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This paper gives an Insight on various research and activities carried out on the process of Abrasive Water Jet Machining (AWJM). AWJM process is briefly explained in the introduction section of the paper. This whole research is based on the process of material removal in AWJM as researched by various scholars. The last part of the paper gives the conclusion framed by us after reviewing the research papers on AWJM.

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International Research Journal of Innovations in Engineering and Technology (IRJIET)

ISSN (online): 2581-3048

Volume 3, Issue 11, pp 61-65 , November - 2019

Abrasive Water Jet Machining

1Khushaal B, 2Tejas HS, 3Preran K, 4Abhishek S, 5Saqlain Imran, 6Dr T S Nanjundeswaraswamy

1,2,3,4,5Student, Department of Mechanical Engineering, JSS Academy of Technical Education, Bangalore- 560060, India

6Associate Professor, Department of Mechanical Engineering, JSS Academy of Technical Education, Bangalore- 560060, India

Abstract - This paper gives an Insight on various research

and activities carried out on the process of Abrasive Water

Jet Machining (AWJM). AWJM process is briefly

explained in the introduction section of the paper. This

whole research is based on the process of material removal

in AWJM as researched by various scholars. The last part

of the paper gives the conclusion framed by us after

reviewing the research papers on AWJM.

Keywords: Abrasive Water Jet Machining, Material Removal

rate.

I. Introduction

Water Jet Machining (WJM), or in other words water jet

cutting, is a mechanically advanced unconventional machining

process where water having a very high velocity is used to

erode away small portions of materials from the workpiece

surface. WJM was initially used for cutting soft materials,

cleaning and removal of coating in early 70s. Softer materials

like wood, plastic and rubber were cut using this technique. It

does not encounter any vibration problems. However, in order

to machine hard materials like metals and granite, another

machining process called Abrasive Water Jet Machining

(AWJM) was developed.

Figure 1: Water jet machining

AWJM is an unconventional machining process which

gets results by the combined efforts of abrasive jet machining

and water jet machining (WJM) such that the drawbacks of

each individual process is overcame . It enhances and betters

the capability of WJM for machining hard or strong materials.

In AWJM, jet of water having very high velocity is mixed

with abrasive particles to improve the efficiency of the process

in terms of material removal rate and making it possible to cut

all the materials (NO matter hard or soft). Here , the high

velocity and high pressure of water is mixed with small

abrasive particles on the workpiece which erodes the material

due to impact causing material removal .This process is

environmentally friendly and does not affect the properties of

the materials (or its internal structure) as it has no thermal

effects. Both WJM and AWJM are modern machining process

that do not create any heat affected zone or residual stress on

the machined surface or workpiece.

II. History

Using high pressure water for hydraulic mining until mid

1800s. It wasn't until the 1930s that small water jets became

an industrial cutter. A paper metering, cutting and rolling press

was developed in 1993 by Wisconsin's paper parents company

which used a water jet pin to cut a horizontally moveable sheet

of continuous paper. The early applications were low and

limited to soft materials such as paper.

In the year 1958, North American aviation swach of Billie

invented a high-pressure fluid-based system to cut hard

materials.

John Olsen along with George hurlburt and Louis

kapcasandy at flow research further improved the commercial

potential of the water jet.

Figure 2: Schematic diagram of WJM

International Research Journal of Innovations in Engineering and Technology (IRJIET)

ISSN (online): 2581-3048

Volume 3, Issue 11, pp 61-65 , November - 2019

III. Process of Material Removal

The basic principle involved in material removal process

is as follows:

A Hydraulic pump pumps water from a reservoir to a

intensifier. The pressure of water is increased to desired level

in the intensifier. Generally, water is pressurized to 200 to 400

MPa. Accumulator then receives the pressurized water, and

stores it temporarily. The flow regulator and control valve

allows the pressurized water to enters the nozzle .The

direction and pressure of water is kept under check using

control valve , while the flow rate of water is regulated by the

flow regulator. Pressurized water entering the nozzle expands

with a huge increase in its kinetic energy, thus creating a very

high velocity water jet. Stresses are induced on the workpiece,

as the jet of water hits and strike the surface of the workpiece.

