1. ABRASIVE JET MACHINING AND STUDY OF PROCESS PARAMETERS

2. Abrasive Jet Machine Introduction
Abrasive jet machining (AJM) is a non-traditional machining
process that can machine material without generating heat and
shock.
Abrasive jet machining (AJM) is commonly used for Cutting,
Cleaning, Drilling and Etching operation

3. Mechanism of AJM Fine particles are accelerated in gas stream .
The particles are directed towards
the focus of machining.
As the particle impacts the surface,
it causes a small fracture, and the
gas stream carries both the
abrasive particles and the
fractured (wear) particles away.

4. Conventional Abrasive Jet Machine
Compressor

5. Constructional Details
Equipments involved in the construction of the
“ Abrasive Jet Machine” are as follows
COMPRESSOR
2. VIBRATOR
3. MIXING CHAMBER
4. NOZZLE
5. MACHINE TABLE
6. PRESSURE GAUGE & REGULATOR

6. Process Parameters 1.Carrier Gas : 2.Abrasive :
The variables that influence the rate of metal removal are as follows :
1.Carrier Gas :
Carbon dioxide, nitrogen & air. Air is most widely used
2.Abrasive :
Aluminum oxide, Silicon carbide, Sodium bicarbonate etc.
3.Velocity of abrasive :
The jet velocity is a function of nozzle pressure & design.
The range of jet velocity is m/min
4. Work Material :
It is recommended for processing of brittle material
5. Nozzle Tip Distance (NTD) :
It is the distance between the nozzle tip & work material.

7. Effect of Process Parameters on Machining
a) Effect of Pressure of carrier gas on Material Removal Rate (MRR)
S.No.
Gas Pressure
(Kgf/cm2)
Material Removal Rate (MRR) (mg/min) 1 5 18 2 6 21 3 7 23 4 8 26
Table a)1 : Effect of Pressure on MRR 5 10 15 20 25 30 1 2 3 4
Pressure (Kgf/cm2)
Material Removal Rate (MRR),
mg/min
Gas Pressure Kgf/cm2
Material Removal Rate
Fig a)1 : Effect of Pressure on MRR
Source : Previous Experiments conducted by M. Roopa Rani and S. Seshan

8. (b) Effect of Nozzle Tip Distance (NTD) on Diameter of Cut.
S. No.
Nozzle Tip Distance
(NTD)
(mm)
Diameter of Cut 1
0.79
0.46 2
5.00
0.64 3
10.01
1.5 4
14.99
2.01
Table b1:Effect of Nozzle Tip Distance on Diameter of Cut.
Fig b1:Shows the effect of Nozzle Tip Distance on Diameter of Cut.
Source : Previous Experiments conducted by M. Roopa Rani and S. Seshan

9. Block Diagram of Fabricated Abrasive Jet Machine

10. Fabricated Abrasive Jet Machine
Photograph of
Fabricated Abrasive Jet Machine

11. Experimental Procedure:
Glass was used as a test specimen, was cut into square and rectangular shape for machining on AJM.
Specimens were cleaned using air jet and weighed on a sensitive scale, accurate to gram .
Each test sample was placed on the work chamber and machined by abrasive jet machine by varying various process parameters
The machine work piece was then removed, cleaned and weighed again to determine the amount of material removed from the work piece.
The size of hole at the top surface and bottom surface was measured and the results were tabulated.

12. Experimental Details:
Experiment No:1- NTD Vs Diameter of Hole
Observation – 1.1
Fig Machined Work piece at Pressure = 5.5 kgf/cm2
Thickness of material = 4 mm

13. Nozzle Tip Distance NTD (mm) Bottom Surface Dia (mm)
Observation Table
Pressure = 5.5 Kgf/cm2
S.No.
Nozzle Tip Distance NTD (mm)
Top Surface Dia (mm)
Bottom Surface Dia (mm) 1 6
7.05
4.51 2 12
8.72
5.05 3 15
11.21
5.33 4 18
11.65
6.65
Table1.1 Effect of Nozzle Tip Distance on Dia of Hole.
Graph
Dia Of
Hole
(mm)
NTD (mm)
Fig Shows the graph of Diameter of Hole vs. Nozzle Tip Distance

14. Experiment No:1- NTD Vs Diameter of Hole
Observation – 1.2
Fig Machined Work piece at Pressure =6.5 kgf/cm2
Thickness of material = 4 mm

15. Nozzle Tip Distance NTD (mm)
Observation Table
Pressure = 6.5 Kgf/cm2
S.No.
Nozzle Tip Distance NTD (mm)
Top Surface Dia mm
Bottom Surface Dia mm 1 6
7.55
4.55 2 12
9.75
5.65 3 15
11.15
5.91 4 18
11.75
6.05
Table1.2 Effect of Nozzle Tip Distance on Dia of Hole.
Graph
Dia Of
Hole
(mm)
NTD (mm)
Fig Graph of Diameter of Hole vs. Nozzle Tip Distance

16. Experiment No:1- NTD Vs Diameter of Hole
Observation – 1.3
Fig Machined Work piece at Pressure = 8 kgf/cm2
Thickness of material = 4 mm

