Abrasive Water Jet Technology Research Articles

Effect of Waterjet Machining Parameters on the Cut Quality of PP and PVC-U Materials Coated with Polyurethane and Acrylate Coatings.

The article focuses on the machining of polymeric materials polypropylene (PP) and un-plasticized poly vinyl chloride (PVC-U) after surface treatment with polyurethane and acrylate coatings using waterjet technology. Two types of waterjet technologies, abrasive waterjet (AWJ) and waterjet without abrasive (WJ), were used. The kerf width and its taper angle, at the inlet and outlet of the waterjet from the workpiece, were evaluated. Significant differences between AWJ and WJ technology were found. WJ technology proved to be less effective due to the creation of a nonuniform cutting gap and significant burrs. AWJ technology was shown to be more efficient, i.e., more uniform cuts were achieved compared to WJ technology, especially at a cutting head traverse speed of 50 mm·min−1. The most uniform kerf width or taper angle was achieved for PP + MOBIHEL (0.09°). The materials (PP and PVC-U) with the POLURAN coating had higher values of the taper angle of the cutting gap than the material with the MOBIHEL coating at all cutting head traverse speeds. The SEM results showed that the inappropriate cutting head traverse speed and the associated WJ technology resulted in significant destruction of the material to be cut on the underside of the cut. Delamination of the POLURAN and MOBIHEL coatings from the base material PP and PVC-U was not demonstrated by SEM analysis over the range of cutting head traverse speeds, i.e., 50 to 1000 mm·min−1.

Investigation on kerf taper in abrasive waterjet machining of aluminium alloy 6061-T6

Abrasive waterjet (AWJ) is an advanced processing technology, which is favored by the processing industry due to its unique advantages. However, in the process of machining, the kerf taper produced by the attenuation of the jet energy seriously affects the processing accuracy of AWJ, which limits the further application and expansion of AWJ technology. In this paper, an experimental study on the kerf taper is carried out, and the influence of processing parameters including cutting speed, material thickness, water pressure and abrasive flow rate on the kerf taper is analyzed. The results show that the cutting speed and material thickness have a great influence on the kerf taper, while the influence of water pressure and abrasive flow on the kerf taper is not obvious. Reducing the cutting speed is conducive to the reduction of the kerf taper, and the kerf taper corresponding to the increase of the material thickness will decrease. On this basis, a kerf taper prediction model is established in this paper, and its effectiveness is verified through experiments.

Water Jet Technology: Experimental Verification of the Input Factors Variation Influence on the Generated Vibration Levels and Frequency Spectra

Vibration measurement belongs amongst the most important activities for the correct and stable operation of machines in terms of quality, economy, and safety. Monitoring the condition of the machine provides the key data for the detection of machine parts damage, thus preventing unexpected failure states and production drop-outs. Therefore, special attention is paid in the paper to the measurement and evaluation of basic parameters of vibration, particularly the frequency of vibrations and the amplitude of vibration acceleration. Experimental measurements were performed while machining the material HARDOX 500/10 on a production system using the abrasive water jet technology (AWJ) with the varied abrasive mass flow and the feed rate. By evaluating the results of measurements, recommendations of suitable and inappropriate combinations of operating parameters were formulated, widening current knowledge in the field of the abrasive parameters and the speed of movement of the technological head influence the amplitudes of vibration acceleration in the operation of production systems with AWJ technology.

Integral modeling of abrasive waterjet micro-machining process

Abrasive water jet technology has been widely used to process fine structures on various materials, but there is no complete model that can describe the entire process. In this paper, the integral modeling process of abrasive water jet micro-machining (AWJM) is presented. The three-phase fluid dynamics model inside the nozzle and the surface evolution model are connected by theoretically calculating the jet erosive efficacy distribution before impacting the workpiece. Several improvements over previously presented models, such as taking into account the divergence angle of abrasive particles and the effect of the nonuniform distribution of each phase on the jet erosive efficacy, have been made. The model was used to predict the surface evolution of micro-channel profiles in 316L stainless steel and 6061-T6 aluminium. For both materials, the radial profile of erosive efficacy shows a normal distribution, and the erosive efficacy of 6061-T6 is two orders of magnitude higher than that of 316L. The results show that the model can accurately predict the profiles of the micro-channels resulting from AWJM. In particular, the average prediction error in the width direction is reduced to 4.5%.