Material removal is achieved as a result of these stresses

acting on the workpiece surface, without creating any Heat

Affected Zone.

The process involves various equipment or units namely:

3.1 Hydraulic pump unit

The main objective of this unit is the momentum transfer

from the water jet having high pressure to the abrasive

particles, which when strikes a workpiece causes material

removal .It consists of 5 sub components namely:

a) Electric motor: An electric motor of typical capacity of 20 -

75 HP is used, to drive the hydraulic pump.

b) Hydraulic pump: An electric motor drives the pump

generating the hydraulic pressure of the order of

approximately 15 –30MPa. It has typically main 2 types:

Hydraulic intensifier pump and/or a Crankshaft pump. The

crankshaft pump is more efficient and hence achieves faster

cutting when compared to hydraulic intensifier pump.

c) Intensifier: The pressure of water is increased to more than

40 times the hydraulic pressure in the Intensifier, as it uses

larger size of oil piston over the normal water piston.

Mathematically the square of diameter ratio of oil and water

piston is equal to water pressure divided by hydraulic

pressure. The pressure of water can be easily manipulated by

controlling the lower pressure oil.

d) Accumulator: The accumulator stores the high pressurized

water temporarily, until very high amount of pressure energy

is required. The fluid is then supplied to eliminate any

variations in pressure producing uniform water flow at the

output.

e) Tubing: Water and the abrasive particles are mixed within a

vacuum chamber called tubing. Flexible tubing is preferred for

pressure <24 MPa . For pressure >24MPa another method

called rigid tubing is employed.

3.2 Water Feeding Unit

Pressurized water (<500 MPa) is made to pass through a

nozzle resulting in a jet of water with velocity as high as

900m/s. Both WJM and AWJM methods have similar units

usually Synthetic sapphire and tungsten carbide form the

material for the nozzle of water jet.

3.3 Abrasive Feed Unit

Abrasive particles are delivered in a regulated manner and

precisely using a hopper and flow control system within the

feed unit to the nozzle. Mainly there are 2 particle delivery

methods namely:

a) Dry abrasive delivery: It is suitable when the distance of

delivery is less.

b) Abrasive slurry feed: It is possible to introduce particles

over a large distance, however this method requires more

power per cut and commercial availability is limited.

3.4 Abrasive Water Jet Nozzle

In general, the characteristics and direction of the flow of

a fluid as it comes out of a pipe can be controlled using a

device called Nozzle. Here high velocity water is emerged

from the nozzle after conversion of high pressure water into it.

Here water and abrasives are blended thoroughly to form a

coherent mixture. The two major configurations that are

adapted are:

a) Single-jet side feed: Here, water jet is located centrally and

abrasives are added on the periphery of the water jet. It is

relatively easy to machine using this configuration. It however

does not provide optimal mixing of the water jet with the

abrasives and wears out at an increased rate, thus making it

less desirable.

b) Multiple-jet central feed: Here, abrasives are introduced

centrally with multiple water jets being added on the periphery

of the abrasive jet. It provides optimum mixing and an

increased nozzle life but it is costly and more difficult to

fabricate.

The movement of nozzle is controlled using computer

based motion controllers.

International Research Journal of Innovations in Engineering and Technology (IRJIET)

ISSN (online): 2581-3048

Volume 3, Issue 11, pp 61-65 , November - 2019

3.5 Worktable

Accurate cutting is ensured by providing easy and precise

motion to abrasive water jet nozzle relative to the workpiece

along all the three axes using computer numerical control

systems. Worktables of many shapes and sizes are easily

available, where it varies from small to very large and can be

chosen as per requirements.

3.6 Drain and Catcher System

Here the energy of abrasive water jet is dissipated to

reduce noise to the lowest possible level and prevent jet from

leaving the workpiece.

 When the abrasive water jet nozzle is in rest and

workpice is in motion (moving) a catcher is used.

