THC Floating head needs to be spring loaded?

[Normsthename]

I am in the process of converting my CNC 3 axis machine to Plasma.
I have the Campbells Design THC300 arriving very soon, and I am purchasing a Hypertherm 1000 Plasma Cutter
I have seen a few photos of floating head designs, but none of them appear to be spring loaded.
Does the torch need to be spring loaded or do you just let gravity do its thing?
The microswitch will offer a little bit of spring but not a lot!

Also the designs I have seen don't seem to allow the torch to be able to continue on upwards if a fault develops, and the Z axis feels the need to ram the plasma torch into the bed
Is this needed or just overkill?

Thanks

Andy

[Torchhead]

Spring loading is NOT needed and actually a negative bias spring (canceling out some of the weight of the torch and cables) is needed if you cut thin material. Any downward deflection of the material will throw off your pierce height.

If you are paranoid about the Z going to far just mount a second switch above the Z home and make it a limit to stop all movement. I have been running a table with a floating head for over 5 years and I have always been fast enough to stop it from destroying anything during a home (touch-off) move. You just need to keep the slide for the floating head clean and lubricated. Mechanical switches are very reliable.

[Normsthename]

Thanks Torchhead for your input
If the 'floating' head only has to trip the microswitch, it only needs about 1/2" of movement???
The roller microswitch I have bought only has about 3.5mm of travel before it is tripped.
I have seen photos of people using 4 1/2" Linear Slide rails for the torch to slide on.
Seems like a lot of expense to just give a tiny bit of movement???

Andy

[barnon]

I put my home-slide at the motor lead-screw. It's isolated from the X,Y and Z slides. Doesn't add any more play to the system.