Visualization and evaluation of the spatial kinematic rotation error of a five-axis abrasive water jet cutting head

Abrasive water jet (AWJ) technology has been more and more used in space curved surface machining. Dynamic angle compensation technology based on the five-axis linkage control system was the core to eradicate the errors caused by taper and jet lag in AWJ machining and enabled this technology to get into some precision fields. But the spatial kinematic rotation error of the cutting head in five-axis AWJ machine tool which has a direct impact on AWJ machining performance and accuracy has not been systematically studied. Aimed at this, this paper explored a new method based on spatial meshes to obtain the spatial kinematic rotation error of the cutting head. According to the visualization of the experimental data, the spatial kinematic rotation error was found with no obvious pattern. Then, a dimension reduction method was employed to mining these data and enabled this irregular error to be predicted with mapping method. According to the verification experiments, this new method was proved efficiently and useful in predicting the spatial kinematic rotation error.

Failure Mechanism and Effect of Nozzle Parameters on Abrasive Water Jet Rock Breaking

Abrasive Water Jet (AWJ) technology has vast application prospects in the assisted drill-blasting of tunnel excavation, with the advantages of fast-breaking speed, low tool wear, less dust, and good mobility. Nevertheless, AWJ technology has some limitations and shortcomings, such as the small effective fracturing range and parameter mismatch, which influence the fracturing effect of AWJ. To solve the abovementioned issues, it is necessary to study the failure mechanism of rock impacted by AWJ and nozzle parameter effects on rock fragmentation. Based on the coupling algorithm of Smooth Particle Hydrodynamics and Finite Element Method (SPH-FEM), in this research, the numerical model of AWJ impacting rock was established, and the result was verified with Computed Tomography (CT) scanning after the AWJ impacting rock experiment and image processing technology. Through the analysis of the stress characteristics of typical particles in the rock model at different stages and positions, the formation and expansion mechanisms of the crater and the cracks were revealed. Additionally, in this research, the comprehensive damage factor of rock (X) representing the fragmentation degree was defined. By comparatively analyzing X-values with certain technical parameters of AWJ, the importance ranking of the nozzle parameters, the effect of each nozzle parameter on the rock fragmentation, and the optimal parameter combination were also investigated.

Parameter Optimization and Effect Analysis of Low-Pressure Abrasive Water Jet (LPAWJ) for Paint Removal of Remanufacturing Cleaning

As an environmentally friendly method, water jet (WJ) technology plays a significant role in the field of remanufacturing cleaning. The cleaning capacity of a WJ is severely restricted by the water pressure, while the impact force will be too large and may damage the cleaned substrate as well as cause energy waste if the pressure is too high. However, by adding abrasives, the cleaning capacity of a low-pressure water jet (LPWJ) will be considerably improved. Although abrasive water jet (AWJ) technology has been used in mechanical machining for decades, very limited research work can be found in the literature for remanufacturing cleaning. In this paper, the role of abrasives in low-pressure abrasive water jet (LPAWJ) cleaning was described. Cleaning performance with different parameters (abrasive feed rate condition, water pressure and standoff distance) in paint removal was experimentally investigated by using the Taguchi design of experiment. The experimental results indicated that the water pressure was the most dominant factor and the optimal parameter combination was the second feed rate condition, 9 MPa water pressure and 300 mm standoff distance. The influence law between the cleaning performance and various factors was explored, which can provide remanufacturers with directions in selection of the optimal parameters in the LPAWJ cleaning process. By designing contrast experiments, the results showed that the cleaning capacity of an LPAWJ is better than that of a pure LPWJ and the residual effect in terms of changes in surface roughness, residual stress and morphology is a little larger.

Advances in Modeling of the Kerf Formation considering the Primary and Deflection Jets for the Abrasive Water Jet Technology

Processing of difficult to machine materials is a promising application for abrasive water jet kerf cutting and milling. However, due to the large number of interactions of an energy-bound cutting process, a precise prediction of the material removal is crucial for its application. Based on an analytical approach, a material removal simulation model is introduced considering the primary and deflecting jet impacts to rapidly predict various cutting situations. The model describes fundamental cutting mechanisms considering the water jet’s material removal rate and is calibrated for titanium aluminides. The model allows for a comprehensive kerf prediction and thus potentially accelerates the process design improving the productivity and quality for abrasive water jet kerf cutting and milling.

