Water Jet Process Research Articles

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.

Quality formation of the surface layer during abrasive waterjet cutting

The process of waterjet cutting of sheet materials and the obtained treated surfaces is studied. A dependence for determining the roughness of the obtained surfaces is derived, the adequacy of which is confirmed experimentally. Recommendations on technological design and implementation of this processing in production are given. Keywords waterjet cutting, part, surface roughness, tehn_rostov@mail.ru

A new metric for assessing the surface roughness of agate plates cut by abrasive water jet

Agate plate cut by abrasive water jet (AWJ) process has several methods for assessing its quality, but there is no consensus among researchers about to which one is the most accurate and consistent method to use. The present work presents a new approach to classify the quality level of an agate surface cut by the abrasive water jet process, which is called comparative roughness criterion (Rcc). This method represents, in percentage terms, the thickness of the agate plate which is composed by the smooth zone (with good finish) in relation to the total thickness. An experimental study was conducted to validate this ratio, where the thickness of the smooth surface was defined by a surface roughness measured of the cut surface. A roughness ranging between 4 and 6 μm was found in the border between the smooth and rough region of the agate plates cut by AWJ. Therefore, the comparative roughness criterion (Rcc) based on roughness measurements proved to be a quantitative metric for evaluating the finish of cut agate plates under different AWJ processing conditions.

New model for the prediction of the machining depth during milling of 3D woven composite using abrasive waterjet process

The goal is to study the influence of abrasive water jet (AWJ) machining parameters (jet pressure, traverse speed and scan step) on the cutting depth of 3D woven Carbon Fibres Reinforced Polymer (CFRP) composite. The original material linked to this non-conventional milling process has not been treated yet. The depths of cut were measured and characterized as a function of the machining parameters. Finally, two prediction models for the cutting depth are proposed and validated experimentally.An increase in cutting depth with the pressure and a decrease as the traverse speed and/or the scan step increase were observed. The first prediction model, based on the pocket depth measurements, has a mean error of 5%. However, the error increases (up to 23%) when the pocket becomes shallow (lesser than 1 mm). The second prediction model, based on the algebraic sum of elementary passes modelled with Gaussian bells, shows at first a mean error of 12%. A correction was performed depending on the erosion regime piloted by the depth of the elementary trench constitutive of the pocket. This enhancement, performed thanks to the primary jet diameters measurements with high speed camera, has improved the second model with a mean error of 5% (error <16%).

Experimental investigations on abrasive water jet machining of nickel-based superalloy

Waspaloy is often used in aviation combustion chamber at extreme environments. Waspaloy is also a nickel-based superalloy with exceptional strength properties at a temperature of 980 °C. In this experimental investigation, waspaloy is used to analyse the kerf angle (KA), surface roughness (SR) and material removal rate (MRR) during abrasive water jet machining. The effect of various parameters such as traverse speed, abrasive flow rate, water pressure and stand-off distance on KA, MRR and SR was discussed. The striation formation was analysed for different set of process parameters. The striations were also analysed using atomic force microscopy. An attempt was done to relate the jet impinging angle and nature of striation formation. It was found that the increase in declination angle decreases the formation of striation during water jet process of waspaloy.

Liquid jet penetration and breakup in a free supersonic gas jet

The interaction of a coherent liquid jet with a free supersonic gas jet is of importance in cooling high-temperature exhaust plumes generated by ground rocket tests. Further, the associated phenomena are distinct from the well-studied jet in supersonic crossflow due to the unbounded nature of the gas jet, its shock train structure, and the relative sizes of the two jets. This work utilizes non-intrusive diagnostics including focused color Schlieren, high-speed diffused backlit imaging, and volume-illuminated imaging to study the interaction process of a high Reynolds number water jet with a free supersonic air jet. The effect of the water jet on the shock train structure and its dependence on water injection location and pressure are studied. The ensuing water jet breakup mode is investigated and found to exhibit distinguishing characteristics from known breakup modes observed at high Reynolds and gas Weber numbers. Finally, the water jet penetration height is quantified, and the ability of existing correlations from the literature to predict the penetration height are investigated.

Study on the influence of the working regime on the quality of cut in the case waterjet processing of S 235 steel

The current paper presents the influence of different working regimes on the quality of cuts performed by abrasive water jet processing on S 235 steel. Four process parameters were varied: pressure (P), feed rate (Vf), quantity of abrasive material (Q) and distance between the cutting head and workpiece (h). Four quality parameters were analysed: width of the processed surface at the jet inlet (Li), width of the processed surface at the jet outlet (Lo), inclination angle of cut (α) and surface roughness (Ra). The analysis was done for three material thicknesses: 1mm, 6.5mm and 10mm.

