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Water Jet and Abrasive
Water Jet Machining
Principle, Working,
Equipment’s, Application, Advantages and Disadvantages
Principle Of Water Jet Machine
engineeringinsider.
This
process works on the basic principle of water erosion.
In this
process, a high-speed well-concentrated water jet is used to cut the metal. It
uses the kinetic energy of water particle to erode metal at the contact
surface.
The jet
speed is almost 600 m/s. It does not generate any environmental hazards.
For
cutting hard materials, abrasive particles are used in the water jet. These
abrasive particles erode metal from the contact surface.
Equipment – Parts Of Abrasive Water Jet Machine-
Hydraulic Pump:
In the
water jet machining process, a hydraulic pump is
used to pump the water from the storage tank for the machining process. It is
connected to an electric motor of about 100 Horsepower.
Hydraulic Intensifier:
As the
name implies, it is used to increase the water pressure for further process.
Hydraulic intensifier accepts water from the pump at a small pressure about 4
bar. The water pressure at the outlet of the intensifier is about 3000-4000
bars.
Hydraulic Accumulator:
A
hydraulic accumulator is used when a large amount of pressure energy is
required for an instant. It used to eliminate pressure fluctuation. It supplies
fluid at high pressure when required.
Tubing System:
Tubes
are used to supply high-pressure water to the nozzle for further cutting
process. It increases the kinetic energy of the fluid. Its diameter is about
10-14 mm. It provides flexible movement and does not allow any significant
loses.
Flow regulator:
Flow
regulators are used to regulating the flow according to cutting requirement.
For high cutting load, high pressurized water is supplied at the high rate.
Abrasive:
Abrasive
particles are used in abrasive waterjet machining for machine hard material. Generally,
Aluminium oxide, Silicon carbide etc. used as abrasive particles.
Nozzle:
As we
know, nozzles are used to convert pressure energy into
kinetic energy. This nozzle converts high pressure of water into a
high-velocity jet.
This
high-speed water jet strikes at work surface which is used for machining. There
is a possibility of erosion at the orifice of the nozzle due to high-pressure
water jet.
Therefore
high wear resistance material is used for the nozzle. The size of the nozzle is
about 0.2 – 0.4 mm.
If
abrasive waterjet machining is used, abrasive particles mixed in water stream
before entering into the nozzle.
Drain and Catcher-
The
drain and catcher system is used to remove debris and other
machined particle form water. It separates metal particle from water
and this water is further sent to the reservoir. It also used to reduce noise
associated with WJM.
Working:
The
working of waterjet machining can be summarized as follows-
§
First
water is filled in the water reservoir. It provides water for cutting
operation.
§
A pump
sucks water from the water reservoir and sends it to intensifier.
§
Intensifier
increases the water pressure from 4 bar to 4000 bars. It sends water to an
accumulator which store some pressurize water.
§
This
high-pressure water now sends through tubing system to the nozzle. The water
passes through flow regulator valve which regulates the flow.
§
Now,
this high-pressure water enters into the nozzle. Nozzle converts some pressure
energy of water into kinetic energy.
§
A
high-speed high pressurize water jet is available at the nozzle exit.
§
This
water jet sends to strike at the work surface. It erodes metal from the contact
surface. Thus metal removal takes place.
This is
a whole working process of waterjet machining.
The
drain and catcher system is used to remove debris and other
machined particle form water. It separates metal particle from water
and this water is further sent to the reservoir. It also used to reduce noise
associated with WJM.
Working:
The
working of waterjet machining can be summarized as follows-
§
First
water is filled in the water reservoir. It provides water for cutting
operation.
§
A pump
sucks water from the water reservoir and sends it to intensifier.
§
Intensifier
increases the water pressure from 4 bar to 4000 bars. It sends water to an
accumulator which store some pressurize water.
§
This
high-pressure water now sends through tubing system to the nozzle. The water
passes through flow regulator valve which regulates the flow.
§
Now,
this high-pressure water enters into the nozzle. Nozzle converts some pressure
energy of water into kinetic energy.
§
A
high-speed high pressurize water jet is available at the nozzle exit.
§
This
water jet sends to strike at the work surface. It erodes metal from the contact
surface. Thus metal removal takes place.
This is
a whole working process of waterjet machining.
Application:
§ It is used in aerospace industries.
§ Abrasive jet machining is used to cut hard
metal like stainless steel, titanium, Inconel etc.
§ It is used for machining or cutting
reinforced plastic.
§ Use to cut stone which reduces dust in the
environment.
§ Used to machining PCB.
Advantages and Disadvantages:
Advantages:
§
It does
not change mechanical properties of the workpiece. It is useful for machining
heat sensitive material.
§
It is
environment-friendly because it does not form any dust particle and used water
as cutting fluid.
§
Good
surface finish.
§
No
physical tool is required.
§
It can
cut both soft and hard material. For machining soft materials, water jet
machining is used and for machining hard materials, abrasive water jet
machining is used.
§
It is
ideal process for laser reflective materials where laser beam machining cannot
be used.
§
Lower
cost of machining.
Disadvantages:
§
It
cannot be used for machining material which degrades in presence of water.
§
Low
metal removal rate.
§
High
initial cost.
§
The
thick material cannot be machined easily.
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