how do you guys who do this handle the wiring?
Just remove the extruder and leave all wires connected? Heat bed as well? turn it off from repetier?
Create some sort of disconnect harness(s) for the printing components?
Some other concept i didnt even think of?
Anything else i shoud be aware of?
thanks so much…
I am also trying to decide how I am going to handle the tool change between spindle and extruder.
My idea is to use a 2 positions 6 pins switch (DPDT) and leave the wires connected all the time. So I would only have to change the tool and not mess with the wires. I don’t use a heated bed.
Disclaimer:
My electronics knowledge is limited even at an hobby level so I’m not even sure this makes any sense.
pins on one side
Cooling fan ground <- D9 (RAMPS) ground -> 12V relay input signal (This is to turn on/off spindle by software. I would also have another manual switch for safety)
the other side
Extruder fan (ground) <- 12V ground (RAMPS) -> disconnected
The corresponding positives would also have to be directly connected to cooling fan, extruder fan and 12V relay positive power pin and also another ground to the relay ground power pin.
Does this stand any chance to work?
I just leave it all wired up. I usually even leave the little cooling fan going, best to put a tiny switch on this one though. That is until you just decide to build a second one… 
I leave mu hotend wired up all the time. I do have a small plug on the cooling fan wires that is from an R/C receiver battery. I also use a similar plug for the PWN signal for my laser so I can disconnect it an put it away and minimize how dusty it gets.
great thanks. Will wire it up today or tomorrow and see how a print goes got through a few mdf carves now and things are seeming good.
I’ve made three swappable Z axis so far. One for 3D printing, one for CNC milling and one for plasma cutting.
It is easier and faster to change the whole axis than to disconnect everything and having to re adjust clearances/alignments each time. All you need is an additional stepper motor, a few tubes, a bit of threaded rods and to print again a few parts.
For the wires, I made quick disconecting plugs, one for the heating element, an other one for all the fans/sensors (using basic dupont connectors) and a last one for the motor, using RJ45 plugs. Takes 3 seconds to plug/unplug everything. The whole harness can be taken apart in a few seconds too if needed. For that, instead of using cable ties to attach your harness to the CNC, I recommend you to use velcro bands. Just cable tie the harness wires together, and use the velcro bands to attach this harness on your machine, it makes maintenance super easy and sometimes it could be useful to take the whole wiring system off, like if you have electric noise interferences issues. Plus, it costs nothing.
I suggest you to consider having several Z axis, it makes tool changes and maintenance very easy, doesn’t cost much more, makes things cleaner and gives you more opportunities to fully customize each axis, so that they are as good as they can be for each function.
I just finished transitioning to Printing from routing. I took the time to make two multi pin connector bundles that include only the Printer specific connections. Extruder/stepper, hotend, thermister,and fans on one connection and heater bed (bigger wire)and thermister on the other connector. I shouldn’t have to open my electronics box when I change over.