A study on the interaction of jet with constituent layers of multilayered structure in through kerfing with abrasive waterjets

Abstract Abrasive waterjet technology is favored over solid cutting tools for cutting of multi-layered structures in view of its non-contact nature and its ability to cut a wide range of materials. However, the stochastic nature of abrasive water jet (AWJ) interacting with a multi-layered structure (MLS) produces a non-uniform kerf geometry. This non-uniformity depends on the characteristics of jet i.e. jet energy, the duration of interaction of jet with the material, and the nature of material exposed to the jet during cutting. This paper attempts to cover a study that systematically analyses the geometry of kerf generated in MLS and a stack of multiple materials with each material having different mechanical properties. It also covers a study to analyse the role of interfacial adhesive layer on kerf profile variation, and the preferential orientation of multi-layered structure and stacked materials, with its top layer, having an appropriate mechanical resistance (MR), in order to arrive at a strategy to present the structure or a stack of materials to AWJs for producing near uniform kerf profile. Hence, AWJ cutting experiments were carried out over a single- and double- layered structures (SLSs, DLSs) with two different materials such as aluminum (Al), mild steel (MS), which showed a completely different kerf geometry when these materials are stacked in different ways. Stacking of these materials in different ways produced kerf of different geometry not only in the materials but also at their interface. This systematic study enabled to suggest the correct presentation of MLS and also a stack of multiple materials with a suitable material in top layer, to AWJ, for producing near uniform kerf in them. Further, this study also suggested several hypotheses like the importance of relative MR of adjoining layers, critical jet traverse rate, pseudo focusing nozzle, and the choice of layer placement in producing near uniform kerf on MLS and a stack of materials, so as to minimize the efforts in post machining of AWJ cut surfaces. Finally, the relevance of the proposed hypotheses was validated by analyzing the kerf formed over MS-rubber-MS and rubber-MS-rubber configured three-layered structure.

Observation of cryogenically cooled ice particles inside the high-speed water jet

The Ice abrasive water jet technology uses cryogenically cooled ice particles instead of the mineral abrasive used in the Abrasive water jet technology. The aim is to avoid contamination of workpieces with mineral abrasives and to reduce the environmental impact of this technology. The ice particles are sucked into a high-speed water jet with speeds of up to 600 mxs-1 using the Venturi effect. Direct observation of the process is very difficult due to the extreme operating conditions. We have clearly shown that at least some of the ice particles, which have cryogenic temperatures when entering the high-speed water jet, neither completely melt nor are completely crushed in contact with the jet. Further on, the erosion capability of ice particles was evaluated by blasting the aluminium and glass surfaces at two impinging angles and compared to garnet mineral abrasive, showing that ice particles have the potential to generate similar damage in the workpiece material as garnet. These findings pave the way for exploring the potential of abrasive waterjet technology in a wide range of new applications, such as food processing, medical implant and turbine blade manufacturing, and post-processing of parts manufactured with additive manufacturing technologies.

An abrasive water jet assisted back reaming technique based on percussion drilling for reducing non-production time in geothermal energy development

Abrasive water jet (AWJ) technology is one of the fastest growing methods of cutting materials in recent years. Because percussion drilling can cause numerous impact cracks around the borehole, and these impact cracks can reduce the mechanical properties of the rock around the borehole. This makes it possible to improve AWJ reaming efficiency. The present paper investigates the influence of key jet parameters on AWJ reaming performance according to the specific problems encountered in the Gonghe geothermal well (GH-01). Additionally, the required time for AWJ reaming is analyzed and discussed. The results indicate that there is an existence of optimum value of jet standoff distance (s/d0 = 3) for the AWJ reaming performance. Moreover, the high jet traverse speed will lead to deterioration of reaming performance. If the jet traverse speed is controlled under 50 mm/s, the slower the speed is, the better the reaming performance is. In the context of reaming a defined depth of rock, jet pressure has no significant effect on reaming performance. The requirement of reaming can be met by using jet pressure at 35 MPa. Although the effect of the inclined jet on penetration depth is better than that of the vertical jet, the vertical jet can produce a wider penetrate width. Compared with conventional reaming, the time spent on AWJ reaming is 55 %–67 % less than that of conventional reaming when the depth of reaming is 100 m. All the above merits have provided a theoretical foundation and experimental proof for the field application of the AWJ reaming technique.

Study on the breaking process and damage characteristics of abrasive water jet impacting concrete based on acoustic emission

The breaking process and damage distribution characteristics of concrete are the theoretical basis for improving the quality and safety of concrete impacted by abrasive water jet (AWJ) technology. Therefore, the process of AWJ impacting concrete is monitored online based on acoustic emission (AE) technology in this paper. The results show that the AE signals of AWJ impacting concrete have two peaks in frequency domain, the low frequency signals are generated by AWJ and the high frequency signals are generated by concrete breaking. The autoregressive (AR) model is used to estimate the power spectrum of AE signals. The variations of AWJ signals and concrete crushing signals in the impact process are analyzed based on the power of AE signal defined by the area under the power spectral density (PSD) curve. Through monitoring the development process of erosion hole inside the transparent materials impacted by AWJ, it is verified that the power of the concrete crushing signals after the formation of the erosion hole can reflect the penetration rate well. In addition, the damage characteristics of concrete specimens impacted by AWJ are studied in this paper by measuring the transverse ultrasonic velocity of the specimens before and after impact.

