First Build 5 x 12 Steel Frame CNC router

[Boyan Silyavski]

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.

Then test.Now all must work normal





About the dust, i see. You are right that dust extraction better not be choked down. I assume you will fit a kind of shoe there. Or you will extract only the fine dust not to float around in the air? I use sometimes my dust shoe only like that, without the brush attachment. Chips stay on table but no fine dust in the air.

[JAZZCNC]

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.!

[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...

[JAZZCNC]

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.

Again another obvious suggestion but got to be said to eliminate. Not got loose Pulley.?

When you say line filters on the VFD's you are talking input line filters correct?

Yes Input line Filters.

Did you Earth the Frame.?

Re: Separate ground rod then I'd say not because want to use the same ground that mains supply does so don't introduce ground loops. However I'm not expert on this and don't know the differences between American and UK electrics other than frequency.

[Scott Damman]

Again another obvious suggestion but got to be said to eliminate. Not got loose Pulley.?



Yes Input line Filters.

Did you Earth the Frame.?

Re: Separate ground rod then I'd say not because want to use the same ground that mains supply does so don't introduce ground loops. However I'm not expert on this and don't know the differences between American and UK electrics other than frequency.

I appreciate all of the "obvious" questions as it is easy to overlook items when troubleshooting... Yes confirmed no loose pulleys, I also have been watching the actual belts on the servos on X (hard to watch both of course) but it looks like the master is moving before the slave. I plan to swap cables to those motors and then swap drives and find where the issue follows. I can then hopefully pinpoint, cables, drive, motor being the culprit. (or still noise)

Frame grounded and I have a ground going to the gantry and to the Z axis to make sure each part is grounded in the frame.

So the separate ground would need to be bonded back to the ground ref in our house (as I believe this is code). My thinking here would be that this ground rod would give a much shorter path to earth for the Hf noise. Not sure it would make a difference or not just something I was thinking of trying.

One question I have is about running cables in the same drag chain, I had assumed that having good shielded cables that I could run all of the cables together in the same chain. Is this a No/No?

I have been looking into line filters to try to get some ordered for the servo drives and the VFD for the spindle.

[JAZZCNC]

Frame grounded and I have a ground going to the gantry and to the Z axis to make sure each part is grounded in the frame.

Not good idea unless you know they are isolated. It's little things like this that can easily introduce ground loops. I would remove the Gantry and Z axis earths and check again.

Also don't Earth the PC chassis to the Star point. This can cause all sorts of strange happenings. The PC PSU will have it's own path back to earth so adding another affectively creates G-loop.!

One question I have is about running cables in the same drag chain, I had assumed that having good shielded cables that I could run all of the cables together in the same chain. Is this a No/No?

If all is correct regards Grounding etc and with good wiring practices then shouldn't be problem. I do this all the time and don't have any issues.

However it's always good idea to keep some seperation of high power/frequency cables like VFD or Mains voltage in respect Signal wires. Esp if the wire runs are long which guess may be on your machine.

[Davek0974]

Also don't Earth the PC chassis to the Star point. This can cause all sorts of strange happenings. The PC PSU will have it's own path back to earth so adding another affectively creates G-loop.!

This is a major one - spent weeks debugging a plasma table build just because i grounded the PC case to the table, disconnect it and instant fix!

[ba99297]

Yes confirmed no loose pulleys, I also have been watching the actual belts on the servos on X (hard to watch both of course) but it looks like the master is moving before the slave.

Have you ever check your belts(tooth size, tension)?
Also are your motors and ballscrews bases tight enough?

[Boyan Silyavski]

Gantry have to be grounded to frame on Plasma otherwise you can weld the Hiwin balls together I believe that is correct to connect gantry to machine body whatever the machine, to avoid that bearing fault, it had its own name, but i forgot it...

[JAZZCNC]

Gantry have to be grounded to frame on Plasma otherwise you can weld the Hiwin balls together I believe that is correct to connect gantry to machine body whatever the machine, to avoid that bearing fault, it had its own name, but i forgot it...

Yes to the machine frame but not back to the Star point. Only one Earth cable should go back to this point.! Scott is runnig separate cables back to the Star point which Can/does create Earth loop.!