Z axis issues

This forum is for general discussion about Aspire
Post Reply
User avatar
jarm2
Vectric Craftsman
Posts: 244
Joined: Wed Jun 13, 2012 9:16 pm
Model of CNC Machine: C&CNC electronics 4x4 ext aluminum table
Location: Harpster, Idaho

Z axis issues

Post by jarm2 »

I couldn't find the previous post on my z axis issues so I will start a new one. I did find the problem and it was mechanical, not controller or software. The folks at C&CNC were fantastic to work with and we were able to zero in on a clamp type coupling that was slipping by a few thousands each time the spindle raised, causing the bit to gradually go lower into the piece. Below is some of the steps we took to find the problem.
C&CNC
Your next step has to be to remove the motor and encoder and set it up so you mark a zero point on the shaft and a pointer (youcan mount a pulley with teeth or a disc with markings) and do a bunch of moves but bring it back to the beginning and pause long enough to check it . This narrows it down to the motor/encoder /driver . If its dead on then it HAS to be mechanical . The encoder controls the shaft position . You are gaining down even on lifts
You have to start out each time at exactly he same spot. and zero the DRO . In the code after you run a series of up and down you do a return to Z zero and an M1 pause to see how far off zero you are
ME
I recoupled the z motor. I cleaned and tightened the coupling as tight as possible. Running the z tests again seemed to show a slight .02 up movement this time with three test runs. It appears something in the coupling was allowing the unwanted movement. I will cut the long file tomorrow and see if it really is solved. Fingers crossed. I will probably modify the coupling with a flat spot on the ball screw shaft and an allen screw in the coupling. It was relying only on friction and although very tight, could possibly have been slipping. Thank you for all your help in searching for the problem. Sorry about not finding the coupling issue sooner. The cut tomorrow will let me know for sure.
With the coupling locked in place and the allen screw tightened to the new flat on the shaft, I am back in business. Thanks to those who offered suggestions and helped me find the solution.
Happy carving.
Aspire 11 ViaCAD Pro 12 Corel 2019 W 10, 2.2 kw spindle wireless pendant

User avatar
Adrian
Vectric Archimage
Posts: 14546
Joined: Thu Nov 23, 2006 2:19 pm
Model of CNC Machine: ShopBot PRS Alpha 96x48
Location: Surrey, UK

Re: Z axis issues

Post by Adrian »

Your original thread was moved to the Hardware section by the looks of it as it wasn't an issue with Aspire.

viewtopic.php?f=35&t=37507

User avatar
jarm2
Vectric Craftsman
Posts: 244
Joined: Wed Jun 13, 2012 9:16 pm
Model of CNC Machine: C&CNC electronics 4x4 ext aluminum table
Location: Harpster, Idaho

Re: Z axis issues

Post by jarm2 »

Thanks, Adrian. I didn't think to look there.
Aspire 11 ViaCAD Pro 12 Corel 2019 W 10, 2.2 kw spindle wireless pendant

Post Reply