 When the abrasive water jet nozzle is in motion

(moving) and workpiece is in rest a settling tank is

used.

IV. Working of Abrasive Water Jet Machining

Process

As seen in the above schematic diagram , water is pumped

to the intensifier from the reservoir with the aid of a hydraulic

pump .The intensifier increase the low pressure water to high

pressure water, of pressure upto 3000 to 4000 bar (300MPa to

400MPa). This high pressure water is sent to both the

accumulator as well as the nozzle. The accumulator stores the

high pressure water and supplies it at the moment it is

required. It is used to eliminate the fluctuation of high pressure

requirement of machining hard materials. Then the high

pressure water is sent to the nozzle, where the high pressure

energy of water is converted to high kinetic energy of water

(water expands with tremendous increase in its kinetic energy

or velocity), resulting in a very high velocity water jet leaving

the nozzle in the form of a narrow beam.

Figure 3: Abrasive water jet machining process

Abrasive particles such as garnet, olivine or aluminum

oxide is mixed with water within the nozzle. A mixing

chamber is present in the nozzle where the abrasives get

mixed with the high pressure water using either of the

configurations i.e single-jet side feed or multi-jet central feed.

The high velocity jet of water emerging from the nozzle is

directed towards the workpiece, when the jet of water strikes

the workpiece it removes the material due to erosion, stresses

induced on the workpiece and fracture of small parts of the

workpiece at the contact point. The water jet after machining

is gets collected by the drain and catcher system. Here the

debris, metal particles from the water is removed and it is

supplied to the reservoir tank. This is how the entire process of

material removal takes place using Abrasive Water Jet

Machining.

V. Abrasive Water Jet Machining Process for

Various Materials

Advanced Composite Materials also known as advanced

polymer matrix composites are advanced composite materials

(ACMs). Compared to other materials, these materials have

high strength, dimensional stability, light weight with low

rigidity, temperature and chemical resistance and are easy to

process. D.V. D.V. Srikanth et al carried out research into the

impact of various parameters such as Pressure

Granite / Marbles Granite is a common type of felsic

intrusive igneous rock that is granular and phaneritic in

texture. Granites may be predominantly white, pink or grey,

depending on their mineralogy. Investigation of the behavior

of five artificial rock-like materials subjected to abrasive water

jet cutting. The effects of the AWJ operating variables on the

width of the kerf have been studied

Advanced Ceramic Materials The most recent ceramic

materials, which offer high-performance features as opposed

to unconventionally built products, are silicon carbide,

alumina, silicon nitride, zirconia, alumina and titans. D. V.

Srikanth et AL, work conducted to determine effect on MRR

and Kertf of fibre glass of the Abrasive jet machining process

parameters. Lalchhuanvela, H.; Doolin, B.; Bhattacharyya,

researched Alumina ceramics process machining by varying

parameters of the ultra-sonic process, such as abrasive grain

sizes, slurry concentration, power rating, tool feed rate and

slurry flow rate. C-H. C-H. Tsai H.-W. Chen, done

experiments by laser machining for shaping ceramic,

defocused laser beam is applied throughout the length of the

groove-cracks to generate a great thermal stress, which makes

the two groove cracks link together. The material removal is

due to the linkage of the groove-cracks. From the

International Research Journal of Innovations in Engineering and Technology (IRJIET)

ISSN (online): 2581-3048

Volume 3, Issue 11, pp 61-65 , November - 2019

experimental results they observed surface roughness and the

inspection of crack defects.

Glass is a solid amorphous substance, which is not

crystalline. This is commonly used for decorative applications

in tableware, windows and decorative applications. The

youngest one is the bottle of silicate. Axinite, Glass products

can solve several specific problems and can have applications

in design engineering. Such products can operate in conditions

in which plastics and metals struggle and have to form part of

the arsenal of the manufacturer. N. Jagannatha, Investigations

have been performed in order to find the effect on MRR and

Ra on soda lime through abrasive hot air jet machinery.

