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This study deals with the kerf's characteristics and examines the morphology of its upper part, known as the initial zone, when subjected to abrasive water jet machining. The hydrodynamics of the abrasive water jet were analyzed in relation to technological parameters, including traverse speed, abrasive mass flow rate, and stand-off distance, and their impact on the structural integrity of Copper 5457-T. Key assessments included the kerf's top width, edge bevelling, the extent of the upper region impaired by abrasive particles, and subsurface hardness. The varied process parameters significantly influenced the kerf's geometric features and structural integrity. Contrary to previous assertions, zones exhibiting post-peening effects were identified around the contact boundary. Microhardness tests revealed variations along the profile, influenced by the abrasive mass flow rate and kinetic energy distribution. The study found traces of compressive residual stresses in the contact area, suggesting deeper penetration of abrasive particles than initially anticipated, leading to the presence of compressive residual stresses in the subsurface regions. [ABSTRACT FROM AUTHOR]

Submerged jets have a variety of practical applications due to their versatility in providing efficient and environmentally friendly options for treatment in various industries. The physical background is based on the continuous water jet (CWJ) application powered via stagnation pressure. However, it is known that impact pressure is much more effective than static pressure. When the impact pressure is repeated with a high frequency per time unit, the erosive effects of water can be used even at pressures below 100 MPa, which is attractive from the point of view of the low demands of the hydraulic system. Surface modification utilising impact pressure can be achieved by employing the pulsed water jet (PWJ) method. The combination of parameters such as the traverse speed and trajectory pattern can control the number of water clusters impacting the material surface. So far, the field of application of PWJ for surface treatment has mostly been investigated water atmospheric conditions. This article focuses on the possibility of the surface modification of AISI 304L stainless steel using the PWJ method under submerged conditions. The results are compared to those obtained under atmospheric conditions. The reference samples were treated by the same technological conditions using a continuous water jet (CWJ). The affected surfaces were characterised using areal surface roughness parameters Sa, Sz, Sp, and Sv, and the surface topography and mechanism of erosion wear were evaluated by scanning electron microscopy. A significant increase in all roughness parameters was confirmed using the PWJ compared to the CWJ method (both in atmospheric and submerged conditions), which confirms the importance of using impact pressure. The surface treatment by PWJ under submerged conditions resulted in a decrease of the surface roughness parameter Sa by approximately 97% compared to atmospheric conditions at a traverse speed of 2 mm/s for perpendicular interleaved trajectory, nevertheless, the homogeneity of treatment over a larger area was improved. [ABSTRACT FROM AUTHOR]

Erosion caused by water droplets is constantly in flux for practical and fundamental reasons. Due to the high accumulation of knowledge in this area, it is already possible to predict erosion development in practical scenarios. Therefore, the purpose of this study is to use machine learning models to predict the erosion action caused by the multiple impacts of water droplets on ductile materials. The droplets were generated by using an ultrasonically excited pulsating water jet at pressures of 20 and 30 MPa for individual erosion time intervals from 1 to 20 s. The study was performed on two materials, i.e. AW-6060 aluminium alloy and AISI 304 stainless steel, to understand the role of different materials in droplet erosion. Erosion depth, width and volume removal were considered as responses with which to characterise the erosion evolution. The actual experimental response data were measured using a non-contact optical method, which was then used to train the prediction models. A high prediction accuracy between the predicted and observed data was obtained. With this approach, the erosion resistance of the material can be predicted, and, furthermore, the prediction of the progress from the incubation erosion stage to the terminal erosion stage can also be obtained. [ABSTRACT FROM AUTHOR]

