It involves the use of high velocity water jet to smoothly cut a soft workpiece. It is similar to Abrasive Jet Machining (AJM).
In water jet machining, high velocity water jet is allowed to strike a given workpiece. During this process, its kinetic energy is converted to pressure energy. This induces a stress on the workpiece. When this induced stress is high enough, unwanted particles of the workpiece are automatically removed.
This article contains the following sections:
The apparatus of water jet machining consists of the following components:
- Reservoir: It is used for storing water that is to be used in the machining operation.
- Pump: It pumps the water from the reservoir.
- Intensifier: It is connected to the pump. It pressurizes the water acquired from the pump to a desired level.
- Accumulator: It is used for temporarily storing the pressurized water. It is connected to the flow regulator through a control valve.
- Control Valve: It controls the direction and pressure of pressurized water that is to be supplied to the nozzle.
- Flow regulator: It is used to regulate the flow of water.
- Nozzle: It renders the pressurized water as a water jet at high velocity.
- Water from the reservoir is pumped to the intensifier using a hydraulic pump.
- The intensifier increases the pressure of the water to the required level. Usually, the water is pressurized to 200 to 400 MPa.
- Pressurized water is then sent to the accumulator. The accumulator temporarily stores the pressurized water.
- Pressurized water then enters the nozzle by passing through the control valve and flow regulator.
- Control valve controls the direction of water and limits the pressure of water under permissible limits.
- Flow regulator regulates and controls the flow rate of water.
- Pressurized water finally enters the nozzle. Here, it expands with a tremendous increase in its kinetic energy. High velocity water jet is produced by the nozzle.
- When this water jet strikes the workpiece, stresses are induced. These stresses are used to remove material from the workpiece.
- The water used in water jet machining may or may not be used with stabilizers. Stabilizers are substances that improve the quality of water jet by preventing its fragmentation.
- For a good understanding of water jet machining, refer the schematic diagram above.
- Water jet machining is a relatively fast process.
- It prevents the formation of heat affected zones on the workpiece.
- It automatically cleans the surface of the workpiece.
- WJM has excellent precision. Tolerances of the order of ±0.005″ can be obtained.
- It does not produce any hazardous gas.
- It is eco-friendly.
- Only soft materials can be machined.
- Very thick materials cannot be easily machined.
- Initial investment is high.
- Water jet machining is used to cut thin non-metallic sheets.
- It is used to cut rubber, wood, ceramics and many other soft materials.
- It is used for machining circuit boards.
- It is used in food industry.