Z Axis Issues

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BillConroy
Posts: 4
Joined: Tue Sep 01, 2020 7:42 pm

Z Axis Issues

Post by BillConroy »

I had a project on the CNC (Shark 510) machine. It was the 4th consecutive carve of the same project. I stepped into the house for dinner, when I came back the Z axis had bottomed and I can validate the Shark machines aluminum just fine as I nicely carved into the top of the base. This was the fourth time I ran the exact same code consecutively through the machine, the first 3 without issue, so I assume the code is fine. The current carve was 5 hours into the carve and was performing exactly as expected when I walked away for dinner Has anyone seen the system bottom the Z axis out for no apparent reason during a carve. I have the system connected to a ups to isolate it from power issues. I'm a little nervous about running machine again until I figure out why this occurred. During a 10 hour carve, it's pretty tough to be at the machine 100% of the time ready to hit the kill switch if machine does something unexpected.

Bill Conroy

Rando
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Location: Hoquiam, WA
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Re: Z Axis Issues

Post by Rando »

How do you validate your GCode? Before I run any toolpath, I always run it through an independent viewer to check the extents of movement, and for anything unusual...like a finishing pass that tries to cut the OUTSIDE of a pocket... A free online one is:

https://ncviewer.com/

That will tell you whether the problem is in the code you told the machine to run, or if it's a problem with the machine itself.

If I had to guess, based on your saying it happens on long runs, I'd say "thermal issue".

If you have a traditional NWA system, does the controller box have a fan? If not, then it's entirely likely that one half of the z-axis stepper drivers over heated, and shut itself down to avoid thermal damage to the chips. They do that. That's why I opened the case of my controller and added a FAN to it. Now I don't have any stepper driver heat issues.

The other thing to watch for is static buildup, but it doesn't sound like you're experiencing that. No major painful static shocks when you approach the machine?

The other, potentially dangerous thing to check is the connector wires that go to the controller, at the end of the plug-in stepper motor cables. There have been (quite a while ago) reports of burned wires resulting from intermittent or broken pins/wires in the connectors. Fires have been mentioned, though I don't remember anyone saying the house burned down from it.

Anyway, hope those ideas help. Let us know if you find anything.

Regards,

Rando
=====================================================
ThomR.com Creative tools and photographic art
A proud member of the Pacific Northwest CNC Club (now on Facebook)

monitoringpost
Posts: 89
Joined: Wed Nov 02, 2011 10:40 pm
Location: Canada

Re: Z Axis Issues

Post by monitoringpost »

Rando wrote:
Sat Oct 24, 2020 2:34 pm
That's why I opened the case of my controller and added a FAN to it. Now I don't have any stepper driver heat issues.
Care to share a photo? If you didn't tap into the relay for power what did you use?

Craig

BillConroy
Posts: 4
Joined: Tue Sep 01, 2020 7:42 pm

Re: Z Axis Issues

Post by BillConroy »

When I say the code was validated it was through use. I ran the same files through the machine four times in a row. First couple of time I run a project, I stay next to machine until the entire project runs. I never removed the usb key from the control pad. I did turn machine down between the 4 project runs. The finishing tool path was a little over 60% with no issues. I have the water cooled spindle and the garage I run it in is around 65 degrees. Your post implies I would need to look at getting fan in the controller box?

Bill Conroy

Rando
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Location: Hoquiam, WA
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Re: Z Axis Issues

Post by Rando »

monitoringpost wrote:
Sat Oct 24, 2020 2:59 pm
Rando wrote:
Sat Oct 24, 2020 2:34 pm
That's why I opened the case of my controller and added a FAN to it. Now I don't have any stepper driver heat issues.
Care to share a photo? If you didn't tap into the relay for power what did you use?

Craig
they make 120VAC computer-style fans like this one on Amazon, just one of many. Then just wire it up in parallel with the input to the power supply.

https://www.amazon.com/SXDOOL-Cooling-B ... 08CC5VP3D/

just remember to hide it from any dust flying around! Cooling is all well and good, right up until someone throws a metal chip between the CPU pins and someone loses a controller. I'd share a picture, but it will just get you thinking...I did a BUNCH of stuff to the inside of their controller. Bad Thom. :geek:

a photo of the inside? nah..and the outside was done OFF the CNC machine...ugly! nothing special really.... blow air INTO the box over the driver boards; that will do the trick...again, IF you don't blow metal chips and sawdust into it. Mine is well underneath the table where the system runs, at the place where the least amount of chips come flying out.