Effect of abrasive type on marble cutting performance of abrasive waterjet

Abrasives play a critical role in the erosion process of abrasive waterjet (AWJ). Therefore, they can significantly affect the performance and profitability of cutting. In the relevant literature, there is no comprehensive study investigating the effect of abrasive type on the rock cutting performance. The current study aims to fill this gap. Various abrasives (garnet, white fused alumina, brown fused alumina, silicon carbide, glass beads, and emery powder) are used on this basis. Marble samples are cut in the tests in which the cutting parameters are kept constant. Cutting performances of the abrasives are investigated based on some performance outputs (the cutting width, cutting depth, kerf angle, and surface roughness). The study revealed that the silicon carbide and fused alumina (brown and white) present higher cutting performances in terms of the cutting depth and kerf angle. It is also concluded that the abrasives produce similar cutting widths and the glass bead produces smoother cutting surfaces. Additionally, it is demonstrated that cutting performance of the AWJ is highly affected by abrasive density and hardness.

Design, analysis, and performance verification of a water jet thruster for amphibious jumping robot

In nature, certain aquatic animals and seabirds are capable of leaping from water surface and overcoming aquatic obstacles with ease. Inspired by that, researchers have developed various underwater robots, which can perform the aquatic jumping motion. Although there are several ways to achieve it, the water jet propulsion is the most appropriate approach for the amphibious jumping robot, which is under development. In this paper, a high-performance water jet thruster powered by liquid nitrogen is proposed to be the potential actuator for the amphibious jumping robot. The theoretical jumping model is built to optimize the initial volume fraction of water inside thruster and analyze its parameters' variation during water jet. Then the computational fluid dynamics simulations by ANSYS FLUENT software are carried out to analyze the self-pressurization process of liquid nitrogen as well as the water jet process. Finally, the proof-of-concept outdoor experiments present that the 3.7 kg thruster's maximum aquatic and terrestrial jumping heights are 25.1 m and 24.4 m, respectively. A simple heat transfer analysis between water and liquid nitrogen is also conducted, and the order of magnitude estimation of heat transfer coefficient is given to be 265W/ (m2·K) based on the experimental reaction time.

Effective location of micro joints and generation of tool path using heuristic and genetic approach for cutting sheet metal parts

This paper proposes a heuristic and genetic approach for cutting sheet metal parts that identify effective locations for micro-joints, thereby generating an optimized tool path. In the current industrial practice of Laser, Plasma and Abrasive Water Jet (AWJ) processes, one or more micro-joints (also known as a stitch) are used to link the cut parts with the sheet. These micro-joints are randomly given along the part geometries by the shop floor engineer. The number of micro-joints is directly proportional to that of the piercing points, which highly influences the tool travel path and the process time. This ongoing research effectively locates three micro-joints in a specific orientation by considering the centroid point of the part geometry. This approach eliminates the excessive micro-joints in a parts layout. Considering the contour of the parts as segments, each one of them is cut by the tool with a piercing (lead in / entry) point just away from the micro-joint. The varied orientation of micro-joints generates different tool path to cut all the segments in the layout in a specific sequence which is represented by a genetic string. The genetic algorithm is customized in such a way that it suits the proposed approach. And such a genetic algorithmic process finds the near optimal string with an objective to reduce the tool travel distance. The effectiveness of the proposed approach is demonstrated with the randomly generated parts layout. The results show a significant improvement in the tool path.

Micro-Abrasive Water Jet and Micro-WEDM Process Chain Assessment for Fabricating Microcomponents

The capability to manufacture high-precision components with microscale features is enhanced by the combination of different micromanufacturing processes in a single process chain. This study explores an effective process chain that combines micro-abrasive water jet (μ-AWJ) and microwire electrical discharge machining (μ-WEDM) technologies. An experimental spring component is chosen as a leading test case, since fine geometric features machining and low roughness on the cut walls are required. The advantages deriving from the two technologies combination are discussed in terms of machining time, surface roughness, and feature accuracy. First, the performances of both processes are assessed by experimentation and discussed. Successively, different process chains are conceived for fabricating two test cases with different sizes, displaying some useful indications that can be drawn from this experience.

Investigation of the process of abrasive waterjet cutting of steels based on numerical simulation

The paper presents the results of 3D modeling the process of abrasive waterjet cutting of structural carbon and stainless steel workpiece. The Johnson-Cook model is selected as a material model. Distributions of stress fields in the cutting zone are obtained, as well as the dependences of depth of cut on jet traverse rate at jet velocities of 400 ... 700 m / s and dependences of cutting force on jet velocity at jet traverse rates of 100 ... 400 mm / min.