The Effect of Abrasive Waterjet Machining Parameters on the Condition of Al-Si Alloy.

This paper analyses the effect of the abrasive waterjet cutting parameters’ modification on the condition of the workpiece surface layer. The post-machined surface of casting aluminium alloys, AlSi10Mg and AlSi21CuNi, was characterised in terms of surface roughness and irregularities, chamfering, and microhardness in order to reveal the effect that variable jet feed rate, abrasive flow rate, and sample height (thickness of the cut material) have on the quality of surface finish. From the analysis of the results, it emerges that the surface roughness remains largely unaffected by changes in the sample height h or the abrasive flow rate ma, whereas it is highly susceptible to the increase in the jet feed rate vf. It has been shown that, in principle, the machining does not produce the strengthening effect, that is, an increase in microhardness. Owing to the irregularities that are typically found on the workpieces cut with higher jet feed rates vf, additional surface finish operations may prove necessary. In addition, chamfering was found to occur throughout the entire range of speeds vf. The statistical significance of individual variables on the 2D surface roughness parameters, Ra/Rz/RSm, was determined using factorial analysis of variance (ANOVA). The results were verified by means of artificial neural network (ANN) modelling (radial basis function and multi-layered perceptron), which was employed to predict the surface roughness parameters under consideration. The obtained correlation coefficients show that ANNs exhibit satisfying predictive capacity, and are thus a suitable tool for the prediction of surface roughness parameters in abrasive waterjet (AWJ) technology.

Some Technical Issues and Critical Assessment of Abrasive Water Jet Machining ( AWJM ) Process

This paper is focused on reviewing previously carried out work and written in literature. Non- conventional abrasive water jet technology is being utilized to machine variety of metals, their respective alloys and nonmetals. Mainly concentrated on Titanium alloys and difficulty in its machining. Numerous variables associated with the technology and their consequence on response variable were analyzed and summarized in this review. Paper conclude numerous gaps in research along with future scope.

Modelling of surface roughness in abrasive waterjet cutting of Kevlar 49 composite using artificial neural network

In abrasive waterjet machining (AWJM), water acts as an accelerating medium and abrasive particles are used for cutting materials. This is a cost effective and environmentally friendly technique. Kevlar 49 is one of the most commonly used composite materials and is extensively used in aerospace industries where high strength-to-weight ratio and excellent corrosion resistance are required. This material can be processed by only by abrasive waterjet machining technology due to its high strength. The quality of AWJM is depending upon the process parameters of this technology. This paper provides an experimental investigation for the performance analysis of process parameters on machining Kevlar 49 using abrasive waterjet technology. In this paper mathematical model is also being developed to predict the surface roughness to find the relation between the inputs and the outputs. The first part predicts the surface roughness based on the pressure and the traverse speed whereas the second part indicates the surface roughness variation with standoff distance and the mass flow rate. The model is developed with the back-propagation algorithm using artificial neural network (ANN). The initial weights are assumed, and the algorithm predict and update the weights until it could predict the actual value. The final model is used to verify the results and is found that it is more than 95% accurate. Hence this model is used to study surface roughness by varying all the parameters theoretically.

Experimental investigation into the effect of abrasive process parameters on the cutting performance for abrasive waterjet technology: a case study

In abrasive waterjet (AWJ) process, abrasive properties are of critical factors that influence machining performances. Abrasive process parameters including abrasive material, size and flow rate, exert a significant impact on cutting ability and quality of AWJ. In this paper, monolithic abrasive material (garnet, alumina and silicon carbide) and corresponding mixing abrasive materials are adopted to evaluate the effect of abrasive process parameters on the cutting ability and quality, respectively. Two kinds of cutting experiments are conducted with a monolithic abrasive to explore the influence of variation in abrasive material, size and flow rate on the machining performance. The cutting depth experiments for evaluating the cutting ability in terms of cutting depth are conducted with a right trapezoid aluminium alloy block. The kerf cutting experiments are taken to evaluate the cutting quality by the kerf taper angle, kerf width and surface roughness. On this basis, AWJ experiments with mixing abrasive materials are taken to probe into the composition of mixing abrasives’ effect on cutting performance. It is found that the abrasives consisting of 75% alumina and 25% garnet in mass fraction lead to a maximum cutting depth of 41.7 mm and the smallest surface roughness of Ra 2.1 μm under the flow rate of 130 g/min.

