I understand the most of your idea and it seems to be good, but i don't have clear if i should use the spindle in rpm mode, or as rotary axis in degree mode... because my first idea was to use 2 axis ... one rotary and the second linear, like a normal mill.
Another question would be... how can i generate my profiles with that component, an idea that comes to my mind to apply the offsets would be using a gauge to measure the original lobe and then transpose those points as offsets to the different positions of the lobe. And what do you think about milling the cams with a rotary axis and a X axis, like normal mill? that would be simpler since i can generate the profile with any cam software. Thanks in advance. Regards. 2010/5/5 Andy Pugh <a...@andypugh.fsnet.co.uk> > On 5 May 2010 19:00, Leonardo Marsaglia <leonardomarsagli...@gmail.com> > wrote: > > > > So andy, you think that with G33 i will have the wait for the index pulse > as > > if i'm doing a regular thread along the Z axis? and because of that it > > wouldn't be quite right for making lobes..because the movement won't be > > continuous Correct me if i didn't understand > > It is worse than that, really, as it will only do straight, linear > moves which always start at the index pulse. > A cam is made of at least 2 arcs (and probably more) starting at > different times during the revolution. > > I think that a HAL module to offset X by an amount dependent on the > current spindle angle is the most likely solution. There is a utility > called "comp" that makes this rather easier. > http://linuxcnc.org/docs/html/hal_comp.html > You would wire the X-axis-position-command into the new function, and > then thoe output would be a synchronously-offset X-command to feed to > the PID or stepgen function. The function would need a reverse-path to > take the actual position, subtract the offset, and pass that back to > the axis-feedback pin so that following errors would still be > detected. > One reason I like this approach is that it means that you don't need > any special postprocessor, you can use simple G-code and let the HAL > module read the cam profile out of a file. (This also means that you > can change profile very easily) > You would probably still use G33, but only to define the amount of > extra cut per rev to apply on top of the profile generator. > > Depending on how fast your X-axis is, this would also work with a > conventional lathe tool rather than a milling cutter. It wouldn't be > as fast though. > > -- > atp > > > ------------------------------------------------------------------------------ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
