Water jet cutting uses a high-pressure jet of water, or water with an abrasive added, to cut materials. It is a non-thermal process that causes no heat damage. The document discusses the principles of water jet cutting, the types of water jets, how it works, its applications and advantages over other cutting methods like having no heat-affected zones and being able to cut almost any material.

1. WATER JET CUTTING
Presented By:
V.LOGANATHAN M-TECH (PDM)

2. INTRODUCTION TO WATER JET
 Key element in WJM is a jet of water.
 Water jet travels at velocities as high as 900 m/s.
 When the jet of water strikes a work piece surface, the erosive force of water removes the
material rapidly.
 The water, in this case, acts like a saw and cuts a narrow groove in the work piece material.
 True cold cutting process – no HAZ (Heat Affected Zones), mechanical stresses or operator
and environmental hazards

3. PRINCIPLE
 When the a high pressure (150-1000 MPa) and high velocity (540-1400 m/s) of water jet
comes out of nozzle and strikes the work piece of the material, its kinetic energy is converted
into pressure energy including high stresses in the work material. When this induced stress
exceeds the ultimate shear stress of the material, small chips of the work piece material get
loosened and fresh surface is exposed.
 The fluid flow rate is typically from 0.5 to 2.5 l/min
 Water is the most common fluid used, but additives such as alcohols, oil products and
glycerol are added when they can be dissolved in water to improve the fluid characteristics.

4. WHY USE WATER JET?
 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.

5. HOW WATER JET WORKS?
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.

6. SCHEMATIC LAYOUT OF WJM

7. TYPES OF WATER JET
PURE WATER JET
Pure Water jet is the original water cutting method. In
which pure water is compressed at very high pressure &
released through a narrow opening.
ABRASIVE WATER JET
Abrasive water jet is same as pure water jet 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.

8. PURE WATER JET CUTTING
1. Water under pressure
2. Water nozzle
3. Pure water jet
4. Work piece
5. Cut width

9. PURE WATER JET CUTTING
 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.

10. PURE WATER JET CUTTING
 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

11. ABRASIVE WATER JETS
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

12. ABRASIVE WATER JETS
 In abrasive water jet, the water jet stream accelerates abrasive particles and
those particles erode the material from the work piece.
 The abrasive Water jet is hundreds of times more powerful than the 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.

13. TYPES OF ABRASIVE MATERIALS
 garnet , aluminum oxide , olivine , silica sand , silicon carbide , etc .
 Virtually any material can be cut by using abrasive jet
machining method , i.e. harder materials like titanium to steel.
 Abrasive particles must be hard ,high toughness, irregular in
shape & edges should be sharp (usually about 0.001 in)

14. PARAMETERS AFFECTING THE
PERFORMANCE OF WJM

15. CUTTING RATES FOR DIFFERENT
MATERIAL THICKNESSES

16. ADVANTAGES OF WATER JET
CUTTING
 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

17. ADVANTAGES (CONTINUED)……
 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.

18. DISADVANTAGES
 Abrasive powder cannot be reused.
 Very thick parts can not be cut with Water Jet
 One of the main disadvantages of water jet cutting is that a
limited number of materials can be cut economically.
 Taper is also a problem with WJM in very thick materials.
 WJM is very expensive process. It is not suitable for mass
production because of high maintenance requirements.

19. PROCESS COMPARISON
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.

20. PROCESS COMPARISON
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.

21. PROCESS COMPARISON
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.

22. COMPARISON OF COMPONENT
SURFACE
20 mm mild steel, cut with the abrasive water jet (left)
and the laser jet (right)

23. STRUCTURE ANALYSIS
 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

24. ENVIRONMENTAL ISSUES AND
FUTURE
 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 .

25. CRYOGENIC ABRASIVE JET MACHINING
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.

26. MATERIALS, WHICH ARE GENERALLY
MACHINED USING WJ AND AWJ
 Steels
 Non-ferrous alloys
 Ti alloys, Ni- alloys
 Polymers
 Honeycombs
 Metal Matrix Composite
 Ceramic Matrix Composite
 Concrete
 Stone
 Granite
 Wood
 Reinforced plastics

27. APPLICATIONS
• Paint removal
• Cleaning
• Cutting soft materials
• Cutting frozen meat
• Textile, Leather industry
• Surgery
• Cutting
• Drilling
• Turning
• Glass Fiber Metal

28. APPLICATIONS
Aerospac
e
Food Processing
Marble Industry

29. APPLICATIONS
Automotive Electronics and
PCBs
Concrete

30. Ceramic part cut with an abrasive
water jet
Steel gear and rack cut with an
abrasive water jet
APPLICATIONS

31. PARTS MADE BY WJM
STAINLESS STEEL MILD STEEL

32. HARDENED STEEL ALUMINUM
TITANIUM COPPER

33. CERAMIC
STONE
WOOD RUBBER