fabrication of optimal abrasive water jet machining using … · 2018-05-14 · fabrication of...

DOI:10.23883/IJRTER.2018.4285.5EUS1 13

Fabrication of Optimal Abrasive water jet Machining

using Finite element approach

Lavish Patel1, Mukesh Dubey2 1Mechanical Engineering Department, Bhilai Institute Technology, Durg 2Mechanical Engineering Department, Bhilai Institute Technology, Durg

Abstract—In this article a computational investigation has been carried out to examine the performance characteristics of abrasive water jet machining (AWJM). A two-dimensional model of

nozzle for AWJM has been developed using ANSYS 14.5 where the simulation has been performed

in ANSYS Fluent. The influence of operating pressure on nozzle outlet velocity has been examined.

The simulation has been under taken by SIMPLE Algorithm at high pressure. Moreover, effect of

various parameter of nozzle such as convergence angle, nozzle length, jet diameter ratio on turbulent

intensity, pressure distribution, and skin frictions have been seen

Keywords—AWJM, CFD, Velocity

I. INTRODUCTION

(In the field non-convectional machining, Abrasive water jet machining is the technique of

removing material from the surface owed to the erosive exploitation of fine-grained abrasive

particles which is allowed to impact at high velocity. To achieve this high velocity, the abrasive

particles are permitted to pass within a nozzle along with compressed carrier gas, which is typically

air. [1]

This machining process has the advantage over conventional machining processes i.e. it over

the accurate control on the material removal rate. The advancement in better and newer designs, the

convenience of tine-grained hard materials, and the development of improved quality,high strength,

nevertheless costlier materials have called for precise and accurate machining processes. Significant

research has been done so far in this area are reviewed and ideas regarding unexplored areas are

discussed in this paper. The potential of the technology is outlined and assessed.

II. LITERATURE REVIEW

P. S. Jain and A. A. Shaikh [2] studied the various processes for cutting the polymer matrix

composites like cotton fiber polyester composites. In this study they compared the processes like

CO2 Laser, water jet cutting and diamond saw cutting with their process parameters. Based on

experimentation carried out they concluded that laser cutting is better over water jet and diamond

saw cutting because of fiber pull out in diamond saw and fiber curling and pulling out in multiple

directions which is observed in water jet cutting. Regarding water jet cutting they commented that

fibers may be affected by water moisture.

According to Dirk [3] Cutting edge preparation is utilized to increase the stability of cutting

tools and to improve the adhesion strength of a subsequent coating. In his work wet abrasive jet

machining with a robot guided system allows to prepare local tool areas and to realize a specific

design of the cutting edge, as well as advantageous surface qualities. His work concentrates on the

requirements and challenges in preparing and designing the cutting edge micro shape using wet abrasive jet machining. Important factors of the process as well as resultant shapes and topography

effects of the machined cutting edges are discussed.

International Journal of Recent Trends in Engineering & Research (IJRTER) Volume 04, Issue 05; May - 2018 [ISSN: 2455-1457]

@IJRTER-2018, All Rights Reserved 14

Pawar et al. [4] Silicon nozzle with high wear resistance in this process. The erosion rate is

depend upon variable pressure and standoff distance. In this experimental investigation sea sand is

using as abrasive material first time for erosion process in Abrasive Jet machining process. The

material removal rate at different condition were calculated by changing pressure and standoff

distance. The study of work surface found to be 0.0289 gm/sec and at the pressure 5 kg/cm2. The

analysis of 95% prediction bound of the silicon carbide has generated cubic polynomial model and R

square value is 0.9897 which is very closed 1. The value obtained of MRR experimentally and after

the calculation is within the limit and percentage of error is very less. The relative hardness of

abrasive against targeted material which is not taken into consideration of model. The depth of

cutting hole type are 4 mm to 6 mm. on glass work piece. In contrast to conventional erosion from

some studies elaborated by using abrasive water jet machine and no detailed investigation were

carried out about sea sand as an abrasive material.

Srikanth and Rao [5] Abrasive jet machining also known as micro-abrasive blasting or pencil

blasting is a non-traditional machining process in which the metal removal takes place due to high

velocity abrasive particles. The abrasive particles are propelled by high velocity carrier gas

(commonly air). This process is specially used for edge shapes and intricate shapes. The metal

cutting or drilling is performed due to high impact of abrasive particles on the work surface. This

machining technology proves good results when tool life is taken into consideration, given the fact

that the abrasive material can be reused several times before abrasive particles lose their cutting

effect. It is already proved that this technique is effectively adopted for polishing and deburring

processes. The present study highlights the influence of different parameters of Abrasive jet

machining like Pressure, SOD, Abrasive Flow Rate, on the Metal removal and Kerf width on

Ceramic Tiles, the type of abrasive particle used for this experiments is Al2O3. The experiments are

conducted according to TAGUCHI method of L9 orthogonal array and RSM, latter compared with

the Results of ANOVA using STATGRAPHICS.

