Abrasive - how this works and how to choose the right type of abrasive

The abrasive used in water jet cutting is typically a Garnet type of 80 up to 120 microns in diameter. The quality of this abrasive has a great influence on the cutting power of the water jet. The abrasive must have a high cutting efficiency, but cause low wear on the focusing tube and mixing chamber, create very little dust and be environmentally friendly.

The following factors must be considered in determining a suitable abrasive :-

• The grain of the abrasive must be less than half the focusing tube diameter

• The hardness of the abrasive has a direct effect on the cutting power of the water jet

• The dust content of the abrasive must be low or it creates sludge in the waste water

• Quality and repeatability of the cutting results

The differences between the abrasives available on the market are large, so care must be taken in choosing a suitable supplier. GRS has suppliers of high quality abrasive that can be recommended.

Starting to Cut

Before any cutting process can start, the water jet must pierce the material. Therefore the water pressure, the amount of abrasive, the motion of the cutting head and the time that the nozzle is focused piercing all determine the penetration of the material. The pressure build up in the work piece must not be so high as to destroy the material at that point. This is particularly important when cutting glass and laminated material. All our machines have the ability to change the piercing pressure easily, via the software.