ABRASSIVE JET MACHINING (AJM)

Abrasive jet machining

1. AJM uses a stream of fine grained abrasive (of size 10 to 40 microns) mixed with the air or some other carrier gas at high pressure.
2. This stream is directed on the work surface by using a suitable nozzle.
3. The velocity of carrier gas or air is upto 200 to 400 m/sec.

Working :-

1. Through hopper, fine grained abrasive powder is filled in a mixing chamber.
2. The gas or air is supplied under pressure into the chamber, pressure of gas varies from 2 to 8 kg/cm square.
3. The gas is supplied through the pipeline which carries a pressure gauge and regulator to control the flow.
4. This mixture of high pressure gas and compressed air is passed through a nozzle on the surface of workpiece, and due to high speed mixture erosion takes place and metal gets removed.

Advantages :-

1. Brittle materials of thin sections can be easily machined.
2. No direct contact between the tool and workpiece, hence less damage to the workpiece surface.
3. Holes of any shape and intricate cavities can be machined.
4. Power consumption is low.

Disadvantages :-

1. Am is only suitable for brittle materials, as MRR is high for brittle materials.
2. MRR is kowalska i.e. upto 0.05 cubic centimeter/hr.
3. The used abrasive powder can not be reused.

Applications :-

1. It is used for drilling holes, cutting slots, cleaning hard surfaces, deburring, polishing, etc.
2. It is used for producing high quality surface.
3. Used for aperture drilling of an electronic microscope