Why dont you consider doing what we do with the Z axis on plasma machines. I am also looking at doing a PnP machine in the new year and this will be my approach.
When we get a M3 in the gcode of a plasma job, we store the current Z position and then go through a whole process of probing the material to calculate the pierce and cutting hieghts of the torch. This is done in a component and not in gcode. I would imagine that one can do it for all axis if you know how much to correct by. On a PnP machine the part is taken to a camera or mirror that looks at the orientation of the component as it was picked up. It is then moved and turned as far as rotation and position goes to match a reference for that component. Either a picture or reference in memory. The correction that was required to locate the component over the reference is then applied to the next move or offset from the target position. When the placement is done the correction is again removed and the next move is directly to the correct location without any offsets. On 2013-11-18 18:02, Kirk Wallace wrote: > On 11/17/2013 12:42 PM, Philipp Burch wrote: >> Hello everyone, >> >> for some time now, I'm using LinuxCNC to control a dispenser to treat >> PCB panels (applying glue or globtop to electronic dies). Because not >> all of these panels are exactly aligned in the machine, a webcam sits on >> the Z joint using which I can get the real positions of fiducial marks >> on the panels. A python script then calculates a coordinate system >> offset and rotation from those positions and applies it to one of the >> G5x coordinate systems. This works OK.Why >> I would tend to not change the machine coordinate system or the >> kinematics. I see the problem more as not knowing where the target is >> rather than how to get to the target. One method might be to have a >> fixture with accurate key points. The PCB is mounted to the fixture then >> scanned to fix the target points relative to the key points. A g-code >> file is then created with the new target set, the fixture is mounted to >> the dispensing machine and the new g-code file run, repeat as needed. >> >> Or, use g-code moves to get the camera close to a target, invoke a scan >> routine to find the target (x, y, rotation), then g-code to dispense, >> repeat for all targets. >> -- Regards /Groete Marius D. Liebenberg +27 82 698 3251 +27 12 743 6064 ------------------------------------------------------------------------------ Shape the Mobile Experience: Free Subscription Software experts and developers: Be at the forefront of tech innovation. Intel(R) Software Adrenaline delivers strategic insight and game-changing conversations that shape the rapidly evolving mobile landscape. Sign up now. http://pubads.g.doubleclick.net/gampad/clk?id=63431311&iu=/4140/ostg.clktrk _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
