Assembling the carriage (front) drag chain and finalising the sensor wiring

Due to the way the carriage and cross slide assembly are constructed, there's no sensible means of getting the front mounted linear encoder and limit switches for the Z axis passed over to the rear, so that they can use the drag chain I've just implemented at the rear of the machine.

It only has to convey the 3 small signal cables, so the size of the drag chain is mainly dictated by the requirement to be large enough for robustness. Igus don't do anything that looks appropriate and certainly nothing that would be described as "fully enclosed".

This Chinesium drag chain from Amazon looks like a possibility, so I got myself a length of it and went from there.

I need to make u some brackets to mount the ends on the machine. Here's what we have currently:

This is the read head for the linear encoder:

Yes, those are threaded M4. Very handy.

Something like this should work for the moving end. This would attach to the moving head of the encoder using those 4 spare M4 threaded holes.

And perhaps something like this for the fixed end, which would attach to the bracket that supports the Z axis ballscrew and servo motor assembly.

Ah, but this would force the lower section of the chain to sit below the lowest reach of the bracket due to the bend radius, so a slight adjustment is required. 

With some thought and refinement, I can provide a route for the cables to emerge without needing to thread the connectors

Looks good:

Clear out the M4 threads:

And wop it op. I should provide a support under the lower section but otherwise it looks like a success from here. Obvs I could have terminated the chain just under where the current fold is but I'd then have needed to either provide a conduit for it or make another hole through the chip tray.

The various signals cables (limit switches, encoder read head, servo motor etc) are all different lengths - some too short, others too long. So this is the time to make them all the same length. Messy and slow but it needs to be done.

Combined X and Z axis limit switches:

Z axis limit switches:

Z axis encoder read head:

It's a good thing I took photos of the wiring before chopping off the connections and extending them. When printed out on the new Kyocera printer, the green and blue wires come out the same (blue) colour. Some manual notation is required! Here's the printed copy held up against the same image on the screen.

Almost done now. Then mount the cabinet on the machine and check to see if my wiring modifications were error free. And get the machine running again.....