Roxana Nedelcu [6] analyzed conventional and non-conventional machining processes of

composite cutting and stated the requirements of each process along with their advantages and

disadvantages. She considered conventional processes like turning, drilling, milling and grinding and

nonconventional processes like abrasive water jet machining, laser machining technique, electric

discharge machining and ultra-machining. She did not recommend particular processes for composite

cutting but concluded that every composite material possesses unique machining characteristics and

machining processes should be selected according to material characteristics.

Shah [7] conducted experimental investigations to study the effect of abrasive water jet

machining process parameters on material removal rate of granite material. Analysis of variance

(ANOVA) is carried out to optimize the AWJM process parameters for effective machining. He

considered the process parameters like abrasive water pressure, transvers speed and standoff distance

for his studies. Based on experimental investigations he formulated a mathematical model to predict

the material removal rate. Based on the results obtained he concluded that transvers speed is most

significant factor in deciding the MRR. MRR increases with increase in hydraulic pressure and SOD

up to a certain limit.

Alberdi et al. [8] aims at studying the behaviour of a machinability model in composite

materials. The machinability index for various composite materials with different thicknesses was

found experimentally, which showed very different results for different materials. A study of the

effect of the abrasive waterjet process parameters on the quality of cut (taper and surface roughness)

was carried out.



However, AWJ cutting of composite laminates possesses several challenges. There are a few

studies that analyse the effect of input parameters on the quality of the cutting edge, e.g. Kalla et al.

[9], Shanmugan and Massod [10] and Wang [11], or investigations that optimise process parameters

for trimming CFRP materials with good quality, e.g. Etxeberria et al. [12]. Nevertheless, industrial

end users still need to develop process knowledge, since machine manufacturers do not provide good

databases for composite cutting. It is necessary to develop a methodology to adapt the process

parameters for each type of FRP & CFRP material which will allow AWJ trimming operations to be

easily carried out on composite materials.

III. MATHEMATICAL MODELLING

In system abrasive water jet machining is been analyzed with different aspect ratio. The wall shear

stress is analyzed during cutting process and the effect of nozzle convergence has been examined, in

additional to varying the orientation also the heat transfer and shear stress is taken in consideration

with the wall surface of the nozzle.

The equations governing this problem are those of Navier-Stokes along with the energy equation.

The Navier-Stokes equations are applied to incompressible flows and Newtonian fluids, including

the continuity equation and the equations of conservation of momentum on the x and y

According to equations

2 1 11 2

1 2

2 2

1 1

2 2

2 1 2

1( )

u u uu u

t x x

u ug T T

x x x

1

* *

2

* *

1 2

0u u

x x

x1 momentum equation

1

* * * * *

* *1 1 1 1 1

1 2* * * * *

1 2 1 2

*Pr

*

u u u u upu u

t x x x x x

x2 momentum equation

1

2

** * * *

* *2 2 2 2

1 2* * * * *

1 2 1 2

2

*Pr

*

Pr *

uu u u upu u

t x x x x x

Gr T

Energy equation * * * 2 * 2 *

* *

1 2* * *2 *2

1 2 1 2*

T T T T Tu u

t x x x x

Since in order to check the accuracy of developed computational model of AWJM which is

coupled with Navier stokes equation and additional boundary conditions are provided through which

heat transfer and mass flow, stress, etc other parameters are calculated and contour figures are

generated and illustrated in the in this paper.

IV. MATHEMATICAL MODELLING The governing equation of abrasive water jet machining is solved by using ANSYS Fluent solver.

In ANSYS 14.5 computational model has been developed in geometrical section with given



geometrical parameters from the base paper i.e. [13-14]. After that the geometrical model is extended

to mesh section in which complete geometry of AWJM is discretized into various numbers of nodes

and elements whim is in order of 105 . Furthermore, the geometrical mesh model is further named

such inlet, outlet, axis, wall section, etc. so that proper boundary conditions can applied in order to

evaluate performance characteristics of abrasive water jet machining.

Without convergent nozzle

Convergent nozzle

Fig. 1 Computational model detail of AWSJ nozzle

Fig. 2 Boundary condition



V. RESULT AND DISCUSSION

Figure 3 Validation of present work with the Numerical Simulation and Experimental

work of Guihua et al. [13, 14]

In order to validate the present work a computational model of abrasive water jet machine has been

developed and compared with the available literature of Numerical Simulation and Experimental

work of Guihua et al. [13, 14] and found that the obtained results are within acceptable limit and

showing same trend as shown in figure 3.



Figure 4 contour plot of velocity magnitude

Fig 4 shows the counter plot of velocity distribution cross the three-different nozzle. It can seen

that the velocity distribution in all the nozzle is quite different.

Figure 5-6 shows the turbulence intensity along the length of the nozzle corresponding to various

inlet operating pressure. It has been observed that with increasing operating pressure, turbulence

intensity significantly increases. In figure 5-6 the turbulence intensity reaches its peak value at the

narrow region just before the start of focus tube length and in the focus tube the turbulence intensity

has approximately been constant throughout the focus tube length. It can be seen in figure 6-7

From the above, it can be revealed that on changing section significantly increase change in

turbulence intensity takes place in the critical region.



