Re: opencamlib
Anders Wallin
I'm replying to the list also, since others may be interested.
There are two cutter-location methods: drop-cutter and push-cutter.
You can think of drop-cutter as axial tool projection, i.e. we drop
down the cutter, along it's axis, until it touches the model.
Push-cutter could be called radial tool-projection, i.e. we push
radially (in the x or y direction) the tool into contact with the
model.
Currently it would be fairly simple to introduce a rotation (and
translation?) transformation on the STL file, recreate the
search-tree, and run drop-cutter or push-cutter on that. The
cutter-location algorithms don't need to know that the triangles came
from a rotated STL, they just operate on triangles.
This could be useful for "3.5D" machining, where the CAM-user more or
less predefines the position of the 4th axis. For example we run one
kind of 3-axis operation with A=0, then rotate to A=90 and run another
3-axis operation.
Figuring out some algorithm where the rotation angle is computed
automatically would lead to "real" 4 or 5-axis paths.
If you've read the freesteel blog Julian talks about non-axial tool
projection. This is the more general case which can be thought of as
drop-cutter, but with the tool oriented at some angle. I haven't
thought much about how to do this, but I have a feeling it's not
"rocket-science" just a fair bit of work... The same problem as above
remains: if you would have a non-axial drop-cutter function, how do
you figure out the actual 4/5-axis path?
Anders
> Hi!
> Do you think it is doable to code a 4th axis thing into opencamlib
> dropcutter tests?
> Maybe by rotating the geometry before doing the dropcutter tests,
> maybe even before creating the triangle search tree?
> Do you have any hints what would be necessary to do, and where to start?
> Or is it better to "unroll" the geometry from 3d cartesian to 3d
> cylindrical, and then use the opencamlib as it is, finally changing
> one axis i.e. "Y" to "A"?
> very nice greetings,
> Bernhard
> active in:
> Ultimaker 3d printer firmware (sprinter/marlin)
> pcb2gcode
> grecode