The power of the waterjet machine comes from its ability to direct a thin stream of high velocity water at the material being cut. This extreme pressure of the water on its own is capable of cutting many materials that tend to be either softer or more delicate. To cut harder materials an abrasive is mixed in with the water. This abrasive causes a more powerful erosion or cut, and gives the machine the ability to process harder materials.
What is an Abrasive?
An abrasive is a fine substance that is added to the water to increase its cutting capabilities. The most common abrasive used with waterjet machines is called garnet, or more specifically red garnet. This stone has a few significant characteristics that make it ideal for high powered cutting:
- It is a fairly hard type of stone, making it a powerful abrasive
- When garnet fractures it breaks into tiny but very sharp pieces
- Garnet is not highly reactive so it is unlikely that it will have a chemical reaction with any material you are cutting
For Waterjet usage, garnet can be found in two forms. First, there is the alluvial form which signifies that garnet comes from river beds. Due to the flow of water in river beds, this form of garnet tends to be smoother and as a result not as effective for cutting purposes. The second form that garnet comes in is mined garnet. This type comes often mixed with other rock types, and therefore has to be ground down and filtered out. In the grinding process the grains of garnet acquire sharper edges thus contributing to mined garnet’s higher cutting effectiveness. Although it is more effective it is also more expensive because of the process required to acquire it.
What can be Cut Using Abrasive Waterjet Technology?
Abrasive waterjet technology is known for cutting the harder materials such as ceramic, metal, stone, and glass, in comparison to pure waterjet cutting that is often used for softer materials such as rubber, fabrics, plastics and wood. It is therefore important to understand your cutting requirements as well as the type of material you will be working on in order to get the optimal performance from your waterjet machine.