What is a Floating Head?
When it comes to Plasma Cutting, it's important to understand that the material is rarely flat or perpendicular with the cutting torch. Because of this we need a way for the machine to know where the top of the material actually is in relationship to the current X and Y coordinates. To solve this problem we use a method referred to as a "Z Touch-off or Torch Touch-off". This is a way for the machine to probe the top of the work-piece in an effort to set the Z height offset (Z origin). This probing occurs every time we begin a cut. In general, there are two common ways to achieve this. The first is by using the torch consumable shield and the work-piece as a electrical switch so that when they contact, it triggers an input on the machine control that then sets Z to "0.000". This method works great as long as your work-piece is free from Rust, Paint, etc and that your consumable shield is in good shape. So if your not in a perfect world, this method carries pretty low process reliability along with it. It's unfortunate that many manufactures still use this method because it's easier to implement than a Floating Head. The Floating head is a device that allows the torch to float in the Z positive direction in order to trip a mechanical switch. They are a fairly tough device to design and some designs work better than others. Most manufactures floating head designs look much different than each other because of the tight design requirements. Think about it, the head has to float very freely in the Z positive direction only and return to the bottom position without any delay, it can't have play in any other direction or cut quality and precision will suffer. Some designs require a mechanical adjustment of spring pressure when cutting on thin materials that deflect easily.
The image above is of our floating head that we designed for our Xmotion Plasma Cutting machines. We decided to design a magnetic torch break-away right into our floating head assembly to keep it sleek and compact. The Floater base and Floater body are machined from 6061 Aluminum. The floater slide's up and down with 4 precision roller bearings guiding it along a machined track. We keep a tight hold on the torch with a Machined UHMW Torch holder that clamps together with 6 socket headed cap screws. The Torch Holder and Floater body are guided together with a tapered boss and pocket design and held together with neodymium magnets. The breakaway is rigid and play free, it only detaches if a "shearing" event occurs. This will save your very expensive torch from being destroyed during a machine crash!