What is a waterjet cutting machine? Can you really cut through robust materials with water?
Water jets are an interesting topic, and we’re frequently asked about them, especially in the world of laser cutting. First, we’d like to start by looking at the power of water! Water jets can be used to cut materials that range from the hardest of stone to very thin pieces of steel. As a matter of fact, you can even see Formula 1 cars with water-jet cut titanium panels on their chassis. The application depends on the power and type of nozzle used; it also depends on what kind of material you want to work on. Why is there so much confusion surrounding this subject? Is it because they sound too good to be true? Well, let me tell you right away: Yes, waterjets do sound too good to be true… But they are not! Cutting through robust materials with water is really possible!
Waterjets are not your average cutting machines… They have a high-pressure stream of water injected at the focus point. The high velocity of the water basically erodes the material due to cavitation effects. This phenomenon occurs when the pressure in a liquid changes very quickly. When this happens, there is an increase in temperature which results in small pockets of gas being formed. These are microscopic bubbles that implode after they are formed; it generates enormous amounts of energy that is released into the surrounding area! During all these micro-explosions, shock waves are produced, and it’s mainly thanks to them that we can cut through hard materials… But you must two things: firstly, too much pressure is just as bad for the machine itself, or in the case of rotary tools, it would mean that you lose the seal and your workpiece comes out looking like a piece of Swiss cheese. Secondly, you need to keep an eye on the water level! If the pump cavity is empty during operation, there’s no more cutting fluid left and both your machine and your workpiece will end up fried!
In summary: don’t underestimate industrial quality waterjets even though they look like toys. They can be used to make a whole array of things from large gems with a diamond-coated tool tip down to true masterpieces which are only possible by using industrial equipment. But let’s get back to our hobbyist stuff…
For me, the most interesting things you can cut with a waterjet cutting machine are plastics, soft metals like aluminium and brass but also rubbers. These materials are so un-durable that they will be stretched out of shape or even melted before your eyes!
For all other common materials like wood or stone, it probably is more practical to use a router with a round spindle. Unlike waterjet cutting machines, routers are generally fit for many different jobs which makes them very versatile tools in home workshops. However, if you want to make extremely intricate wood carvings (like carved lettering for example), then perhaps an industrial quality waterjet is something worth considering.