How abrasive waterjet cutting works
A waterjet cuts the way a river cuts a canyon — only faster, and aimed. High-pressure water, charged with garnet sand, erodes a clean path through almost any material. Here is the whole path of the jet, from the pump to the kerf.
Water only
Plain high-pressure water with no abrasive. The jet is soft and fast, so it suits gaskets, foam, rubber, food and thin soft goods. It cuts cleanly and quickly, but it does not have the teeth to get through hard materials.
Water + garnet
Garnet sand is added to the stream, turning the jet into a cutting tool that erodes hard materials — stone, glass, ceramic and metal. This is what shops mean by “waterjet” in fabrication, and it is what every Rich machine is built to do.
Six stages, top to bottom.
- 01
The intensifier pressurizes the water
A hydraulic intensifier pump takes ordinary filtered water and raises it to ultra-high pressure — on Rich machines, up to 600 MPa (about 87,000 psi). This is the heart of the system. Rich designs and machines its own intensifiers in-house, with indirect hydraulic pressurization, a maintenance-free accumulator and PLC self-diagnosis.
- 02
Water exits a tiny orifice as a thin, fast jet
The pressurized water passes through a small hard-jewel orifice (typically sapphire, ruby or diamond). The pressure drop accelerates the stream to several times the speed of sound, forming a coherent, hair-thin jet of water.
- 03
The jet enters the mixing chamber
Below the orifice, the high-velocity jet passes through a mixing chamber. The speed of the water creates a vacuum that pulls abrasive into the stream — no separate pump is needed to feed it.
- 04
Garnet abrasive is drawn into the stream
Fine garnet sand is metered into the chamber and entrained by the jet. Garnet is hard, sharp and consistent, which is what gives the jet its cutting teeth. Rich machines feed abrasive pneumatically from up to 200 kg of storage, with a valve that keeps water from returning to the sand and spoiling the feed.
- 05
The focusing tube aligns water and abrasive
The water-and-garnet mixture passes through a hardened focusing tube (also called a mixing tube or nozzle). This collimates the stream into a single, tightly-focused cutting jet — a fast-moving column of water carrying thousands of abrasive particles.
- 06
The jet erodes a narrow kerf through the material
The focused jet strikes the material and cuts by rapid erosion — the garnet particles abrade away a narrow slot called the kerf. There is no blade, no flame and no electrical arc. The same jet that cuts 1 mm foil can cut 100 mm stone; only the speed changes.
Cold cutting: no heat, no warping.
That has real consequences on the floor. Because there is no heat-affected zone (HAZ), the metal next to the cut keeps its original temper and hardness — no annealing, no micro-cracks, no discoloration. Thin and tall parts don't warp. Hardened steel, tool steel and heat-sensitive composites can be cut without changing their properties. And the edge comes off the table square and ready, often needing little or no secondary finishing.
It is also a versatile process: the same machine moves from 1 mm aluminum to 100 mm marble by changing the feed rate, with no tool change. For a fabricator running mixed work, that range is the whole point.
See it cut your material.
Rich engineers its own IP68 cutting head and intensifier in-house — the parts that decide your cut. Tell the configurator what you run and get the right machine.