My problem is in tool height changes. Whenever the tool height is changed, the Z axis tool travel length is changes i.e increased or decreased. so the milling goes wrong. i.e, the tool cuts my work table. is the tool height is associated with motor tuning (i.e, steps/unit). . . Can any one plz help me in this regard?
Not sure what you are meaning here. Are you using more than one tool and the new tool cuts off on depth? If yes then you either need to set all your tools up in the tool table if they are preset in holders or you need to rezero the new tool when you place it in the collet.
also I have an external ESTOP button which is connected to the PC through USB. This button is just an NO switch connected to a board and it'l be activated when pressing and triggers the space key in my computer so that the ESTOP will be activated in the controller through MACH3. What I need in this setup is, I want to stop the spindle when the ESTOP is activated. I tried the settings in mach3 general config. But no use.
First thing to say is USB is not the safest way to connect an E-Stop but thats up to you.
If Mach is in E-Stop the spindle should stop, assuming of course the spindle is being controlled from Mach, so not sure where your problem lies. Maybe I am just not understanding what you are meaning.
And my milling works properly when I setup the motor inputs under ports&pins option as Active high (direction input). I connected three limit switches for three axis but i works correctly when the direction input are setted as Active low. If direction input are stated as active high, then the machine moves reversely while homing (ref all home) I cant link these two conflicts and resolve. I want my machine and limit switches to work with active high config.
Config menu then Homing and Limits, you can tell Mach which way to home (Negative or positive) from there.
Hood