Mathematical model for micro-hole boiling and micro

nutrition on glass, developed by J.M. Fan. They contrasted

predictive models with experimental results and concluded

that they are well in line with experimental findings.

An alloy is a metal and a different component

combination. A metallic bonding character distinguishes

alloys. A solid metallic solution (singles phases) or a metallic

combination of phases (two or more solutions) Alloys may

include brass, silver, solder, iron, long-lasting aluminum and

bronze. Vasanth's analysis of titanium alloy machinability has

been carried out. They consider an effect on surface roughness

and topography by the process parameters to improve the

process. The experimental results have shown the most

important part in determining surface quality is the abrasive

flow rate and stagnation. M. Uthayakumar et al. have been

studying the machinability of super alloys based on nickel.

The system parameters selected include the water jet pressure,

jet nozzle speed and stopping distance. Differences of throat

length, brazing wall inclination and removal rate (MRR) are

assessed by adjusting the selected system parameters. They

found that the jet pressure is the most important factor

affecting surface morphology and surface quality from

experimental results.

VI. Advantages and Disadvantages

The advantages of AWJM are as follows:

 Water is cheap, non-toxic, readily available, and can

be disposed easily. It is eco-friendly process as no

hazardous gases are produced.

 It has the ability to machine workpiece without

leaving any mechanical stresses or change in

microstructure of workpiece as there is no heat

affected zone.

 Complex geometry and intricate cuts can be achieved

easily with excellent surface finish and in relatively

clean and dust free environment.

 Maintenance and operating cost is low as there are no

moving parts associated in this process.

 Both hard and soft materials can be machined using

AWJM, however very thick materials cannot be

machined.

 The precision of machining is excellent. The

tolerances of the order of ± 0.005 inch can be

achieved easily.

 It has multidirectional cutting capacity.

 No heat is produces though it is continuously fooled

by supply of water.

 Grinding and polishing are eliminated which reduces

secondary operational tools.

The disadvantages of AWJM are as follows:

 The equipment is quite expensive, making the initial

investment too high. Due to high cost it becomes

unsuitable for mass production.

 Though it is possible to machine hard materials, but

to do it satisfactorily (with required precision and

surface finish) requires reducing the material removal

rate to a great extent, thus increasing the time for

each cut.

 Very thick materials cannot be machined with

required accuracy; the water jet dissipates in such

cases and may result in wider cut at the bottom of

workpiece than at the top of workpiece.

 The narrow kerf allows tight nesting when multiple

parts are cut a single blank.

 Very thick parts cannot be cut with this operation.

 Slow material removal rate.

Applications of WJM:

 It is very useful in fields where cutting and drilling

soft materials is required

 It used in turning operation and also in paint removal

 Pocket milling and cutting

 Textile, lather industry and cleaning

 Penning and surgery

Optimal tracing or numerical control allows more

complicated profiles to be cut at optimum rates and it is

particularly suitable for difficult-to machine materials.

Steel and brass can also be cut by water jets. Jet cutting is

employed over Sheet cutting in shoe industry.

VII. Conclusion

Various materials can be machined using process. BHRA

has successfully cut materials using high pressure water jets.

Efficiency of Abrasive Water Jet Machining process is

International Research Journal of Innovations in Engineering and Technology (IRJIET)

ISSN (online): 2581-3048

Volume 3, Issue 11, pp 61-65 , November - 2019

impacted by nozzle wear, which intern depends on certain

process as well as geometrical parameters such as nozzle

length, nozzle diameter, orifice size, nozzle inlet angle. From

the literature point of view compared to all parameters,

transverse speed is the most effective parameter for MRR.

Another important parameter for increase in MRR is Abrasive

flow rate. It is required to find suitable condition for the

process parameter to give better quality of cutting surface. A

safer and more effective tool is expected to emerge in the

coming years for quality cutting with WJM opening the door

to a new era in modern machining.

REFERENCES

[1] Dixit, A., Dave, V., & Baid, M. R. (2015). Water jet

machining: an advance manufacturing process. Int J

Eng Res Gen Sci, 3(2), 288-292.

