I’ve got a piece of wood that’s 2-1/4" thick that I’m trying to cnc. I’ve also got a long 1/4" straight bit that I’m using that sticks out of the router by 2-1/8". When I do the initial probe everything looks great. However as soon as I start the program the z-assembly moves up and hits top limit and of course resets the 0 position 3/4" lower than the top of the wood surface. How to I get the z-assembly to not move up so high so it doesn’t exceed the top limit?
Did you home the machine first?
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Yes, top of the wood (z) is homed to 0.
How much clearance/retraction height do you have in you design file? It may be trying to go beyond machine limits to hit that height
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Great… thanks Mitch! You pointed me in the right direction. I forgot the z-gap was defined in the design software. Works now!
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Just to be clear ‘homing’ and ‘zeroing’ are different things. The machine will prompt you to home the machine when it first boots up and this will prevent it from crashing into the end limits. It would also throw you an error code when you load the g-code and it sees the program would exceed the limits. You can run a program without homing first but your machine will have no idea how far it can travel before it tries to run past the limits, I suspect this is what’s happening for you.
Zeroing tells the machine where your material is located, and corresponds to the zero point in your cad software.
Refer to the Homing and Zeroing sections in this post https://forum.onefinitycnc.com/t/help-my-toolpath-says-under-or-over-with-videos
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Grim, thanks for that info and the link. I wasn’t aware of the differences between homing and zeroing. Most of the stuff I’ve cnc’d is small enough that I haven’t had to concern myself with hitting the limits. I’ve typically avoided homing simply because it takes time and I also thought it was an unnecessary step. Now I know… thanks again!
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