This slide contains theoritical and analytical study about "about abrasive water jet machining process" and it has also discription about " OMAX 60120 abrasive water jet machine.Here analytical stydy is done with mainly ss-304 material.

1. “ABRASIVE WATERJET MACHINING (NON CONVENTIONAL MACHINING)”
Abstract:- IPR has procured a 3 axis precision abrasive Waterjet cutting system of approx. 3.2
meter x 1.5 meter XY travel. The machine can cut complex flat parts out of most materials (and
wide range of thickness) including metal, plastic, glass, ceramics, stone and composites. Extremely
hard, reflective and nonconductive materials can also be cut. The machine does not create heat-
affected zones or mechanical stresses.
The aim of this project work is to learn the basic abrasive Waterjet cutting application on R&D
purpose. Studies on the various dependent parameter such as Water Pressure (Pw), Cutting Speed
(V), Nozzle diameter (d),Abrasive Index, Machinability Index of the material, Quality to be cut and
depth of cut etc. Each cutting process has significant depended on these parameters.
ABRASIVE WATERJET MACHINING
Introduction:-
 Waterjet process provides many unique capabilities and advantages
 The Waterjet process is recognized as the most versatile and fastest growing process
compliment other technologies such as milling, laser, EDM, plasma
True cold cutting process – no HAZ, mechanical stresses or operator and environmental hazards
Not limited to machining – food industry applications
History:-
Dr. Franz in 1950’s first studied UHP water cutting for forestry and wood cutting (pure WJ)
1979 Dr. Mohamed Hashish added abrasive particles to increase cutting force and ability to cut
hard materials including steel, glass and concrete (abrasive WJ)
First commercial use was in automotive industry to cut glass in 1983
Soon after, adopted by aerospace industry for cutting high-strength materials like Inconel,
stainless steel and titanium as well as composites like carbon fiber
PROCESS OFABRASIVE
WATERJET CUTTING
JET LAGAngular Edge shape
(Common Abrasive) (Hard Rock Abrasive)
 Garnet is hard, tough and inexpensive
 80 Mesh – Most common general
purpose Garnet water jet abrasive
ATTACHMENTS FOR OMAX 60120:
 Tilt–A-JET :Taper removal attachment
 Terrain Follower : To maintaining stand off distance for non planner surface
 Rotary Axis: 6-axis Path to create 3D shapes,
 Precision Optical Locator (POL): To determine the precise location of parts,
 Variable Speed Solid Removal System (VS-SRS) : Optimal abrasive removal during
operation using VFD.
 Drill Head Attachment : 100% reliable piercing of composites and laminates
 Bulk Abrasive Delivery System : Feeds abrasive from 600lb abrasive Hopper to the
machine
 A-Jet : Allows bevels cutting up to +- 60 degrees
SUMMARY OF THE PROJECT:
The basic on Waterjet technology and its Applications area is studied.
Studied the benefit of the CNC abrasive Waterjet machining , its advantages over other
machining techniques. A best example is almost all materials can be cut using AWJM with
zero HAZ.
Studied the capabilities of the OMAX 60120 Abrasive Waterjet Machine and understood the
various features of the Attachments such as Tilt-A-Jet, Terrain Follower, Rotary Axis,
Variable Speed Solid Removal System (VSSRS), Precision Optical Locator and Drill Head
attachment.
Installation requirement for OMAX 60120 machine and its safety concern. As material and
pump technology advances faster cutting rates, longer component life and tighter tolerances
will be achievable
Analytical approach to calculate various parameters such as cutting speed, depth of cut etc.
for SS304 material.
REFERENCE:
[1] M. Hashish, A model for abrasive water jet machining, J. Engg. Materials
Tech., Vol.111, (1989), pp.154-162.
[2] J. Zeng and T. J. Kim, An erosion model of polycrystalline ceramic in
abrasive water jet cutting, Wear, Vol.199(2), (1996), pp.275-282.
[3] http://www.omax.com/waterjet-cutting/machine/model/60120.
http://waterjets.org/index.php?option=com_content&task=view&id=81&Itemid=51.
[4] http://waterjet-cutting.blogspot.in/search/label/maintenance%20waterjet
ANALYTICALAPPROACH
Used to cut much harder materials
Water is not used directly to cut material as in Pure, instead water is used to accelerate abrasive
particles which do the cutting
80-mesh garnet (abrasive) is typically used though 50 and 120-mesh is also used
Standoff distance between mixing tube and workpiece is typically 0.010-0.200 – important to keep
to a minimum to keep a good surface finish
Orifice is made of Sapphires, Rubies with 50-100 hour life
Diamond Orifice has 800-2,000 hour life
Standard Tungsten Carbide lasts 4-6 hours (not used much anymore)
Premium Composite Carbide lasts 100-150 hours
Consumables include water, abrasive, orifice and mixing tube
Summer School Programme, Institute For Plasma Research, Bhat Gandhinagar, Gujarat (July 2014)
SUMMER SCHOOL PROJECT 2014, INSTITUTE FOR PLASMA RESEARCH, BHAT, GANDHINAGAR
1
• Over Head Tank (OHT)
2
• Water Purification System (R.O System cum Water Softener)
3
• Chiller Unit (To protect the High Pressure Pump from excess heating)
4
• High Pressure Pump (20ksi - 60 ksi)
5
• Control Valve & Flow Regulator
6
• High Pressure water from Orifice (Jewel)
7
• Abrasive Mixed at Mixing Tube
8
• Pressurized mixture from Nozzle
9
• To Work Piece
]}1.15
V = {
- Zeng Modified Cutting Speed Equation
Where,
P = Stagnation pressure of the Waterjet in thousands of PSI (KSI), typically 55 KSI.
d = Orifice diameter in inches, typically 0.014
Ma = Abrasive flow rate in lb./min., typically about 0.8
fa = Abrasive factor (1.0 for garnet)
Q = Quality, Set to 3.0 to calculate clean cut speed
H = Material thickness in inches
D = Mixing tube diameter in inches, typically 0.030 to 0.040
V = Traverse speed in IPM
M = Machinability of material
0
0.5
1
1.5
2
2.5
3
3.5
4
0 1 2 3 4 5 6
CuttingSpeedV(IPM)
Finish Quality (Q)
Cutting Speed vs Finish Quality
SS 304 material by
taking H = 2 inch
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0 100 200 300 400 500
CuttinSpeedV(lPM)
Machinability
Cuttin speed vs. Machinability
Carbide SS 304
Titanium
Aluminum
Glass
Nylon
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 10 20 30 40 50 60 70
CittomgS[eedV(IPM)
Water Pressure Pw (Ksi)
Cutting Speed vs. Water
Pressure
0
0.005
0.01
0.015
0.02
0.025
0 1 2 3 4 5 6 7
CUTTINGSPEED
H(DEPTH OF CUT)
CUTTINGSPEED VS. DEPTH OF CUT
HOW HIGH PRESSURE IS GENERATED:
 Direct drive pump
 Intensifier pump
Direct drive pumps are gaining acceptance in the Waterjet
industry due to their simplicity and high efficiency.
Abrasive
Pw=55ksi,H=3 inch
SS-304 material by
taking H=3 inch
Pw=55ksi,ss-304
material
JET LAG
Produced 3800 bar to
4100 bar by 60 ksi, 40
Hp Direct drive pump