[2] Nanduri, Madhusarathi, David G. Taggart, and

Thomas J. Kim. "The effects of system and geometric

parameters on abrasive water jet nozzle

wear." International Journal of Machine Tools and

Manufacture 42.5 (2002): 615-623.

[3] Jegaraj, J. John Rozario, and N. Ramesh Babu. "A

strategy for efficient and quality cutting of materials

with abrasive waterjets considering the variation in

orifice and focusing nozzle diameter." International

Journal of Machine Tools and Manufacture 45.12-13

(2005): 1443-1450.

[4] Srinivasu, D. S., and N. Ramesh Babu. "A neuro-

genetic approach for selection of process parameters

in abrasive waterjet cutting considering variation in

diameter of focusing nozzle." Applied Soft

Computing 8.1 (2008): 809-819.

[5] Momber, Andreas W., and Radovan

Kovacevic. Principles of abrasive water jet

machining. Springer Science & Business Media ,

2012.

[6] Parikh, Pratik J., and Sarah S. Lam. "Parameter

estimation for abrasive water jet machining process

using neural networks." The International Journal of

Advanced Manufacturing Technology 40.5-6 (2009):

497-502.

*******

Citation of this Article:

Khushaal B, Tejas HS, Preran K, Abhishek S, Saqlain Imran, Dr T S Nanjundeswaraswamy, "Abrasive Water Jet

Machining" Published in International Research Journal of Innovations in Engineering and Technology (IRJIET), Volume

3, Issue 11, pp 61-65, November 2019.

... The effects of stand-off-distance on MRR and penetration rates have been reported by Ingulli [7], Sarkar and Pandey [8], Verma and Lal [9], and Venkatesh et al. [10]. All the investigations indicate that as the stand-off-distance increases the MRR and penetration rate increase and on reaching an optimum value, they start decreasing. ...

... The effect of nozzle pressure has been reported by Ingulli [7], Sarkar and Pandey [8], Wolak [11], Murthy et al. [12], and Verma and Lal [9]. Their investigations indicate that after a threshold pressure, the MRR and penetration rates increase with the nozzle pressure. ...

R. Balasubramaniam
J. Krishnan
N. Ramakrishnan

A large number of investigations on the abrasive jet machining (AJM) with output parameters as material removal rate (MRR), penetration rate and surface finish have been carried out and reported by various authors. But no detailed investigations are known to be carried out on the shape of the abrasive jet machined surface. Deburring, which includes the edge conditioning/shaping, offers a potential application area for AJM. In this paper, a semi-empirical equation is derived to obtain the shape of the surface generated in AJM. With the help of this equation, it is shown that the abrasive jet machined surface is reverse bell mouthed in shape with an edge radius at the entry side of the target surface. It is also observed that the entry side diameter increases with the input parameters. The effects of particle size, stand-off-distance, center line and peripheral velocities of the jet on the generated shape are also discussed in this paper. The result of this work was compared with the result of earlier abrasive jet deburring experimental work for edge radiusing and found satisfactory.

... The selection of abrasive particles depends on the hardness and Metal Removal Rate (MRR) of the work piece. Most commonly, aluminum oxide or silicon carbide particles are used [4]. Abrasive Jet Machining is used for drilling, deburring, etching, and cleaning of hard and brittle metals, alloys, and non-metallic materials [2]. ...

Dr D V Sreekanth
M. Sreenivasa Rao

p class="Default"> The demand for micro products is rapidly increasing in chemical, marine and aerospace industries. The super alloys which have high strength and corrosion resistance properties play a major role. Hastelloy which is difficult to machine by the conventional processes can be machined by using AJM. Hastelloy C276 sheet of thickness 1mm has been drilled on the AJM test rig using variable process parameters. In this paper optimization of process parameters of Abrasive Jet Machining of Hastelloy C276 by RSM methodology is presented. The values obtained in RSM Analysis were compared with the Analysis of Variance (ANOVA). Various levels of experiments are conducted using L15 orthogonal array for both MRR and KERF. Journal of the Institute of Engineering , 2018, 14(1): 170-178</p

... The nozzle pressure effect has been reported in many [15]- [19]. They proved that after threshold pressure, the Material Removal Rate (MRR) and the penetration rates have increased with increasing the nozzle flow pressure. ...