Recently, the demand for lightweight multilayered parts in electronics and biomedical fields has been accelerated and shown great interest in understanding the combined effect of multilayered materials. However, these industries are still facing the challenge of developing dissimilar multilayered materials that can be suitable for biomedical applications. In this context, magnesium emerges as a promising biocompatible material used for several biomedical applications. However, the issues related to joining magnesium alloys with other similar materials still need to be solved. Moreover, friction stir additive manufacturing (FSAM) occupies a niche domain for developing or joining biocompatible materials such as magnesium alloys with low weight and high strength. Therefore, the present work highlights the development of a multipurpose three-layered multifunctional laminated composite plate of magnesium-based AZ31B–Zn–Al 1100 through the FSAM route. Microstructural and morphological examinations were carried out by light microscopy and FESEM equipped with EDS analysis and line mapping. Moreover, the grain refinement at the interfaces during the FSAM was also addressed using the electron backscattered diffraction (EBSD) study. Further, investigation on mechanical properties such as tensile test with fractography analysis and microhardness variation at the cross-section of the built-up section has been investigated. Furthermore, the corrosion and tribological analysis was also performed, and a 3D profilometer was used to visualize the corroded and worn-out surfaces. The microstructural results revealed that the average grain size of 6.29 μm at interface AZ31B–Zn and 1.21 μm at interface Zn–Al 1100 occurred, improving the bonding strength and overall properties. The tensile strength has occurred as 171.5 MPa at 15.5% elongation, whereas maximum microhardness is reported as 105 HV at the interface of AZ31B–Zn and 84.6 HV at the interface of Zn–Al 1100. The corrosion rate was calculated as 0.00244 mm/day, and the average coefficients of friction (COF) for both the interfaces, such as AZ31B–Zn and Zn–Al 1100, are 0.309 and 0.212, respectively. [ABSTRACT FROM AUTHOR]

Lightweight composite materials for potential thermal applications are the contemporary demand for manufacturing and aircraft industries where the possibility to improve and tailor the desired properties is based on the application. Carbonized eggshell powder is a solid lubricant with absorbent capability and has proven as a reinforcement for metallic base composites. In the present work, an attempt is made to investigate the effect of carbonized chicken eggshell powder (3 to 9% by weight) on the microstructural and thermal properties of Al7075 alloy processed by solid-state friction stir processing. An infrared thermography and three K-type thermocouples equipped with the base plate at three equal distances are used to measure the temperature with respect to time. The comparative study of microstructure and grain structure analysis has been done by light microscopy, scanning electron microscopy, and electron backscattered diffraction methods. The findings explored the dynamic recrystallization and grain recovery with a reduced grain size of 6.2 to 10.3 µm at a varying percentage of eggshell powder (3 to 9%) in the stir zone. The thermal conductivity and coefficient of thermal expansion (CTE) were measured for the temperature range of 50 to 400 °C. In addition to it, differential thermal analysis (DTA), thermo-gravimetric analysis (TGA), and derivative thermo-gravimetric analysis (DTG) are conducted for the temperature range of 25 to 900 °C to discuss the endothermic, exothermic nature, and degradation characteristics. The result revealed the decreasing trend of thermal conductivity, and CTE values were found in the range of 97 to 53 W/mK and 26.6 to 24 × 10−6 K−1 (heating cycle), 27.2 to 23.8 × 10−6 K−1(cooling cycle), respectively. Furthermore, the higher and lower thermal conductivity of 108 W/mK and 62 W/mK is observed at higher and lower terminal voltages, 250 V and 100 V, respectively. The DTA, TGA, and DTG curves explored the maximum weight loss, which varies up to 5.25% with exothermic peaks and decomposition steps for each surface composite. [ABSTRACT FROM AUTHOR]

There are many technological ways to activate biocompatible surfaces, but in some cases, there are not reliable for elderly patients. It has been found that surfaces created using pulsating water jets have a structure similar to trabecular bone structures. Such a similar shape to the endoprosthesis stems would enable faster fixation. The paper presents a novel way of utilizing the water hammer effect caused by forced multiple droplet impingement with a spatial frequency of 40,000 i/s on Ti6Al4V titanium alloy surface under different technological conditions. The objective was to create a structured surface with desired values of surface profile parameters Ra and Rz to increase the possible potential for implant osseointegration, fixation and stability. Pulsating water jet was generated at pressures from 20 to 100 MPa using a circular nozzle with a diameter of 1.32 mm. Two different strategies of the jet trajectory, namely linear and cross-hatch strategy, were investigated. Results were compared with grit blasted followed by plasma spray-coated femoral stem for cementless total hip arthroplasty. It has been found that variation in the input parameters results in significant changes in the surface generated. Samples whose surfaces were generated using energy intensity lower than 5 KJ/mm2 and have surface roughness in the range Ra = 4 – 8 μm were selected for surface topography and morphology analysis along with the commercial femoral stem. SEM analysis revealed the absence of foreign contamination and steeper surface heights on pulsating water jet treated samples compared to standard femoral prosthetic. The cross-section images showed the presence of sub-surface voids and craters of different sizes due to the jet's action. Surface topology is similar to trabecular shape. This indicates that roughening the surface increases the surface area and thus has potential bone tissue ingrowth during osseointegration. [ABSTRACT FROM AUTHOR]

