Papers by Keyword: Water Jet Cutting

Abstract: This work aims to reveal the effect of the stand of distance (SOD)during the abrasive water jet cutting processes of Material implant stainless steel 316L on its corrosion properties. Abrasive water jet cutting processes were conducted in 5 different SOD there are 1, 2, 3, 4, and 5 mm between the nose of the nozzle and substrate surface. After these processes, the cross-section of the substrate was evaluated on its corrosion character using the potentiodynamic polarization method under Cl based solution. This process was conducted at room temperature with an almost steady state condition scan using Ag/AgCl/KCl as the reference Electrode and Pt as the counter electrode. The Results show that the corrosion resistance decreased as the SOD increased.

Abstract: The authors of the article analyzed the properties of the fluidized bed during the formation of the abrasive-polymer compound for waterjet cutting. It is noted that in the process of applying the polymer shell to the surface of the abrasive grain in the fluidized bed, the effect of slippage and the absence of the influence of the installation wall on the value of the longitudinal velocity of particles near it is observed, which allows to increase the productivity of creating an abrasive-polymer compound.

Abstract: The article presents the results of experimental studies of differences in the nature of impact destruction of single garnet grains penetrating the target material, and presents the results of numerical simulation (modeling) of the contact interaction of an abrasive particle with a flat obstacle, which allowed determining the volume ablation of the material under the action of a single abrasive particle, and makes it possible to predict the performance of waterjet cutting.

Abstract: This study shows the influence of calcinations temperature and particle size of natural garnet mineral on its hardness and abrasiveness (H/A) for use in water jet cutting of tough materials. A standard commercial sample of the mineral was characterized in terms of the hardness and abrasiveness properties. The sample was sized to 4 fractions having the size of <60 um, > 60 < 100 um, > 100 < 200 um and > 200 < 250 um designated the symbols, FF, MF, MC and C respectively. Each fraction was separately heated in controlled conditions at temperatures up to 1000°C at a heating rate of 10°C/min in an electrically heated tube furnace. Soaking time at the maximum temperature was 60 minutes. Hardness and abrasiveness properties of the heat treated samples were tested to cut marble having a thickness of 30 mm. Results revealed that H/A of the garnet mineral increased by heating at temperatures up to 750°C and exhibited gradual decrease with higher temperatures up to 1000°C. Results were explained in the light of a structural irreversible metamorphism (SM) of the garnet crystals; almandine Fe₂ + 3Al₂Si₃O₁₂ and propel Mg₃Al₂Si₃O₁₂. Metamorphism involved reorientation of the crystals followed by coherence to form dense grouping. At higher temperature, irreversible thermal expansion of the structure sets in. Characterization of the mineral was carried out with the help of XRD, SEM and FT-IR measurements.

Abstract: Parametric optimization model was made by now for abrasive water jet process, only for materials with uniform hardness. Pieces, subject to deep carburized treatment with high hardness in layer and softened in core, have a different behaviour and it is necessary to estimate new values of the system processing. Experiments consisted in cutting with abrasive water jet of rectangular samples with 10 mm thickness and deep carburized layers with 8 mm thickness, obtained as a result of deep carburized heat treatment. Abrasive water jet, initially meets the carburized layer with 62 HRC, after perforation followed the layer with fine sorbite structure (30 HRC). The different hardness causes a change in the trajectory of abrasive particles, determining deformations and micro cracks in materials to the limits of carburized layers. Choosing an optimal cutting regim becomes important not only economically, as well as qualitative. Measurements allow drawing conclusions that can be generalized to the materials with different hardness.

Abstract: The development of complex component assemblies from non-orthogonally oriented panels is laborious with currently available methods. The reason for this is the lack of integrated solutions in planning, fabrication and assembly. Thus, applications in architectural design are mostly restricted to geometrically simple, orthogonal shapes. We present a novel dovetail joining method that aims at facilitating the realization of polyhedral structures. Dovetail elements as well as panels may be fabricated using CNC water jet cutting technology. Compared with conventional processes, the presented method adopts the potential of industrial fabrication strategies and by that increases the reliability of respective processes while decreasing cost synchronously.

Abstract: In this paper research elements regarding the effect of water pressure variation on cut surfaces quality are presented in the field of abrasive water jet cutting of materials hard to process by machining such as austenitic stainless steels, in this case with a thickness of 20 mm. Selection of the optimal cutting process based on technical and economic criteria takes into consideration the type and thickness of the targeted material and also the physical and geometrical quality requirements. The present paper contains experimental research results regarding abrasive water jet cutting of austenitic stainless steel EN 1.4306 (ASTM 304 L) at different values of water pressure. The abrasive material used is Garnet with particle granulation 80 Mesh. By making roughness measurements and hardness examinations of the cut surface an evaluation will be made of the surface quality defining the optimal pressure values.

Abstract: The automation of hydro-erosion manufacturing processes comes to increase the demands on engineering works in the preparation of production, at shortening of deadlines for implementation of scientific knowledge into practice, at the design of production processes and at the economization in production processes. This process is associated with extensive utilisation of mathematical methods, using of computational procedures for specific tasks and at the utilisation of methodology of mathematics for methods of formulating solutions. During the solving of problem, there is mostly used: operational analysis, set theory, theory of structures, theory of algorithms and languages.

Abstract: Results of an experimental investigation of effects of two advanced technologies for materials cutting, namely water-jet and electroerosive cutting, respectively, are described. Water jet cutting, with abrasive particles and specific parameters, and electroerosive cutting were applied to an aircraft Al-alloy sheet Al 2124 T851 of a considerable thickness, namely 50.8 mm. Reference batch of specimens was manufactured using fine finishing milling. Surface quality of each of the cutting and machining technologies was evaluated and fatigue strength was investigated. Three point bend fatigue tests performed at constant stress amplitude showed a considerable deterioration effect of both technologies on fatigue strength. The damaging effect of both technologies was comparable. Fractographical analysis using scanning electron microscopy (SEM) showed fatigue crack initiation in numerous surface micro-notches occurring as a result of the cutting. In addition, the crack initiation was frequently accelerated by surface or subsurface fairly large particles of intermetallic phases. This mechanism also occurred with milling specimens.

Abstract: Water jet cutting is an advanced technology of separating and machining materials. It is well known, however, that fatigue properties are particularly strongly affected by surface conditions and quality of surface layer. Water jet cutting was applied to two types of aircraft sheets, namely Al-alloy sheet of fairly high thickness 50.8 mm and steel sheet of thickness 25 mm. Fatigue resistance and crack initiation mechanism of the materials after the cutting were compared with those studied using a reference batch of specimens manufactured by fine milling and grinding, respectively. Character of surface damage caused by water jet cutting resulted in a considerable reduction of fatigue strength in comparison with milled or ground surface, respectively. The results are evaluated considering effects of microscopic character of surface conditions, like numerous micronotches caused by the technology used, on fatigue initiation process, as well as effects of subsurface inclusions on fatigue crack initiation and early growth.