How to Choose Plasma Cutting Settings

Plasma cutting can seem complicated when you first encounter settings such as amperage, feed rate, pierce delay, air pressure, and torch height. The good news is that you do not need to guess every value.

The goal is to begin with a reliable cut chart, understand what each setting controls, and then make small adjustments based on what the finished cut tells you.

The Five Main Plasma-Cutting Settings

The most important settings are:

1. Cutting amperage
2. Feed rate
3. Pierce delay
4. Gas or air pressure
5. Torch height

These settings work together. Increasing amperage without changing the nozzle, speed, or torch height can produce a wider kerf, more bevel, heavier dross, or shorter consumable life.

Start With the Correct Cut-Chart Profile

A cut chart is a tested collection of settings for a particular combination of:

• Plasma power source
• Torch
• Consumables
• Material
• Material thickness
• Cutting current
• Plasma gas

Two different 85-amp machines may not perform identically. Their torches, nozzle designs, gas controls, arc characteristics, and consumables may be different.

Reference chart versus factory chart: When an exact manufacturer chart is unavailable, another manufacturer’s chart may provide a useful starting point. It must be labeled as a reference and confirmed with test cuts.

Step 1: Select the Material

Begin by choosing:

• Mild steel
• Stainless steel
• Aluminum

All three can be cut with compressed air, but their recommended speeds and cut behavior are not identical. Clean, dry air is essential because water, oil, and debris can reduce cut quality and shorten consumable life.

Step 2: Enter the Actual Thickness

Measure the plate when accuracy matters. Material sold as 6 mm may measure slightly above or below its nominal thickness.

The calculator accepts millimeters or inches and displays both systems. When the exact thickness is not listed, interpolation should occur only between compatible rows using the same material, current process, torch family, and gas.

Step 3: Choose the Cutting Amperage

A common beginner mistake is operating the plasma cutter at maximum current for every job. An 85-amp machine does not need to cut every plate at 85 amps.

Lower amperage is often preferable on thinner material because it can provide:

• A narrower kerf
• Better detail
• Less heat input
• Better edge quality
• Longer consumable life

The machine maximum is only a capacity limit. The cutting amperage is the current selected for the material and thickness.

Always install consumables rated for the chosen process. Do not run a 45-amp nozzle at 85 amps.

Step 4: Set the Feed Rate

Feed rate is the speed at which the torch moves across the plate.

Cutting too slowly can cause

• Thick, bubbly bottom dross
• A wider kerf
• Excessive heat input
• Rounded or melted details

Cutting too quickly can cause

• A narrow kerf
• Strong edge bevel
• Trailing or curved drag lines
• A hard bottom bead
• Incomplete penetration

Quality, Balanced, and Speed Priority

Quality Priority favors edge finish and dimensional accuracy.

Balanced is the recommended starting point for most users.

Speed Priority favors production rate but should remain within the tested chart range.

Step 5: Set the Pierce Delay

Pierce delay is the time the torch remains over the starting point before cutting motion begins.

When the delay is too short, the plate may not pierce fully before the torch moves. When it is too long, the pierce hole grows unnecessarily and molten metal can blow back toward the torch.

Begin with the chart value and adjust in small increments. A few tenths of a second can make a noticeable difference.

Step 6: Set the Air Pressure

Compressed air helps form the arc, remove molten metal from the kerf, cool the torch, and support consumable performance.

Some plasma cutters require manual adjustment. Others regulate pressure automatically. Use the setting specified for the selected machine rather than copying a pressure from an unrelated plasma cutter.

Pressure is not airflow: A regulator may show acceptable pressure while the compressor cannot supply enough air during a long cut. Check pressure while air is flowing.

Step 7: Confirm Torch Height

Mechanized plasma cutting normally uses two different heights:

Pierce Height

The torch starts farther from the plate to reduce molten-metal blowback.

Cut Height

After piercing, the torch lowers to the operating height. Incorrect cut height can cause bevel, poor arc stability, excessive dross, a wider or narrower kerf, and faster consumable wear.

Run a Test Coupon

Before cutting an expensive part, test the settings on a small piece of the same material.

A useful coupon includes:

• A straight line
• A square
• A circle
• A small internal hole
• Several cuts at slightly different speeds

Change only one setting at a time. If speed, amperage, height, and pressure all change together, you will not know which adjustment improved the result.

Read the Finished Edge

A Simple Beginner Workflow

1. Select the correct machine or reference profile.
2. Select the material.
3. Enter the measured thickness.
4. Enter the machine’s maximum amperage.
5. Choose Quality, Balanced, or Speed.
6. Calculate the starting settings.
7. Install the correct consumables.
8. Confirm pressure and airflow.
9. Verify pierce height and cut height.
10. Run a test coupon.
11. Change only one setting at a time.
12. Save the successful settings.

Final Thoughts

Choosing plasma-cutting settings is not about finding one universal formula. It is about matching the material, thickness, torch, consumables, amperage, speed, pressure, delay, and height as one complete process.

Begin with a trusted chart or clearly labeled reference profile. Use the calculator to organize the starting values, then confirm them through controlled test cuts.