We have had many inquiries about HOMING a milling machine. From the first NM-135s to our NM-200s, one must ask, do I really need a HOMING switch? The answer would depend on the controller software. It so happens, that MACH3 can be used to function very well without HOMING switches.
The need for HOMING switches is used to establish the machine zero co-ordinates. Once set, all G-code offsets can be used for your projects.
So, the only requirement is to move the table to a known position and preset the machine co-ordinates to zero. This can be accomplished by disabling the homing function in the “Config/Ports and Pins/Inputs Signals” menu. When this is done, anywhere you place the table and select the “Ref All Home” button, the machine origin will be located to this location.
If absolute accuracy is needed to establish a machine zero for your project, the best way to do this is by using dial indicators to measure the axis position relative to a stable machine reference or to a point on your project part or fixture. This procedure only needs to be done after each time the computer is powered up.
Next time your HOMING switch is inoperative, give this a try to keep your