What to look for in a plasma cutting machine: Part 1December 1, 2014 REDWIRE is news you can use from leading suppliers. Powered by FRASERS.
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You’ve done your research — plasma cutting versus oxyfuel cutting — and you’ve determined plasma cutting is the right process for you. Now it’s time to buy a machine. Where do you start?
Lincoln Electric has compiled this list of factors to consider when making a buying decision.
Determine the thickness of the metal that you will most frequently cut
Most plasma cutting power sources are rated on their cutting ability and amperage. Therefore, if you most often cut ¼-inch thick material, you should consider a lower amperage plasma cutter. If you most frequently cut metal that is ½-inch in thickness, look for a higher amperage machine. Even though a smaller machine may be able to cut through a given thickness of metal, it may not produce a quality cut. Every unit has an optimal range of thickness; make sure it matches up with what you need.
Select your optimal cutting speed
Do you perform most of your cutting in a production environment or in an atmosphere where cutting speed isn't as critical? When buying a plasma cutter, the manufacturer should provide cutting speeds for all thickness of metal measured in IPM (inches per minute). If the metal you cut most frequently is ¼ inch, a machine that offers higher amperages will be able to cut through the metal much faster than one rated at a lower amperage. For production cutting, a good rule of thumb is to choose a machine that can handle approximately twice your normal cutting thickness. If you are performing long, time-consuming cuts or are cutting in an automated setup, be sure to check into the machine's duty cycle — the time you can continuously cut before the machine or torch will overheat and require cooling. The higher the duty cycle, the longer you can cut without taking a break.
Can the machine offer an alternative to high frequency starting?
Most plasma cutters have a pilot arc that utilizes high frequency to conduct electricity through the air. However, high frequency can interfere with computers or office equipment that may be in use in the area. Thus, starting methods that eliminate the potential problems associated with high frequency starting circuits may be advantageous.
Compare consumable cost versus consumable life
Plasma cutting torches have a variety of wear items that require replacement, commonly called consumables. Look for a manufacturer that offers a machine with the fewest number of consumable parts. A smaller number of consumables means less to replace and more cost savings. Look in the manufacturer's specifications for how long a consumable will last.
Test the machine and examine cut quality
Make test cuts on a number of machines — at the same rate of speed, on the same thickness of material — to see which machine offers the best quality. Look for a plasma cutter that offers a tight, focused arc.
These are just some of the factors to consider when buying a plasma cutting machine. Stay tuned for Part 2, where Lincoln Electric will provide more buying tips.