Guidance on additional spindles and tool change.
- PotbellyMachine1
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18 Aug 2016 00:15 #78966
by PotbellyMachine1
Guidance on additional spindles and tool change. was created by PotbellyMachine1
I am currently working to add 2 additional spindles to my cnc router. Each spindle will have independant vertical movement via dedicated steper motor and drive. Is it possible to operate each spindle as a seperate joint and switch which one responds to Z during a tool change? I am currently using a parallel port setup.
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18 Aug 2016 00:44 #78969
by andypugh
Replied by andypugh on topic Guidance on additional spindles and tool change.
It might be easier to link the extras to (for example) the V and W commands.
re-allocating Z is possible, but you will have a "bumpless transfer" issue, I suspect. Your change-over code needs to move the stepper or one axis into the exact same absolute position as the other before switching.
re-allocating Z is possible, but you will have a "bumpless transfer" issue, I suspect. Your change-over code needs to move the stepper or one axis into the exact same absolute position as the other before switching.
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18 Aug 2016 01:02 #78970
by PotbellyMachine1
Replied by PotbellyMachine1 on topic Guidance on additional spindles and tool change.
Does it need to be in the same position in Z only or in X and Y also? I had hoped I could use tool table offsets for the X and Y values and simply return to a standard safe height before making the change and the machine would automatically correct X and Y.
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18 Aug 2016 08:53 #78978
by andypugh
Yes, X and Y offsets will handle the different spindle positions.
The problem that I am considering is that there is only one HAL signal that corresponds to the Z position (axis.0.motor-pos-cmd) and that ends up as being almost an arbitrary number of steps that have been sent to the stepgen since switch-on. Depending on how long the homing move has been this number can be almost anything. For three step-generators to share this number you need to take precautions to make it correct for all of them.
This machine might be easier to configure in the new "master" branch because then you can configure it as an XYZZZ machine, and all three Z motors can home independently. You could then simply enable the stepgen on the motor that you want to move, and do a bit of fiddling with the feedback signals (stepgen software-feedback) to stop an f-error being triggered by their inactivity.
When you enable a spindle Z-axis the spindle will then travel to the correct new position at a speed and acceleration corresponding to the stepgen limits, rather than the axis limits. If you always return to home before switching those moves should be small.
If you don't want to use the Master (development) branch then you could consider using the gantry hal component to allow each Z to home separately.
Replied by andypugh on topic Guidance on additional spindles and tool change.
Does it need to be in the same position in Z only or in X and Y also? I had hoped I could use tool table offsets for the X and Y values and simply return to a standard safe height before making the change and the machine would automatically correct X and Y.
Yes, X and Y offsets will handle the different spindle positions.
The problem that I am considering is that there is only one HAL signal that corresponds to the Z position (axis.0.motor-pos-cmd) and that ends up as being almost an arbitrary number of steps that have been sent to the stepgen since switch-on. Depending on how long the homing move has been this number can be almost anything. For three step-generators to share this number you need to take precautions to make it correct for all of them.
This machine might be easier to configure in the new "master" branch because then you can configure it as an XYZZZ machine, and all three Z motors can home independently. You could then simply enable the stepgen on the motor that you want to move, and do a bit of fiddling with the feedback signals (stepgen software-feedback) to stop an f-error being triggered by their inactivity.
When you enable a spindle Z-axis the spindle will then travel to the correct new position at a speed and acceleration corresponding to the stepgen limits, rather than the axis limits. If you always return to home before switching those moves should be small.
If you don't want to use the Master (development) branch then you could consider using the gantry hal component to allow each Z to home separately.
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15 Sep 2016 22:42 #80479
by PotbellyMachine1
Replied by PotbellyMachine1 on topic Guidance on additional spindles and tool change.
I have the first additional spindle in operable condition now. Presently I have been operating it by using it as W. I attempted to use the tool table for offests but the X and Y values seem to have no effect. I included G43 in the program to make it use the offset i think?
The offset seems to be X+6.25" Y-1.3125"
Current useable table area is X 56" Y 28"
I did note that the help document said that X and Y work on a lathe and mentioned Z for a mill and I would assume diameter.
Do I need to modify something to use the X Y offsets on a mill style machine? I did tool change correctly i think as the machine prompted at each M6. (The config i was using has the manual tool prompt) I am curious to see what the screen looks like in axis if i get the tool offsets to work.
I was able to use G54 for the main spindle and G55 for the second one so i could avoid having to manually offset X and Y coordinates when I use W. Unfortunately the display shows the actual machine movement so it isn't very easy to verify program. For example my drilled hole done by W does not appear in the slot done by Z in axis even though on the part it works.... Would the tool offsets appear the same in axis?
I am still interested in the tool change to switch spindles even if I can't make axis match the part as it would seem to make using available Cam software easier...
Is there a recommended way to run two versions on one machine? Would prefer to not lose my current functional setup.
How long until the new Master is the mainstream version?
Thanks
The offset seems to be X+6.25" Y-1.3125"
Current useable table area is X 56" Y 28"
I did note that the help document said that X and Y work on a lathe and mentioned Z for a mill and I would assume diameter.
Do I need to modify something to use the X Y offsets on a mill style machine? I did tool change correctly i think as the machine prompted at each M6. (The config i was using has the manual tool prompt) I am curious to see what the screen looks like in axis if i get the tool offsets to work.
I was able to use G54 for the main spindle and G55 for the second one so i could avoid having to manually offset X and Y coordinates when I use W. Unfortunately the display shows the actual machine movement so it isn't very easy to verify program. For example my drilled hole done by W does not appear in the slot done by Z in axis even though on the part it works.... Would the tool offsets appear the same in axis?
I am still interested in the tool change to switch spindles even if I can't make axis match the part as it would seem to make using available Cam software easier...
Is there a recommended way to run two versions on one machine? Would prefer to not lose my current functional setup.
How long until the new Master is the mainstream version?
Thanks
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16 Sep 2016 08:19 #80486
by andypugh
Replied by andypugh on topic Guidance on additional spindles and tool change.
[quote="PotbellyMachine1" post=80479 I attempted to use the tool table for offests but the X and Y values seem to have no effect. I included G43 in the program to make it use the offset i think?[/quote]
G43 will only have any effect if a tool is selected.
At the very bottom of the Axis GUI I think it tells you the current tool offsets, you can check there.
Are you sure that the offsets are in the tool table for the tool you selected?
G43 will only have any effect if a tool is selected.
At the very bottom of the Axis GUI I think it tells you the current tool offsets, you can check there.
Are you sure that the offsets are in the tool table for the tool you selected?
It could be quite a long time. The more people that test it and report no issues, the sooner it will be the released version.How long until the new Master is the mainstream version?
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