Abrasive jet machining uses a stream of fine grained abrasive mixed with air or some other carrier gas usually nitrogen at high pressure. Here abrasives used are sodium bicarbonate, glass power, silicon carbide are aluminum oxide. The particle size rages from 10m to 50µ. The smaller size particles are used to obtaining good surface finish. For rapid removal rate of material larger size particles are used. In Abrasive jet machining Nozzles are made up of tungsten carbide or ceramic to withstand high degree of abrasion wear.The metal removal rate of abrasive jet machining process is usually 16mm³/min in cutting of glass and the velocity of jet ranges from 150 to 300m/min.
In abrasive jet machining the material removal treatment occurs because of erosion due to the abrasive particles impacting on the work-surface at high speed through a nozzle. The filtered gas is supplied at a pressure limit between 1.96 to 7.85 bar to the mixing chamber that comprises abrasive powder. The mixing chamber is made to vibrate at 50Hz for proper mixing of abrasive particles with gas. Thus, the mixture is passed into a connecting hose that emerges from a nozzle with high velocity. In abrasive jet machining pressure regulator is employed to regulate the gas flow while the abrasive powder feed rate is regulated by the amplitude of vibration of the mixing chamber.
Applications of Abrasive Jet Machining
- Abrasive Jet Machining is employed in micro welding, fine drilling and aperture drilling for electronic microscope.
- This machining process used for intricate profiles on fragile and hard metals
- Abrasive Jet Machining employed to perform cleaning and cutting operations on materials like silicon, germanium,quartz and also for machining for semiconductors.
Advantages of Abrasive Jet Machining
- The main advantage of Abrasive Jet Machining is to machine the intricate holes and cavities of harder materials of desired shape.
- Machining can be performed easily for brittle materials of thin sections.
- Heat generated in this process is very less
- Initial investment is low.
Dis-advantages of Abrasive Jet Machining
- In Abrasive Jet Machining the Material removal rate is low
- Abrasive Jet Machining is not applicable for ductile materials and also poor machining accuracy.
- Abrasive powder can’t be recycled.