Non-thermally affected surfaces created by abrasive water jet, among many other advantages, are manufactured with geometric inaccuracies. These geometric inaccuracies are mainly related to waviness, especially in the lower parts of thick engineering components. Therefore, the study establishes a link between the surface quality and abrasive water jet material disintegration parameters related to striation mark displacement. The materials used for the experiments (aluminum, steel, and polyethylene plastic) are selected to cover a wide range of hardness values. These materials are often machined, which enables to draw practical reference values from the results obtained. Experiments are used for determination of the surface quality to assign a range of surface roughness profile parameters Rz and Ra, as soon as no clear striation marks are recordable on the surface for particular materials with specific mechanical properties. [ABSTRACT FROM AUTHOR]

The local residual stresses (tensile) generated on the surface of a component during its manufacturing (machining, welding) cause deterioration of its service life. To eliminate the negative effect of the stresses, the surface is treated using different methods (shot peening, laser shock peening, heat treatment, water jet peening). The application of ultrasonic technology to modify the continuous jet has been intensively researched for treating advanced stages of erosion. In this work, the modifications in the mechanical properties (tensile strength, micro-hardness and residual stress measurements) of AISI 304 Tungsten inert gas welded joints were investigated after ultrasonic pulsating water jet treatment in the incubation stage of erosion. This revealed that the initial tensile residual stress in the welded joints was converted to compressive stress after the treatment. The micro-hardness of the joints after the treatment increased about 40% in the heat affected zone in the near-surface region. Also, the tensile properties increased by about 37.8% and 34.6% in yield strength and ultimate strength, respectively. The microstructural examination of the near-surface region showed the grain reformation mechanism. [ABSTRACT FROM AUTHOR]

Ultrasonic pulsating water jet for non-thermal and selective removal of acrylic bone cement is studied. Variation of acoustic chamber length is used for tuning of the ultrasonic system into the resonance regime to gain maximum power transmission. The study investigates the minimal technological conditions such as nozzle traverse speed and supply water pressure required to generate disintegration grooves in bone cement mantle. It also proposes the safe standoff distance range, which is essential for its potential application during the extraction of bone cement without compromising host bone. Palacos R+G bone cement was used for the experiments. Generated groove depths were measured using MicroProf FRT and analyzed using SPIP software. Depth values showed an increasing trend with an increase in acoustic chamber length, decrease in traverse speed, and increase in supply pressure values. From the entire experimental domain, a maximum depth of 615 μm was obtained at 22-mm chamber length, 0.5-mm/s traverse speed, 10-MPa pressure, and a standoff distance of 4 mm. Brittle fractured surface features like material chipping, micro-pits, cracks, and sheared material layers were observed in the SEM images. Disintegrated debris, diameter 21–37 μm, conceived from pit diameters can be used to design a suction unit. Real-time control of the disintegration process using accelerometer sensors was shown. The results support the idea of using pulsating water jet for bone cement removal in a single blind hole. Minimal technological parameters reduce reaction force of the hand tool, allowing bone cement removal without bone fracture or perforation. [ABSTRACT FROM AUTHOR]