Figure 5 Variation of turbulent intensity at 400bar

Figure 6 contour plot of turbulent Intensity

Fig. 7 Velocity distribution along the nozzle length



Fig 7 shows the Velocity distribution along the nozzle length. It has been seen that increase in

operating pressure the cutting velocity increases and get constant along the focal region of the

nozzle. It has also been observed that major increase in velocity is seen at the convergence section.

Fig.8 Effect of Nozzle convergence angle on turbulent intensity

Fig. 8 shows the effect of Nozzle convergence angle on turbulent intensity. It has been seen that

turbulent intensity first increases significantly and then start decreasing as nozzle convergence angle

increases.

Fig. 9 Effect of Jet diameter ratio on turbulent intensity

Fig. 9 shows the effect of Jet diameter ratio on turbulent intensity. It has been seen that turbulent

intensity decreases linearly as jet diameter ratio increases

VI. CONCLUSION

From the above investigation various conclusion has been drawn which are as follows:

This machining technique is best for machining composite material due to having low tool wear, nearly low thermal damage.

The cutting velocity increases as operating pressure increases.

The nozzle plays a major role in amplifying cutting velocity.

At higher convergence angle, the friction is more at the junction between the convergent and



focal region.

The increase in abrasive content in the volume fraction leads to more wearing of nozzle, which leads to burr formation.

It has been seen that turbulent intensity decreases linearly as jet diameter ratio increases

It has been seen that turbulent intensity first increases significantly and then start decreasing as

nozzle convergence angle increases

REFERENCES I. N. Ramachandran and N. Ramakrishnan, A review of abrasive jet machining, Journal of Materials Processing

Technology, 39 (1993) 21-31

II. P S Jain and A A Shaikh “Experimental study of various technologies for cutting polymer matrix composites”

International Journal of Advance Engineering Technology E-ISSN0976-3945, vol.II/issue I/Jan-Mar/81-88

III. Dirk Biermann, Robert Aßmuth, Sebastian Schumann, Michael Rieger, Bernd Kuhlenkötter Wet Abrasive Jet

Machining to Prepare and Design the Cutting Edge Micro Shape, Procedia CIRP, Volume 45, 2016, Pages 195-198

IV. N.S. Pawar, R.R. Lakhe, R.L. Shrivastava, Validation of Experimental Work by Using Cubic Polynomial Models

For Sea Sand as an Abrasive Material in Silicon Nozzle in Abrasive Jet Machining Process, Materials Today:

Proceedings, Volume 2, Issues 4–5, 2015, Pages 1927-1933

V. D.V. Srikanth, M. Sreenivasa Rao, Application of Taguchi & Response Surface methodology in Optimization for

Machining of Ceramics with Abrasive Jet Machining, Materials Today: Proceedings, Volume 2, Issues 4–5, 2015,

Pages 3308-3317

VI. Roxana Nedelcu “A concise analysis on composite machining technologies” International Conference of Scientific

paper AFASES 2013Brasov, May 2013

VII. R V Shah “A study of Abrasive water jet Machining process On Granite Material” International journal of

Engineering Research and Applications (IJERA) ISSN: 2248-9622, vol.2, issue 4, 08/2012

VIII. Alberdi, A. Suárez, T. Artaza, G.A. Escobar-Palafox, K. Ridgway, Composite Cutting with Abrasive Water Jet,

Procedia Engineering, Volume 63, 2013, Pages 421-429

IX. Kalla, D. K., Dhanasekaran, P. S., Zhang, B., Asmatulu, R, 2012. Abrasive Waterjet Machining of Fiber Reinforced

Composites: A Review. AIP Conf. Proc. 1431, 535-542.

X. Shanmugan, D. K., Massod, S. H., 2008. An investigation on kerf characteristics in abrasive waterjet cutting of

layered composites. Journal of Materials Processing Technology 209, 3887-3893

XI. Wang, J, 1999. A machinability study of polymer matrix composites using abrasive waterjet cutting technology.

Journal of materials processing technology 94, 30-35

XII. Etxeberria, I., Suárez, A., Orbanic, H., Lebar, A., 2010. Abrasive water jet trimming and piercing and surface

evaluation of carbon fibre reinforced polymers. 20th International Conference on Water Jetting, Graz, Austria

XIII. GuihuaHu, Wenhua Zhu, Tao Yu and Jin Yuan, “Numerical Simulation and Experimental Study of Liquid-solid

Two-phase Flow in Nozzle of DIA Jet”, IEEE international conference korea (2008)

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Two-Phase Flow in Nozzle of DIA Jet”, ICIC 2008, CCIS 15, pp. 92–100, 2008. © Springer-Verlag Berlin

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fabrication of optimal abrasive water jet machining using … · 2018-05-14 · fabrication of...

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