Second CNC table build, here we go again....

[Davek0974]

Yes, but then there would be a risk of losing the torch alignment when the torch clamp is released to remove the torch. Hopefully with the clamp mounted firmly from the base, it will stay fixed once aligned.

[Davek0974]

Got the floating head mount fitted to the Z-axis, probably work better when i fit a means to stop the carriage and torch falling off the bottom

[njhussey]

Dave, I'm probably being a bit thick....but how are you moving your Z axis up and down? From what I can see you've got your Z stepper mounted on the profile behind the fixed Z front plate? Is there something on the bolttom of your Z front plate that connects to the stepper behind the plate?

[Davek0974]

No, the round object sticking out of the top is the coupling for the stepper, it's just not fitted yet :)

It means i can move the z up and down by hand easily.

Inside its a standard screw type affair.

[njhussey]

No, the round object sticking out of the top is the coupling for the stepper, it's just not fitted yet :)

It means i can move the z up and down by hand easily.

Inside its a standard screw type affair.

OK I'm still being thick ....but I'm still not seeing how you're connecting your stepper/screw to the front of the Z axis, your torch holder?

That's the front of your Z, how's that connected to your stepper/screw or whatever??

[Davek0974]

Ok, looking at the diagram you quoted, the long 5mm slab at the base is the large flat vertical plate shown in my picture :)

The Hiwin rail/block in diagram is shown on the bottom left of my picture - the block is not fitted yet.

[njhussey]

I get that Dave, but not how the block and torch mount connect to the stepper?

[Davek0974]

Ah, right.

Behind the plate lies one of these -
http://www.ebay.co.uk/itm/NEMA23-75m...item4881441268

Its a standard Z-axis unit, screw drive, 2mm pitch, 75mm travel - the motor sits on top and drives the screw direct, the middle block is fixed to the gantry carriage and the upper/lower blocks move with the motor/screw.

Works well.

[njhussey]

Ah ok, so why do you need the rail and block on the plate that's moving up and down? Fine adjustment? Surely mounting the torch holder on the bottom of the plate will be enough?

[Davek0974]

Ah ok, so why do you need the rail and block on the plate that's moving up and down? Fine adjustment? Surely mounting the torch holder on the bottom of the plate will be enough?

The second rail/block you mention is the floating head, it only moves a few mm, just enough to trip a switch as the torch probes the metal surface before cutting.

You can't do initial height sensing without one.