I forgot to clarify. Usually you don't touch off for X coordinate in G54 because your centerline is always the center of rotation of the chuck. So basically you only use Z axis touch off for different part lengths.
And the only time you need to find the centerline is whenever you mount a drill on your turret. I rarely do that, but a dial indicator on the chuck could be used to dial by hand around the drill fixture and adjust the X position until it's centered. El sáb, 3 dic 2022 a las 21:54, Leonardo Marsaglia (<ldmarsag...@gmail.com>) escribió: > Hi John, > > From what I understand you're talking about a normal parallel lathe so > here are my thoughts: > > >> The Z axis is more interesting. Before homing I imagine the tail stock >> has to be loosened and moved all the way to the right as far away from the >> headstock to ensure finding a home switch. Or a home switch could be >> somewhere in the middle but then which direction to search? >> > > I think the safest setup in this case (given your Z axis can crash with > the tailstock if you forget to move it all the way to the right) will be > having the home switch towards the chuck side (with a proper > independent limit switch right at the left of the home switch to avoid > crashes when homing). This way you can set up your homing sequence to first > home the X axis to move it to a safe place and then home the Z axis towards > the chuck. > > How does one determine, with that tool tip, where the lathe centerline is >> and set that so G54 X is 0.000? >> > > I think you're asking about tool setting. If you have tool fixtures that > ensure that whenever you change your tool you get the exact same tool > position then it's just like a CNC turret. You just take a skim cut on the > diameter (or maybe use some fine paper to gauge the tool against the > workpiece) and then measure and input the diameter (or radius depending if > you're in G7 or G8) in the touch off popup. > > > >> The chuck can be 3 jaw or 4 jaw, 5C colletor even a faceplate or the >> arbor for turning between centers. In other words 5 different Z locations >> relative to that G53 Z=0 position found when homing. >> >> And if the work is chucked in and sticks out 3" then do we try and make >> that end G54 Z=0? >> > > Exactly, you're going to have to touch and set every tool Z coordinate and > also your G54 Z coordinate with respect to your works end face. > > > > El sáb, 3 dic 2022 a las 21:32, John Dammeyer (<jo...@autoartisans.com>) > escribió: > >> What with playing around with my new tool setter and trying to decide >> where to put it I've come up with another set of questions which I've not >> really asked but now has been bugging me for a while. >> >> Home switches for a LinuxCNC controlled lathe. For the X axis I can see >> this as pretty simple as usually nothing impedes movement outward. Place >> it at the end of travel and it can serve as both a home and limit switch. >> >> The Z axis is more interesting. Before homing I imagine the tail stock >> has to be loosened and moved all the way to the right as far away from the >> headstock to ensure finding a home switch. Or a home switch could be >> somewhere in the middle but then which direction to search? >> >> Alright. So we've established a pair of X=0, Z=0 for home and this is >> set into the G53 X and Z locations. As I see it the next problem is with >> tools. Put a carbide insert cutter into the tool holder and it extends out >> to the centerline and to the left of the carriage. >> >> How does one determine, with that tool tip, where the lathe centerline is >> and set that so G54 X is 0.000? >> >> The chuck can be 3 jaw or 4 jaw, 5C colletor even a faceplate or the >> arbor for turning between centers. In other words 5 different Z locations >> relative to that G53 Z=0 position found when homing. >> >> And if the work is chucked in and sticks out 3" then do we try and make >> that end G54 Z=0? >> >> In the past for non-CNC, say I have a DRO on the lathe, I'll face off the >> end and then set Z to 0.000. If I want to turn 2" I'll move the carriage >> until the DRO reads -2.000. At this point I could reset Z to 0.000 or just >> make all cuts go from 0.000 to -2.000. >> >> Next if scratch the surface with the tool and set G54 Z=0.000 and then >> cut a pass at 0.010" I've now made the surface round with respect to the >> rotation. If I measure it at 1.020" in diameter then I now know the real X >> 0.000 centerline is 0.510". Set the G54 X value to 0.510" and from then on >> I can specify a final diameter and X positions for each cut which may >> already exist in the G Code. >> >> It's all about finding the reference positions on the lathe. Change tool >> and it needs to be done again. How is it generally done with LinuxCNC. >> Is there a tutorial for that somewhere? >> >> Thanks >> John >> >> >> >> _______________________________________________ >> 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
