Hello all,
I've been a member for some time but never posted before. I just finished a colossal build of my machine that I've been designing, building, redesigning and rebuilding for many years now. It is a gantry router type setup but it's geared toward metal machinning.
Attachment 275238
Everything works great and unlike my previous machines where working on metal was more like grinding (the chips were dust) and I could only take light cuts, this machine is biting in and making actual milled chips and I can finally take aggressive cuts and do high speed machining tool paths with high feed rates/aggressive cuts.
On to my question:
I currently align the gantry to the table (the two 1.5x4.5 80-20 extrusions in the middle of the machine) by clamping a dial indicator to the z-axis and jogging the x axis back and fourth turning individual ball screws by hand to "skip" motor steps until it's perfectly aligned to the table. It has to be this way because I do relatively decent precision metal work and things have to be square.
Currently both of my stepper motors are driven by the same pulse/dir signals but they have two separate drivers.
I noticed that if I jog the gantry into an obstacle (or otherwise do something irregular) which causes the Y axis (gantry forward and back motion) to skip steps.... this immediately throws alignment out of whack and I have to tear down my current setup, clean table, clamp dial indicator and do all of that again which is a big pain.
Now I could in theory create limit switches and align them perfectly but limit switches don't have good repeatability.
My absolute best idea (but as much as I like the geeky and over-complicated vibe of the idea I cringe at the idea of having to write the macro to do this):
-Wire the controllers to have independent pul/dir controls
-Setup one of them a SLAVE A axis
-Write a mach 3 macro that will use a touch probe to jog to the table and actually:
---measure the angle of the gantry vs table,
---disconnect slave axis and jog it or the master axis to adjust for the angle.
Once again, I LOVE the thought of doing this but really don't want to actually code the macro (I smell a lot of grinding sounds and crashing gantries, bent touch probes...so on).
Any other ideas? Does anyone else do this kind of stuff?
Thanks for looking.