A. El-Domiaty
Hassan Mohamed Abd El-Hafez
M.A. Shaker

Drilling of glass sheets with different thicknesses have been carried out by Abrasive Jet Machining process (AJM) in order to determine its machinability under different controlling parameters of the AJM process. The present study has been introduced a mathematical model and the obtained results have been compared with that obtained from other models published earlier [1-6]. The experimental results of the present work are used to discuss the validity of the proposed model as well as the other models.

Tikendra Nath Verma

The present study aims to investigate performance, combustion and emission characteristics fueled with microalgae biodiesel a direct injection diesel engine. The engine was operated at constant engine speed (1500 rpm). Performance, combustion and emission characteristic such as BTE, SFC, MRPR, ID, smoke level, and carbon dioxide (CO2) emission, have been measured at full load condition, for diesel (B0%) and spirulina biodiesel (B100%) with constant injection timing (23.0° b TDC) and fuel injection pressure (FIP) 220 bar. The numerical results found that reduction in BTE, MRPR, ID, smoke, and CO2 by 3.4%, 17.65%, 32.1%, 44.0%, and 6.0% respectively; but higher of SFC by 6.66%. Results have been shown in graphics.

AP Verma
Ghanshyam Lal

The paper presents a theoretical analysis for estimating the abrasive particle velocity in air-abrasive jet using continuum approach applied to two-phase flow system. Subsequently a theoretical model for predicting the material removal rate in abrasive jet machining (drilling) has been developed using semi-empirical fracture mechanics relationships and quasi-static indentation approach. Numerical results have been computed and compared with experimental results.

Sang-Lae Lee
Ji-Hwan Kim

In this study, it is investigated the stability boundary of Functionally Graded (FG) panel under the heats and supersonic airflows. Material properties are assumed to be temperature dependent, and a simple power law distribution is taken. First-order shear deformation theory (FSDT) of plate is applied to model the panel, and the von-Karman strain- displacement relations are adopted to consider the geometric nonlinearity due to large deformation. Further, the first-order piston theory is used to model the supersonic aerodynamic load acting on a panel and Rayleigh damping coefficient is used to present the structural damping. In order to find a critical value of the speed, linear flutter analysis of FG panels is performed. Numerical results are compared with the previous works, and present results for the temperature dependent material are discussed in detail for stability boundary of the panel with various volume fractions, and aerodynamic pressures.

Chandra
Bhaskar
Jagtar Singh

As Abrasive jet machining (AJM) is similar to sand blasting and effectively removes hard and brittle materials. AJM has been applied to rough working such as deburring and rough finishing. With the increase of needs for machining of ceramics, semiconductors, electronic devices and L.C.D., AJM has become a useful technique for micromachining. This paper deals with various experiments which were conducted to assess the influence of abrasive jet machining (AJM) process parameters on material removal rate and diameter of holes of glass plates using aluminum oxide type of abrasive particles. The experimental results of the present work are used to discuss thevalidity of proposed model as well as the other models. With the increase in nozzle tip distance (NTD), the top surface diameter and bottom surface diameter of hole increases as it is in general observation of abrasive jet machining process. As the pressure increases, the material removal rate (MRR) is also increased.

The versatility of the abrasive water jet in cutting almost any engineering material is a very special feature of this technology. Figure 9.1 shows an example for the machining capability of the abrasive water-jet technique. This figure illustrates several steps of manufacturing a certain complex shape in a hard-to-machine material. Besides cutting, as described in the previous chapters, the manufacturing process includes the following operations: milling turning piercing finishing

Use of water jet has been in existence for over twenty years, but it is yet to reach its full potential in the construction industry. This study examines the role of water jet in heavy construction in general and particularly how it affects the regional contractors in the northeast. A survey was conducted among 215 civil contractors of the Northeast region of the United States and the results were documented in various categories. The paper presents aspects regarding an innovative nonconventional technology, abrasive water jet machining. The study also presents results regarding other technological operations possible to be performed with abrasive water jet.

