How can waterjet cut thru metals?


How can waterjet cut thru metals?

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Friction, the water is pumped out at such a high pressure it’s basically instant erosion. Cutting torches work a similar way as the metal is technically oxidizing at a rapid rate.

Most metal-cutting waterjets include an abrasive in the water (basically, sandpaper grit). They’re not so much cutting the metal as sanding it away really quickly. Which is technically just bazillions of tiny cuts happening really fast.

Water jets run at *very* high pressure (think tens of thousands of psi). That, by itself, is higher than the yield strength of many softer materials and the water can cut those by itself by literally pushing material out of the way.

Sufficient force of anything can cut thru anything. If you put thousands of pounds of pressure behind a water jet its hitting that metal with thousands of pounds of force. The fact that it’s water becomes almost irrelevant. It has to discharge that force on what it hits.

Waterjets designed for cutting use a highly focused ‘beam’ of water to cut through, well, anything, really. The higher the pressure of the water and the smaller the aperture (hole) through which the water flows determines how fast and hard the materials being cut can be.

Although water itself is sufficient to cut through materials when sufficiently focused, an abrasive material (a special type of sand, typically) is generally mixed with the water to increase cutting effectiveness.

Ultimately, this allows water jets, depending on their size and design, to cut anything from reams of paper (yes, as in writing paper) all the way up to massive plates of titanium alloy to make submarine or ship hulls. A sufficiently powerful laser could do this too, but would consume massively more power, be incredibly dangerous if misused and, most importantly, would damage the metal because of the sheer heat generated by said laser. Waterjets, on the other hand, make perfectly clean cuts, don’t burn or damage the material being cut and don’t require a huge amount of power to operate. And they’re much safer to use and don’t emit dangerous radiation or heat.