Machine coordinates and their "stability"

[kucharzb]

Hello,

I wonder how do you approach the subject of machine coordinates - I mean when I finally setup my router so that I have it in 0,0 machine, after few uses or if the servo has some error there start to be slight differences from the "real" position in regard to machine coordinates. This would not be problem if the position of the tool sensor wasnt in machine coordinates or other stuff like probably future tool holder for the tools.

And since there is no way to "reset" them, I need first to move machine to "real" 0,0, then turn off motors and "virtually" move it till maschine coordinates in software also show 0,0 and then turn the motors again on.

Am I missing something or this is just the way it works and I just need to "recalibrate" machine every now and then? I would like to have my machine coordinates somehow linked to homing switches in order to be able to recalibrate it, but does it make sence? Can someone shed some light on this subject?

[ger21]

Machine coordinates should be set by homing the machine to home switches. It should be homed each time you turn on the machine. Once homed, a properly setup machine should not be losing position.

[kucharzb]

obviously, but I am talking about a case when it somehow loses position - also home switches are not 100% precise, like there are always some small discrepancies of 0,01mm - after lets say 100 homings there will be some differences. Not to mentions error of servos or such.

[ger21]

also home switches are not 100% precise, like there are always some small discrepancies of 0,01mm - after lets say 100 homings there will be some differences.

They make very precise home switches that are as accurate as you need them to be.

And since there is no way to "reset" them, I need first to move machine to "real" 0,0, then turn off motors and "virtually" move it till machine coordinates in software also show 0,0 and then turn the motors again on.

You said servo motors, but I'm assuming you meant stepper motors? IF you are doing this with stepper motors, there's a very good chance that the motors are moving when you turn them back on, as steppers will jump to the nearest half or full step (don''t recall exactly) when powered up.

The most accurate method of homing is to use servo motors, and home to the index signal in the servo motor.

[kucharzb]

yes - at the moment I am using CL steppers. Servos are planned for future.