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HUNGARIAN JOURNAL 
OF INDUSTRIAL CHEMISTRY 

VESZPRÉM 
Vol. 39(2) pp. 211-214 (2011) 

CUTTING OF ALUMINIUM ALLOY BY ABRASIVE WATERJET 

K. KUN-BODNÁR, ZS. MAROS 

University of Miskolc, Department of Production Engineering, H-3515 Miskolc – Egyetemváros, HUNGARY 
E-mail: krisztina.bodnar@uni-miskolc.hu 

E-mail: zsolt.maros@uni-miskolc.hu 
 

Aluminium sheets are cut several times by abrasive waterjet cutting. The article summarizes the experimental results 
accomplished for determination of connection between the technological parameters and the depth of kerf. So we defined, 
how the depths of kerf depends on parameters (f, m, p) investigated during the research. Beyond the graphical 
representation of the results, we defined mathematical connection in the paper, with which the depth of kerf can be 
determined at given cutting parameters, before the machining process. 

Keywords: abrasive waterjet, aluminium alloy, efficiency 

Introduction 

Ultra high-pressure abrasive water jet cutting has for the 
last few years become a competitor to various procedures 
that generate heat. The new technique has become 
popular because the heat of cutting does not deform the 
material and the cut surface is of high quality. The fact 
that almost every type of material (both soft and hard) 
may be cut by the method and that the thickness of the 
cut is less limited, are two of the several important 
advantages of the abrasive water jet technology. 

Aluminium alloys are widely used in the fields of 
industry like aerospace and automotive industry. Abrasive 
waterjet cutting is one of the first operations when 
machining from sheet metal blanks. Investigation of 
depth of kerf is widely used for research of efficiency of 
abrasive waterjet cutting. The end-users can influence 
the depth of kerf mostly by the feedrate (f), the abrasive 
mass flow rate (m), and the water pressure. 

Efficiency of the waterjet cutting 

Essence of the abrasive waterjet cutting is not an 
abrasive machining, but a so-called solid erosion process. 
Solid erosion is a material loss occurred because of the 
collision of liquid and solid particles. The process is 
concentrated both in the space and in the time, so the 
erosion speeds up, which results machining process. 
During the collision of the solid particles in the liquid and 
the workpiece different processes can be occurred [1]: 
shear deformation, plastic deformation, crack formation 
and growth, hardening, brittle fracture and local melting 
of the material, (Fig. 1). 

Extent of erosion material removal – and with this 
the efficiency of the cut – depends on many parameters. 

Velocity and mass of particles, loading angle, rate of 
hardness of the workpiece and the abrasive grains, form 
of the particles and the material characteristics are the 
parameters which have significant effect on the machining 
process. All these defined the characteristics of the 
material removal. 

 

 
Figure 1: Material removal processes in course of solid 

particle erosion  
 
When making kerfing test, we do not cut through the 

material, only make cuts and examine what kind of depth 
can be achieved with changing technological parameters. 
When measuring the depth of kerf (Fig. 2), more 
measurements should be made along the cut and average 
of these values gives the depth of kerf (hmax). 

 

 
Figure 2: Kerfing in glass 



 

 

212

From technological parameters affecting on the 
efficiency we investigated the effect of the feed rate, 
pressure, and abrasive mass flow (mass of the abrasive 
grains given to the waterjet during unit time). Other 
parameters such as nozzle diameter and diameter of 
focusing tube, length of focusing tube and type of 
abrasive material were constant. Their values were 
chosen on base of prior experience and professional 
literature. 

Cutting experiments 

Target of the cutting experiments was to define a method 
for the end users, with which the choice of technological 
parameters can be supported. 

Tested material was AlMgSi0,5 aluminium alloy. 
The AlMgSi0,5 aluminium alloy widely used in different 
industrial fields, mainly where the strength does not has 
important role. 

In the circle of researchers investigating the abrasive 
waterjet cutting is accepted that the efficiency can be 
graphically and easy characterised by the so called 
depth of kerf (h). 

