cnc codes

hi everyone,
now there is another machine i have to fix with cnc contorl but i don't know the codes of it. there is a mechanical problem (?) on an axis, so that the movement of the axis causes vibration. but when i was trying to find something, i saw that when i use G0 code the vibrtaion does not occure but when i use G1 vibration occurs again.
i learned that G0 is rapid traverse, and G1 is linear interpolation command.
but what is the difference that causes the vibration ?
thanks

tny said:

hi everyone,
now there is another machine i have to fix with cnc contorl but i don't know the codes of it. there is a mechanical problem (?) on an axis, so that the movement of the axis causes vibration. but when i was trying to find something, i saw that when i use G0 code the vibrtaion does not occure but when i use G1 vibration occurs again.
i learned that G0 is rapid traverse, and G1 is linear interpolation command.
but what is the difference that causes the vibration ?
thanks

Click to expand...

G0 moves move the axis at its maximum feed rate. You can do G1 moves at any feed rate which you need to set by adding an 'F' code to the G1 block. See if you can determine if the vibration occurs at all speeds or just at the lowest feed rates.

My first guess is that there is a "Gain" problem with the axis drive. However, if this system has been running with no problems in the past, you could be looking at a mechanical problem which shows up at certain speeds.

Mechanically there are a few things you can look at. The coupling between the motor and the ballscrew. Check the ball nut for looseness. Check the coupling between the encoder and the motor. Sometimes the encoder coupling fails and will work fine in one direction but not the other. So, see if the vibration occurs in both directions.

Check for "lost motion" (Backlash). Feedback issues could cause what you are seeing.

I hope this gives you a starting point.

Hmmm. We had an Acroloc that had a vibration problem when traversing left or right. We changed the ballscrew, motor, etc, and it never got better.

Ours shook worse during higher speed though. We basically slowed down the one of the gain values on that traverse, that lessened the vibration. The only issue we had with doing that, was with milling circles, the differences in acceleration on the axis caused oblonged holes.

We never could fix the problem, and eventually just phased the machine out for a new one.

I don't know much about CNC codes though.

If it has brush type servo motor take the brushes out and blow the motor out with an air hose. Also check motor cables.

Check the lube system. Make sure the gibbs are lubed up good and ball screw is in good shape. Look for looseness in the nut. If they get worn they can grab. While looking for looseness talk to the operator. Ask if its been holding size on the parts. Backlash in the screw can cause oblong holes chattering etc. Push & pull on the tables you may be able to feal backlash.

What type of control? What type of drives/motors?

my cnc has delta tau controller and faldıc drives. but the axıs with problems, the drive has no name/ mark or etc. there is only a code and when i tried to search at internet i only could find some japanese (or sth else) documents.
i will try the axes with different feed rates.

the machine is a prototype and i didn't worked before.
it was bought before i come to my company, i didn't make it, but now i have to fix it!
that is the real problem

If its never run before the mech side should be good. I would still lube it up good before I got started. Sounds more like a gain problem. Keep in mind that some drives have gain settings as well as the one in the controller. Also Delta Tau makes drives. You may want to check thier web site and see if you see anything that looks like what you have. You should have a feedrate override that will reduce the speed by a %. Move it with the high feedrate and slow it down with the override.