, or got pinched somehow underneath, this will cause the condition you show.

Second, the motor driver itself could be bad. It may or may not be covered by warranty. They are $81 retail. You might be a few bucks cheaper by dealing with SB directly. Care must be taken when installing or you'll bend the pins...they are not bulletproof, but GeckoDrive is a stand up company with great service.

Third, there is an outside chance that the mechanism which holds the screw to the stepper motor itself somehow got bound up, causing a lot of drag...

I would put my money on #1 first, taking nothing for granted & inspecting the wires carefully, with #2 being less probable. If you ran it up and down by hand it probably isn't #3 & running it up and down by hand can smoke the driver, since the motor is a generator...

You can also check the driver-side of the motor wires to check resistance between pairs, but I don't have time to educate you on how to do this.

-B

[Chazz]

OK, sorry for the grammar mixup

I inspected the wiring starting from the Z-axis servo and found that the wires were very tight between the servo and the first cable-tie. I am sure that was my doing from the upgrade. I removed the cable-tie, flexed it a bit, turned it on and the keypad movement was working. I can't see any particular damage. I figured to go for broke and ran the cut (modified to 1 for Z and 3D ramp of 150). The cut completed without incident.

This leads me to think that it was either at the bend where the cable-tie was or inside the servo where the wires are connected. I am feeling a bit cautious about trying to disassemble the servo to check what might have gone on there.

I figure on carefully cutting back the protective sleeve and inspecting the wires where the cable-tie was is next.

Progress!

Thank you... more to come,
Chazz

[Brady Watson]

Good. Glad you got it. I wouldn't try to disassemble the stepper motor any more than carefully peeling back the shrink tubing. You'll let out the magic smoke and it won't run right again. I would just make sure that all of the wiring is properly strain relieved (which also means not introducing strain by cranking down zip ties too hard) - and just go over the entire machine wiring as a double check.

Also, take a few minutes to vacuum the machine really well (avoid compressed air as it can foul the bearing blocks) and give it an overall wipe-down. It will look new again. Instant detailer works well for shining up the blue parts.

-B

[Chazz]

I opened the flexible channel and found the shrink tubing covering the connector for the stepper. As I had it still on as I gently lifted the segment that had the shrink tubing, I heard the stepper stutter. This is good in that it reminded me to shut it off before proceeding; but it also seemed to indicate that the problem wasn't completely solved. After turning the Desktop off, I removed the shrink tubing. I could find no damage on the wires. I plugged the connecter back together and turned the Desktop on. I gently moved the cable around; but it refused to skip/stutter again. I mildly flexed either side of the connectors, the pivot point where the cable-tie was, and where the wires enter the servo.... in no case could I get it to exhibit the fault again.

I suppose it could be that the contact between the connectors got a bit of dust or oxidization preventing a constant and good contact. By pulling it apart and re-assembling it, I could have just cleaned that off.

I need to get a hold of some shrink tubing to cover the connector again.

Thanks to all,
Chazz

[bleeth]

Pick up a can of electrical contact cleaner and use as directed.
I have "solved" electro-mechanical issues with this for years in my shop.
Sawdust is not only bad for your health, it also messes with switches, connections, and circuits all over every woodshop.
Cleaning equipment on a regular basis means more than blasting air at the visible residue.