unconventional machining process with high accuracy and precise dimension...less material removal rate

1. SURESH BEERA
M.Tech Ist year
12ETMM11
Materials Engineering
SEST,UOH.
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2. Introduction
 Machining
 Conventional machining
 Unconventional maching
Based on Mechanical energy
(WJM,AJM,AWJM)
JET : A rapid stream of liquid or gas forced out
of a small opening.
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3. Working principle AWJM
 The cutter is commonly
connected to a high pressure
water pump where the water is
then ejected from the nozzle,
cutting through the material by
spraying it with the jet of high
speed water.
 Additives in the form of
suspended grit or other
abrasives, such as garnet and
aluminum oxide can assist in
this process.

4. 4
AWJM - Elements

5. AWJM Setup
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6. 6
Schematic Setup of AWJM

7. 7
Basic Methodology
 Water is pumped at a sufficiently high pressure, 200-400 MPa
 “Intensifier” works on the principle of pressure amplification using hydraulic
cylinders of two different cross-sections.
 When water at such a pressure is passed through a suitable orifice (nozzle
having  = 0.2 – 0.4 mm), the potential energy of water is converted into
kinetic energy.
 This yields high velocity (~ 1000 m/s) jet of water.
 Such a high velocity water jet can machine thin sheets/foils of aluminium,
leather, textile, frozen foods, etc.
 commercially pure water (tap water) is used for machining.

8. 8
Injection & SuspensionHeads

9. 9
Cutting Heads
Schematic View Photographic View

10. 10
Catcher

11. 11
Typical Parameters in Entrained AWJM
 Orifice – Sapphires – 0.1 to 0.3 mm
 Focussing Tube – WC – 0.8 to 2.4 mm
 Pressure – 2500 to 4000 bar
 Abrasive – garnet and olivine - 125 to 60 micron
 Abrasive flow rate - 0.1 to 1.0 kg/min
 Stand off distance – 1 to 2 mm
 Machine Impact Angle – 60o to 900
 Traverse Speed – 100 mm/min to 5 m/min
 Depth of Cut – 1 mm to 250 mm

12. 12
Material Removal in AWJM
 Mechanism of material removal in WJM or AWJM is rather complex.
 In AWJ machining of ductile materials, material is mainly removed by low
angle impact of abrasive particles.
 Further at higher angle of impact, the material removal involves plastic
failure of the material at the sight of impact.
 In AWJ machining of brittle materials, material would be removed due to
crack initiation and propagation because of brittle failure of the material.
 In water jet machining, the material removal rate may be assumed to be
proportional to the power of the water jet.

13. Advantages
• Cut virtually any material. (pre hardened
steel, mild steel, copper, brass, aluminum;
brittle materials like glass, ceramic, quartz,
stone)
• Cut thin stuff, or thick stuff.
• Make all sorts of shapes with only one tool.
• No heat generated.
• Leaves a smooth finish, thus reducing
secondary operations.
• Modern systems are now very easy to learn
and safe.
•Unlike machining or grinding, waterjet
cutting does not produce any dust or particles
that are harmful if inhaled.
•Waterjet cutting can be easily used to
produce prototype parts very efficiently
This part is shaped with waterjet
using one tool. Slots, radii, holes,
and profile in one 2 minute setup.
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14. Disadvantages
• One of the main disadvantages of
abrasive waterjet cutting is that 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, and
the time to cut a part can be very long.
Because of this, waterjet cutting can be
very costly.
• Another disadvantage is that very thick
parts can not be cut with waterjet cutting
and still hold dimensional accuracy. If the
part is too thick, the jet may dissipate.
Waterjet lag
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15. AWJM vs. other Modern process
After laser cutting After waterjet cutting Abrasive Water jets are much
faster than EDM.
After plasma cutting After waterjet cutting
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16. Practical Applications
 Edge finishing
 Radiusing
 De-burring
 Polishing
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17. 17
AWJM - Applications
 Paint removal
 Cleaning
 Cutting soft materials
 Cutting frozen meat
 Textile, Leather industry
 Peening
 Pocket Milling
 Drilling & Turning
 Nuclear Plant Dismantling

18. SUMMARY
 Only abrasives and water is used in AWJM
 In AWJM no heat generate during machining
 It has faster cutting rates, longer component life and
tighter tolerances will be achievable
 AWJM that embrace simplicity and have a small
environmental impact
 AWJM is have more advantage than other modern
machining process
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19. References
 Modern Machining process P.C.Pandey ,H.S. Shan,tata
mcgraw hill publication.
 Principles of AWJM Andreas W.Momber,Radovan
Kavacevic
 www.flowcorp.com
 www.flowwaterjet.com/Abrasive-Waterjet
 www.waterjets.org
 www.aqua-dynamics.co.uk
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20. 24-10-2014 THANK YOU20