Abrasive Water Jet Machining: Definition, Parts, Working Principle, Advantages, Application
Abrasive Water Jet Machining: Definition, Parts, Working Principle, Advantages, Application
Abrasive-Water Jet Machining (AWJM) is a non-traditional machining process or advance water jet machining process in which abrasive used as a medium.
To overcome the disadvantage of water jet machining, the abrasive particles will be added into the water so that the abrasive particles along with water also come out from the nozzle at a very high velocity to remove the material from the surface of a workpiece to get desired shape and size at high accuracy.
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When an abrasive material is used in the water for the machining process then it is called Abrasive Water Jet Machining (AWJM).PARTS OF AWJM:-
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 abrasive-water jet machining process.
2. Hydraulic Pump-
The hydraulic pump is generally used to pump the fluid from one place to another place whereas here in this unit, it acts as a mediator between the reservoir and the Intensifier. It sucks the water from the reservoir and sends it to the Intensifier.
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. Abrasive Tank-
It’s a storing tank in which abrasive particles are used in the form of powder. The commonly used Abrasive particles are aluminum oxides, sand, garnet, glass particles, etc.
10. Mixing Chamber-
In the Abrasive Water Jet Machining process, 70% water and 30% abrasive particles are used and they are mixed in the mixing chamber.
11. 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 AWJM.
WORKING PRINCIPLE
WORKING OF AWJM
This process works on basic principle of abrasive-water erosion. In this process, a high speed well concentrated abrasive-water jet is used to cut the metal. It uses kinetic energy of abrasive-water particle to erode metal at contact surface.
§ First water is filled in water reservoir. 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.
§ Abrasive such as garnet or aluminum oxide is mixed with water within the nozzle. A mixing chamber is there in the nozzle where the abrasives get mixed with the high-pressure water.
§ 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.
1. It has the ability to cut materials without disturbing its original structure. And this happens so because there is no heat-affected zone (HAZ).
2. It is capable of producing complex and intricate cuts in materials.
3. The work area in this machining process remains clean and dust-free.
4. It has low operating and maintenance cost because it has no moving parts.
5. The thermal damage to the workpiece is negligible due to no heat generation.
6. It is capable of cutting softer materials (WJM) like rubber, plastics or wood as well as harder material (AWJM) like granite.
7. It is environment friendly as it does not create any pollution or toxic products.
8. It has a greater precision of the machining. The tolerances of an order of ± 0.005 inch can be achieved easily.
DISADVANTAGES OF AWJM
1. It is used to cut softer materials. But AWJM can cut harder material of limited thickness.
2. Very thick material cannot be machined by this process.
3. The initial cost of WJM is high.
4. A Skilled labor required.
APPLICATIONS OF AWJM
1. AWJM is typically used to machine those materials which are hard and difficult to machine. It is used to machine thick plates of steel, Al and other commercial materials, reinforced plastics, metal matrix, and ceramic matrix composites, layered composites, stones, glass, etc.
2. AWJM can also be used to perform drilling, pocket milling, turning and reaming.
3. Abrasive-Water jet machining is used in various industries like mining, automotive and aerospace for performing cutting, shaping and reaming operations.
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