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My Z -axis sometimes looses height during the milling process, so in the end my spindle gets stuck and the machine cannot move anymore. I suspect it is the adjustement of the black part here:
https://www.makerfr.com/wp-content/uplo ... cnc-41.jpg.
Can anyone explain how it works and how it can be adjusted to keep my spindle from dropping?
Thanks,

Laurens

Hi Laurens,

Elzet a écrit : ↑13 déc. 2020 12:27 My Z -axis sometimes looses height during the milling process, so in the end my spindle gets stuck and the machine cannot move anymore. I suspect it is the adjustement of the black part.

Are you loosing a lot of height ? Maybe the anti-backlash nut is not the right one. Or maybe it is the TR8 screw which is not the right one. One of them could be not lead: 2mm.
If the both are right, to set the anti-backlash, you need a thin hexagonal nut and a setscrew. Usually they come with the anti-backlash nut. Look at STEP 31 or 32 to know how to mount these parts on the anti-backlash nut. Then tighten the nut just enough to eliminate the play. Do not forget to apply a drop of thread lock on the nut before to tighten it.

See ya

Hi HTeatre,

Thank you for your quick and useful reply. I wasn't aware of this brilliant manual, as I build my machine sometime ago. Until now it worked well, but clearly all the vibrations have had their effect. Step 31 and 32 tell it all. I will get the thread lock tomorrow tighten the screw and see if this solves my problem. And I think it is a good idea to lock many more bolts in the machine so I am afraid I will have to unscrew and fasten a lot of bolts the next week.

Many thanks,

Laurens

Elzet a écrit : ↑13 déc. 2020 15:49 Hi HTeatre,

Thank you for your quick and useful reply. I wasn't aware of this brilliant manual, as I build my machine sometime ago. Until now it worked well, but clearly all the vibrations have had their effect. Step 31 and 32 tell it all. I will get the thread lock tomorrow tighten the screw and see if this solves my problem. And I think it is a good idea to lock many more bolts in the machine so I am afraid I will have to unscrew and fasten a lot of bolts the next week.

Many thanks,

Laurens

... And sorry to have forgotten to write "in the assembly manual" behind STEP 31 and STEP 32. You succeeded in finding the manual, that's the most important.

See ya,

Hi Gilles,

So I took the Z assembly apart to check all tolerances and tighten the bolts with thread lock. After re-assembly I started testing the movement. Manual movement is (as far as I know) is normal.
Then I noticed the problem is probably not mechanical. My Z-motor has difficulty starting and makes first some strange noises without moving. When the movement starts, sometimes it moves not in the right direction. When checking the wiring I noticed the wire to the A-connection of the driver is slightly melt. That is probably caused by a (too) high current.



So now I am afraid it is either a problem with the motor or the driver or maybe even both. Do you have any suggestion how to proceed?

Thanks,

Laurens

Hi Laurens,

The motor seems to work properly, isn't it ? In my opinion the only issue you could have with the Z motor could be a short-circuit on one of its coils. But in this case, the Z motor would not run. You can test there is no short-circuit in one of its coils with a multimeter. Select the ohmeter mode on the multimeter and test the 2 coils circuits. You should measure a small/medium resistance for only 2 pairs of wires, and the values should be the same for the 2 pairs. If the 2 coils seem to be ok, you could do a simple test inverting the motors of 2 drivers/steppers (for example connecting the Z motor on the X driver/stepper and the X motor on the Z driver/stepper). Run a milling file and look at the displacements of the X axis. If there is an issue with the X axis displacements, that means the Z driver/stepper have a malfunction.

See ya,

Hi Gilles,

Thanks to your suggestions I finally found the source of the problem. I measured the resistance of the motor coils. That showed the motor was OK. And then I noticed the grey wire had a very poor connection to the driver. So I reconnected everything properly and my machine works again. I am really happy with that.

So many thanks and a Very Merry Christmas to you!

Laurens

Hi Laurens,

Great ! Thank you and I also wish you a Merry Xmas !

See ya