17. Nozzle Tip Distance NTD (mm)
Observation Table
Pressure = 8 Kgf/cm2
S.No.
Nozzle Tip Distance NTD (mm)
Top Surface Dia mm
Bottom Surface Dia mm 1 6
7.72
5.05 2 12
9.95
5.75 3 15
11.45
5.96 4 18
11.81
6.75
Table1.3 Effect of Nozzle Tip Distance on Dia of Hole
Graph
Dia Of
Hole
(mm)
NTD (mm)
Fig1.3.2 Graph of Diameter of Hole vs. Nozzle Tip Distance

18. Experiment No:2- Pressure Vs Material Removal Rate (MRR)
Observation - 2.1
Fig Machined work piece for determination of MRR at Pr.=5.5 kgf/cm2
Pressure 5.5 kgf/cm Initial weight = gm
Final Weight = gm Time = 20 sec
Thickness = 8mm MRR = 120 mg/min
Fig Machined work piece for determination of MRR at Pr.=6.5 kgf/cm2
Pressure 6.5 kgf/cm Initial weight = gm
Final Weight = gm Time = 20 sec
Thickness = 8mm MRR = 210 mg/min
Fig Machined work piece for determination of MRR at Pr.=7.5 kgf/cm2
Pressure 7.5 kgf/cm Initial weight = gm
Final Weight = gm Time = 20 sec
Thickness = 8mm MRR = 400 mg/min

19. Observation Table Graph Table 2.1 Effect of Pressure on MRR
S.No.
Thickness = 8 mm, NTD = 12 mm
Pressure kgf/cm2
Initial Weight (gm)
Final Weight (gm)
Time (sec)
MRR (mg/min) 1
5.5 20
120 2
6.5
210 3
7.5
400
Table 2.1 Effect of Pressure on MRR
Graph
Fig Graph of Pressure vs. MRR

20. Experiment No:2- Pressure Vs Material Removal Rate (MRR)
Observation - 2.2
Fig Machined work piece for determination of MRR at Pr.=5.5 kgf/cm2
Pressure 5.5 kgf/cm2 Initial weight = gm
Weight = gm Time = 20 sec
Thickness = 12 mm MRR = 90 mg/min
Fig Machined work piece for determination of MRR at Pr.=6.5 kgf/cm2
Pressure 6.5 kgf/cm Initial weight = gm
Final Weight = gm Time = 20 sec
Thickness = 12mm MRR = 213 mg/min
Fig Machined work piece for determination of MRR at Pr.=7.5 kgf/cm2
Pressure 7.5 kgf/cm Initial weight = gm
Final Weight = gm Time = 20 sec
Thickness = 12mm MRR = 480mg/min

21. Observation Table Graph Table.2.2 Effect of Pressure on MRR
S.No.
Thickness = 12 mm, NTD = 12 mm
Pressure kgf/cm2
Initial Weight (gm)
Final Weight (gm)
Time (sec)
MRR (mg/min) 1
5.5 20 90 2
6.5
213 3
7.5
480
Table.2.2 Effect of Pressure on MRR
Graph
Fig Graph of Pressure vs. MRR

22. Conclusion: From the experiment conducted it was observed that:
Abrasive Jet Machine was fabricated with following specification:
Diameter of nozzle = 3 mm
Type of abrasive particle – aluminum oxide (AlO2)
Pressure range – 5 to 8 kgf/cm2
Carrier gas used – Dry air
From the experiment conducted it was observed that:
1. As Nozzle Tip Distance increases, the Top surface diameter and Bottom surface
diameter increases
2. As the Pressure increases Material Removal Rate (MRR) also increases.

23. Scope of Future Work:
In this fabricated abrasive jet unit experiment can be conducted :
1. By using different nozzle tip diameter.
2. By using different type of abrasive particles.
3. By using different sizes of abrasive particles.
4. By using different work material.
5. Also the abrasive jet machine can be improved by retrofitting,
computer numerical control (CNC)

24. References
M. Roopa Rani and S. Seshan “Abrasive Jet Machining-Process Variables and Current Application”Metals Materials and Process,1995 Vol.7 No.4,pp
P K Ray and Dr A K Paul, “Some Studies on Abrasive Jet Machining” Journal of the Institution of Engineers (India) vol 68 part PE 2 November 1987
Alok K.Verma, Cheng Y. Lin Associate Professor ,Engineering Technology Dept. Old Dominion University Norfolk, Virginia “Parametric Study of the Efficacy of Cutting Process in Abrasive Jet Machining (AJM)”
P. C. Pandey & H.S. Shan ,” Modern Machining “ Tata McGraw-Hill Publishing Company , Edition :1980
Production Technology HMT Tata McGraw-Hill Publishing Company , Edition :1980
Maleev & Hartman “Machine Design “edited by O. P. Grover “ CBS Publishing & Distributor
Amitabh Ghosh & Ashok Kumar Malik “Manufacturing Process “East –West Press Private Limited ,New Delhi, Edition 1995

25. THANKS