Waterjet cutting almost seems like an contradiction in terms. Especially when you realize that we are talking about cutting high-grade steels and alloys up to 20cm thick. To put that into context, modern ships have hulls that are 17 – 19 mm thick. How is it even possible for a stream of water to cut through some of the toughest alloys known to modern science, and when was this process invented?

Waterjet technology has actually been around for some time now and at RB Engineering we are the experts. The first recorded use of high-pressure water as a tool was in Roman times, when hydraulic mining was used to excavate soft underground deposits. A more modern form of this concept was developed in the late 1800’s using water jets, again used in mining. Although efficient in excavating gold deposits, this technique was an environmental disaster, resulting in extensive erosion and flooding and was later banned. Later on, in the 1930’s, water jets were used to cut paper, and in the 1950’s, the technology was improved to allow the cutting of plastic. It was only in the late 1950’s that the waterjet technology we recognize today came into existence. In 1958, Billie Schwacha of North American Aviation developed a system, which produced an ultra high-pressure stream of 100,000psi, capable of cutting hard materials. This technology was used on the XB-70 Valkyrie, a six-engine, mach 3 strategic bomber which was a Concorde lookalike of its day. So we can safely say that modern waterjet technology was born to serve the needs of our modern aerospace requirements.

Today’s waterjets have since been refined and improved beyond recognition since their debut. Nozzles have been improved to produce a much finer stream, cutting to specifications of up to five-thousandths of an inch tolerance. And although water pressure has been reduced, typically between 20,000 and 50,000 PSI, the water is forced through a fine nozzle about 0.010” to 0

.015” in diameter, producing water speeds reaching mach 3. Unlike metal cutters, a waterjet will never overheat, its blade will never dull, snap, or otherwise become damaged at a critical point in a project. The cutting process is so fine, that polishing will likely never be required, and waste will be minimal to non-existent.

So in summary, what are the advantages of using a waterjet to cut materials? Lets start off by summarizing what we can cut using this high-tech method of cutting.

• Aluminum
• Brass
• Bronze
• Copper
• Titanium,
• Steel (mild, hardened, high alloy, tool and stainless)
• Hastaloy
• Tungsten
• Zirconium Composites
• Foam
• Glass
• Granite
• Marble
• Plastics
• Rubber

So now we know that this tool can cut through practically any material, what makes it better than any other high-tech cutting solution? Lets compare waterjets to laser cutting.

	Laser	Waterjet
Appearance of the cut surface	The cut surface will show a striated, or streaked structure, which will need further attention.	Depending on the speed of the cut, the appearance of the cut surface will seem to have been sandblasted.
Processing tolerance	Approximately 0.002″	Approximately 0.008″
Burring on the cut surface	Partial burring occurs	No burring occurs
Effect of thermal stress on the cut material	Heat deformation, tempering and structural changes may be present in the material	No thermal stress occurs, as this is a cold process.

 

Surprisingly, a waterjet can cut within tolerances of five-thousandths of an inch, in an odorless, heat and dust free (but unfortunately, not noise-free) manner. By cutting to such fine tolerances, materials are produced with a single-cut process, minimizing, time, materials, labor, and cost, with the first cut giving the quality of a final finished surface. The fact that the process is thermal free means that we need not worry about allowing for deformation of our end product, allowing us to work with ever tighter tolerances and a more attractive end result.