Applications of the abrasive water jet technique in civil engineering

Water jet processing techniques can be successfully applied in many fields of civil engineering, such as: structural engineering, structural reconstruction, renovation, demolition and recycling. The problem of cutting difficult-to-machine materials led to the development and application of today the most attractive method for contour cutting - Abrasive Water Jet Cutting (AWJC). It is a high-tech technique that provides unique capabilities compared to conventional machining processes. This paper, along the theoretical derivations, provides a study on use of water jet in construction and civil engineering. The particular part of this paper deals with the results of the original experimental research on granite and aluminum cutting.

Investigation on abrasive waterjet machining conditions of mild steel using artificial neural network

Abstract Abrasive waterjet machining (AWJM) is one of the unconventional machining practices and is used widely in industries. The key output performance measures in this technique are depth of cut and surface roughness. This paper presents the experimental investigation on machining conditions of abrasive waterjet process in machining mild steel. Taguchi’s method of design of experiments was used to select input process parameters by varying water pressure, traverse speed, abrasive mass flow rate and standoff distance. The depth of cut and surface roughness were measured using Sigma Scope 500 profile projector and surface roughness tester respectively. After getting the required data from the experimental setup the same data is fed to the artificial neural networks and back propagation algorithm procedure is used to train the data using MATLAB programming package. It is observed that the artificial neural network (ANN) model was able to foresee the new set of data. This mathematical modelling tool can be used to predict dynamic varying different types of input to identify the stability of the system.

Komunikasi Sistem Pembaca 2D Dengan Mesin Laser Marking Berbasis PLC

Currently size of Integrated Circuits (IC) become smaller while it needs more information on its label. Therefore 2D data matrix is use to replace standard character for the identification. To improve laser mark machine capabilities to be able to read 2D data matrix, a 2D reader system is required to integrate with existing laser mark machine. This study aims to develop 2D reader system that can read 2D data matrix and communicates with laser mark machine automatically. Communication between 2D reader system and laser mark machine was done through Programmable Logic Control (PLC) inside the machine using serial (RS-232) by utilizes available data memories inside the PLC. The experimental result indicates the 2D reader system able to communicate with laser mark machine and it can differentiate readable and unreadable 2D data matrix. Unreadable 2D Code was caused by different process on the tested material. The readable 2D Code through Chemical Deflash – Water Jet (CD-WJ) process while the unreadable 2D Code run without CD-WJ.

Application of forward five point central difference method in the temperature field model of laser processing silicon wafer

This paper develops an analysis of ultimate capacity of hot-rolled RHS and SHS, Traditional laser processing of silicon wafers usually uses phase transition method to remove materials, resulting in melting material resorting to overheated temperature and forming recast layer after cooling, which will affect the processing quality and material properties. This paper is Based on water jet assisted laser machining and the thought of energy balance, and apply prior to the central five point difference scheme to structure two dimensional transient temperature field model around cutting groove during the process of water jet assisted laser machining. At the same time, it will verify the applicability of the numerical model according to comparing the temperature field and the experimental results.

Optimization of the hydro abrasive jet cutting process of thick steel sheets

In this paper is studied the issue of thick steel sheets cutting on abrasive waterjet machine, due to the abrupt curvature of the jet, caused by energy loss at high thicknesses. Depending on the hardness of the processed material, incomplete cutting occurs and it is evident at a thickness of sheets larger than 30-50 mm. Achieving a cutting with different configuration regimes implies on most of the equipment, turning off the machine, a new configuration and restarting the process of abrasive waterjet cutting which leads to the appearance of traces and marks on cut surface. Choosing the parameters in such a way that cutting is achieved (automatic configuration), leads to obtaining an uncut zone at the exit of the material. This uncut area can be eliminated by an oversized configuration of input parameters, or just reduced by a randomly selected configuration. Both cases lead to large economic losses. The correct choice of machining regime for abrasive cutting of thick sheets, depending on the thickness and the hardness of the material is the aim of these studies and proposed calculation method can be implemented.