This paper addresses the hydroabrasive disintegration of the difficult-to-machine material, Monel K-500. An experiment was performed using a hydroabrasive cutting system with an additional rotating module. The objective of the preliminary experiments was to identify significant technological factors and investigate their impact on the machined surface quality of difficult-to-machine materials. To describe the impact of parameters, experiments were carried out according to the design of experiment. Surface roughness parameters were measured, and surface topography visualisation and analysis were conducted. The results concluded that the abrasive mass flow rate and traverse speed significantly influence the surface roughness and material removal rate. From a practical point of view, the technology can prepare semi-finished workpiece shapes; however, surface finishing is necessary. [ABSTRACT FROM AUTHOR]

The paper deals with the tangential abrasive water jet turning of hybrid aluminium matrix composite fabricated by electromagnetic stir casting technology, consisting A359 aluminium alloy as base matrix and 2% BC and 2% AlO as reinforcing particles with final workpiece diameter of 14.5 mm. The influence of abrasive mass flow rate within 100-400 g/min using two different abrasive grains-olivine and Barton garnet-was studied. Abrasive grains were fed to the water stream created by water orifice of diameter 0.33 mm at pressure level of 300 MPa and a stand-off distance 8 mm. Abrasive type and abrasive mass flow rate, as important technological factors, are evaluated, and topography of created surfaces is analysed using optical profilometry and microscopy methods. A diameter reduction of 25-30% was observed during the experiments. The lowest average roughness value of 6.64 μm was obtained using olivine grains at an abrasive mass flow rate of 400 g/min. The topographical detail of the machined surface revealed several cutting traces, grooves and furrows which show the ploughing nature. [ABSTRACT FROM AUTHOR]

Wire electrical discharge machining (WEDM) process provides a cost effective solution to generate complicated shapes in various exotic materials, irrespective of their hardness. However, WEDM process removes the material by thermal erosion mechanism which in term affects the topography and mechanical characteristics of the material. In view of this, an effort is needed to eliminate the adverse effect of WEDM process on the final product surface. Therefore, the present work evaluates surface morphology, surface roughness, elemental composition, micro-hardness and residual stress of the machined surface produced by various WEDM strategies such as, rough cut and finish cut. Two post-processing techniques namely, grinding and etching-grinding are proposed to remove recast layer and also to improve the surface integrity of the machined surface. The proposed strategy found to be an efficient post-processing technique for complete removal of recast layer and generation of surface with an average surface roughness as low as 0.024 μm, high compressive residual stress as high as 500 MPa and basic elemental composition. The basic mechanism of these process are also explained in details. [ABSTRACT FROM AUTHOR]

Nowadays, the abrasive water jet (AWJ) technology is much in use for cutting materials into complex shapes with high dimensional accuracy. The objective of the present paper is to study the topography as well as the roughness of the surfaces in friction stir welded (FSW) joints, machined by AWJ. It discusses machinability of the FSW joints by AWJ. Subsequently, this paper makes a critical analysis of the surface properties by optical profilometer. Top and bottom surfaces, created by FSW, have also been analyzed using an optical 3D measurement system to determine the morphology and topographic parameters. FSW possesses favourable joining properties and generates a minimum heat-affected zone (HAZ) because of its comparatively low temperature coalescence. Three friction stir welding samples were prepared at 500, 710 and 1000 rpm with a welding speed of 40 mm/min on AA 6101-T6. After analysis, it was found that the sample prepared at 500 rpm and with welding speed of 40 mm/min produces a surface fit for industrial applications in terms of surface roughness and dimensional accuracy. It has also been observed that unlike other conventional or non-conventional processes, no HAZ is generated during the cutting of FSW joints by using the AWJ technology. [ABSTRACT FROM AUTHOR]

The present paper deals with the characterization of failure behavior in the cemented carbide (WC 94-Co 6%) tips of two cutters, i.e., conical cutter and radial cutter, which were used for coal cutting operation in an underground mine. High-resolution microscopes (FESEM and EDS) were used to assess wear mechanisms. The cemented carbide has been studied for its wear behavior for a long time. The ongoing research is necessary because wear mechanisms cannot be classified in single way. The variations in application of the tools may change the tribological characteristics in the cemented carbide. In this study, mainly four wear mechanisms, such as Cracks, Abrasion, Corrosion, and Intermixing of external elements, have been reported. [ABSTRACT FROM AUTHOR]