Rando
=====================================================
ThomR.com Creative tools and photographic art
A proud member of the Pacific Northwest CNC Club (now on Facebook)

monitoringpost
Posts: 89
Joined: Wed Nov 02, 2011 10:40 pm
Location: Canada

Re: Z Axis Issues

Post by monitoringpost »

I'm familiar with the options for powering and fan choices - just thought Rando you'd have a picture to share! I think I'll pass - can't see how it would help much and likely would just suck in sawdust and the like to for sure than over heat components. Mine has never got hot enough that I couldn't lay my hand on it. Doubt very much that over heating is the OP issue.

Craig

monitoringpost
Posts: 89
Joined: Wed Nov 02, 2011 10:40 pm
Location: Canada

Re: Z Axis Issues

Post by monitoringpost »

BillConroy wrote:
Sat Oct 24, 2020 4:44 pm
Your post implies I would need to look at getting fan in the controller box?
Bill,

You said you've run the job a few times before without issue. I seriously doubt heat is an issue - I'd suspect perhaps a brownout or something else gremlin like. My thoughts would be to simply monitor it going forward and if the issues crops up then deal with it. If you do want to check for a heat issue and have an infrared thermometer, the steppers will typically run in the 115* F to 125* F and as low as mid 80's even. The controller - you should be able to lay your hand on it and leave it there without issue. With the aluminum case and other heat dissipating factors inside the controller it shouldn't be an issue. If you do find that the temps are significantly higher than I'd call NextWave.

Craig
Last edited by monitoringpost on Wed Oct 28, 2020 5:33 pm, edited 1 time in total.

Rando
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Re: Z Axis Issues

Post by Rando »

it's not the motors that are getting overheated. just open the box and you'll see for yourself: almost no heatsinking, and NO air movement. It's a recipe for overheating. It's happend to me, it's happened to many others. You can deny reality all you want, but it doesn't change it.

You're not already running your controller on a high-quality UPS...to prevent those brown-out problems (which would look a LOT different than what he described) and power glitches? What....you don't? Why not? You think $200 is too much to spend protecting thousands? $200 is three endmills. Sounds to me like you just lost more than that amount of money in TIME experiencing and now trying to resolve the problem. Put a UPS on it. And put that same UPS on the computer controlling it. Yes, even if its a laptop. UPSs always have better power filtering than nearly all power strips.

And yes, you can put your hand on it because the actual hot parts are buried under several inches of unmoving AIR...not the best heat removal liquid there is....take the cover off and try that on the actual driver heatsinks after a long run and it will feel very different....and likely leave a burn.

Rando
Last edited by Rando on Sun Oct 25, 2020 11:36 am, edited 1 time in total.
=====================================================
ThomR.com Creative tools and photographic art
A proud member of the Pacific Northwest CNC Club (now on Facebook)

Rando
Posts: 634
Joined: Tue Jan 06, 2015 3:24 pm
Location: Hoquiam, WA
Contact:

Re: Z Axis Issues

Post by Rando »

well, try turning off all the fans in your computer...and see how long THAT one runs....that controller is no different: there are perfectly normal operating conditions that can trigger an over-temp condition. Period. There is no conjecture or contention here. Adequate heat management is a requirement for all systems. If you want it to work at the edges of its envelope, you need to actively prevent all the normal failure modes. Otherwise, you need stay well within its envelope with shorter jobs at lower speeds and cut rates.
=====================================================
ThomR.com Creative tools and photographic art
A proud member of the Pacific Northwest CNC Club (now on Facebook)

sharkcutup
Posts: 373
Joined: Tue Mar 08, 2016 5:23 pm

Re: Z Axis Issues

Post by sharkcutup »

Hello,

I am with Rando on this the controller is susceptible to heat induction. I used to have a small fan that would just blow air across the controller eventually I added a fan inside the controller box. I have run my CNC 6 - 8 hrs. in a 78 degree shop with no problems. When I first had gotten my CNC machine I came across two distinctive suspected problems. 1.) The machine was mostly made of HDPE and that the gantry and router carriage travel on rail slides --- the problem was friction which in a lot of cases can create static. System did not have proper grounding. 2.) the Controller had no cooling fan --- the problem suspected of excessive heating.

The first problem I took care of shortly after running the machine a few times. The second was months thereafter when I came across some long duration program runs and suspected I could have a problem with the controller overheating. Better to be safe than sorry!!! Adding a Fan is cheaper than having to replace the controller!

I have had this machine 4+ years now with no major problems to speak of with many satisfied recipients of the projects created from it.

Sharkcutup
Shark HD3 Pro Plus Extended Bed with Water-Cooled Spindle
Facebook: hoganscnccrafts.com

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