Water JET Machining and Abrasive JET Machining & Abrasive Water JET Machining

1. 1
Water Jet & Abrasive Water Jet
Machining Process
Dr. P. Srihari,
Associate Professor,
Dept. of Mechanical Engineering,
AITAM,Tekkali.
August 26, 2015

2. 2
AJM,WJM & AWJM Overview
 Abrasive jet and waterjet cutting machines are used to cut
sheet materials or to remove materials from a surface
 They generate a focused stream of fluid mixed with abrasive
particles. They may use pressurized water or compressed air
as the driving fluid to propel the abrasive particles or jet.
 The equipment consists of components related to the
blasting or jet machining applications such as
◦ pressure generation / intensification,
◦ cabinets,
◦ nozzles or wheels, and
◦ dust collectors;
(or)
 The equipment may be purchased in component form to
either build a custom system from the ground up, or to
replace worn out parts.

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General Applications of AJM,WJM &
AWJM
In addition to cutting, abrasive jet and waterjet cutting machines can
perform a number of secondary procedures.
• Sectioning- Cutting patterns out of sheet or plate materials.
• Deburring and deflashing- Removing sharp edges or discontinuities
from a part.
• Demolition- The destruction of structures or walls constructed of
building materials.
• Hydrodemolition- The destruction of concrete structures or walls.
• Descaling- The removal of heat-treat scale, surface discoloration,
oxides, rust, weld scale or corrosion that ruins appearance and
interferes with welding, painting, plating, coating, drawing and other
processes.
• Stripping- The removal of an existing protective coating or paint layer
to facilitate welding, recoating or adhesive joining.
• Web slitting- These abrasive jet cutting machines typically have a coil
feeder, winder or rewinder.
August 26, 2015

4. 4
Water Jet Machining
 Can water cut Metals???
• WJM works on the principle of erosion effects of a high velocity and small
diameter Water Jet. It is used for cutting and slitting of porous non metals like
wood, leather etc…
• It is also used for machining fiber composites, asbestos, and some kinds of
steels.
• Water acts as a cutting tool which never dulls or breaks.
• WJM does not generate airborne dust, so it is less hazardous and the jet
velocity is as high as 900 m/s.
Water Cutting Steel
Water Jet Machining Applications

5. 5
Schematic diagram of Water Jet Machining
August 26, 2015
Water Jet Machining

6. Abrasive Water Jet Machining (AWJM)
 It is a process that uses a very high speed (supersonic
about 2.5 Mach number) water jet mixed with abrasives
to cut any type of material without in any way affecting
the work material or the environment.
 If the process is used without any abrasives, it is called
as water jet machining.
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How aWater Jet works

7. Equipment
 An intensifier pump to provide high-pressure water,
 The abrasive delivery system and a cutting head for
producing the abrasive water jet,
 Computer controlled manipulator to provide the
desired motion of the cutting head, and
 A catcher that dissipates the remaining jet energy after
cutting.
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Flow International Corporation (2007) Model 30HP Hyplex IFB CN
C AbrasiveWater Jet Cutting Machine

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11. Process Parameters
 Jet velocity
 Feed rate
 Abrasive used and their size
 Work material and its thickness
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12. Process Parameters
 Jet velocity
◦ As the velocity increases the material removal rate
increases which will have an effect on the quality of
the surface produced.
 Feed rate
◦ As the feed rate of the jet increases the jet has lower
time to erode the surface and consequently the
surface finish of the cut edge will be rough.
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14. Process Parameters
 Jet Drag
 Jet Kerf
 Standoff
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18. Advantages
 Cuts through any material irrespective of the hardness
or any other material characteristic.
 Costs with AWJM are less than other machining
methods.
 The quality of the cut achieved by AWJ machine
virtually eliminates additional finishing.
 AWJM is faster than other methods, especially for
materials that would otherwise require a lot of
additional finishing.
 AWJM does not generate a lot of heat during the
cutting process.
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Cutting marble carpets using a water jet machi
ne by Aquacut

19. Advantages
 Scrap material left after using the AWJM remains
unaltered and hence can be reused.
 Since the side forces are low, it is possible to cut thin
(as low as 0.5 mm) walled parts.
 Very little fixturing is required for most parts.
 In many cases, material can be stacked to decrease
production costs.
 Since the water jet cuts with very little force, the
amount of burr generated is extremely small if at all
present.
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Comparison of Different Processes of Cutting