Ignoring Z limit

Another question…

Since the first carve, every time I apply power and connect to the machine, all the motors jolt a few times. Nothing moves, but if your place your hand on them, you can feel them wanting to. Sounds like someone is knocking on the table a few times. Is this normal?

Edit: I was midway through a cut without a problem, the size was off so I stopped and returned it home. I changed its and adjusted the size of the holes, and now its doing this:

Homes correctly, probes good, set X,Y, Carve! The Z axis raises and doesn’t stop when it makes contact with the limit switch, the hard stop fights with the carriage for a few seconds, and then begins to cut, and plunges straight through the material…Please help. I already swapped switches, its only the Z doing it, not a particular switch.

Here’s a video. I have to stop the carve immediately because it will lower through the material. You can hear the machine fighting the hard Z stop.

That’s the steppers engaging. It’s normal and they’ll get warm too. Check to make sure that the switch has space to actually close.

Thank you, its normal for them to hit a few times, like 5-6?

The way mine works, it’ll go up, hit the switch and then it’ll back off whatever it’s set to in the $$. I used longer aluminum spacers that I had here( from my shapeoko2) on the bolts to engage the switches. They break easily, I bought another 10 on ebay. That stopper bolt for the Z may have to be adjusted upwards a bit if it is too low so that the switch can close all the way.

I find it odd this would start happening all of a sudden? The stopper is pretty dead even with max closed position of the switch.

Is the lever straight or bent? They are straight as new, but are pretty flimsy.

They’re straight, I just swapped it with the one that was the Y axis, same problem. Homing sequence is good, but when it begins to carve, it doesn’t recognize it.

So i just ran another carve, these are all G codes from Aspire. The new carve worked perfectly, so I went back to the old one I was having problems with, and of course, plunged through the work. As I look at the toolpath on Easel, its doing exactly what the machine is doing, all the was down to the wasteboard. However in Aspire, my max depth for those cuts are .5 on a 1.5" thick piece of wood. Im going to start over and recreate the file from scratch, something is off.

Nope. Does the same thing, ignores Z limit and bottoms itself out on the material.

Can you share the gcode?
Maybe some screenshots from the toolpaths setup in aspire.

I can share the G code, but I didnt save the file, so I lost the tool path image

Tool kit.gcode (44.8 KB)

So I’m seeing max depth of 0.75" on first glance. How thick was your stock?

The limit switches are, by default, only used for homing. You can email hard limits in your grbl settings, but most don’t due to the fact that good toolpaths don’t smash limit switches and there is a risk of false triggers on a hobbyist level machine.

Wood is 1.138 thick, I just recreated the file, new depths will be .5"

A guess:
You had a start Z of 2". Depending on your setup, you may have crashed the Z on that lift. When that happens, the machine can’t retract as high as it “thinks” it did. Where the controller thinks you’re at 2", you’re actually at 1.5" because of the lost position. When you plunge to .75" (are you cutting foam?) it actually ends up at 1.25" deep.
Check that initial Z height.

I think you’re right. I’ll look at that now. Not foam, pine stock. Each pass should have been limited to .25 cuts.

Heres the new setup. I do recall seeing a 2" Z earlier…maybe even 2.5. Not sure how that would have happened

That 0.5" looks better. Make sure you preview the cut. Easel will show you what it’s going to do or you can use something like this if you move on from Easel.

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