Laser and plasma cut with heat — and for most jobs that is fine. But there are materials and parts for which heating is unacceptable: the metal's properties change, the geometry warps, the structure is ruined. This is where waterjet comes in.
How it works
A jet of water at a pressure of several thousand atmospheres is mixed with fine abrasive — usually garnet sand — and exits through a nozzle about a millimetre in diameter. In essence it is extremely fast erosion: the abrasive knocks out microparticles of the material. The metal barely heats up in the process — the temperature in the cutting zone stays close to room temperature.
The advantages
- No heat-affected zone. Hardened steel is not tempered, the metal does not lose strength along the edge.
- Cuts almost anything. Besides metals — stone, glass, ceramics, composites, rubber, layered materials.
- Great thickness. Waterjet confidently handles thicknesses out of reach for laser.
- A dross-free edge. The part usually needs no thermal finishing after cutting.
The price you pay
The main downside is speed and cost. Waterjet cuts noticeably slower than laser, consumes abrasive and water, and the equipment is more demanding to maintain. So on thin metal, where a laser finishes in seconds, waterjet cutting is not economically justified.
Another nuance: at large thicknesses a slight cut taper and jet deflection appear, which somewhat reduces precision at the bottom of the edge.
When to choose which
For sheet metal up to 20 mm, small holes and batch parts, laser cutting remains the fastest and cheapest option. Waterjet makes sense when the material cannot tolerate heat, when you need to cut something other than metal, or when the thickness exceeds the laser's capabilities.
Describe your part — material, thickness and requirements — and we will tell you which technology fits, even if it turns out not to be our service.
