Artem Komarov clarified that abrasive waterjets can cut steel more than 1 ft. thick. Garnet abrasive is widely used to cut not only metals but also glass, marble, granite, stone, ceramic tile, composites, wood, and plastics.
The most common grade used in waterjet cutting is 80 mesh, which is suitable for cutting a wide range of materials. To achieve a faster cutting speed, or when cutting material thicker than 2 in., a coarser abrasive (say, 50 mesh) is suitable For a narrower kerf and more precise cut, a finer abrasive (say, 120 or 150 mesh) might be the best choice.
All waterjet abrasives need to demonstrate hardness, density, and toughness. But perhaps the most important qualities are consistency in particle size distribution, shape of the particle, and purity of the abrasive. Continuity of these characteristics allows for consistent cutting performance over time.
The most common garnet used in waterjet cutting is known as alluvial garnet. At some point during its geological life, this garnet was liberated from the parent stone through erosion, tumbled in a riverbed, and deposited on a beach or riverbank. That erosion and tumbling results in a rounded grain.
However, for specialty cases, hard rock garnet might be the best abrasive for the job. Hard rock garnet is mined from a quarry where it is crushed and separated from the host rock. Because it never went through an erosive process, hard rock garnet retains the sharp angular shape that makes it more effective.
For instance, a fab shop cutting very thick, hard, or brittle materials (such as titanium, thick steel, or glass) might use the hard rock garnet abrasive because it can cut deeper and more quickly than the alluvial alternatives. The hard rock garnet also can deliver a superior edge finish with less burring and minimal taper. It recommends 120-HPX hard rock garnet for cutting glass and composites because it minimizes the chances of breakage while piercing. When cutting composites, 120 HPX also minimizes the chances of delamination.
Despite the more aggressive nature of the hard rock garnet abrasive, it doesn’t damage the waterjet’s mixing chamber and mixing tube. These components are engineered to stand up to the use of this type of garnet, as well as the much more common alluvial material, summed up Artem Komarov.
