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Why Pressure Isn’t Everything

Modern water jet cutting machines run at dedicated centres can produce around 90,000 PSI, this a sizeable increase in pressure from even a decade ago.

You might assume that the trend will continue and in time to come, pressure will go into six digits, past 100,000 PSI and beyond.

This may be the case, certainly water jet cutting will continue to develop as you would expect of a technology that is now so widely used.

However a focus purely on pressure is to ignore how water jet cutting actually works.

Water jet cutting does not cut purely through the water jet, water at any pressure will not cut through metal, stone and plastic. The earliest water jet cutting machines used water alone and, while they could cut card and paper, they weren’t a whole lot of use for more complex materials.

It is the addition of an abrasive – typically garnet – that transforms the water jet into a high-powered cutting force. The waterjet is therefore a vehicle for delivering this garnet at high speed – it is the particles travelling at high speeds that perform the cutting.

This might lead to an assumption that greater speed is still beneficial. This though, is to ignore issues that arise as water pressure and so the speed of the stream get ever higher. If you have an ultra-thin cutting head and extremely high pressure, there comes a point where less abrasive can be held in the stream and so the cutting force is actually reduced.

Water jet cutting is therefore much more than simply creating a stream as powerful as possible and combining some abrasive. The combination has to be carefully matched, ensuring the speed of jet and amount of garnet leads to the required cutting force,

The video below is a little dated, it’s from around a decade ago, but it explains these concepts well.

Advances in water jet cutting have actually gone in different ways. The software has become more advanced, making cuts quicker and more efficient. A huge advance has been in XD Cutting – this is the ability to cut in three dimensions and so make complex parts in a single process.

The power has not been an issue for some time. There are very few materials water jet cutting cannot cut, and it can cut metals to a depth of 25 centimetres (and often more still).

Water jet cutting works because water and abrasive come together, and in a similar vein pressure is just one aspect. There is also the width of the cutting head, the use of the right abrasive, and the quantity of abrasive compared to the water flow. Then there is the software, the expertise of those using the equipment and huge leaps such as XD cutting.

Pressure matters, but it is only one part of the story, as any true water jet cutting expert will tell you.


Work with the UK’s leading Water Jet Cutters

At TMC, we are a water jet cutter who serve the whole of the UK and increasingly Europe too, with clients across the content trusting us to work on their projects.

Despite our success, we remain a company that focusses on every client and work on projects of all sizes. If you think water jet cutting might be of use for your project, please do get in touch for an obligation-free chat.

Call us on 01625 610 441 or use our Contact Form.