Y axis shut down

[meatbal80]

I have had my y-axis shut down twice now in the last 2 days both times in the middle of a file ruining my material. I am very confused as to the cause of this shut down.

After the axis freezes i can turn off the controller for a short while and then turn it back on and it works fine. I had this problem last summer on all of the axis's not just the Y, with no pattern that i could recognize. My shop is in Phoenix AZ and is not climate controlled, add the vacuum motors direct mounted to the table and right around the CNC can peak over 110f pretty quickly. The controller is located under the CNC, is the 4G in the silver computer style case. It is already on its side so that the controllers are vertical, and i added a 120mm fan on the top to push more air through the case.

After the first freeze 2 days ago I went and got some sheet foam insulation and a small A/C unit (7000 BTU). I proceeded to block in the A/C with the controller and cool it. Yesterday I was back up and running knowing that the controllers would have a hard time over heating (if that is the problem). After about 2 hours of cutting all 2d cuts (3-10 min on then 2-3 min to unload and reload material) the y axis freezes again. The cost of all of this material and the time to go get it is eating up my profit very quick.

These are the possibilities that i can think of, i am just not sure where to look or how to test:
1. Stepper motor over heating (was told that these could handle very high heat 200+ degrees F.) - touched Y motor after freeze while uncomfortably warm not burning.

2. Controller card over heating (A/C kept case nice and cool) - touched driver after freeze was cool to the touch.

Not sure if it could be anything else, haven’t made any changes to the setup in many months and have run hundreds of hours without this problem this spring.

[dana_swift]

Joel.. it sounds like the heat sink grease between the driver and the case is either missing or inadequate.

Dismount the Y driver, apply fresh heat sink grease, and re-assemble. That is how the drivers are supposed to dissipate the heat they generate.

It does not take a lot of grease, it should just barely squeeze out from under the mounting plate (heat sink) when you have it just right.

If the Y axis is without proper grease- I would worry about the others.

---

On the other hand if there is adequate grease, the cooling fins on the outside of the controller box may be blocked. That is WHY they are there.

Check that also-

D

[meatbal80]

Dana,

I have never pulled the drives and checked inside them, will definetly check the drivers before starting for the day. As for the fins being blocked, the controller i have does not have fins. It is the computer style enclosure.

[dana_swift]

I just looked up some products you can consider:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=CW7270-ND

That is $12.64/tube. One should do you, probably enough to re-do all the drivers.

If you have a good electronics store locally they should sell it also. Call to be sure..

Digikey also sells some boron nitride high performance grease, which is about four times as expensive, that is not necessary for this type of application.

D

[br928]

Joel,

If this is a 4G with Gecko drives, it sounds like the drive for the Y axis might be shutting down. These drives monitor themselves and shutdown if they see a problem. When you cycle power it resets. I have had one do this to me several times. When it shuts down you need to look at the indicator light on the Gecko drive. Buy a backup drive and swap it out.

[br928]

I don't think the 4G in a computer case used a heatsink. The Gecko's were mounted straight to the controller board.

[ken_rychlik]

I would swap the y and z driver and see if the problem stays there or moves. Quick test and free to try.

They just slide onto those connector pins. (don't pull it straight off the board, but slide to the side)

Bad drivers are more common than bad motors.

It may be worth pulling the drivers off of the board and mounting them to an aluminum heat sink bar that would help them dissipate the AZ heat. I would just do the swap test first though, to try and isolate the problem.

[meatbal80]

I have swapped the Y and Z drivers; i kind of hope that the problem moves giving me a relatively definitive answer.

Just spoke to Frank at tech support (definitely not sorry i chose a shop bot tech support is first class, especially since i purchased my bot used. Thank you). We discussed the possibility that the drivers have been damaged due to overheating in the past. Frank suggested that if i am to replace the drivers (not sure if they all might be damaged) that i upgrade to the 203 drivers from the 202.

Has anyone done this upgrade, what was your experience? Frank said that he heard that the new 203 drivers performed better than the 202 drivers. What if any performance improvements did you see?

I am waiting to the tech guys to get in at Gecko to ask about sending in my drivers for testing to hopefully identify the problem once and for all.

[br928]

You can not mix the G202 and the G203's. The G202 is common +5V and the G203 is common ground (step & direction inputs). They must all be the same. The G201X has a universal common (+5 or ground), and would be a good choice if you only wanted to change one.

I have mixed G202 and G201X without a problem.

[br928]

Gecko is great about testing and replacing a drive if it is found bad. They are quick too, usually within a day of receiving it. But it is doubtful they will find an intermittent problem such as the one you are having. There are too many variables that change once it gets out of your system and on their test bench. Best thing to do is identify which drive is marginal and replace it. That's what I did.

[Brady Watson]

The G203s are a superior drive to the G202s. I've lost 3 202s over the years...never a 203. I even sent one to Geckodrive to be checked - came back - same issue. It must be OK during testing and flake out under CNC control.

-B

[br928]

The G201X is build with the same technology as the G203V. I just doesn't have some of the "idiot proof" features of the G203. Since you are plugging it into a board and not hand wiring it you don't need it. Save $26 ea. ($121 vs $147).

If you go with the 203V's you will have to change them all and change the common jumper on the 4G board.

[Brady Watson]

This is true...

But, I'd rather spend the extra ducks for reliability/protection. But's that's just me :D

-B