A Guide to Selecting an Abrasive for Waterjet Machining
The profitability and performance of your Water jet cutting equipment is dependent on several important factors, and one of them is abrasive type and size. Your abrasive selection should start with assessing the material as well as the cutting specifications. A fabricator will consider the difficulty associated with cutting the material as well as the intended surface finish when deciding on a proper abrasive for the job. To do the job well, the abrasive product should be hard, tough, and dense enough, on top of having the right shape.
You could select a naturally-occurring or artificial abrasive for your water jet cutting equipment, but it has to have the attributes below:
There’s the need for waterjet cutters to have a fair compromise between speed and part wear. The use of a softer abrasive leads to a longer nozzle life but a slower cutting rate. If the abrasive in question is extremely hard, work progresses rapidly but nozzle tear accelerates. Finally, your equipment’s cutting accuracy and uptime are lowered, with frequent nozzle replacement introducing more maintenance costs. An abrasive that lies from 7 to 8 on the Mohs scale is ideal for a long lasting cutting tool and excellent working speeds.
Mass multiplied by velocity is the function defining the key cutting power of a waterjet. Thus, an abrasive is great if it carries the most dense particle, which the water jet accelerates to optimal velocity. In the end, this achieves maximum cutting power. A balance is required here since an abrasive a very-low density abrasive won’t pack a punch, whereas an extremely heavy abrasive will not accelerate to optimal velocity, failing to harness the full power of the water jet. A product with a specific gravity of 4.0 is perfect for balanced cutting force and acceleration.
How friable or tough the water jet cutting abrasive is will certainly impact its effectiveness. If it’s extremely friable, it’ll break in the focusing tube, resulting in an abrasive that’s too fine for effective cutting. An extremely tough abrasive will round through mixing, and it’ll get excessively blunt for efficient cuts. As such, pick an abrasive that’s appropriately tough for the lowest breakdown rate possible, and to generate sharp cutting edges.
There are numerous particle shapes for different abrasives, from beads, such as steel shots, and extremely sharp crystals for silicon carbide–an artificial product meant for high-tech application. It’s easy for a fabricator to pick spherical particles if they view a sphere as the best form to deliver mass that’s projected through a very powerful water stream. However, some balancing must be achieved for acceleration, wear, and cutting efficiency when choosing the right particle shape for an abrasive, with any water jet cutting project.