Very often, when a fabricator is planning to buy a new machine, the most common question that arises is, which is better – oxyfuel cutting or plasma cutting? Another common question is if the particular part should be cut using oxyfuel or plasma. The debate, of course, is limited to mild steel as you cannot use oxyfuel to cut aluminium or stainless-steel plates.
What Are Oxyfuel and Plasma Cutting?
When considering metal fabrication, the cutting method you choose makes all the difference to the durability and the quality of the final product. However, before we actually compare both the cutting methods, let us understand both of them briefly.
Oxyfuel cutting uses a combination of fuel gases to heat the metal and makes use of oxygen at a very high pressure to oxidise and blow away the metal chips that have been cut. The fuel gas commonly used for oxyfuel cutting are LPG, hydrogen, acetylene, propylene or natural gas.
Plasma cutting, on the other hand, heats gases such as oxygen, nitrogen or hydrogen to very high temperatures and ionises it for electrical conductivity. An electric arc is created, which melts the metal and the gas blows away the molten metal.
Oxyfuel Cutting and Plasma Cutting – Which Is Better?
A brief look at the pros and cons of both oxyfuel and plasma cutting can give you a clearer idea of which method is best for you.
The process of oxyfuel cutting is more cost effective in terms of the setup of the cutting equipment. The oxyfuel system does not require regular maintenance. However, in terms of the application, oxyfuel cutting is limited as it cannot cut steel and aluminium, as the gas combination causes the metal to degrade. Also, in the case of oxyfuel cutting, the torch requires preheating before it can be used, which increases the cost. Oxyfuel cutting has low piercing and cutting speeds. While it takes around 30 IPM (inches per minute) for thin materials, it takes around 15 IPM for materials that are 1.5 inches thick or more. And, the slower the speed of cutting, the cost will be higher.
The biggest advantage of plasma cutting is its speed. It can cut mild steel of 1-inch thickness at around 80 IPM and the cutting speed for thinner materials is around 150 IPM. There is no need to preheat the torch in case of plasma cutting, which reduces the costs. In a single workpiece, you can get multiple pierces easily and quickly. Plasma cutting is very accurate, can be very fine and can be replicated on several pieces.
Plasma cutting can be used to cut several kinds of metals including aluminium and steel. The high speeds of plasma cutting results in faster operation times, decreased downtime, improved productivity and increased profitability. However, the main limitation of the process is that the initial cost and investment in the equipment is much higher compared to oxyfuel cutting.
When we look at both the cutting processes, oxyfuel and plasma, plasma cutting has several advantages over oxyfuel, which is primarily the reason why many fabricators and manufacturers are choosing plasma over oxyfuel cutting.