The document discusses abrasive waterjet machining (AWJM). It begins by explaining that AWJM uses a high pressure water jet mixed with abrasive particles to cut materials. It then discusses the history and development of AWJM, the types of water jets (pure water jet and abrasive water jet), how AWJM works, its applications in cutting a wide variety of materials, advantages like lack of heat affected zones and ability to cut complex shapes, and comparisons to other machining methods. The document provides examples of materials cut with AWJM and concludes by discussing trends in using more environmentally friendly methods like cryogenic abrasive jet machining.

1. Presented by:
Umair Bukhari

2. Muhammad Umair
Bukhari
http://onlinemetallurgy.com

3.  It is a tool using a jet of water at high velocity and
pressure
 The process is same as water erosion found in nature
but is greatly accelerated and concentrated.
 True cold cutting process –no HAZ, no mechanical
stresses and environmental hazards.
 Not limited to machining –It has food industrial
applications.
 They are fast, flexible, reasonably precise.

4.  It can cut almost everything, with greater
efficiency and productivity.
 It is one of the fastest growing major
machine tool processes in the world due to
its versatility and ease of operation.
 Water jets cut accurately, reduced scrap-
saving money through greater material
utilization.
 As it is software oriented, we get correct
shape, dimensions and size.

5.  Dr. Franz in 1950’s first studied water cutting
for forestry and wood cutting.
 1979 Dr. Mohamed Hashish added abrasive
particles to increase cutting force and ability to
cut hard materials including steel, glass and
concrete.
 First commercial use was in automotive
industry to cut glass in 1983.
 Soon after, adopted by aerospace industry for
cutting high-strength materials like stainless
steel and titanium as well as composites like
carbon fiber.

6.  High pressure (60,000 psi), which when
bombarded on the work piece erodes the
material.
 A high velocity water jet when directed at a
target in such a way that, its velocity in
virtually reduced to zero on striking the
surface. Because of this water jet will make a
hole in the material if the pressure is high
enough.
 Many variables such as nozzle orifice
diameter, water pressure, cutting feed rate and
the stand distance affect the performance.

7. Stainless steel plate
(50 mm thick) machined
with AWJ
Different engineering components machined with
AWJ, shows the obtainable accuracy and precision
(Photograph Courtesy – Omax Corporation, USA)

8.  The two types of water jets
 Pure water jet
 abrasive water jet.
 A pure water jet is used to cut soft materials,
and within just 2 minutes the very same water
jet can be transformed into an abrasive water
jet to cut hard materials by adding abrasives
to it.
 Pure water jet uses pure pressurized water
whereas abrasives water jet uses abrasives like
Aluminum oxide, silicon carbide and garnet.

9.  Schematic diagram of
pure water jet cutting:
1. Water under pressure
2. Water nozzle
3. Pure water jet
4. Work piece
5. Cut width (kerf)

10.  Pure Water jet is the original water cutting
method. In which pure water is compressed at
very high pressure & released through a
narrow opening.
 It forms water jet, which comes out at the
speed of up to 850 m/s
 The largest uses for pure water jet cutting are
disposable diapers, tissue paper, and
automotive interiors .
 Provides Very thin stream (0.004 to 0.010 inch
in diameter is the common range) .
 Very little material loss due to precise cutting.

11.  Non-heat cutting ,Usually cuts very quickly.
 Able to cut soft, light materials(e.g., fiber glass
insulation up to 24" thick).
 Used to cut soft, thin, or porous material
 Silicone
 VCT (tile)
 Foam
 Cork
 Teflon
 Composites
 Plastic

13.  Schematic diagram of
abrasive water jet cutting:
1. Water under pressure
2. Water nozzle
3. Water jet
4. Abrasive feed (unpressurised)
5. Mixing chamber (vacuum
chamber)
6. Abrasive nozzle (focusing tube)
7. Water jet with abrasive
8. Cut width (kerf)

14.  In the abrasive water jet, the water jet stream
accelerates abrasive particles and those
particles,not the water, erode the material.
 The abrasive Water jet is hundreds of times
more powerful than a pure Water jet.
 Extremely versatile process, No Heat Affected
Zones, No mechanical stresses
 Easy to program
 Thin stream (0.020 to 0.050 inch in diameter)
 10 inch thick cutting, Little material loss due to
cutting
 Quickly switch from pure water jet to abrasive
water jet.

