I figure I’ll lead with I’m fairly new to CNC and this is my first post on the forum. I was doing a probe zeroing on my thickest material yet 1.875". Probe finished and I went to run I hit start and the z dropped into the top of stock about 1/16". So then I was stuck I couldn’t turn router on (usually turn on at second bit pop up) and I didn’t know how to get out of continue pop up. So I raised bit up in chuck to let it start running so I could stop program. So then I tried a manual zeroing and same thing happened. Then I hit start and zero dropped into top of stock about 1/16 again. Probably not the best thing to do but I lifted router just enough to turn on so I could see what would happen. I then hit start and it ran the program fine just lightly cut into stock at beginning. I had just zeroed, why did it drop past point I just zeroed? Any ideas? I’ve never noticed this issue on shorter stock.
Can you post your gcode’s first 20 lines or so?
Did the Z crash at the top, even for a moment, before the plunge?
My first guess whenever this happens with thick material is that your retract / safety height was higher than your Z-axis could go. The Z-axis will reach its limit, but “think” it moved higher than it did. Zero is lost. When it comes back down, it plunges too far.
Where would I get the first 20 lines of GCode from? Newbie here.
What you are saying actually did happen. I only had about a mm between probe and bit when I started probing and it did top out on z switch. So a few questions on that. Would I need to rehome the machine to reset this or what after that happened? Also when I couldn’t fit the probe under with enough room could I have raised router in the clamp some to allow more room or is that not advised? Just trying to understand working with thick material best practices. I guess I could just plan to manual zero in the future too.
Let me know if you see anything here. I’ve been running two other programs on the same stock after homing and it is consistently dropped into the stock about 1/32 to 1/16". That is after manual zeroing.
Thanks. So I’ve adjusted the safe retract and at the beginning of program it sets correct to start the program then runs correctly. I’m still having the same issue when I go to change end mills to a ball end and then rezero the Z only. It always drops below stock top zero again about 1/16". I’m using the probe for the z zeroing. Then it always cuts low into material.
FYI this is one inch stock. If it helps to know… I build all the programs I want to run in one Carbide Create file then disable any bit changes for the first G Code save then disable first bit and enable second part of program that is done with ball end mill and save that G code. All from the same set up file with the .05 safe retract height.
Any ideas where the bit change Z zero issue is coming from.
Thanks for any help you can provide.
Tucker
gcode from second program if it helps:
%
(TOOL/MILL,0.1,0.05,0.000,0)
(FILENAME: )
()
G21
G90
G0X0.000Y0.000Z1.270
(TOOL/MILL,6.3500,3.17500,1.000,0.0)
M6 T202
M3 S8333
G0X86.995Y111.672
G0Z1.270
G1Z-2.337F317.5
G1X86.995Y44.967F1905.0
X86.987Y44.146
X86.964Y43.329
X86.925Y42.515
X86.871Y41.706
X86.827Y41.168
X86.776Y40.633
X86.686Y39.833
X86.619Y39.303