What is abrasive water jet cutting? This technology has its roots in the use of water in the 1930s when it is being utilized to cut materials that are relatively soft and tender such as paper and sometimes food. Through the years, the technology involving high-pressure water was further developed and fine-tuned. Nowadays, waterjet abrasive machine is one of the most popular applied techniques in precision metal cutting.

Some of the classical applications of water jet machining include complex shapes that are being cut out from composite material sheets or large-scale metal, and this would include even the very thick ones.

Basically, this technology, abrasive water jet cutting, it involves the use of high-pressure stream of water that is mixed with abrasive. The solid stream of water is directed onto a very narrow line towards the workpiece, taking away the material by virtue of eroding it. Garnet powder is added and used as the granular abrasive, and is expected to enhance even further the high-PSI water stream’s cutting ability.

By putting the abrasive into the water through the nozzle, the waterjet can be switched between water and water-only as necessary. With this, you have the liberty to utilize the machine as water-only for positioning. As for the abrasive, it would be directed instead to the workpiece.  

Any Issues So Far with Abrasive Cutting?

Much like any other precision metal cutting strategies, there is, this method of cutting too has its own set of trade-offs. These are the sacrifices and benefits you will need to take into account first when trying to make up your mind whether you will want to have it as your cutting method of choice or not.  Here are some of the potential issues you’d likely encounter in water jet cutter.

Hazing the Surface Finish

With waterjet abrasive cutting blasting away the material at a rate of 60,000 PSI or even more, it is capable of giving any exposed material that matte finish, a characteristic which is being sought after by many. The hazing process can be done strictly for cosmetic purposes. It could be functional if it is going to have any impact on the surface finish.  

Oh Your Nibs

Here is an example analogous to the reason why it is such a struggle to have waterjet cut through a fibrous material, where there would be streams of water sliding around the object you need to cut as opposed to going through it seamlessly:

The moment the stream of waterjet gets itself to the end section of the cut path, there would be streams of water shooting up through the air, and much like anything else, the energy it centers itself on favors the path with the least amount of resistance. This is referred to as a nib, defective end cut because it is not seamless and clean.  

No Tougher than Tungsten

There are several variables that will drive the ability of waterjet abrasive machining to cut, but the level of hardness of the abrasive particles as well as the PSI are among the principals here. For instance, for food and paper-based materials, the waterjet alone can cut through them, no need for added abrasive particles in the waterjet. After all, who would like having abrasive particles left on their cheddar cheese?

But if it is necessary that you make use and add some abrasive particles to your water jet machine, it necessitates that the metal you will try to cut it with should be way softer than the abrasive. When you feed your abrasive particles into the machine’s nozzle, that automatically becomes part of the abrasive stream.

Even if you can use waterjet abrasive machining cut through tungsten, it is inevitable for this not

to present you with a certain level of difficulty. This will stem from the fact that tungsten and garnet used as abrasive particles have almost exactly the same range or level of hardness.  

To Water Jet Cutting or Not to?

When trying to cut intricate shapes out of a large sheet of material, it wouldn’t make sense why anyone would settle to waterjet abrasive cutting — or even laser cutting, oxy-fuel, or plasmas. For these methods, we will leave the discussion about them to the experts.

For applications like a 2-axis cut-off for small precision rods, tubes, and wires, other methods would often prove themselves as the better choice here.