Shapeoko 3 dropping USB connection

CNC Machines Shapeoko 3
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I have an unusual issue but my setup is also somewhat unique.

Basically I am setting up an Shapeoko 3 for use in a community workshop. To keep our insurers happy I had to implement several extra safety systems.

The CNC is in an enclosure and when the doors are open all power is cut from the router. The way this works is opening the doors triggers a relay that cuts power going to the router. The relay is energised when the door is closed and powers down when the door is open. The relay coil is 12V and is powered from a separate 12V PSU.

The problem is the CNC has developed a habit that the USB connection drops out sometimes when the door is opened. It doesn’t happen every time but from my testing it seems to happen about 1 in 20.

During my troubleshooting I have disconnected everything from the switching side of the relay but the issue persists.

The CNC is connected to a Pi5 but I have also tried it connected to my laptop and the issue persisted.

When it drops connection sometimes I can just hit “Connect Cutter” to get it back online. Sometimes I have to power cycle the CNC control board to get it to connect, and sometimes Carbide Motion keeps crashing when I hit connect until I have power cycled the controller.

So with everything disconnected from the relay it seems that just having a relay triggering in the general vicinity is causing the control board to lockup.

I’m really struggling to think of what the problem is. I’m using the V2.4e control board.

Has anybody else had issues with the control board dropping its USB connection?

I would really appreciate any suggestions as to what I can try next.

Thanks.

2

Have you grounded the machine?

Most disconnects on 3s are caused by static from dust collection. The machines are not grounded from the factory.

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Do you have a suppression/fly back diode across the relay coil? Shown as D1 below.

image
image582Ă—600 10.5 KB

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4

So not an electrician here but have an S3 and had the same problem I do not have the door relay but a full enclosure kept hearing about the static but was unsure on grounding so I put a dryer sheet hanging from a bungee cord and I havent had a static disconnect since. Other thing for you to look at is the wear of your router brushes this causes a lot of EMI issues. Also gives the enclosure a nice lavendar or whatever dryer sheet scent the wife has smell! Lol

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5

Grounding, Grounding, grounding…

Make sure the frame is grounded.
Make sure the router is grounded.
Make sure the dust collection is grounded.

Since doing all 3 I have not had a disconnect on my XXL ever since. period.

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I am having a similar experience so I will try everything possible to remedy. I have an unused UPS and will use it. I will ground the frame, also. The Makita router does not have have a grounded plug and my dust collection is presently a Rigid shopvac. Both have plastic housings and neither have grounded plugs as a result. I have read pros and cons of running ground wire around vac hoses and wondered if anyone has had a positive experience.

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GROUND EVERYTHING. LOL
static discharge will cause disconnect.

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I’ve had copper wire wrapped around my vacuum hose and connected to a ground for years, and I can say I haven’t had any static issues.

Of course, everything else in my setup has solid grounding as well.

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Make sure the USB cable has ferrite cores on either end or is extremely short.

10

My Dewalt also doesn’t have a ground wire but I added one by removing a housing screw that went into the metal body. Ran that over to a grounded conduit.

I think that 1 change made the biggest difference.

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Thanks, Nick. I have yet to do that. I have changed the router brushes and run a ground wire the length of the vacuum hose and have had good results so far. I used feel the static electricity before while peeking in at the cutter but that has now stopped. I have run a couple of 2 hour carves recently and have not had any issues. Thinking I may go ahead with grounding the router body as you have done.

12

Apologies for not updating this thread.

I knew about people reporting issues with static but I didn’t think this was the likely cause of my issues because during my testing the CNC wasn’t even moving.

I was leaning towards the relay back EMF issue, I originally didn’t add any protection as I thought everything was separate enough.

I have since added a diode to the relay coil and haven’t been able to replicate the drop out issue so I think the problem is now solved but time will tell.

Thanks to everybody that offered suggestions.

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ground
ground1920Ă—2050 274 KB

Here is how mine is done.

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I get disconnects after a minute.
May I ask
I have a copper wire here but that hasn’t helped - it wraps round the hose all the way back to an earth

IMG_3550
IMG_35501920Ă—2560 393 KB

Perhaps it has to be on the router body like you have?
Where does the other end of your black wire go?
Do you think the wire should be insulated?

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Is that an enameled copper wire you have there?
If so, it might not do much.

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ok, I will try a “proper” bit of insulated earth cable. You can see from the picture that the black mounting is earthed via the green cable. But does the router need earthing as well or are the mounting and router electrically connected?

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The router should be double-insulated (to comply with safety requirements for a hand-held power tool), but the housing/metal body arguably should be connected to ground — the aluminum mount is anodized, which may interfere with that, so the usual approach is to connect the spindle body to the dust shoe/hose which in turn go to ground.

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