A mathematical modelling of Abrasive Waterjet Machining on Ti-6Al-4V using Artificial Neural Network

Ti-6Al-4V is classified among the most commonly used Ti-alloys and is extensively used in aerospace and medical industries where low-density, high strength and outstanding corrosion resistance are required. This material cannot be processed by conventional machining methods because of its high strength. Abrasive Waterjet Machining, abbreviated as AWJM, is an unconventional machining process suitable for machining Ti-6Al-4V as it generates less heat affected zone. The quality of AWJM is governed by process parameters, the selection of these parameters is critical in this technology to achieve the desirable output measures. This paper provides an experimental investigation for the performance analysis of process parameters on machining Ti-6Al-4V using abrasive waterjet technology. In order to select appropriate parameters, a mathematical equations were developed using Regression Investigation Method (RIM) Artificial Neural Network (ANN) procedures. Based on the input and output data collected from the experiments, modelling is done and tested for the different set of data to ensure the accuracy. These mathematical models can be used to identify the static and dynamic behavior of the process. These models will further help in simulating the process, expanding the design facilities and studying the physical and chemical variation in the process. Models provide understanding the operations, control methods and the possible optimization. The developed models also help in documenting the performance of the existing system.

An investigation of abrasive waterjet machining of cubic boron nitride (CBN) with a softer abrasive material

For an effective machining of high-performance materials, high-strength cutting materials, e.g. cubic boron nitride (CBN), with high resistance to any kind of wear are used. However, these materials must also be able to be machined in order to produce geometric elements such as chip breakers or chip grooves. According to the current state of the art, grinding and laser beam technology are used for this purpose. In this paper, an attempt was made to use the erosive removal mechanism of abrasive water jet technology to cut a harder material with a softer abrasive. Within the framework of a full factorial test plan, the removal rate, the macroscopic kerf geometry on CBN were investigated by means of abrasive water jet machining. It could be proven that it is possible to remove a harder material with a softer abrasive by means of abrasive water jet technology.

Experimental study on hole characteristics and surface integrity following abrasive waterjet drilling of Ti6Al4V/CFRP hybrid stacks

Abrasive waterjet (AWJ) technology has been demonstrated to be a feasible manufacturing process for machining composite and titanium alloys to its specific advantages. However, AWJ cutting of composite/metallic hybrid stacks possesses several challenges. In this work, experimental results were analyzed including hole quality and surface morphology/integrity during abrasive waterjet drilling of Ti6Al4V/CFRP stacks with different operating conditions. The influence of some key parameters involving traverse speed, hydraulic pressure, stand-off distance, and stack layup on hole quality was studied. Experimental array having 16 trials was designed based on full-factorial statistical analysis. Results showed that hole edge rounding was prevalent at the entrance irrespective of processing parameters due to erosion effect of abrasive particles. Ti6Al4V/CFRP layup configuration was preferred to obtain better geometrical consistency in terms of hole diameter. The variation of hole roundness was relatively high (up to 0.57 mm) when drilling hybrid stacks with Ti6Al4V/CFRP configuration. Ridges, fractured fibers, and small voids were generally observed on CFRP surface, while wear tracks and embedded fractured particles were typically found on titanium surface due to various material removal mechanisms.

Effect of Waterjet Machining Parameters on Cut Quality of Polymeric Composite Materials Based on Biological Reinforcement in Form of Cotton Post-harvest Line Residues

Composite materials are prospective materials. An intensive research on biological reinforced composite materials has taken place in recent years. The paper deals with utilization of just this biological filler in an area of the composite materials based on a synthetic laminating resin. A microparticle and short-fibre filler based on cotton post-harvest line residues was used within the research. Many research studies devote to an evaluation of mechanical properties and an interaction of the filler and the matrix. Also a production of a final product is an integral part of the composite material development, namely in terms of a practical application. The research focused on an essential production part, namely machining by means of a water jet technology and an optimization of the cutting process based on an evaluation of a traverse speed and a cut quality. The research results proved that it was suitable to use the abrasive water jet technology for the cut uniformity (the kerf taper angle) and a deformation elimination of outlet part of the water jet from the composite material. In case of using the water jet technology without abrasive it is suitable to use lower values of the traverse speed, ca. 250 mm/min.