Abrasive Jet Machining (AJM) Principles
In abrasive jet machining process, a focused steam of abrasive particles (of size x to xl microns) carried past times high describe per unit of measurement area gas or air at a velocity of close 150 to 300 m/sec is made to impinge on the function surface through a nozzle, too the function stuff is removed past times erosion past times the high velocity abrasive particles. The within diameter (ID) of the nozzle through which abrasive particles menstruum is close 0.18 to 0.80 mm too the stand-off distance (i.e. distance betwixt nozzle tip too workpiece) is kept close 0.3 to 20.0 mm. The procedure tin endure easily controlled to vary the metallic removal charge per unit of measurement which depends on menstruum charge per unit of measurement too size of abrasive particles. This procedure is best suited for machining super alloys too refractory type of materials, too also machining sparse sections of difficult materials too making intricate difficult holes. The cutting activity is cool because the carrier gas serves every bit coolant.
When an abrasive particle (like Al2O3 or SiC) having precipitous edges hits a brittle too delicate stuff amongst a high speed, it makes dent into the stuff too lodges a modest particle from it past times a tiny brittle fracture. The lodged out or article of apparel particle is carried away past times the air or gas. The operating elements inward AJM are abrasive, carrier gas too the nozzle every bit schematically shown inward the next Figure
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Abrasive Jet Machining (AJM) Principles |
The distance betwixt the nozzle tip too the function surface has peachy influence on the diameter of cut, its cast too size too also charge per unit of measurement of stuff removal. The next Figure shows the variation inward the diameter of cutting amongst modify inward the stand upward off distance (SOD). It is evident that the SOD changes the abrasive particles spreads (i.e. covers wider area) on the function surface too consequently increases the diameter of the cut.
The basic Units of AJM
The basic unit of measurement is schematically shown inward next Figure. It consists of gas render arrangement (compressor), filter, describe per unit of measurement area regulator, mixing chamber, nozzle assembly too the function belongings device. In the mixing chamber, the abrasive is allowed to menstruum into the gas stream. The mixing ratio is by too large controlled past times a vibrator. The particle too gas mixture comes out of the nozzle within the machining bedchamber of the machine tool unit. The feed displace tin endure given either to the function belongings device or to the nozzle.
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| AJM setup |
- Water Jet Machining Process .
- Laser Beam Machining
- Electrical Discharge Machining (EDM) Principles
- Electrochemical machining process
Abrasive Jet Machining (AJM) Advantages:
- This procedure is quite suitable for machining brittle, oestrus resistant too delicate materials like, glass, ceramic, germanium, mica etc.
- It tin endure utilized for cutting, drilling, polishing, deburring, cleaning etc. of the materials.
- The depth of harm to the surface is really little.
- Holes of intricate shapes could endure produced efficiently.
- The surface machined tin bring practiced complete (by controlling the grain size mainly).
AJM Disadvantages:
The materials removal charge per unit of measurement is low. For example, for glass, it is 0.0164 cm3/min.
- The tapering of hole especially, when the depth of the hole is more, becomes almost inevitable.
- A dust collecting bedchamber is a basic requirement to foreclose atmospheric pollution to sweat wellness hazards.
- The abrasive particles may stay embedded inward the function surface.
- Abrasive particles cannot endure reused.
AJM Applications:
- Abrasive jet machining is best suited for machining brittle too oestrus sensitive materials similar glass, quartz, sapphire, ceramics etc,
- It is used for drilling holes, cutting slots, cleaning difficult surfaces, deburring, polishing etc.