A Quick Guide to Buying a Plasma Cutter
Are you thinking of buying a plasma cutter? Its can be overwhelming to purchase equipment that is new to you, not to mention there are so many models and manufacturers and models to select from.
As a start, there are a few questions you should ask yourself:
> How often in a day do you plan to use the equipment? What duty cycle should it have in other words?
> What type of electrical service is available where you plan to use it? Is it 50 amp 220 volt single phase, or maybe 30 amp 110 volt single phase? What other equipment will be using the same circuit at the same time?
> How much portability are you looking for? Will you use it strictly in your shop or outside as well? Ca you supply the machine with compressed air when you bring it to a remote location? Will you be using an air bottle or portable compressor? How can you provide electric current onsite?
> What material are you going to cut and what is its probable thickness?
> Will you only do manual cutting exclusively, or will you probably use your plasma cutter with a CNC cutting machine? Typically, higher the plasma cutter amperage output come with a greater duty cycle at lesser amperages. A lot of people think that a higher-capacity machine is always better, but this isn’t true. Fabricators usually consider oxy-fuel as superior to plasma for cutting steel that have a thickness of .5 inch or more; this is because of the 4 to 6-degree bevel in the cut face made by the plasma. You won’t notice it in thinner materials, but as the thickness increases, it becomes more obvious. Also, plasma has no advantage over oxy-fuel in terms of speed at thicknesses beyond .5 inch.
It is almost useless to buy a plasma cutter that cut 1.5 plate, if you will be using acetylene for the work anyway. If you intend to cut non-ferrous metals like stainless or aluminum, which could not be cut by oxy-fuel, think 50 to 80 amp 220 volt plasma cutter. If you’re going to use your plasma cutter outside the shop sometimes, you have to consider getting one of new breed of semi-portable types. These are little powerhouses weighing below 100 lbs., but they have the ability to cut .75″ to 1″ in a snap. You’ll be needing a compressor or bottle of air, plus a portable generator.
If you think you may automate your plasma cutting at some stage, you should choose a unit that uses a low frequency starting circuit. A high-frequency start works like your car’s spark plug. Instead of using a relatively lower voltage pilot arc to start the plasma process, it relies on a high voltage spark, which causes electrical interference like destroying files, locking up the computer, and so on.
Source: Plasma Cutter