5-axis kinematics
29 Oct 2011 20:55 #14393
by andypugh
Replied by andypugh on topic Re:5-axis kinematics
hempul wrote:
I was trying to explain that reading motion.toolofset.z is not the correct way to proceed.
If you look in the file menu, then at "edit tool table" you will see that the tool table has a column for W offsets. If you put the tool length in there, then the kinematics code will compensate correctly (as it uses W). As EMC2 has seen a change in W-offset from the tool table it won't (or shouldn't) f-error when you G43.
You might also find the various versions of G10 interesting.
I have set up my ini and hal-file to activate all nine axis and the AXIS display seems to
know what I want to do. The kinematics however do noting for the u,v,w-axes. What
I have to do is thus code for the transformation to the joints according to the current
plane set by the G5x or the G92 command.
...
How can I read the tool diameter or should I put the diameter in another row as well
so it can be read the same way as motion.tooloffset.z ?
I was trying to explain that reading motion.toolofset.z is not the correct way to proceed.
If you look in the file menu, then at "edit tool table" you will see that the tool table has a column for W offsets. If you put the tool length in there, then the kinematics code will compensate correctly (as it uses W). As EMC2 has seen a change in W-offset from the tool table it won't (or shouldn't) f-error when you G43.
You might also find the various versions of G10 interesting.
Please Log in or Create an account to join the conversation.
30 Oct 2011 12:59 - 30 Oct 2011 13:16 #14421
by hempul
Replied by hempul on topic Re:5-axis kinematics
Here is my message again but without pictures. I tried to show the effect of having som distance beteen the joints.
I think I now understand some of the problems concerning the tool change.
If the angular joints A and B is set to zero, the new position is to be achieved only by moving the Z joint. However if A and B joints does not comply to the presumed zero requirement, the new position move will include all linear joints.
This is not a problem since the G43 may be executed in a preferred position after a tool change.
I tried to execute all axis after the G43 but that did not help.
In order to keep the controlling point unchanged I do need the tool length and the tool diameter. So far I have only tested with the offset.w parameter and looks ok. It is now possible to rotate an A,B setting around the C-axis with a constant controlling point.
Concerning my last mail about a fixed plane. Forget it! I have learned that u v w are following the current tool position pointing in the w direction no matter how G92 is used.
What I intended to do is still simple enough. A tool tip on a fat shaft can mill a deep hole by rotating the angle needed to avoid the fat shaft, at the same time as an u v rotation take place. The angle for this set is defined by the G92. Then the movement through the hole can not be performed by a w-move as I assumed, because a w vector will keep changing direction, but it is not much more difficult to use an x, y, z-vector. Have I got it right? Trigonometric can be so confusing.
I have recently started to test all joints but I haven´t made any spindle yet, so there is more fun to look forward to with this great software.
I think I now understand some of the problems concerning the tool change.
If the angular joints A and B is set to zero, the new position is to be achieved only by moving the Z joint. However if A and B joints does not comply to the presumed zero requirement, the new position move will include all linear joints.
This is not a problem since the G43 may be executed in a preferred position after a tool change.
I tried to execute all axis after the G43 but that did not help.
In order to keep the controlling point unchanged I do need the tool length and the tool diameter. So far I have only tested with the offset.w parameter and looks ok. It is now possible to rotate an A,B setting around the C-axis with a constant controlling point.
Concerning my last mail about a fixed plane. Forget it! I have learned that u v w are following the current tool position pointing in the w direction no matter how G92 is used.
What I intended to do is still simple enough. A tool tip on a fat shaft can mill a deep hole by rotating the angle needed to avoid the fat shaft, at the same time as an u v rotation take place. The angle for this set is defined by the G92. Then the movement through the hole can not be performed by a w-move as I assumed, because a w vector will keep changing direction, but it is not much more difficult to use an x, y, z-vector. Have I got it right? Trigonometric can be so confusing.
I have recently started to test all joints but I haven´t made any spindle yet, so there is more fun to look forward to with this great software.
Last edit: 30 Oct 2011 13:16 by hempul.
Please Log in or Create an account to join the conversation.
30 Oct 2011 14:05 #14426
by andypugh
Replied by andypugh on topic Re:5-axis kinematics
Just to be even more clear, according to Chris (who wrote 5axiskins) nothing should be connected to the two 5axiskins.. pins. They should be set to a fixed value in the HAL file, then tool length changes should be done via the tool table, using the W column.
Please Log in or Create an account to join the conversation.
01 Nov 2011 07:35 #14477
by hempul
Replied by hempul on topic Re:5-axis kinematics
I am not convinced that we have a mutual understanding, but I believe that you have guided my thinking in a better direction. Some misunderstanding may perhaps initiate some new ideas as well.
Thanks!
Thanks!
Please Log in or Create an account to join the conversation.
Time to create page: 0.218 seconds