I'm just guessing 200 rpm because of the speed I can develop on the Mazak now wich is 10 meter/min. I would love to have some more speed available but that will come with testing.
What I intend to do with the grinder is something like this: https://www.youtube.com/watch?v=UGgR1GFOFhU This guy did it with a chinese control and used the spindle as a C axis. Is another way of doing it but I really preffer the spindle tracking method. I already have a cylindrical grinder that's waiting to be retrofitted with LCNC. In fact, right after the Mazak I plan to start working on that machine. I don't see it as a problem to compensate for the wheel radius because as you know HAL can handle almost anything. The only real problem I see is how to get a good measure of the grinding wheel as you dress it. The most primitive idea I have is to measure the wheel before placing it into the machine and then keep track of its diameter as it gets dressed. But sometimes we have to adjust the offset of the dressing tool because a diamond just detaches from the tool and then you need to correct for that difference. Although little variations in wheel radius are not that significant in such diameters (600 mm more or less) I would like to have a way to measure the wheel without stopping it. By the way these machines don't use the small CBN wheels because they are anything but new. The first thing I have in mind for measuring the wheel are two laser pointers one above the other so when the wheel "touches" the first beam you have the first point of the circumference and then the wheel continues moving until it "touches" the second beam and now you can calculate the lenght of the circular sector and hence the radius. The problem is, this is just theory and having such a system working with the accuracy needed escapes from my actual knowledge and experience in optics which is very poor. I attached a picture so it's more clear what I came up with in my head. So I guess the measure the wheel and keep track of the diameter will be my first method to compensate for the radius. El sáb., 21 mar. 2020 a las 20:35, Gene Heskett (<ghesk...@shentel.net>) escribió: > On Saturday 21 March 2020 16:11:44 andy pugh wrote: > > > On Sat, 21 Mar 2020 at 17:44, Leonardo Marsaglia > <ldmarsag...@gmail.com> wrote: > > > I intend to turn automotive camshafts, that is with a minimum of > > > 180º of base circle (sometimes called heel I think), and a maximum > > > lift of about 8 mm > > > > In that case the high resolution encoder might be good. I doubt that > > you will me machining camshafts at 20,000 rpm. > > (Especially not if the cutter needs to dive in and out) > > > > For grinding you need to consider how the contact point rolls above > > and below the centre line. I did do the maths, when I did the > > crank-grinding mock-up. But only for a circular but eccentric result. > > Another thought or 2 here. > > The weight of the grinder you'll have sitting on the crossfeed will > effect your usable spindle rpms by slowing down the maximum attainable > accel's. My nema 24, x on the sheldon, geared 2/1 has a 3o ipm max > limit, so that motor will need a serious boost in top speed to even try > doing that at 200 rpm. > > If room for its diameter, the use of a flat faced CBN wheel would > eliminate some of the math by eliminating the calculation of the wheels > up and down due to the curvature of the wheel face but I think whats > available is way too big for this. The use of CBN should however > lengthen the cutting life of the wheel compared to the alox versions, > particularly if running wet as I have seen it done in some of the you > tube videos. > > Cheers, Gene Heskett > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > Genes Web page <http://geneslinuxbox.net:6309/gene> > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users >
Grinding wheel example.PDF
Description: Adobe PDF document
_______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
