ICE JET MACHINING
PROF. N. D. GHETIYA
Generation of the Ice and apparatus
Hardness Of Ice particle
Comparison of AWJ, WJ & IJM
Machining is a broad term to describe removal
of material from a workpiece.
•Otherwise the process is non
•IJM is a non-traditional
Why Non-traitional machining
Traditional machining processes are UNSATISFACTORY OR UNECONOMICAL
Work piece MATERIAL is too HARD, STRONG, OR TOUGH
Work piece is TOO FLEXIBLE TO RESIST CUTTING FORCES or TOO DIFFICULT
TEMPERATURE RISE or residual stresses are undesirable or
Part SHAPE is very COMPLEX with internal or external profiles or small holes.
What is ice jet machining?
• In Abrasive water Jet Machining process(AWJM)
abrasive particles like silicon carbide and
aluminum oxide are used for machining.
• Ice jet machining is Derivative of AWJM
machining process in which ice particles are used
in place of abrasive particles.
• The ice particles can be prepared beforehand
using an ice particle generator, stored in a
reservoir and then fed to the conventional
entrainment based jetting head.
AWJ and IJ
• In AWJ, waste of water is very high as waterjet
contains abrasive particles. To reuse the water
very complicated water cleaning system has to
• While in IJ, ice is used instead of Abrasives. So
as ice melts into the water, water treatment
gets eliminated and we can reuse the water.
• Also solid waste is produced in the AWJ
technology and it pollutes the environment.
• While compared to AWJ, IJ technology is
Other Processes done with use of
Dry ICE DEBURRING PROCESS
Removal of burrs from edges and holes.
Where burrs could not be removed with any
other means like filing or grinding.
Dry ICE BLASTING PROCESSES
Used for cleaning purpose
Cleaning of engine block can be done with ice
blasting process effectively
Generation of ice
There are 2 approaches:
• Generating the ice in a generator before mixing
it to the water jet.
• Forming ice particles during water jet formation
by introducing a cooling gas like liquid nitrogen.
Generation of ice
Using Ice Generator
Figure shows ice
generation by introducing
the liquid nitrogen to the
atomized water droplets.
Temperature of the liquid
nitrogen is -196 C.
As the water comes into
contact with liquid
nitrogen it is converted
into ice particles.
It is collected into the
storage tank and
By introducing cryogenic gas to
• Liquid Nitrogen is
directly introduced to
the jet of the ice.
• Due to low temperature
of the LN, ice particles
are formed into the jet
• Apparatus for the IJM are different depending
upon the procedure by which the ice particles
basically components like
nozzle, compressor, atomizer etc remains
• The compressor used for the purpose can
produce maximum pressure of 340 Mpa.
• The ultrasonic atomizer used in the ice particle
generator can produce uniform water droplets
of 45 to 90 microns and 2 ltr/hr to 12 ltr/hr.
• The diameter of the nozzle is 0.175mm and
diameter of focusing tube is 0.75mm.
• Standoff distance is kept 3mm to 5mm.
Ice formed at 8° C and 60 micrometer. Mean dia.
Of the ice was found to be 91.8microns
IceJet machning apparatus developed under Project
TECNALIA, UL, IAMCUT
• WATER PRESSURE:50 to 700 Mpa
for harder materials: 700 Mpa
for softer materials: 50 Mpa
• Water nozzel diameter:0.1mm to 0.3mm
• Speed of water jet:500 to 900 m/s
• No heat affected zones.
• Treatment of all kind of materials.
• All the ice found on earth, Crystal Structure of
Ice is Hexagonal Closed Pack (HCP)
• For study of the hardness of ice, we have to
know about the Crystal axis(c-axis) ice crystal.
• The hardness of the ice is not isotropic. After
experiments it is found that hardness changes
with the orientation of c-axis.
Hardness of Ice Crystal
Brinell Hardness Test
• An Olsen Baby Brinell Hardness Tester was
• The machine comes equipped with a 1/16
inch ball to be used with a load of 12.61 kg.
• Preliminary tests with ice samples showed
that this load caused excessive cracking
Modifications had to be done.
Modifications in the equipment
1. The 12.61 kg. Load was replaced by a
platform on which different weights could be
2. The 1/16 inch ball was replaced by a
hardened 1/8-inch ball. The weight of the
ball stem plus platform was 570 g. which
was added to the weights placed on the
platform to give the total load applied.
Specimen of Ice
• Approximately 7×4×1 cm cubes were
used, oriented so that the c-axis Lay parallel
to the large face of one plate and normal to
the large face of the other.
• Polished to a mirror finish, and freeze onto
glass sheet to provide hard base.
Calculation of BHN
• Brinell hardness numbers were computed from
the standard Brinell formula:
• H is the Brinell hardness number
• K is the applied load in kilograms
• D is the diameter of steel ball in mm.
• d is the diameter of the impression in mm.
• As standard equipment was not used, the
equation also had to be modified.
k is the hardness number
ǝ is the width of the cut in microns
Measuring the results
• The specimen was coated with liquid
• Because the indentations were made at low
temperature, and measurements were made at
higher temp. so considerable fogging was
• So for accurate results, indentation made on
the ice was measured on the polystyrene sheet.
• By the experiment a
graph was plotted of
BHN vs Temprature and
it was found that the
hardness of ice
increases with decrease
• After doing the experiment it was found that
the hardness of the ice particle was higher
parallel to the c axis and less perpendicular to
the c axis of the ice particle.
• BHN of ice was found to be ranging between 4
Comparison of AWJ, WJ and IJM
Comparative study of material Drilling by WJ and IJ
Cost analysis for AWJ, WJ and IJM
Cost in Rupees/hour
• By doing the technical analysis of the IceJet
technology it can be concluded that
production and injection of ice particles in to
the water jet it is not a complicated task but it
requires continuous monitoring of the process
to control the temperatures in order to avoid
clogging and melting of the ice particles.
However this can be automated.
• By doing the economic analysis, it can be seen
that costs are very similar for AWJ and IJ.
• Most significant expense is the cost of
• The costs of AWJ will reach the costs of IceJet
in the near future as abrasives are minerals &
are limited in source.
• Ice Jet is an environmentally friendly process
which makes worth its value.