Arcs in the UV plane
05 Oct 2013 04:52 #39561
by jhllt67
Arcs in the UV plane was created by jhllt67
Hi,
I just got my machine up and running, it is a tilting head 5 axis very similar to the Vismach example config and uses maxkins. I have been messing around with the various functions and discovered that arcs are not supported in the 3 UVW planes.
I'm just wondering why this is, technical limitation, not implemented yet, gcode standard etc.
Also are there any work-arounds? I would like to use helical interpolation to drill angled holes. It seems that canned cycles are supported in those planes but the requires tool changes for different hole sizes. I guess that I could break the arcs up into line segments in the g-code but that is not ideal either.
I don't have a specific part I need to make or anything. Just curious mainly.
Thanks
I just got my machine up and running, it is a tilting head 5 axis very similar to the Vismach example config and uses maxkins. I have been messing around with the various functions and discovered that arcs are not supported in the 3 UVW planes.
I'm just wondering why this is, technical limitation, not implemented yet, gcode standard etc.
Also are there any work-arounds? I would like to use helical interpolation to drill angled holes. It seems that canned cycles are supported in those planes but the requires tool changes for different hole sizes. I guess that I could break the arcs up into line segments in the g-code but that is not ideal either.
I don't have a specific part I need to make or anything. Just curious mainly.
Thanks
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05 Oct 2013 06:33 #39566
by andypugh
A good (and very complicated) question.
I think it is under "not implemented" partly because quite what arcs in those planes necessarily are is not always clear.
For example, a knee mill could have Z as the quill and W as the knee. In that case XZ arcs and XW arcs are very nearly the same (and trivial) whereas in a 5-axis machine the W axis might be a (possibly synthetic) rotated Z axis.
But, that should not have to be a problem for the motion planner to solve, If the G-code interpreter sees an arc in UV then it only needs to send the correct UV position numbers.
One not very defensible reason for this is that XYZ are internally stored in a "pose" structure which can handle a limited level of Pythogorean stuff, whereas UVW are not, for reasons I am not clear on.
At this point in time it is something to figure out in CAM, I am afraid.
Replied by andypugh on topic Arcs in the UV plane
arcs are not supported in the 3 UVW planes.
A good (and very complicated) question.
I think it is under "not implemented" partly because quite what arcs in those planes necessarily are is not always clear.
For example, a knee mill could have Z as the quill and W as the knee. In that case XZ arcs and XW arcs are very nearly the same (and trivial) whereas in a 5-axis machine the W axis might be a (possibly synthetic) rotated Z axis.
But, that should not have to be a problem for the motion planner to solve, If the G-code interpreter sees an arc in UV then it only needs to send the correct UV position numbers.
One not very defensible reason for this is that XYZ are internally stored in a "pose" structure which can handle a limited level of Pythogorean stuff, whereas UVW are not, for reasons I am not clear on.
At this point in time it is something to figure out in CAM, I am afraid.
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05 Oct 2013 19:26 #39581
by jhllt67
Replied by jhllt67 on topic Arcs in the UV plane
Interesting, I think I will try to dig into the source code and see if I can figure out how it works (not that I could change anything, I'm an amateur coder at best).
Thanks for the reply.
Thanks for the reply.
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