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Plasma Cutter vs Oxyfuel – Difference and Comparison

One of the problems of excessive marketing is that it tends to polarize opinions to an extent where a factual comparison of two cutting processes is no longer possible. Hence, many users either swear by the efficacy or cost-effectiveness of oxyfuel cutting or hail the speed and versatility of the plasma cutter.

Though we have focused primarily on the plasma cutter reviews in the past, we believe that the best choices in any market can be made only when the alternatives are well known. To this end, we’ve come up with a short essay dealing with plasma cutter vs oxyfuel – difference and comparison.

The Difference Between Plasma Cutter and Oxyfuel

Oxyfuel cutters have far greater vintage than the plasma cutter, and till recently, dominated the metal cutting industry. One reason for this was because it depended on the traditional methodology of heating and oxidation of metals to cut them. In more specific terms:

  1. The torch blows a stream of natural gas (or any other fuel gas) onto the metal at high pressure, heating it to kindling temperature, or the temperature at which the metal oxidizes.
  2. High-pressure oxygen is blown onto the metal and this rapidly oxidizes the metal and also blows the oxide away, leading to the area of impact being emptied of metal. This area is essentially the “cut”.

As we have explained in detail while studying the best plasma cutters, this cutter works through the creation of an arc that turns a gas or air moving at high pressure into plasma. This melts the metal and the continuing stream of gas blows the molten metal aside, creating the “cut”.

The differences in the processes can be summarized as:

Pros and Cons of Each Cutter:

Now that we have gone through the first part of the Plasma Cutter vs Oxyfuel – Difference and Comparison, let us look at the comparative benefits of the two types of cutters. For this we shall assume that cutting table, electrical supply (where needed), tools and manpower costs are constant for both types of cutters, and that they are being used under similar workroom conditions.

Pros of Oxyfuel Cutter:

  • Cost of fuel: Natural gas costs as little as $0.0001 per cubic foot in North America, while oxygen costs about $0.01 per cubic foot. Both of these are cheaper than electricity and as long as the fuel is available in the area, cutting using an oxyfuel cutter is quite a cheap proposition. Note however, that due to speed considerations, the effective cost is often higher than that of the plasma cutter .
  • Portability: Where electricity is not available or proper circuitry is not available, the oxyfuel cutter can still work because it essentially needs only a minimal amount of electricity to run the internal motor channelizing the fuel and oxygen to the metal. This apart, availability of fuel can allow the unit to work even in forests and this makes it the choice unit for removal of debris from crashed airplanes and damaged trucks in remote areas.
  • Many torches can be used in parallel: If proper provision is made, a number of torches can be deployed in parallel provided they are cutting the same metal piece and the cut is itself parallel. In recent times though, plasma cutters have caught up with oxyfuel cutters in this regard.

Cons of the Oxyfuel Cutter:

  • Extremely slow speed: Cutting speed of the oxyfuel unit falls to a lowly 15 IPM (inches per minute) when the thickness of the metal is 2 inches or greater. Further, even in the 0.25 inch to 1.5-inch segment, the speed is abysmal compared to the plasma cutter. This means that the amount of oxygen spent cutting one inch is greater than the amount of electricity spent cutting the same inch using a plasma cutter. This means that despite the cheapness of fuel and oxygen, the costs are not equitable. Further, slow speed means greater man hours and this is especially worrisome in areas with high manpower costs.
  • Cannot cut many metals: Since the process requires that the melting point of the oxide be less than the actual metal, the process is confined to carbon steel. Aluminum oxide has a high melting point while stainless steel does not oxidize at all. Thus they cannot be cut using an oxyfuel cutter.
  • Preheating required: As the earlier section of this Plasma Cutter vs Oxyfuel – difference and comparison essay showed, the latter requires preheating, and this wastes time and money.
  • Inflammable gases involved: Since both the natural gas and the oxygen can explode and burn at the slightest contact with fire, working with huge amounts of gas is a health hazard.

Pros of Plasma Cutter:

  • Extremely versatile: One of the benefits of using a plasma cutter is that it is capable of cutting most metals and in doing so, provides a good option for small hobbyists and professional garage owners who have to handle a wide range of metals. Hence, while oxyfuel is fine for large enterprises, most of the smaller units today prefer plasma cutters.
  • Large range of cuts: As seen in the table above, the plasma cutter can achieve a significantly large range of cuts and piercings and this adds to the versatility of the unit.
  • Excellent Speed: Plasma cutters can cut 1-inch mild steel at speeds of 80 IPM, compared to only 20 IPM for oxyfuel options. This speed reaches a marvelous 150 IPM when the mild steel is 0.5 inches (or less) thick. Such speed is also visible when aluminum, carbon steel, stainless steel and copper are being cut. Due to such speeds, the effective cost of cutting using a plasma cutter is lower, even though fuel and oxygen are cheaper than electricity.
  • Compatibility with welders: Most of the units available in the market today support technologies that allow for usage with generator-run welders. This allows the units to double up as part-time welders as well, though the welding assembly is significantly different from the cutting one and regular use of the same machine for both purposes is somewhat unintuitive.
  • Clean cut with narrow kerfs: Due to there being no chemical processes involved, the chances of there being excess residues is reduced. This allows the cutter to achieve precision incisions with a very low kerf area.

Cons of Plasma Cutter:

  1. Dependence on Electricity: The motor runs at such high voltage and amperage that a generator or extremely powerful battery is the only alternative to mains power. This reduces the portability of the unit.
  2. Heavy and requires compressor: Products are generally quite heavy due to the inclusion of a large transformer. Further, because an additional air compressor is required, the overall assembly is made even more difficult to move around. As our studies on plasma cutters would show, both these problems are being tackled. Cutters weighing just 22 pounds are available, while the provision for inbuilt compressors is making external compressors unnecessary.
  3. Cost: Plasma Cutters, being results of a comparatively new technology, are still pricier than their oxyfuel counterparts. This too, however, is changing rapidly as technology progresses with each passing year.

Conclusion

While the actual efficacy of the plasma cutter depends on the extent to which the user has managed to carry out maintenance of the plasma cutter, the above article should suffice to impress upon you the fact that the considerations of cost and versatility give the plasma cutter a slight edge over the oxyfuel unit in all processes except those requiring exclusive use of carbon steel.

While the larger starting cost would still push some folks towards the older oxyfuel units, it should be clear from this essay on Plasma Cutter vs Oxyfuel – Difference and Comparison that the existing benefits and constant improvement are allowing the plasma variant to push ahead constantly, thus indicating that the future clearly favours the plasma cutter over even the most advanced oxyfuel units.

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