Abrasive waterjet cutting technology – precise and careful
Abrasive waterjet cutting is now a well-established processing technique and an excellent complement to both laser cutting and plasma cutting. A great advantage is that the method is cold, and thus does not cause internal tension, molten edges or hardening of the material being worked. Cutting with water and sand, i.e. pure natural materials, also creates a good work environment free from pollution in the form of the gases that can arise using other methods.
Many people are also discovering more areas of use than they first planned for, as they can cut basically all materials without changing the tool setting. The investment in the equipment, which is already far lower than for other methods, can thus pay off even sooner than expected.
How it works
With abrasive waterjet cutting a high-pressure pump produces a water pressure of about 4,000 bar that is pressed against a plate made of industrial diamond – a so-called sapphire. The sapphire has a hole, and a thin jet of water 0.1 mm in diameter is created. When the jet passes through the focusing nozzle the diameter increases to about 1 mm. This creates a negative pressure in the mixing chamber and abrasives are drawn in.
Many parameters come into play to get a good result. In general, when cutting you aim to get through the workpiece and adjust the feed speed according to the desired surface finish on the cut surface. The abrasive cutting jet removes materials through particle erosion. Particle erosion means that it takes time for the jet to work its way through the workpiece, thereby allowing the marking of hole centres for future post-working, e.g. centres of drill holes, thus punch marks are no longer needed and the hole centre always ends up in the right position. Abrasive waterjet cutting creates fine tolerances and fine cuts, but the cut surface becomes slightly conical.
Advantages of the method
Here are some advantages of abrasive waterjet cutting compared with methods such as laser and punching.
- Abrasive waterjet cutting is a cold-processing method. It thus does not give rise to internal tensions, molten edges or hardening of the working material.
- The method is well suited to small series, as the setup times are often short.
- Extremely thin sheets and sheets up to 300 mm thick can be cut. The greatest volume of sheets being cut is ones with a thickness of between 2 and 10 mm.
- There is almost no limitation on the 2D appearance of the cutting contour. The outline is drawn using a CAD program and is transferred to the cutting panel using CAM.
- Small cutting edges that lead to simple rigging. In the past ten years the method has grown more than any other competing method.