The abrasive jet can be used to cut any material. Even diamonds have been cut, using diamond dust as the abrasive. Make all sort of shapes with only one tool. Virtually no heat is generated in the work piece. No mechanical stress. Fast set up.

1. How does it work?
• Fine particles (0.025mm) are accelerated in a gas
stream (commonly air at a few times atmospheric
pressure).
• The particles are directed towards the focus of
machining (less than 1mm from the tip).
• As the particles impact the surface, it causes a
small fracture, and the gas stream carries both the
abrasive particles and the fractured (wear)
particles away.

3. Factors affecting the process
• Material removal rate.
• Geometry of cut.
• Roughness of surface produced.
• The rate of nozzle wear.

4. Material removal rate (mmr).

5. These factors are in turn affected by,
•The abrasive
Composition; strength; size; mass flow rate.
•The gas
Composition, pressure and velocity.
•The nozzle
Geometry; material; distance to work; inclination to work.

6. Abrasive.
• Materials - Aluminum oxide (preferred); silicon
carbide.
• The grains should have sharp edges.
• Material diameters of 10-50 micro m 15-20 is
optimal.
• Should not be reused as the sharp edges are worn
down and smaller particles can clog nozzle.

7. Gas jet.
• Mass flow rate of abrasive is proportional to
gas pressure and gas flow.
• Pressure is typically 0.2 N/mm² to 1N/mm²
• Air, N2 & CO2 can be used.

8. Nozzle.
• Must be hard material to reduce wear by
abrasives: WC (lasts 12 to 30 hr); sapphire
(lasts 300 hr).
• Cross sectional area of orifice is 0.05-0.2
mm².
• Orifice can be round or rectangular.

9. •Head can be at right angle, or straight.

10. Summary of AJM.
• Mechanics of material removal - Brittle fracture
by impinging abrasive grains at high speed.
• Media - Air, CO2.
• Abrasives: Al2O3, SiC, 0.025mm diameter, 2-
20g/min mass flow rate, non-recirculating
• Velocity = 150-300 m/sec
• Pressure = 2 to 10 atm.
• Nozzle - WC, sapphire, orifice area 0.05-0.2
mm², life 12-300 hr., nozzle tip distance 0.25-
0.75 mm.

11. Summary of AJM.
• Critical parameters - abrasive flow rate and
velocity, nozzle tip distance from work surface
and abrasive grain size.
• Materials application - hard and brittle metals,
alloys, and nonmetallic materials (e.g.,
germanium, silicon, glass, ceramics, and mica)
Specially suitable for thin sections.
• Applications- drilling, cutting, deburring,
etching, cleaning.

12. Applications of AJM.
Above: A spring machined from 1/8" brass.

13. !
Above: Company name machined from a file. The
abrasive jet machines from hardened steel as easily as

14. Above: A rack and a gear machined with an abrasive
jet. Material is 1/2" (13mm) steel.

15. Above: Some sort of friction plate made from 1/4"
(6mm) stainless. The circle pattern was etched into the
material using the abrasive jet with a feed rate so rapid

16. Above: 2" (50mm) thick concrete. It's pink
because there was a pigment added to the
concrete.

17. Advantages of AJM.
• The abrasive jet can be used to cut any
material. Even diamonds have been cut,
using diamond dust as the abrasive.
• Make all sort of shapes with only one tool.
• Virtually no heat is generated in the work
piece.
• No mechanical stress.
• Fast set up.

18. Disadvantages of AJM.
• Because of the very small stream of abrasive
particles, the material removal rate is low.
• The abrasive powders cannot be reused since the
points and edges get worn down. However, the
cost of most abrasives is relatively low.
• Because of its nature, AJM usually requires some
type of dust-collecting system.