The use of waterjet cutting wastes in the production of building materials

Investigation and involvement in the production of new, earlier not used manufacturing waste and consumption is the current task directly associated with preservation of natural resources and protection of biosphere from pollution. To such waste, we refer dispersed waste of metalworking formed while cutting of metals, operation of crushing machines, etc. The purpose of this work is to study the composition and properties of waste from hydro-abrasion (waterjet) cutting of metals and estimation of their use in the production of building materials. They are related to V class of hazard the conditions of their formation are such that no new compounds arise complicating their possible application. The essence of the process of waterjet cutting, mechanism of waste formation, substance composition and volumes of waste accumulation at the enterprises, current situation in the sphere of their utilization is described. The composition and properties of the abrasive applied – garnet sand composed mainly of ferrous-aluminium garnet – almandite – one of the most hard and durable of known useful minerals. A complex investigation of waste from waterjet cutting was carried out: the average and bulk density, granulometric composition, chemical composition were determined, the electron microscopic study of various waste fractions was performed. It was found that in the process of cutting, the destruction of abrasive particles occurs, the size and shape of granules changes as well as the nature of their surface, a large amount of dust fraction appears, where particles of cut metal fall. At the same time, in the process of sand particles destruction, new abrasive faces arise, and their recycling is possible. It was established that waste of waterjet cutting of metals present very small, practically uniform heavy sands with high content of dust fraction, in the chemical composition of which prevail ferric oxides, silicon and aluminium oxides. Such characteristic of waste allowed mark possible ways of their application: 1) in the production of pottery work as inert additives and flux-additives, 2) in the production of Portland cement as corrective iron-containing additive and component of raw mix for high ferriferous cements; 3) as a filling agent in mortars, including special mortars, 4) as a pigment for voluminous painting of building materials, etc. Positive results have been obtained on the use of waste from waterjet cutting in the production of ceramics. A raw mix consisted by 50% (by mass) of montmorillonite clay and by 50% of waste from waterjet cutting of steel. After burning at 900° C, physical mechanical properties of samples have been determined. The results obtained permitted to make the conclusion about the possibility of using these waste as the poly-functional additive in the manufacture of ceramics.

Economical Considerations over 3D Printing Components for Abrasive Water Jet Machinery

The purpose of this research is to analyse the technological and economical aspects of making 3D print pieces to produce functional parts and subassemblies for abrasive waterjet processing equipment. The authors of this paper intend to make a clarification on the technological and economic approaches of material that can be used to make such a reference in terms of economic efficiency and technology. In the paper are analysed all the aspects involved in generating the necessary elements on the mechanical side of them by FDM (Fused Deposition Modelling). The paper is structured in a five chapters in which it is presented in a logical order the analysis of the materials that can be used in the mentioned technological field, the technological parameters specific to the analysed process, the method of generating the parts and their realization from a practical point of view and presenting the main economic aspects that involve the manufacturing costs of specific parts through 3D printing technology for components of water jet processing equipment with suspension abrasive media.

New concept of tunnel boring machine: high performance using water jet and diamond wire as rock cutting technology

Abstract Tunnel boring machines are important tools in underground infrastructure projects. Although being well established equipment, these machinesare based on designsof more than 60 years ago and are characterized by big dimensions, enormous weight and high power consumption. Commercial aspects should be noted too. The model adopted by the TBM industry requires constant replacement of cutter discs and specific labor skills, usually offered by the same manufacturingcompany. In some cases the cost of replacement parts and technical assistance can be higher than the acquisition cost of an entire machine. These aspects are no longer compatible with the concept of sustainability that is an important aspect of currentsociety. While the technical characteristics require a large quantity of steel and several inputs, the adoptedmodel is not competitive. One alternative is looking for new technologies that break the old paradigms and allow the development of high performance concepts with lower social and environmental impact. This studydealswith this opportunity by proposing a high performance tunnel boring machine that makes use of high power water jet and diamond wire to compose a double shield cutter head. It works in two stages. In the fristone, an annular cut is executed by hydrodemolition,and in the second one, the diamond wire station slices the rock core. Only with the action of diamond wire is the rock core separated from the rock mass and the removal process is finished. A smart water jet nozzle movement system is described and non circular tunnels can be executed. The new technologies involved requirea different type of backup system, lighter and smaller. The non-existence of mechanical contact between the equipment and the rock mass at theexcavation front allows low power consumption. The advanced rate and primary excavation cost analyses can also be encountered herein. It shows that it is possible to reach an advanced rate of 174 m/day in soft and porous rock and 0.64 m/day in hard and non porousrock, whereas the NTNU method indicates only 55m/day and 13m/day underrespective conditions. On the other hand, the excavation cost is high for both conditions. One option is to use sand as an abrasive in the water jet process, reducing by half the primary excavation cost. It is reasonable to say that the proposed concept can be considered as an alternative for tunnels in soft rock and high porosity, and needs better performance of the water jet system to become an alternative for hard rock.