An Engineer’s Guide to Waterjet Cutting

You don’t get much closer to the spirit of engineering than in the beginnings of waterjet cutting.“I got started years ago, in about ’71,” said Dr. John Olsen, one of the originators of waterjet technology and currently VP of operations at Omax Abrasive Waterjets. “I had been reading about some experiments done on rock cutting in England and a friend of mine and I thought it would be fun to try and build a pump and cut something. That was a kind of back-alley operation; it was in my garage and his garage.”

It might sound like many of the stories you hear about start-ups in Silicon Valley today, but the connections between waterjet and computing technologies run deeper than that, as Dr. Olsen explained:“Oddly enough, one of the biggest changes that made abrasivejets practical was the advent of the PC. A jet is not a very rigid tool—it bends all over the place and makes taper and what-have-you. To make precision parts, you need quite a bit of computing power to predict what the shape of the jet will be so that you can compensate for it. At the time, we were told ‘Nobody will ever accept a PC on the factory floor. Doesn’t that sound funny today?”

Waterjet Basics
Pure vs. Abrasive Waterjet

In the broadest sense, the term ‘waterjet’ encompasses any cutting tool that utilizes a high-pressure stream of water. More specifically, waterjets can be divided into pure and abrasive subcategories.

The term ‘pure waterjet’ refers to cutting tools that use only water, while the term ‘abrasive waterjet’ or sometimes just ‘abrasivejet’ refers to—as you might have guessed—waterjets that use an abrasive to accelerate the cutting process.Pure waterjet is used for cutting softer materials, including gasket, foam, food, paper, plastic and carpet.Abrasive waterjet is used to cut harder materials, such as metal, ceramic, stone, wood and glass.Waterjet abrasives are typically made of garnet, with grit size ranging from 50 to 220 mesh, though 80 is the most common. Many waterjet machines are capable of switching from pure waterjet cutting to abrasive waterjet cutting, making them uniquely versatile.

Read more: An Engineer’s Guide to Waterjet Cutting