Water jet cutting used to be an odd one out for metalworking machines. Autogenous, plasma and laser were the machines and techniques for the production of more complex products; each with its own pros and cons. What these techniques have in common is that it introduces heat into the material. As a result, changes may occur in the composition, color and shape of the material.
The principle of water cutting
There are several manufacturers for water cutting machines, each with its own specific characteristics. First of all, the operation of water cutting machines. The pressure of the (filtered) tap water is raised to working pressure by pumps. The working pressure is normally between 3500 and 4000 bar. The water then hits the material at more than 700 meters/second. For imaging: the water pressure in your home is between 1.5 and 4 bar.
An abrasive or abrasive can be added at the opening – where the water is sprayed onto the material (also called a nozzle). Usually this is a very fine sand. The combination of water and abrasive causes a wearing effect on the product. This is certainly necessary for harder materials such as steel, stainless steel, titanium, aluminum and stone. The combination of factors ensures that tolerances from approximately ±0.5mm are achievable. As the thickness of the material increases, the tolerance becomes wider. For example, with 50mm thick aluminum the tolerance for a hole becomes approximately ±2mm. That is still very accurate at this thickness. If soft materials are cut, such as foam rubber, you can cut with clean water.
Special operations
In addition to cutting, material can also be marked. You remove a small piece of the material. In this operation, the pressure is much lower and the speed of movement of the head is higher.
Most water cutting machines have a 2D cutting head. This means that the water jet can only cut straight down. At 2.5D, the cutting head can move between 90° and 45° angles, allowing you to make bevels on products. The 90° angle is downward, perpendicular to the plate and the 45° angle is the maximum angle of movement. Because the head can also rotate around its axis, you can make this chamfer around a contour or larger hole. There are even 3D water cutting machines, which allow you to process not only flat sheet, but also products with complex shapes.
Advantages of water cutting are:
- a high and constant cut quality
- steel, stainless steel, aluminum, titanium, copper, brass, zinc can be cut very well with water
- no significant heat input: material properties remain the same and plastic/composite can also be cut
- no deformation or discoloration
- non-chemical process that prevents toxic fumes from forming
- cut at higher thicknesses is virtually burr-free (from approx. 6 mm)
- small hole diameters in thick materials (0.2-0.6x the plate thickness) can usually also be cut. 0.2 is not feasible for plate thicknesses of >10mm, because the radius also needs space to penetrate the material. For example: with 15mm plate, the smallest hole diameter should be 5-6mm Read More
