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General Mach Discussion / Re: Spindle servo on lathe is 10% fast
« on: May 02, 2019, 03:41:57 AM »
Spindle pulleys in Mach is where you set the max velocity and any gear ratio.
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Mach3 TURN does not even have G96 (CSS) and G97 (to turn off CSS and go back to speed per rev).It does, G96 is CSS, G97 turns it off G50 is max RPM. As mentioned however it does not work correctly, the spindle speed will vary but the axis feed gets locked at the current feed/rev and converted to feed/min until a new feedrate is commanded.
Hi,
Mach4Hobby has CSS.
I suspect though that it suffers from the same fault that Mach3 does.
Mach3, according to the thread Hood linked to, makes a pretty fair approximation to constant surface speed
but cannot do Feed per Rev accurately. As was pointed out for Feed per Rev to be accurate requires that the spindle
be synchronized with the X axis and that is incompatible with buffered control system.
Mach4, despite it differences, is still a buffered control system and therefore probably not capable of accurate Feed per Rev
for exactly the same reason as Mach3. I have not tested it an Mach4 nor does my setup allow for it to be tested. I would
caution that if you require accurate Feed per Rev then Mach4 warrants investigation.....
Accurate Feed per Rev can be obtained by a C axis as opposed to a free running spindle. This is certainly capable of being
done in Mach4 and I can't imagine any reason that it could not be done in Mach3 as well.
Craig
If you want "basic turning" capability why not simply have a separate lathe profile for your milling machine, mounting the tool on the table and putting the work in the chuck? "Turn" is based on "Mill" with the mill laid on its left side then on its back. You could probably make your own screen. This could be interesting: http://www.vinland.com/CNC-Mill-Lathe.html
I can't do mill spindle 'turning' as i need to pass 25mm bar through the spindle, mill spindles can't do that
I'll try a new mill profile, designate the mill X-axis as lathe Z-axis and the mill Z-axis as the lathe X-axis, spindle will be declared as a servo spindle drive is CS-Labs setup.
See how that goes......
And also to add, CSS does not work in Mach3.https://www.machsupport.com/forum/index.php?topic=25647.0
Myth BUSTED?