floating head THC system

[cutterguy]

I am considering buying a ganntry kit from Precision Plasma LLC. Can someone explain how their torch height control system works? What do they mean by a floating head. Does it still us arc voltage to maintain cutting height? I am currently using a Plasmacam so all that is not visable to the operater.
Cutterguy

[I Lean]

It does use arc voltage for the height control during cutting. The "floating" part is how it does the initial material sensing...torch moves down until it touches material. The "floating" part moves until it closes a microswitch, then it moves up a predetermined amount, zeros the Z axis, and moves up again to the initial pierce height.

Watch this video, and you can see what it does. It's doing the touch-off sequence every pierce here. (ignore the weird torch firing, I was triggering it manually at the time) http://www.youtube.com/watch?v=aLdcgiePDU0

[WSS]

Ron's stuff is high quality. His Z slide is very accurate. Will you put a blade runner kit on it (CandCnc)?

WSS

[cutterguy]

Ya, good chance that I will go with the Bladerunner system. Do
Do you not have trouble with plate deflection on this metal? Maybe its not a problem

Cutterguy

[WSS]

We are "transitioning" to a PlazPak-4 servo system from CandCnc and will use a float head Z. If it does deflect, you can put a adjustable tension spring to help lift the Z plate on thin sheet.

WSS

[I Lean]

Mine is the Bladerunner Dragon-cut, seen in the video. With my K2 Z axis, I've only had any issues with the metal bending under the torch if it's thin (14 ga or thinner) and either warped up/not touching the slats, or over an empty area (no slats close by)

It's something to watch for when it happens, but nothing to stress about.

[WSS]

I Lean,

Cool video. The torch cycles pretty quick. I am glad to see that. Can you set the "search" down speed of the THC? I went with a K2 floater because of the size of our torches. I just got in our PN-200 today, it looks like fun. The servos are massive NEMA34 frame, except for the Z which is a NEMA24.

WSS

[I Lean]

I Lean,

Cool video. The torch cycles pretty quick. I am glad to see that. Can you set the "search" down speed of the THC? I went with a K2 floater because of the size of our torches. I just got in our PN-200 today, it looks like fun. The servos are massive NEMA34 frame, except for the Z which is a NEMA24.

WSS

Yes you can--you choose the max IPM of the Z just like normal, and you'll also set the percentage of that speed for while it's doing the touch-off, as well as where it goes to that speed.

Mine is set at 100 IPM for the Z travel, and it goes to "homing" speed 1/2" above the material, if I recall correctly. The speed of that is whatever the default was, I'm thinking it was 20%....so 20 IPM when homing.

The only catch is when it's in it's rapid mode, it won't stop if you hit the home switch. If you have your Z height set wrong, (it thinks it's higher than it is) it can rapid down into the material and just keep on going. It won't respond to the Z home switch until it's in the slower "home mode". I've had it lift my whole gantry off the rails before--glad I have a lightweight gantry at that time!