Water knife and plasma cutting: Comparing their differences

Water knife cutting

Water knife cutting systems break down materials by pushing a mixture of water and abrasive (usually garnet) through ceramic nozzles. The mixture shoots out of the nozzle at over 50,000 PSI and can cut through almost any material. In other words, the water knife cutting system is a high-speed corrosion system.

Plasma cutting



Unlike water knife cutting, plasma cutting uses compressed gas and electricity to cut the material. The process involves forcing compressed gas at high pressure through a narrow opening where it comes into contact with an electric arc.

When it comes into contact with an electric arc sent through the nozzle, it causes a reaction. The gas used for this process can be nitrogen, oxygen, argon, etc., depending on the metal type and thickness. In addition, the gas is heated until it reaches a certain temperature level and enters the fourth state of matter, plasma. The plasma produced during this process is so hot that it can cut metal cleanly at high speeds.

Flexibility of materials

While both techniques can cut metal, they differ in the range of materials they can easily cut and the thickness of the material.

In terms of material flexibility, the water knife has the upper hand. Because it can cut through almost everything on Earth. However, common metal materials it can cut include steel, aluminum and copper. It can also cut other materials such as styrofoam, rubber, textiles and paper.

Plasma cutting, on the other hand, can only cut conductive metals. It works by combining electrons with a gas to produce a plasma arc for cutting. Still, this limits its cutting ability compared to a water jet. However, since most metals conduct electricity, this does not pose a challenge to cutting. Common metals cut using plasma cutting include aluminum, steel, copper, alloys, gold, titanium, and stainless steel.

Therefore, for material choice, water knife cutting wins the debate between water knife and plasma cutting!