CUTTING MATERIALS WITH WATER- WATER JET MACHINING EXPLAINED !!

Water Jet Machining (WJM) also called as water jet cutting, is a non-traditional machining process in which high velocity jet of water is used to remove materials from the surface of the workpiece. 

WJM can be used to cut softer materials like plastic, rubber or wood. In order to cut harder materials like metals or granite, an abrasive material is mixed in the water. When an abrasive material is used in water for the machining process, than it is called as Abrasive Water Jet Machining (AWJM).

Working of Water Jet Machining (WJM):

• 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.

Advantages of Water Jet Machining (WJM):

1. Water jet machining is a relatively fast process.
2. It prevents the formation of heat affected zones on the workpiece.
3. It automatically cleans the surface of the workpiece.
4. WJM has excellent precision. Tolerances of the order of ±0.005″ can be obtained.
5. It does not produce any hazardous gas.
6. It is eco-friendly.

Disadvantages of Water Jet Machining:

1. Only soft materials can be machined.
2. Very thick materials cannot be easily machined.
3. Initial investment is high.

Applications of Water Jet Machining:

1. Water jet machining is used to cut thin non-metallic sheets.
2. It is used to cut rubber, wood, ceramics and many other soft materials.
3. It is used for machining circuit boards.
4. It is used in food industry.