Improving Cut Quality

We sometimes receive calls from people who have questions about cut quality. When talking about cut quality, cut angle and dross are two of the things we hear about the most.

Cut angle: Although the ideal is a square cut, there will  be times when you wind up with a positive (more metal removed from the top of the cut) or negative (more metal removed from the bottom) cut angle.

The first thing you’ll want to do if you have a cut angle problem is determine the cause. Is the angle occurring because of a mechanical problem or is it an operational issue? A simple test will help you determine if the cause is mechanical. Make a test cut and measure the resulting angle. Next, rotate the torch 90° in its holder, make a second cut and measure that angle. If the two angles are the same, then the problem is likely caused by your plasma or drive system. 

If the two angles are different, then the problem is likely with your torch-to-work distance and the solution is to adjust your torch height, or if you are using a torch height control, adjust the amperage. Lower your torch height or decrease your amperage to correct a positive cut angle. Raise your torch height or increase your amperage to correct a negative cut angle.

Dross: Although dross is inevitable when cutting with plasma, there are things you can do to minimize it as much as possible. Dross falls into one of three categories: excess dross, low-speed dross, and high-speed dross.

Excess dross—lots of dross on the top edge of both pieces of the plate—results when the torch or voltage, if using a torch height control, is too low. The solution is to simply adjust the torch or the voltage in small (5 volts or less) increments until the dross is reduced.

Low-speed dross forms when the torch’s cutting speed is too slow and the arc angles ahead. It forms as a heavy, bubbly deposit at the bottom of the cut. If you’re seeing this type of dross, then the solution is to increase your cut speed.

High-speed dross forms when the cut speed is too fast and the arc angles behind. It forms as a thin, linear bead of solid metal attached very close to the cut and is firmly attached to the bottom. To reduce high-speed dross, decrease the cutting speed and the torch-to-work distance.

If you have further questions about this technical tip, you can give the Hypertherm Technical Service team a call at 800-643-9878 or send an email to