In the article, a design and experimental study of the non-traditional turning tool is carried out and compared to commercial tools. The quality and the efficiency of the machining process is considerably affected by the cutting tools, there being a tendency to look for new non-traditional tools and their geometry. One such tool is a tool with a linear cutting edge. Research into its application towards machining capabilities and its comparison to the classical, mass produced, tools was the goal of this investigation. For this reason, the tools were designed at FMT TU Kosice with the seat in Presov to find new solutions to preserve the tool's advantages and eliminate its disadvantages. After tool designing, various types of experiments were carried out, dealing with the roughness of machined surface and the turning force. The shapes of the chips and life time of the tools were investigated together with the technological aspects (i.e. feed and speed). Regression analysis and the finitary method of matrix inversion were selected as the methods to interpret the experimental results. The results show that a tool with a linear cutting edge achieves lower values of the surface profile parameter Rz at higher feeds, compared to a commercial tool, which is especially designed to finish the turning operations. On the other hand, from the point of view of energy consumption, the selected commercial tool is more effective. These findings will enable the producer to make a better decision on which type of tool should be used for machining in specific conditions to achieve the best machined surface quality at the required level of energy consumption. [ABSTRACT FROM AUTHOR]

The paper deals with the verification of suitability of water jet and abrasive water jet application for the disintegration of rotating samples of wood plastic composites (WPCs) with diameter d = 36 mm. The influence of selected technological factors (traverse speed of cutting head v [mm/min] and size of abrasive particles [MESH]) on the topography of resulting surfaces has in particular been studied. Surface topography and quality have been assessed using the methods of optical and confocal microscopy and optical profilometry. The presented procedures and results of experiments demonstrate the technology of abrasive water jet as an appropriate tool for the rough machining of WPCs and similar composite materials. In addition, the application of this technology can effectively solve the problem of the melting of the polymer matrix and its subsequent sticking to the functional parts of a cutting tool resulting from conventional turning. [ABSTRACT FROM AUTHOR]

The paper deals with tangential abrasive water jet (AWJ) turning of Incoloy alloy 925. The aim of the experiment was to analyze the impact of the AWJ traverse speed (1.5-9 mm/min) on the surface quality in terms of micro-structure formed on the created surface. The water pressure was set to 400 MPa and the spindle revolution to 34 rpm. Australian garnet ( MESH 80) was used as an abrasive component. The surfaces were visualized and qualitatively described using a laser confocal microscope. Basic roughness parameters of the surfaces ( Ra, Rq, Rz) were measured using an optical profilometer. The presented experimental results demonstrate that the technology of abrasive water jet turning is an appropriate tool for rough machining of difficult-to-machine materials. [ABSTRACT FROM AUTHOR]

The article focuses on the turning of sandstone through the use of abrasive waterjet (AWJ). Topics discussed include the importance of technological innovations, the machining management, and the sandstone surface analysis. Also mentioned are the mechanical and physical properties of rock materials, the rock fabrication, and the importance of AWJ technology.

Conical pick is a widely used tool for cutting coal in mines. It has a cemented carbide tip inserted in a steel body. Cemented carbide has been in use for many years for coal/rock cutting because it has the optimum combination of hardness, toughness and resistance against abrasive wear. As coal/rock is a heterogeneous substance, the cutting tool has to undergo various obstructions at the time of excavation that cause the tool to wear out. The cracks and fractures developing in the cemented carbide limit the life of the tool. For a long time, different wear mechanisms have been studied to develop improved grades of cemented carbide with high wear resistance properties. The research is still continuing. Moreover, due to the highly unpredictable nature of coal/rock, it is not easy to understand the wear mechanisms. In the present work, an attempt has been made to understand the wear mechanisms in four conical picks, which were used in a continuous miner machine for underground mining of coal. The wearing pattern of the conical pick indicates damage in its cemented carbide tip as well as the steel body. The worn out parts of the tools have been critically examined using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) point analysis. Mainly four types of wear mechanisms, namely, coal/rock intermixing, plastic deformation, rock channel formation and crushing and cracking, have been detected. The presence of coal/rock material and their respective concentrations in the selected area of worn out surface were observed using the spectra generated by EDX analysis. [ABSTRACT FROM AUTHOR]

