Flame Cutting

Oxy-flame cutting has been utilised in one form or another for hundreds of years. It is perhaps the crudest form of thermal profiling, although developments have increased its accuracy. It is generally only used for cutting carbon steels.

Advantages include the ability to process very thick section, it is very tolerant of poor material, and the initial equipment cost and subsequent running costs are quite low, thereby allowing very competitive cut-part costs.

Disadvantages include low accuracy, the minimal amount of detail achievable and a pronounced taper of the cut edge.

 

Plasma Cutting

Plasma cutting is used to cut any electrically conducting metal, and works by blowing a high-speed gas jet towards the material to be cut. An electric current is used to turn the gas to plasma, which is hot enough to melt the material, and the cut takes place.

Advantages include increased accuracy over flame cutting combined with a smaller heat-affected zone. It is capable of cutting much thicker materials than laser technology, and the initial capital costs, although higher than flame, are lower than laser.

Disadvantages include high running costs compared to flame cutting (comparable to laser cutting); it is generally less accurate than laser technology, its consistency is suspect, and the range of materials is limited to those that conduct electricity.

 

Water Jet Cutting

Water jet cutting comes in two flavours - pure water and abrasive. The first employs high pressure water to carry out the cutting, the second mixes an abrasive dust (usually silicon, or sapphire) with the water jet to assist the cuting process.

The major advantage is it is not a thermal process, and therefore there is no heat-affected-zone, and materials that give off dangerous gases when cut using heat are completely safe to cut. Because of this water jet cutting offers in-matched flexibility and versitility with regard to the type of materials that can be cut. This combines with reasonable accuracy, and a very smooth cut edge.

Disadvantages include its cost - capital and running costs tend to be roughly equivalent to laser cutting, but the cut speed is lower, therefore leading to higher part costs. It is less accurate than laser cutting, and is not really suitable for cutting thin polished materials.

 

Others

There are various other cutting processes employed in industry. These include metal powder cutting, metal arc cutting, oxygen lance cutting and chemical flux cutting. These are all thermal processes and similar to laser, plasma or flame cutting principles outlined here. There is, as usual, some excellent information available on wikipedia should you wish to delve!