Hello Andy, and thanks for your answer. My idea is to copy or acquire the shape of the lobe using one of those testing machines for camshafts, they have an encoder on the rotational axis and a linear digital sensor to measure the elevation of the lobe as the angle changes. Using this it's very easy to generate the profile in any software for part modeling (Solidworks for example). I guess that this way it's not that tricky to generate the G-code with the tool diameter compensation, since CAM software would be doing all the job. Please correct me if I'm missing something.
I think that's pretty doable, but I was curious about using nurbs in LinuxCNC, I guess using cam software is easier having the right lobe profile, may be even easier than creating a component like you did with the eccentric turning, at least for me :) . 2012/12/14 andy pugh <[email protected]> > On 14 December 2012 01:28, Leonardo Marsaglia > <[email protected]> wrote: > > > I know there are several Cam programs that could mill a lobe, but I think > > is better to use nurbs or something like that to generate the toolpath > > without using a Cam program, the only tricky thing would be the radius > > compensation for the tool that could be done with some trigonometric > > calculations > > The tricky part is not the machining of the profile, but in > calculating the profile. For a given relationship between lifter > position and camshaft angle the calculation of required cam profile is > very much complicated bythe geometry of the follower. > A roller follower in a linear guide can be trivial if one simply > machines the cam using a milling cutter of the same diameter as the > cam follower. > Any other situation is more complicated, due to the movement of the > contact point angularly as the tangent point changes (very markedly > indeed for flat followers) and as the rocker arm swings for roller > followers. > > If you have a dedicated machine setup for the job then you can > generate the cam profile outside of the G-code. This example: > http://www.youtube.com/watch?v=FpP7iTKuWpw > Is just running a normal lathe OD turning cycle. The profile is > generated by a lookup table into a special HAL component. > > -- > atp > If you can't fix it, you don't own it. > http://www.ifixit.com/Manifesto > > > ------------------------------------------------------------------------------ > LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial > Remotely access PCs and mobile devices and provide instant support > Improve your efficiency, and focus on delivering more value-add services > Discover what IT Professionals Know. Rescue delivers > http://p.sf.net/sfu/logmein_12329d2d > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > -- *Leonardo Marsaglia*. ------------------------------------------------------------------------------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial Remotely access PCs and mobile devices and provide instant support Improve your efficiency, and focus on delivering more value-add services Discover what IT Professionals Know. Rescue delivers http://p.sf.net/sfu/logmein_12329d2d _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