The paper deals with the determination of vibration emission frequency depending on the impact of abrasive particles during cutting of materials. In order to verify the investigated hypothesis, the factor of the abrasive mass flow rate m = 250 and 400 g min at the traverse speed of cutting head v = 50, 75, 100 and 150 mm min was determined. The Barton Garnet with MESH 80 and focusing tube with diameter of 0.8 and 1.4 mm were used in the experiment. Vibrations were recorded during experimental cutting by sensors PCB IMI type 607A11 placed on the stainless steel AISI 309. During the experimental sample cutting, vibrations were monitored and consequently processed by the LabVIEW 8.5 software. Research results are useful for improving the quality of surface created by abrasive water jet, and they can encourage the on-line process control of abrasive water jet cutting with the minimum human intervention in case of a fault or error during the supply of abrasives to cutting head. [ABSTRACT FROM AUTHOR]

Direct Metal Deposition (DMD) is a blown powder laser deposition process that can be used to quickly produce fully dense metallic parts and to repair or modify high-value components. This paper illustrates the use of dimensional analysis to develop a mathematical model for the control of layer deposition in DMD. A brief explanation of the material deposition process is presented and the factors affecting the metal deposition is identified so that they can be used in modeling the height of the metal deposited. The validity of the generalized model is verified from experimental data of H13 steel and Ti material and it is found in good agreement with experimental findings. [ABSTRACT FROM AUTHOR]

The paper discusses connections of acoustic emission in abrasive water jet cutting. Introduction focuses on theoretical knowledge on this technology and offers analysis related to current state of the art of the problem research. Further description of performed experiments is presented in case in which acoustic emission behaviour was observed with the exactly scheduled change of cutting conditions or rather cutting head traverse speed v. The beginning of the initial part contains FFT spectral analyses and comparison of the examined sections of the experimental samples. Consequently a graphical representation and comparison of peak-to-peak values (maximal amplitudes) and values of AE at the time of experimental cutting follow. At the close of the work, the analyses are expressed as dependence on the cutting head traverse speed v with expressed regulation equations applicable in the close-loop control process with minimum human intervention and in case of fault conditions-broken focusing tube, fractured water nozzle. [ABSTRACT FROM AUTHOR]

Mining and petroleum drill bits are subjected to highly abrasive rock and high-velocity fluids that cause severe wear and erosion in service. To augment the rate of penetration and minimize the cost per foot, such drill bits are subjected to increasing rotary speeds and weight. A rotary/percussive drill typically hits the rock 50 times per second with hydraulic impact pressure of about 170-200 bar and feed pressure of about 90-100 bar, while rotating at 75-200 rpm. The drill rig delivers a high-velocity flow of drilling fluid onto the rock surface to dislodge cuttings and cool the bit. The impingement of high-velocity drilling fluid with entrained cuttings accelerates the erosion rate of the bit. Also, high service temperature contributes to softening of the rock for increased penetration. Hence, there is a need to optimize the drilling process and balance the wear rate and penetration rate simultaneously. This paper presents an experimental scanning electron microscopy (SEM) study of electroplated (nickel-bonded) diamond drills for different wear modes. [ABSTRACT FROM AUTHOR]

The paper deals with basic research of vibration generated at abrasive waterjet cutting of materials and their analysis of frequency spectrum in the plane cut. As an experimental material, stainless steel AISI 309 has been used. Experimentally controlled factor involved in the experiment was abrasive mass flow rate with values m = 250 and 400 g min at a constant traverse speed v = 100 mm min. The vibrations were recorded during experimental cutting by sensors PCB IMI type 607A11 placed on experimental material along the cut at a distance of 50 mm from the cutting plane. Data collection was carried by NI PXI measurement system and frequency analyzer Microlog GX-S. Signal was evaluated by virtual instrument created in the object-programming environment LabView 8.5. Various sizes of amplitudes were observed depending on the distance of abrasive waterjet cutting process from the beginning of the cut. Two peaks of frequency bands have been also found: the first between 500 and 600 Hz and the other at approximately 12.5 kHz. Using this method is possible to ensure the determination of technology efficiency of the material removal process. [ABSTRACT FROM AUTHOR]