Kerfing tests (Fig. 3) were accomplished on the given 
aluminium alloy for the investigation of the efficiency. 

 

 
Figure 3: Kerfing tests in AlMgSi0,5 Aluminium Alloy 

 
The technological parameters were ranked in two 

groups in the course of cutting experiments, so called 
group of constant and changing parameters. The values 
of constant parameters were determined on base of 
facility of the machine, the changing parameters were 
chosen by preliminary tests. Table 1 shows the applied 
parameters for the experiments. 

 
Table 1: Parameters of Cutting Experiments in Aluminium 
Alloy 

Constant parameters 
Material AlMgSi0,5 
Nozzle diameter 0.25 mm 
Diameter of focusing tube 0.8 mm 
Length of focusing tube 70 mm 
Stand of Distance 2 mm 
Abrasive GARNET #80 

Changing parameters 
Pressure, MPa 200; 250; 300 
Abrasive mass flow, g/min (100); 200; 400 
Feedrate, mm/min 100; 300; 500; 700; (800) 

Experimental results 

The average of depth of kerf was measured after the 
cutting experiments (h). 

Like it can be seen on the Fig. 4, increase of the 
feedrate results decreasing of the depth of kerf, mainly 
at small feedrates, the curves are hyperbolic.  

Feedrate cause the most characteristic effect on the 
extent of the depth of kerf. Feedrate has great effect on 
the machining costs as well. Because of this the feedrate 
should be chosen always the maximal extent with which 
the prescribed accuracy and surface quality till can be 
assured.  

 

 

 
Figure 4: Effect of the feedrate on the depth of kerf at 

different pressures and abrasive mass flow rates,  
on AlMgSi0,5 aluminium alloy 

 
On the basis of Fig. 5 we can say that the effect of 

changing of the pressure is linear. Interesting to 
recognise that at 100 mm/min feedrate, role of change of 
the pressure is significant while at higher pressures (at 
800 mm/min) this effect is not so significant. (inaccuracies 
of the curves is decreasing at higher feedrates). This 
phenomenon can be explained with the extent of the so 
called loading time. Increasing the federate the loading 
time is decreasing, so the higher speed of the abrasive 
grains, originating from the higher pressure, is not able 
to effect significantly on the efficiency.  

Extent of the abrasive mass flow rate increases the 
depth of kerf (Fig. 6) particularly at increase of small 
abrasive flow rates. In the investigated interval the 
depth of kerf increased on double. If the mass flow rate 
exceeds a given value, there are too much abrasive 
grains will banged up from the machined surface, which 
results the decreasing of the depth of kerf. This can be 
observed only at kerfing tests, but will not appear at real 
cut through process. 



 

 

213

 

 

 
Figure 5: Effect of the pressure on the depth of kerf at 

different feedrates and abrasive mass flow rates,  
on AlMgSi0,5 aluminium alloy  

 
 

 

 

 
Figure 6: Effect of the abrasive mass flow rate on the 

depth of kerf at different feedrates and pressures,  
on AlMgSi0,5 aluminium alloy  

Summarised effect of the parameters 

Common investigation of the cutting parameters can be 
accomplished with help of mathematical models. In this 
case at optional technological parameters preliminarly 
can be defined the extent of the depth of kerf.  

In the young history of abrasive water jets many 
scientists have described the effect of material removal 
by theoretical modelling. The models stretch from 
simple to complicated terms to describe the influence of 
different process parameters.  

The most important predictive models, that have been 
proposed in the literature. [2] They can be subdivided as 
classic (Tikhomirov, Hashish, Zeng and Kim), partly 
empirical (Oweinah, Blickwedel, Matsui) and empirical 
(Chung, Kovacevic, Brandt C.) models. 

