I have a quick question regarding my Z axis. I’m new to CNC’ing and got my OX running and it is working great, I am very impressed. I have a slight problem when milling multiple parts on a sheet of plywood. After milling a few shapes, I notice the Z axis is dropping ever so slightly but I can see it plunge a little bit deeper by say the 4 shape it cuts and obviously bogs the router. I can see by the coupler that it has in fact gone down ( by locating the grub screw hole orientation) and with a manual turn while milling, I can lift it back to position and it runs fine after being corrected on the fly. Is there a thread that anyone is aware of where I can trouble shoot this issue? Both the X and Y axis are running perfectly and so is the Z except for on longer jobs where it seems to compound itself over each additional shape. My wheels are tight and not slipping so could it be backlash? Oh and my spoiler board is parallel to the gantry so it’s not that. Any help would be greatly appreciated! All the best and thanks in advance.
What drives the z axis? Belt? Screw?
Acme screw, with an anti backlash nut. I just read a tip from another member in another post suggesting to keep the Z axis motor always energized as the weight of the bit and dust shoe may be enough to pull it down when not energized. Sounds like it may be a start!
Yes, I had the same issue with myOX. Using a heavy router and if I don’t keep the stepper energized at all time it would slowing ‘slide’. Everything powered off, it only took a light pressure to manually do ‘slide’ downward.
I also switched Z stepper from a NEMA 17 to a strong NEMA 23, a similar model to my X and Y steppers. Runs firm and cool since.
After my sixth rebuild, I used a belt drive. It works fine now. I used an adapter plate, 9mm 3t belt. I had tried four couplers. I was ready to weld the joint so it would not slip. The weight is distributed better and the Z motion works well.
Glad you got some help. Setting to energize the motor is easy, but you prob ably know that already. I also read that “some” friction, tight wheels is your friend. Watch the heat in that z axis motor as holding is when it gets hottest. Sounds like we have similar setups.
This is a good group and have helped me get past some issues. Good luck going forward.
If you set your motors to hold at full power they will get really hot just sitting there.
Hey thanks all for the info! I set my z motor to be energized all the time and found it did quite well and doesn’t get hot at all. BUT! After cutting for a while, the router did take a dive, much deeper than it had before but again after a lot more cutting. I had to hit stop and it happened twice, so it held the correct z position for much longer but when it did drop, it did so much deeper both times. I’ll give it a few more rounds to make sure these occurrences weren’t just a fluke and report back.
Oh and I am running Nema 23’s with a Dewalt DWP611 so it isn’t overly heavy I wouldn’t think.
I haven’t tuned the pots on the motors from their factory settings maybe the z needs more juice? Just guessing here.
Just a follow up incase anyone else runs into what I did. It seems like it was in fact the pot setting on the tinyg board for the z motor. As soon as I upped it, everything went perfectly. I noticed that I was not able to rotate the motor by the coupler by hand which meant it had the proper torque and by leaving the z motor energized all of the time, it hasn’t dropped once since. Nor has it heated up, So thanks for the help! Much appreciated.