Water is one of the natural resources with a powerful erosion force which allows it to get through the mountains, shaping hard cliffs and granite rocks on its way to downstream. A water hose sprays the water outdoor in a powerful manner, and if you add more pressure, the water force increases significantly. Same principle applies to water jet cutting machines: the water is shot through a narrow hole at very high pressure, ensuring water with a significant power to cut into the substrate. Mix the water with a hard abrasive like red garnet and the cutting force increases exponentially, being able to cut with extreme precision, almost any type of material, from cardboard and rubber to ceramic, steel, titanium, stone and quartz.
Almost any abrasive material has been tested to determine how effective is for the water jet cutting machine. It has been concluded that the best abrasive is the red garnet, thanks to a unique series of features such are: hardness, density, friability and particle shape, that maximize the cutting properties of water jet machines.
Hardness. Water jet cutting needs an optimal balance between the cutting force and the wear of the cutting machine parts. A soft abrasive prolongs the life of the nozzles, but slows down the cutting. An abrasive too tough increases the cutting speed, but erodes the nozzles too quickly, leading to dead operating times and increases in the costs of repairing machine parts. The hardness of red garnet is about 8 on Mohs scale, which effectively balances the need to cut quickly, but also provides a reasonable operating lifetime for the equipment.
Density. The cutting force of water jet machine is a function of two factors: the weight of the abrasive multiplied by the velocity. The ideal abrasive has the greatest weight that water can accelerate to maximum velocity, offering ultimate cutting speed. An abrasive that is too light will not cut the material and a material that is too heavy will not accelerate to the maximum velocity, slowing down the cutting speed. Red garnet is almost four times heavier than the water, a value that falls in the optimal range for both cutting and acceleration.
Friability. Abrasive friability has an important part in water jet cutting machine. An abrasive that is too friable will break down in small pieces when passing through the equipment nozzle, being shot as dust on the surface and not being able to cut it. An abrasive that is too tough to fracture in the nozzle, only rounds at its corners, being shot on the substrate as dull particles with no force to cut. Red garnet with its semi-friable nature that makes it fracture in angular particles with sharp edges when passing through the nozzle, provides superior cutting speed than any other abrasive material.
Particle shape. Abrasive materials can take multiple shapes - from perfect spheres, like steel shots or glass beads - to needle like shape, that can be found in silicon carbide particles. However, it has been found that the angular shape with multiple sharp edges like the shape of red garnet, is the most suitable for high cutting speeds.
Red garnet is a natural rock that can be found in the Almandine mines. It is a chemically highly stable material that does not contaminate other surfaces by contact. Red garnet needs to take a special refinement process to reach specific characteristics of purity and uniform particle size distribution in order to be successfully used with water jet cutting machines. GritSablare.ro is the national leader of supplying best quality red garnet for water jet cutting machines. The red garnet provided by us is carefully processed after mining, to reach a high level of purity by eliminating other traces of different materials that are found in the rock, which interfere when cutting - for example, by clogging of nozzles or contaminating the surfaces. Further, the dimension of red garnet particles is strictly observed to obtain a material of relatively uniform particle size which is best for water jet cutting, because there is no need to continuously change the cutting settings of the machine to readapt at different new sizes of the material in order to effective cut the surface.