aarongough
Stainless
- Joined
- Oct 27, 2014
- Location
- Toronto, Canada
Hey All!
I know many of you will already know/have used the procedure shown in this video, but I know there are many newer people who will not know how to work out where backlash is coming from on a CNC machine, so I figured I would put together a video! This is something that I would have loved to have available when I was getting started working on machines.
In the video I cover the basics of how to work out where the backlash is coming from, as well as disassembly and reassembly of the Z axis with indicator checks before and after, as well as little tips along the way.
This procedure should apply to most CNC machines, though it may be more difficult on machines with tensioned screws where access to the end of the screw might be impaired. In this case I'm working on my Fadal VMC15.
There are some things I had to cut or skip over in order to make the video watchable:
1) The best way to measure backlash is with all backlash compensation in the control turned off. To do this on a Fadal you type this in at the command line: `bl,1,0,0,0` with the first `1` being the axis number, in this case the X axis. You would need to repeat this for each axis.
2) On a Fadal you would set the backlash comp afterwards by entering the measured backlash the same way: `bl,1,2,2,2` would enter 2 tenths of backlash compensation at the start, middle and end of the ballscrew. You would need to repeat this for each axis with your measured values.
3) It's a good idea to remove power from the machine when your head/hands/fingers are anywhere near a pinch point or unguarded belt, etc... In the video I keep the power off when doing disassembly and then only power back up when I am clear of the machine. Note that the machine cabinet has an overhead LED light that is not powered by the machine.
If you guys have any suggestions on how to make this process easier, or any tips/tricks that you've picked up over the years please let me know!
Hope the video is helpful to someone!
-Aaron
I know many of you will already know/have used the procedure shown in this video, but I know there are many newer people who will not know how to work out where backlash is coming from on a CNC machine, so I figured I would put together a video! This is something that I would have loved to have available when I was getting started working on machines.
In the video I cover the basics of how to work out where the backlash is coming from, as well as disassembly and reassembly of the Z axis with indicator checks before and after, as well as little tips along the way.
This procedure should apply to most CNC machines, though it may be more difficult on machines with tensioned screws where access to the end of the screw might be impaired. In this case I'm working on my Fadal VMC15.
There are some things I had to cut or skip over in order to make the video watchable:
1) The best way to measure backlash is with all backlash compensation in the control turned off. To do this on a Fadal you type this in at the command line: `bl,1,0,0,0` with the first `1` being the axis number, in this case the X axis. You would need to repeat this for each axis.
2) On a Fadal you would set the backlash comp afterwards by entering the measured backlash the same way: `bl,1,2,2,2` would enter 2 tenths of backlash compensation at the start, middle and end of the ballscrew. You would need to repeat this for each axis with your measured values.
3) It's a good idea to remove power from the machine when your head/hands/fingers are anywhere near a pinch point or unguarded belt, etc... In the video I keep the power off when doing disassembly and then only power back up when I am clear of the machine. Note that the machine cabinet has an overhead LED light that is not powered by the machine.
If you guys have any suggestions on how to make this process easier, or any tips/tricks that you've picked up over the years please let me know!
Hope the video is helpful to someone!
-Aaron
