How to choose, fit and look after the one-piece cutting and gouging cartridges used on this style of plasma system.
What is a one-piece cartridge and how is it different from a traditional consumable set?
On cartridge-type plasma systems, a single cartridge takes the place of the separate shield, retaining cap, nozzle, electrode and swirl ring found on a traditional torch, so there is less chance of building the stack up wrongly or mixing parts.
Because it is one unit, you replace it as a whole rather than changing the nozzle or electrode on their own. Cartridges are made for one family of torch and power supply, so check in the manual that the one you choose is listed for your system.
How do I tell which type of cartridge I need for the job?
Some cartridge systems use different cartridge types for different processes, such as hand cutting including drag cutting, mechanised cutting (which can sometimes be used by hand if you hold a stand-off), gouging, and specialist work. Some are colour-coded, which helps stop parts being mixed up.
The colour is a quick check, not a substitute for the part number in your manual. Each type also comes in different current ratings, so match both the type and the rating to your unit and the work you are doing.
Can I use a hand cartridge on a machine torch, or the other way round?
Hand and machine torches are designed for different jobs, and their cartridges are listed separately by process and current rating. A mechanised cartridge is made for a machine torch working on a cutting table, while hand cartridges are made for a hand torch. Some operators use a mechanised-type cartridge by hand with a stand-off, but that depends on the torch and the maker's instructions.
Do not assume a cartridge from a different torch style will fit or cut correctly. Look up your torch in the cartridge table in the manual, or ask our team to help you check before ordering.
How do I make sure a cartridge matches my power supply and torch?
Start with the manual for your power supply and torch: it lists the cartridges that suit it. Compare the part number with the one on the cartridge you are replacing, and with the current rating of the unit you will be cutting on.
Some cartridge systems read information stored in the cartridge so the power supply can set the right mode for the job, which makes choosing the right type more important than with loose consumables. Cartridges for a larger or smaller unit in the same family may look similar, so never choose by appearance alone.
What is the difference between a maximum-control and a maximum-removal gouging cartridge?
Gouging cartridges are for removing metal, such as old welds or defects, rather than cutting through. Typically there are two styles: a precision type for small amounts of metal and shallow, accurate gouges, and a heavy-removal type for deep or wide gouges. If you are new to gouging, the precision style is the gentler place to start.
Use a gouging cartridge in gouge mode and a cutting cartridge in cut mode. Keep the torch at the small stand-off the maker describes, because molten metal can splash onto the cartridge and damage it. Hot metal sprays out when gouging, so wear the protective equipment named in your manual, such as gloves, eye protection, hearing protection and protective clothing, and point the torch away from people.
What is an ohmic ring and do I need one?
An ohmic ring is a small clip-on part used with a mechanised cartridge on a cutting table. It connects the cartridge by a wire to the torch height control, which uses ohmic contact, the electrical connection made when the torch touches the plate, to find the surface of the metal before each cut.
It is a separate accessory, not part of the cartridge, and it is only relevant where a torch height control uses this method. Hand cutting does not need one. Check your cutting table or height control documentation to see whether it is required, and how many rings you are likely to use.