Hypertherm Machine Torches FAQs
Practical answers on fitting, setting up and looking after a plasma machine torch on a cutting table, positioner or automated system.
What is the difference between pierce height and cut height?
They are two separate settings. Cut height (standoff) is the distance between the torch tip and the plate while cutting. Pierce height is the higher setting used to start the hole, so molten metal blown back from the pierce does not land on the nozzle and shield.
A common rule of thumb is to pierce at roughly one and a half to two times the cut height. Piercing too low is a leading cause of early consumable and torch damage, while piercing too high can stop the arc transferring to the plate. Take the exact values from the cut chart for your consumables, material and current.
How does torch height control keep the cut consistent?
Arc voltage rises as the torch moves away from the plate and falls as it gets closer. A torch height control reads that voltage while cutting, compares it with a target set from the cut chart, and raises or lowers the torch to hold the distance steady. This lets the torch follow warped or uneven plate.
The voltage reading also shifts as the electrode and nozzle wear, so a worn set can leave the torch sitting at the wrong height. If cut quality drifts, check the consumables and the actual cut height as well as the voltage setting.
What causes dross on the bottom edge of machine-cut parts?
Dross is usually down to three things: cutting speed, current and standoff. Cutting too slowly, with too much current or too low a standoff, tends to give thick, rounded low-speed dross. Cutting too fast, with too little current or too high a standoff, tends to leave a small hard bead along the bottom edge.
A worn nozzle is a frequent cause of dross and top spatter, so look at the nozzle first. Then change one setting at a time in small steps and compare the edge. Always work from the cut chart for your material, thickness and consumables.
How do I know when to change the consumables on a machine torch?
Look at how the parts have worn rather than changing them after a fixed number of hours. Replace the nozzle if the orifice is gouged, oversized or out of round, and replace the electrode when the pit in the insert has become too deep. Falling cut quality, more dross or a changing bevel are your cue to inspect.
Running parts until they fail can ruin the plate and damage the torch itself. Keep a note of arc-on time or number of starts for a typical set so you can plan changes, and replace the electrode and nozzle together where the maker advises.