16.  The applications and materials, which are generally machined
using WJ and AWJ, are given below:
 Application
• Paint removal
• Cleaning
• Cutting soft materials
• Cutting frozen meat
• Textile, Leather industry
• Surgery
• Cutting
• Drilling
• Turning
• Glass Fiber Metal
Materials
• Steels
• Non-ferrous alloys
• Ti alloys, Ni- alloys
• Polymers
• Honeycombs
• Metal Matrix Composite
• Ceramic Matrix Composite
• Concrete
• Stone – Granite
• Wood
• Reinforced plastics

17.  There are no heat affected zones (HAZ)
 The material does not get warped, discolored or
hardened
 Ability to manufacture burr-free parts
 No jagged edges or burrs
 Near net shape cutting
 Eliminates the need for secondary operations
 Can cut through thick materials
 Up to 12” in thickness

18.  Cheaper than other processes.
 Cut any material. (mild steel, copper, brass,
aluminum; brittle materials like glass, ceramic,
quartz, stone)
 Make all sorts of shapes with only one tool.
 Unlike machining or grinding, water jet cutting
does not produce any dust or particles that are
harmful if inhaled.

19.  Leaves a smooth finish, thus reducing
secondary operations.
 Clean cutting process without gasses or
oils.
 Water jet cutting can be easily used to
produce prototype parts very efficiently.
An operator can program the dimensions
of the part into the control station, and the
water jet will cut the part out exactly as
programmed.
 Get nice edge quality from different
materials.

20.  A limited number of materials can be cut
economically. While it is possible to cut tool
steels, and other hard materials, the cutting rate
has to be greatly reduced.
 Another disadvantage is that very thick parts
can not be cut with water jet cutting and still
hold dimensional accuracy. If the part is too
thick, the jet may dissipate some, and cause it to
cut on a diagonal.
 Taper is also a problem with water jet cutting in
very thick materials. Taper is when the jet exits
the part at a different angle than it enters the
part, and can cause dimensional inaccuracy.
Water jet lag

21. Water jets vs. Lasers cutting
 Abrasive water jets can machine
many materials that lasers cannot.
(Reflective materials in particular,
such as Aluminum and Copper.
 Uniformity of material is not very
important to a water jet.
 Water jets do not heat your part.
Thus there is no thermal distortion or
hardening of the material.
 Water jets are safer.
 Maintenance on the abrasive jet
nozzle is simpler than that of a laser.
After laser cutting
After water jet cutting

22. Plasma cutting Vs. Water jet
cutting
 If the parts require no mechanical post-processing,
for example, if they only need to be welded or they
are simple parts, plasma cutting is more cost
effective.
 If the parts are required post processing, or if
aluminum or other materials are used that are not
well suited to plasma cutting, then water jet
cutting is usually the most cost effective option.

23. Flame cutting Vs. Water jet cutting
 If the cutting edge quality of flame cutting fulfills
the requirements, then flame cutting is more cost-
effective than water jet cutting.
 Water jet cutting provides benefits with respect to
the surface, because depending on the process
there are no weld spatters and no burr formation.
 The part can also be processed further without
thermal heat treatment and straightening.

24. Water jets vs. Electrical discharge
machining
 Water jets are much faster than EDM
 Water jets machine has a wider variety
of materials (virtually any material).
 Uniformity of material is not very
important to a water jet.
 Water jets do not heat the surface of what they
machine.
 water jets require less setup and can cut even non
conducting materials.
 water jets can be considered to be like super-fast
EDM machines with less precision.

25. 20 mm mild steel,
cut with the abrasive water jet (left) And
the laser jet (right)

26.  Water jet cutting is a cold process, so there
is no structural influence.
 The heat transfer during laser, plasma and
flame cutting changes the structure

27.  Nowadays, every manufacturing process is being re-evaluated
in terms of its impact on the environment. For example, use
of conventional coolants in machining and grinding is being
looked upon critically from the point of view of its impact on
environment. The environmental issues relevant to AWJM
are,
 water recycling
 spent water disposal
 chip recovery
 abrasive recovery and reuse
 Environmental issues and concerns have lead the researchers
to use such mediums and abrasives that do not require
disposal, recycling or lead to pollution. Work is going on in
the area of high-pressure cryogenic jet machining .

28. In Cryogenic Abrasive Jet
Machining,
liquid nitrogen replaces the
water phase and dry ice crystals
(solid CO2 crystals) replace the
abrasive phase leading to no need
of disposal or waste generation.
The removed work material in
the form of microchips can be
collected much easily reducing
the chances of environmental
degradation.

29.  Relatively new technology has caught on
quickly and is replacing century-old methods
for machining.
 Used not only in typical machining
applications, but food and soft-goods
industries
 As material and pump technology advances
faster cutting rates, longer component life and
tighter tolerances will be achievable
 Gave us the way for new machining processes
that embrace simplicity and have a small
environmental impact

31. AbrasiveWaterjet

32. RedTinted Glass
9.25” Aluminum