The Fabricator - Sample Issue

If you’re maintaining the proper travel speed, the sparks will exit the workpiece at a 15- to 20-degree angle.

CFIGURE 1 An air filter and dryer help maintain the air quality needed for optimal cutting.

Improving manual

plasma cutting quality

Get more life; fast, clean cuts > > >

By Don Keddell

Perform a Preflight Check

Plasma cutting is easy to learn, and cutters are simple to use. In fact, it’s so easy that many users go right to work as soon as they remove the unit from its packaging. However, that approach may not optimize your plasma cutter’s capabilities. Here are some tips and suggestions for best practices that will increase your efficiency and precision and prolong the life of your plasma cutter and consumables.

Read the Manual

The first and most important step is one that many users fail to do: Take the time to read the manual thoroughly and familiarize yourself with your particular plasma cutter. It pays to do so because the manual contains important information on getting the most from your plasma cutter.

Note that plasma cutting produces fumes and gases that may be hazardous to your health. Proper ventilation and attire are required. Please review your owner’s manual for important safety information on the proper practices used and attire worn for plasma cutting.

Develop a “preflight routine” for using your plasma cutter, starting from the back of the machine and working forward.

1. Check the power cord to make sure it is in good condition and that it is plugged into the correct type of primary power supply. Some units allow you to plug them into any power supply from 208 to 575 V. Other units require a specific voltage, so it is up to you to make sure the unit is plugged into the correct power supply and any power selection switches are correctly set.

2. Check your air supply to make sure you have the correct airflow and pressure entering the machine. Your owner’s manual should list the air requirements.

3. Dry air is important for plasma cutting because it maximizes cutting capacity. Install an air filter and/or dryer on the machine, if it does not come equipped with one (see Figure 1). Check, clean, and replace the filter and dryer in accordance with the manufacturer’s recommendations. It is important to have some type of sealant on the connection to decrease the risk of an air pressure leak.

4. Connect the torch, if it is not already connected.

5. Make sure all of your consumables are in place and correct for the job and that they are snug and secure. Overtightening the cup can result in intermittent cutting.

6. If applicable, select the proper process. On some high-output machines, a switch allows the user to choose between cutting and gouging.

7. Turn on the machine.

8. Check the air setting (see Figure 2). The pounds per square inch (PSI) setting may be different for cutting and gouging. On some plasma cutters, you can turn the amperage down to zero, which turns on the airflow and allows you to set the correct pressure.

9. Set the output to the correct setting.

10. Check the ground connection to the workpiece. Although plasma can cut through painted metal, it does require a solid connection on a clean part of the workpiece as close to the work area as it is practical to do so.

11. Make sure you have all of your safety gear in place. Your owner’s manual will have more details, but generally you want the same type of protec-

CFIGURE 6 Angle the torch forward to cut the last section of the metal at the end of a cut.

tive gear as you wear when welding. If the table is wet and you lay your bare arm on it, you can become part of the circuit and receive a shock, so make sure you are wearing welding leathers, along with proper gloves and eye protection. Usually a No. 5 shade is the minimal eye protection required, but darker shades may be needed, depending on amperage. See your owner’s manual for the manufacturer’s recommendation. A face shield also is recommended.