Madhusarathi Nanduri
David Taggart
Thomas J. Kim

Nozzle wear dependence on abrasive water jet system, parameters and nozzle geometry is experimentally investigated. Experimental procedures for evaluating long term and accelerated nozzle wear are discussed. Accelerated wear tests are conducted to study the effects of nozzle length, inlet angle, diameter, orifice diameter. abrasive flow rate, and water pressure on wear. An empirical model for nozzle weight loss rate is developed and is shown to correlate well with experimental measurements. (C) 2002 Published by Elsevier Science Ltd.

Pratik J. Parikh
Sarah S. Lam

The abrasive water jet machining process, a material removal process, uses a high velocity jet of water and an abrasive particle mixture. The estimation of appropriate values of the process parameters is an essential step toward an effective process performance. This has led to the development of numerous mathematical and empirical models. However, the complexity of the process confines the use of these models for limited operating conditions; e.g., some of these models are valid for special material combinations while others are based on the selection of only the most critical variables such as pump pressure, traverse rate, abrasive mass flow rate and others that affect the process. Furthermore, these models may not be generalized to other operating conditions. In this respect, a neural network approach has been proposed in this paper. Two neural network approaches, backpropagation and radial basis function networks, are proposed. The results from these two neural network approaches are compared with that from the linear and non-linear regression models. The neural networks provide a better estimation of the parameters for the abrasive water jet machining process.

D. S. Srinivasu
N. Ramesh Babu

This paper presents a neuro-genetic approach proposed to suggest the process parameters for maintaining the desired depth of cut in abrasive waterjet (AWJ) cutting by considering the change in diameter of focusing nozzle, i.e. for adaptive control of AWJ cutting process. An artificial neural network (ANN) based model is developed for prediction of depth of cut by considering the diameter of focusing nozzle along with the controllable process parameters such as water pressure, abrasive flow rate, jet traverse rate. ANN model combined with genetic algorithm (GA), i.e. neuro-genetic approach, is proposed to suggest the process parameters. Further, the merits of the proposed approach is shown by comparing the results obtained with the proposed approach to the results obtained with fuzzy-genetic approach [P.S. Chakravarthy, N. Ramesh Babu, A hybrid approach for selection of optimal process parameters in abrasive water jet cutting, Proceedings of the Institution of Mechanical Engineers, Part B: J. Eng. Manuf. 214 (2000) 781–791]. Finally, the effectiveness of the proposed approach is assessed by conducting the experiments with the suggested process parameters and comparing them with the desired results.

In Abrasive Waterjet (AWJ) cutting, orifice and focusing nozzle diameter undergo continuous change in their dimensions due to erosive nature of high velocity abrasive waterjet. This particular phenomenon can affect the efficiency and quality of the process. To achieve maximum efficiency and desired quality with this process, the parameters need to be optimally selected from time to time considering the changes in the dimensions of orifice and focusing nozzle. In an effort to develop strategies for this purpose and to build the knowledge base for adaptive control of the process, the present work aims to study the influence of orifice and focusing nozzle diameter variation on the performance of abrasive waterjets in cutting 6063-T6 aluminum alloy. The performance was assessed in terms of different parameters such as depth of cut, material removal rate, cutting efficiency, kerf geometry and cut surface topography. In order to maintain the desired performance, it is essential to monitor the condition of nozzles and suitably adjust the process parameters with a view to control the process. Towards the latter, the present work attempts to suggest a strategy that can aid in replacing the nozzles at an appropriate time for maintaining the performance of process within certain limits so as to maintain the precision in machining with abrasive waterjets.

Source: https://www.researchgate.net/publication/337973039_Abrasive_Water_Jet_Machining

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