Machine cutting path not programmed

I had my machine go ‘rogue’ today and plow, at high speed, my new and expensive compression bit into through the wasteboard and across some t-track before the bit snapped and I hit the E-stop about the same time.

Is it possible this is caused by running the router and the controller on the same circuit? What is the consensus about what causes this?

My simple answer is ‘yes’, voltage transients from a brushed motor can effect low voltage signals and almost always with unwanted results. There are a lot of variables that can play into that though.

In contrast, I have been running the router and controller on the same circuit all along. Additionally, my router power cable (though shielded) successfully runs in the same drag chain raceway as the axis cables. Our utility power is particularly stable and clean as the supply is from a stand alone utility co. transformer along with all house filtration.

I’ve noted there have been a couple of Z axis height errors that I’ve not been able to trouble shoot, thus they may be related to router caused voltage spikes.

Has your problem occurred more than one time? You might try air cutting with no bit while switching the router on/off to see if you can replicate it.

I love when someone gives such a basic solution as “You might try air cutting with no bit while switching the router on/off to see if you can replicate it.” and I realize, this is awesome advise. Why didn’t I think of that. An “air cut” while powering the router on and off would be the risk free way to possibly see if the router causes interference. Awesome advice.

I’m just asking a relatively obvious question, but have you used the file before? Are you sure it’s not programed to ‘go rouge’?

In my experience, having the router and controller on the same AC circuit should not cause an issue. There is enough power conditioning for the controller than any induced EMI on the AC line should not affect the controller operation.

Now, induced EMI from the router on the control lines of the steppers is a different matter. That is possible, and if it is happening, it can be very difficult to debug because it is usually random.

How old is your router? If the brushes are worn, the router may generate a lot more EMI due to the extra sparking within the motor. Secondarily, if you have a drag chain, there might be some coupling there, though I am still not convinced about the real world effect (anyone with empirical evidence I’m all in for changing my opinion).

Phil’s advice for air cutting is a good one - I’d do the same with the shop vac too. You might have a static electricity problem as well. Static gets a lot worse in the winter months if you are in one of those seasonal locations.



It only happened once, and I was really pushing the speed limit on the machine at the time. I think I was cutting at 250"/min or something like that. Since I dropped back to ~100 (1/4" bit through plywood) I haven’t had any problems.