Water Jet Machining: Definition, Parts, Working Principle, Advantages, Application

Water Jet Machining (WJM) also called 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.

Water Jet Machining Construction or Parts:

Water Jet Machining Consists of following Various Parts:

1. Reservoir

2. Hydraulic Pump

3. Hydraulic Intensifier

4. Accumulator

5. Control Valve

6. Flow Regulator or Valve

7. Nozzle

8. High Pressure Tubes

9. Drain and Catcher System

1. Reservoir:

The reservoir is used to store water which will be used as a jet. From the reservoir, the water is supplied for the water jet machining process.

2. Hydraulic Pump:

In the water jet machining process, a hydraulic pump is used to pump the water from storage tank for machining process. It is connected by an electric motor of about 100 Horsepower.

3. Hydraulic Intensifier:

It is used to increase the pressure of water to very high pressure. It receives the water from the pump at 4 bar and increases its pressure up to 3000 to 4000 bar.

4. Accumulator:

It stores the high pressurized water temporary. It supplies that fluid when a large amount of pressure energy is required. It eliminates pressure fluctuation conditions in the machining process.

5. Control Valve:

It controls the pressure and direction of the water jet.

6. Flow Regulator or Valve:

Flow regulators are used to regulate the flow according to cutting requirement. For high cutting load, high pressurized water is supplied at high rate.

7. Nozzle:

It is a device that is used to convert the pressure energy of water into kinetic energy in water jet machining. This nozzle converts high pressure of water into high velocity jet. This high-speed water jet strikes at work surface which is used for machining.

8. High Pressure Tubes:

High Pressure Tubes are required for the flow of high-pressure water. They are nearly 6 to 14 mm in diameter. It also allows flexible movement of the cutting head.

9. Drain and Catcher-

The drain and catcher system is used to remove debris and other machined particle form water. It separate metal particle from water and this water is further send to reservoir. It also used to reduce noise associate with WJM.

Working Principle:

This process works on basic principle of water erosion. In this process, a high speed well concentrated water jet is used to cut the metal. It uses kinetic energy of water particle to erode metal at contact surface. The jet speed is almost 600 m/s. It does not generate any environmental hazards. For cutting hard materials, abrasive particles are used in water jet These abrasive particles erode metal from contact surface.

Working:

First water is filled in water reservoir. It provides water for cutting operation. A pump sucks water from water reservoir and send it to intensifier. The intensifier increases the pressure of the water from 5 bars to 3000 to 4000 bar. This high-pressure water from the intensifier is moved to the nozzle as wells as in accumulator.

The accumulator stores the high-pressure water and supplies it at any instant when it is required. It is used to eliminate the fluctuation of the high-pressure requirement of machining hard material.

The high-pressure water is then passed to the nozzle through the control & flow valves where the high-pressure energy of the water is converted into kinetic energy. A very high-velocity jet of water (1000 m/s) comes out through the nozzle in the form of a narrow beam.

This high-velocity jet of water when strikes the surface of the workpiece removes the material from it.

The water jet after machining it gets collected by the drain and catcher system. Here the debris, metal particles from the water are removed and it is supplied to the reservoir tank.

Water Jet Machining Advantages:

The following advantages of Water Jet Machining are:

1. It does not change mechanical properties of work piece. It is useful for machining heat sensitive material.

2. It is environment friendly because it does not form any dust particle and used water as cutting fluid.

3. Good surface finish.

4. No physical tool is required.

5. It can cut both soft and hard material. For machining soft materials, water jet machining is used and for machining hard materials, abrasive water jet machining is used.

6. The weldability of material is not reduced in this process.

7. It is ideal process for laser reflective materials where laser beam machining cannot be used.

8. Lower cost of machining.

Water Jet Machining Disadvantages:

The following disadvantages of Water Jet Machining are:

1. It cannot used for machining material which degrade in presence of water.

2. Low metal removal rate.

3. High initial cost.

4. Thick material cannot be machined easily.

5. Some water mist may be created in the environment which can cause some harm to sensitive equipment’s.

Water Jet Machining Application:

The following application of water jet Machining are:

1. It is used in aerospace industries.

2. Abrasive jet machining is used to cut hard metal like stainless steel, titanium, Inconel etc.

3. It is used to machining or cutting reinforced plastic.

4. Use to cut stone which reduce dust in environment.

5. Used to machining PCB.