There are a lot of different torch designs and consumable parts choices from different manufacturers....so a single "rule of thumb" simply will not apply to them all. As already posted....with major manufacturers (like Hypertherm) you get detailed recommendations for pierce height, pierce delay, cut height, cut speed, amperage and choices of consumables for each material type and thickness. The nozzles (some manufacturers call them a tip) used in good quality plasma cutters are precision manufactured and engineered to provide best cut quality, speed and consumable parts life for a specific thickness range. Plasma cutting nozzles almost always perform best at their maximum amperage recommendation. Operating a 45 amp nozzle at 30 amps will decrease the arc energy density and produce lesser cut quality, operating a 45 amp nozzle at higher amperages will quickly erode the nozzle orifice....shortening the life of the consumables.
If your question alludes to determining the correct plasma cutter for the application....then it is always best to look at these three specs from the manufacturer of the plasma cutter:
1. Recommended Production Cut thickness. The thickness that the systems duty cycle is rated at. Cutting thicker and you will get shorter a shorter duty cycle.
2. Recommended Maximum Pierce Thickness. This is the maximum thickness that the torch will typically pierce (in a mechanized cutting application) without damage to the consumables.
3. Maximum Severance thickness. Under ideal conditions the maximum thickness that you can cut with an edge start (piercing not recommended).
Jim Colt Hypertherm
Farmwelding wrote:How do you figure out the settings for plasma cutting specifically amps. Is there a rule like 1 amp for every ten thousandths thickness or something like that?