You have learned the basics of plasma cutting and are ready to do some cool projects. Not so fast! There’s still more to learn, especially if you’d like to achieve high cut quality. Here’s a list of tips to keep in mind as you take your new machine for a spin.
1. Check consumables
Consumables tend to wear with each cut, so it’s good to inspect them regularly. Check the tip and the electrode for spattering and pit; if slag is present in any holes, it’s best to replace both consumables. You’ll also want to avoid cutting excessively thick materials, which causes the consumables to deteriorate faster.
Additionally, ensure the amps rating of the cutter and the underlying consumables match. If your consumables are rated for a max of 50 amps, but your cutter maxes out at 80 amps, you will burn through them sooner.
Healthy consumables are key to achieving optimal quality cuts, so take steps to improve their durability.
2. Cut from the edge
When possible, start cutting from the metal’s edge. If you start over the workpiece, the sparks will blow back into the torch while it attempts to burn through the metal, damaging your consumables.
If you can’t start from anywhere but the middle, angle the torch to about 45° until it’s gone through, then reposition it to square against the workpiece for the remaining cut. This will make the sparks speed past the torch tip instead of into it after they blow up.
3. Secure the earth clamp
Like welding, CNC plasma cutters come with an earth clamp and a torch, which are required to form the electric cycle that ignites the arc. Make sure to secure this clamp to clean metal; if possible, secure it to the workpiece itself. Avoid clamping to any dirty or far away metal, as this can affect the cut quality.
It’s also crucial to periodically inspect the cables for worn spots and loose connections–these can inhibit the electrical flow.
4. Achieve proper travel speed
In plasma cutting, it’s necessary to vary travel speed according to the dimensions of the material. When cutting thinner material, lower the amperage and switch to a lower-amperage tip to achieve a narrow kerf. For thicker material, set the machine to full output to get a cleaner cut.
One of the indicators of ideal travel speed is the arc exiting the material in the opposite direction of travel (roughly at a 15 to 20 degree angle). If the arc goes straight down or sprays back instead, it means you’re either moving too slow or too fast. Get the travel speed right to reduce dross and improve plasma cut.
5. Trace the path before cutting
For both short and long cuts, practice your movements without pulling the trigger to ensure you have ample freedom to make one continuous cut. Stopping and restarting in the same spot typically brings irregularities in the cut edge and is also hard to do.
Another tip is to make a sample cut on the same type of material that you’ll use for the project. This helps you figure out the right travel speed and settings.
6. Check gas and air quality
To achieve better cut quality, ensure your air is clean and dry. If particles are in the air, use an inline filter to counter the issue. Likewise, if you’re using a multi-gas or oxygen system, it’s smart to invest in high-quality gas along with correct-sized gas lines and regulators.
You should also check for gas leaks and restricted airflow; if found, contact the gas distributor for help.
7. Evaluate edge rounding
Edge rounding is similar to bevel but forms a rounded instead of a sharp shape. Although some top edge rounding is normal during plasma cutting, improper gas pressures and cut height could result in excessive rounding. Arc density is another factor; the denser the plasma arc, the lesser the chances of top edge rounding.
Edge rounding is a great indicator of whether your cut quality will be low or high. If rounding occurs at both the bottom and top edges of the material, remedy the issue by lowering the current (amperage).
8. Inspect the table
Sometimes, improving cut quality has more to do with the table or motion than the plasma arc. Inspect your table to see if it cuts at the right speed or generates unnecessary vibrations or motions. If the table is giving out, it might be time for a replacement.
Squickmon’s is recognized for its CNC plasma table engineering. Our specialists can advise you on which CNC table is the right fit for you. Contact a knowledgeable expert today at 877-786-8325. We’d love to help you improve your cut quality and recommend more essentials for your production line.
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