On base of results of Figs 4-6, mathematical model 
of the cutting process can be written up as follows [3]:  

 
D

CB

f
mp

Ah
&⋅

⋅=  (1) 

where: 
A − constant of the function defined by multivariable 

regression, 
B, C, D – exponents of the function defined by 

multivariable regression, 
h – estimated depth of cut, mm 
p – pressure, MPa 
m&  – abrasive mass flow, g/min 
f – traverse feedrate, mm/min 
 
On base of the experimental results, constants of the 

model and their statistical characteristics can be determined 
(Table 2). Regression analysis of results of cutting 
experiments was accomplished by the MINITAB software. 
Applying the Monno model for the regression we have 
got a multivariable regression analysis, solution of which 
needs a linearization. [4] 

 
Table 2: Regression constants of the Monno model 

Material A B C D R2 
AlMgSi0,5 0.046 1.270 0.706 0.947 95.30%

 



 

 

214

Extent of the defined constants is proportional to the 
effect intensity of the given technological parameter on 
the depth of kerf. With help of this correlation cut 
through depth can be defined at a given technological 
parameter combination before the real machining 
process. The industrial employers of the waterjet cutting 
do not optimise the technological parameters. Setting of 
those machines is happened by test cutting, in practical 
way/method. Special nomograms can be compiled from 
fulfilled results of experiments to help to user in choice 
of technological data. With help of the MINITAB 
software we are also able to generate special nomograms 
for end users of waterjet technology. 

Conclusions 

In the course of examination the feedrate, pressure and 
the abrasive mass flow rate was investigated from the 
several technological parameters effecting on the 
efficiency at an aluminium alloy. Based on achieved 
examination the following statements can be composed:  

Effect of the feedrate is very characteristic. By 
increasing the feedrate the depth of kerf decreases 
decreasing acclivously mainly at slow speeds. Pressure 
of the water increases the depth of kerf. While at small 
federates the pressure has important role, at higher 
federates effect of the change of the pressure decreases. 
This can be explained with the extent of the loading 
time. By increasing the feedrate the loading time is 
decreasing, so the higher grain speed – originating from 
the higher pressure – cannot effect considerably on the 
depth of kerf. 

The extent of the abrasive mass flow rate increases 
the depth of cut. At small abrasive mass flow rates the 
depth of kerf increases linearly. If the extent of the 
abrasive mass flow rate is higher then a given value then 
the depth of kerf will decrease because of the very high 
amount of returned grains from the cut surface. This 
phenomenon does not occur at cut through processes.  

Machining of aluminium alloys with abrasive waterjet 
cutting is accomplished by solid erosion, because of this 
there is no need long time for the cut. This means that 
by increasing the pressure the abrasive grains will have 
high speeds and high energy, which results good material 
removal. Results of this phenomenon the pressure will 
the dominant technological parameter instead of the 
federate. 

 

ACKNOWLEDGEMENT 

The described work was carried out as part of the 
TÁMOP-4.2.1.B-10/2/KONV-2010-0001 project in the 
framework of the New Hungarian Development Plan. 
The realization of this project is supported by the European 
Union, co-financed by the European Social Fund. 
 

REFERENCES 

1. H. C. MENG, K. C. LUDEMA: Wear Models and 
Prediction Equations: Their Form and Content, 
Wear 181-183 Part II., (1995), 443–457 

2. S. BRANDT, ZS. MAROS, M. MONNO: AWJ 
Parameters Selection – a Technicaland Economical 
Evaluation, 15th International Conference on Jetting 
Technology, Ronneby, Sweden, 6-8 September 
2000., 353–366 

3. M. MONNO: Selection of process parameters for 
abrasive water jet (AWJ) cutting, International 
Conference on Cutting Technology, ICCT, March 
5-6, 1997, Hannover, 109–114 

4. K. BODNÁR, ZS. MAROS: Mathematical Estimation 
of Depth of Kerf at Waterjet Cutting, ICT-2007, 
International Conference on Tools, Miskolc, 2007, 
333–338 

5. R. KOVACEVIC: Monitoring the Depth of Abrasive 
Waterjet Penetration. International Journal of 
Machining and Tools Manufacturing, 32, (1992), 
725–736