Machining With Water-jets

Many of us are familiar with CNC process and how it is used in various manufacturing applications, today we will go over the use of waterjets and abrasive gets. The waterjet process is very interesting, the idea that water can cut metal is amazing. Waterjets that is used in machine shops to cut metal is 30 times stronger than the power washers that are used at your local car wash. These water jets are able to cut because they channel the water through an extremely narrow nozzle at a very high pressure to keep the spray coherent.

The process of using pressurized water for mining and cleaning has been around for well over 100 years now. Low pressure waterjets were first used for mining gold California in 1852. Steam and hot water jets were used in the early 1900s for cleaning. High pressure waterjets were introduced for mining in the 1960s, and about 10 years ago industry began using waterjets for cutting.

In the past, only one piece of metal could be cut at a time with a saw or metal cutting mechanical process. It was time consuming and expensive. The waterjet machines used today are faster and more cost efficient, they can cut to within two thousandths of an inch, and have jet speeds around Mach 3. They can cut materials such as Marble, Granite, Metal, Plastic, Wood, And Stainless steel.

A water jet can cut a handful of different materials up to four inches thick. This odorless, dust-free and relatively heat-free process can also cut something as thin as five thousandths of an inch. The tiny jet stream permits the first cut to also be the final finished surface. This single cutting process saves material costs and machining costs. For example, the engineer merely gives a gear drawing to the cutting shop via a diskette or e-mail and gets the finished gear back.

Waterjets cut softer materials, while abrasive jets are used for harder materials. The actual cutting is often done under water to reduce splash and noise. Faster feed rates are used to prevent the jet from cutting all the way through.

The water pressure is typically between 20,000 and 55,000 pounds per square inch (PSI). The water is forced through a 0.010″ to 0.015″ in diameter orifice hole) in a jewel.

Newer technology has also proven that a waterjet can remove the bark from a tree at a distance of 40 feet if one alters the chemistry of plain water by adding “Super water”. The super water is a soluble polymeric chemical that acts like a series of molecular spinal columns or concrete reinforcement bars that tie the individual water molecules together in a more structured way to form a coherent jet.