This paper deals with two methods of determination of technologically optimal factors of a hydrodynamic resonance system leading to the acquiring of maximal fundamental frequency, amplitude, pressure, and energy of oscillations of a liquid jet. These factors are determined by the differential method and the method of state space search into depth. Furthermore, theoretically predicted results are presented, interpreted, and compared with results of laboratory measurements. The benefit of the study is the optimization itself, either for the optimal input factors of the prototype or a maximum possible modification of existing equipment in order to achieve the highest possible material disintegration efficiency. [ABSTRACT FROM AUTHOR]

In the present study, real topographic function and maximal depth of neglected initial zone were analytically developed to predict surface roughness on the top region of surfaces created by abrasive waterjet. An upper area of workpieces was analysed in details. Experimentally created surfaces were measured by HOMMEL TESTER T8000 and non-contact profilometer Micro Prof FRT. As an experimental material, stainless steel AISI 304, AISI 309 and aluminium with a thickness of 10 mm have been used. On the basis of analysis and interpretation of data obtained from the surface, a topography function Ra, which is necessary to be known for the subsequent prediction and control of abrasive waterjet cutting technology, is derived. In the framework of interpretation of measured values, relations among these parameters are systematically analysed and physico-mechanical and distributional principles governing these parameter are formulated newly. Results are very important for further estimation of analytical expression of the real topographic function for any surface created by abrasive waterjet cutting. [ABSTRACT FROM AUTHOR]

The process of material cutting and fracture by high velocity water jets is a complex series of phenomena which may involve compression, tension, shear, erosion, wears, cracking, wave propagation, and cavitations damage. This makes the exact analysis of the jet cutting process to be very complicated. The problem of water jet coal cutting is a multiresponse problem. There are two output variables, depth of cut and cutting width whose optimization will result in the increase in the productivity of coal cutting. In this paper, a Taguchi-Fuzzy decision method has been used to determine the effective process parameters for improving the productivity of coal mines. The Taguchi method of experimental design is a widely accepted technique used for producing high quality products at low cost. The optimization of multiple responses in complex processes is common; therefore, to reduce the degree of uncertainty during the decision making, fuzzy rule-based reasoning was integrated with the Taguchi loss function. [ABSTRACT FROM AUTHOR]

The paper deals with an innovative way of cutting materials by abrasive waterjet with a view to increase its quality. In the research work, we were concerned with the search for a relationship between surface roughness and noise in the abrasive waterjet cutting process. Innovation lies in the use of negative characteristic of the technology—noise, which is a carrier of information about the quality of cutting process. In this way, the noise can be positively used in the on-line control of the technological process. The final result is a project for control of the process of abrasive waterjet cutting of materials by means of feedback according to the on-line measurement of acoustic pressure level L aeq (dB). Instantaneous information about the state of cut according to the instantaneous value of L aeq amplitude allows the automatic regulation of traverse speed of cutting head v p (mm.min−1), which is, together with the pressure p (MPa), one of the most important technological factors of control of production technology from the point of view of economic indicators and qualitative indicators of a semiproduct. The proposed model has been experimentally verified and was simulated in Matlab. [ABSTRACT FROM AUTHOR]

The paper deals with a proposal for surface geometric parameters for advanced quality control of abrasive waterjet technology according to the results obtained by means of non-contact optical shadow method. The main emphasis is put on the analysis of results for defining the process for prediction of new surface creation generated by the set of the abrasive waterjet factors stream of abrasive waterjet, including its geometric parameters. By means of decomposition of measured surface profile according to the root mean square parameter, in four topographical different zones the initial zone, the smooth zone, the transition zone and the rough zone new possibilities for evaluation of the surface quality and optimizing the selected technological factors of the cutting process and their control through the proposed databank conceptual structure are presented. This report deals with the problems of selecting and proposing an acceptable method for surface quality control which is available for continuous measurement and production. [ABSTRACT FROM AUTHOR]