First Build 5 x 12 Steel Frame CNC router

[Scott Damman]

Make sure both servos have exactly the same settings in the servo drives themselves. I do that by copy-paste-upload from one servo to the other in the servo tuning program. So i am 100% sure they work the same. Do so in mach 3 in motor tuning tab and make sure to hit "apply". Close. go out of mach 3, then do check again the result. Then make sure the direction of motors is set right before you rip your gantry.

Boyan, I went through all the parameters manually as the drives from BST Automation dont have a computer hookup. But I was able to confirm that all parameters are the same in the drives.

JAZZCNC
Re: First Build 5 x 12 Steel Frame CNC router

May sound obvious but if you are using pulleys are they the same size.?

If this was Step/Dir setup I'd say the Step pulse was on wrong edge but with Analog IP-A then can't happen.

Does it look like it's running out over time while cutting or is it off straight away.? . . . . It could easily be electrical noise inducing voltage on the signal lines.
This would have the same affect has being told to move fractions of inch more than should. The encoders will always bring it back to zero when homing so very difficult to see.

Does it do it without Spindle Running.?
Do you have any Line filters on the Drives or VFD.? . . . If not fit some because Servo's, esp Analog don't tolerate noise in power line very well.!

Thank you for the thoughts
Both sets of pulleys and belts are the same and came from the same supplier.

It is more of a delay to start, i.e. the master motor starts moving and the slave starts up just slightly after (which racks the gantry). When it comes to a stop the master stop slightly before the slave bringing it back into square.

Happens whether the spindle is on or off.

One thing to note the cables are 1meter longer to that motor than the master motor. I wouldnt think that should cause this but maybe?

I think to your point it is likely noise, I found yesterday while cutting some other parts that my Y is undershooting its commanded position. I was cutting a part that was supposed to be 8 inches in Y and it is 7.85inch. When I run the Y without the spindle on and a dial indication its within 0.001inch... So I am going to have to dig into the noise.

When you say line filters on the VFD's you are talking input line filters correct? I will see if I can come up with some input line filters. Also want to dig into the grounding more and confirm that everything is hooked up correctly. I have everything grounded back to a single point in the cabinet and then that run to our homes earth ground. I am thinking of driving a separate ground rod for the machine to give it a shorter path to ground, good idea? The spindle is run with triple shielded continuous flex VFD cable, the cable shield is connected to the chassis of the VFD using a VFD cable connector, i.e. the shield is connected 360 deg to the chassis of the VFD. The VFD is then grounded back to the single point ground in the cabinet. Open to help on this!


Made some progress on the dust collection adapter first picture is the first half out of the mold and the second is the second half laid up in the mold.




Also worked on a support arm for dust collection tube. It bit overkill but it was fun to make...