Z randomly dives into the project. TERRIFYING!

I am dealing with an issue where randomly during a carve the z axis dives through the project forcing me to emergency stop the project. This is not in the gcode being used. I am using fusion 360 and easel. also on a Mac laptop. I am thinking this is most likely electrical interference but I am not positive. I do run a dust collection system and am wondering if this is the likely culprit or not? I am using the 1000mm x carve with upgraded 23 nema motors and the new controller box. Please help before I lose my mind. thank you in advance for your answers.

I just tried with out any other electrical item except for the computer on in the shop. still had the same problem, it is Radom, not in the code, and caused the machine to lower the zero point making it drag the bit through the project on its way home. This is mind boggling. I also checked all wire connections and tighened them all. HELP!!! LOL

here is the file im carving at the moment but not the only one that has caused this issue. Back Body Carve correct.1.nc (2.6 MB)

last but not least my lap top is a early 2011 Mac, if this could be the issue, I have a 2017 iMac I could move tot he shop to try.

Check the pulley on the a acme scew.Is it tight?
Many hve had the set screws come loose and this causes the spindle to not lift as much as the code directs. Eventually it will not lift enough to clear material during rapid moves.

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its not an issue of lifting up to clear the wood. it literally dives the full depth of the bit, 1.5", and then moves randomly in the wood until I stop it. of course I stop it right away so I don’t know how much movement it does after the dive. but enough to ruin the piece further. after the dive, it has a lower x location for home. its infuriating.

I did check, one of the set screws was slightly loose. Ill do some test runs to see if this was the actual issue. thank you for your reply.

Simulation look okay, so I dont immideately suspect the gcode.

However - there are a lot of Z motion to clear/engage and if your Z-axis for some reason fail to retract it will “double down” into your material. In Fusion360 what have you set your retract values to?

What are your GRBL $112 and $122 values?

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i am not at all familiar with the GRBL setting nor how to check. is there a video with easy to understand instructions? I just rebuilt my Z carriage so that is not the issue. it is smooth and friction free.

Open Easel and press CTRL+SHIFT+D (Or CMD+SHIFT+D on a Mac) to open Machine Inspector.
In the Console window type $$ and press Enter
A GRBL parameter list ($x=y) will follow.
What do the mentioned $-values show you?

While an Z-axis can be smooth and friction free, at higher RPM the available torque will decrease and ultimately reach “zero” even with no load. So if the parameters are too high, your axis is stalling out. That is what knowing your GRBL-parameters may shed some light on.

here is what comes up when i do what you stated. I don’t understand it in the least. LOL hopefully ill learn something here. thank you for the help.

I also am getting a continuous stream of “alarm” codes. not sure what that is but it sounds bad. here is a screen shot of them. they are continuously scrolling.

here are the settings you asked about in fusion. I have not touched these from standard preset values. if this needs to be changed, im happy to do so, I just don’t know what to change.

Hi Carl. What are you using to run the code?

I imported your .nc file into Easel and observed no problems. It moved to position and began the cut. I stopped it, the z retracted and it moved back to home.

*I see in your op you are using easel. Seems to be something local. I would try that other pc and run without a bit or material and see if it repeats.

I think you are correct about trying the other computer. unfortunately im in a wheelchair and moving it is an issue. ill see what I can do. I may also try out the UGS to see if that solves the issue.

Have you had issues like this with other files?

yes on the same project. it happens randomly during the carve. no rime or reason that I can discern. it could happen right away or 3 hrs into the carve

Ah. You may need to do a once over and look for any loose connections. My first guess would be some interference or issue with the usb connection. Those randoms are frustrating to nail down.

agreed. I’ve tried a second usb cable, shorter, I’ve checked all the connections and they appear to be solid. im at my wits end.

Are you using dust collection and if so, properly grounded?