Hello

I would like to design a Z axis head that can do:
1. light weight cnc milling/drilling - This will only be used to mill PCB tracks and drill PCB boards
2. Solder paste dispatching - This is used to dispatch solder paste.
3. Pick and place actuator - This is used to pick and place SMT components

One option I have is to have three separately movable Z axis heads. This is costly as it needs three separate motors, linear rails and lead screws or belts. Other option is to have just one head plate which is driven by a lead screw and moves on a linear rail. This plate can have provisions to accept an extension which can have either the spindle (for 1 above), solder paste dispatcher (for 2 above) or pick n place actuator (for 3 above), one at a time. This extension has to be easily attachable/detachable from the main head. Obviously this will also involve electrical connections, but for the moment I just want to concentrate on mechanical aspect.

With this option, how do I make sure the attached extension positions it self consistently relative to the main head all the time? Are there any standard methods to achieve this?

Thanks