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Wire Arc Additive Manufacturing (WAAM) is a widely adopted method for functional part production. This study delves into substrate deformation during WAAM deposition, revealing that lower plate thickness leads to increased Z-direction deformation due to reduced internal resistance against thermal residual stress. Experiments and simulations on 6 mm, 8 mm, and 10 mm substrates confirm that thicker substrates exhibit lower deformation, especially 10 mm ones. Consistency between experimental and simulation results validates our findings. The study analyzed the deformation resulting from dual-sided deposition on a 10 mm substrate. Simulation indicated minimal deformation, measuring 0.02 mm (compared to 0.17 mm from single-side deposition), while experimental results showed 0.13 mm deformation (compared to 0.28 mm from single-side deposition). This demonstrates its effectiveness in minimizing deformation by neutralizing residual stress effects on both sides of substrate. A case study demonstrated sacrificial material deposition on one side of the substrate, achieving symmetrical geometry that countered residual stress. This research contributes valuable insights for material deposition and processing, emphasizing the role of substrate thickness and the potential of dual-sided deposition for deformation control. [ABSTRACT FROM AUTHOR]

The problem of improving the quality of metal materials during additive manufacturing of workpieces is a relevant one. Additive technologies based on melting the starting material face a number of problems related to controlling the quality of the created material, which are primarily associated with overheating of the material in the working area and non-stationary thermal conditions during formation of the product. The possibility of creating monolithic metal products of significant size and weight with specified material characteristics by the method of layer-by-layer plasma metallization is currently effectively unexplored. The defect rate, chemical composition, structure, and properties of the material formed by plasma metallization are determined by thermochemical and gas-kinetic processes at all stages—from melting and wire spaying to the collision of particles on the substrate and the formation of the monolith. Development of a technology for the formation of a monolithic, defect-free material with a controlled chemical composition, structure, and properties by layer-by-layer plasma metallization would solve the problem of manufacturing large-sized products with a developed surface, ensure high process productivity, and reduce residual internal stresses and plastic deformations during additive manufacturing of special-purpose products. This article presents the results of a study of the possibility of additive manufacturing of workpieces by layer-by-layer plasma metallization from 308 LSi steel. It is shown that control over the structure and properties of the formed material can be achieved. Provided certain conditions for the formation of the two-phase plasma jet are fulfilled, it is possible to ensure that the structure and properties of the resulting material are close to those obtained by traditional methods. Metal created by layer-by-layer plasma metallization has high tensile and creep strengths, but is inferior in terms of ductility. [ABSTRACT FROM AUTHOR]

Improving the quality of metals in additive manufacturing is of great interest currently. To date, there has been almost no research on the creation of monolithic workpieces by layer-by-layer plasma metallization. The present study shows that a uniform distribution of molten material over the workpiece surface may be obtained. A model is proposed for drop formation and separation in different plasmatron configurations. [ABSTRACT FROM AUTHOR]

Rapid casting (RC) is a phrase that refers to a specific casting process technique that reduces total production lead time. The technique for achieving it is Additive Manufacturing (AM) or Rapid Prototyping (RP). AM techniques were employed for RC to create complex shapes and sand a 3D mould from a CAD model. This article aimed to examine the performance of Rapid Ice Investment Casting (RIIC) compared with other RC processes such as Direct Wax Investment Casting (Direct Wax IC), Lost Foam Casting (LFC), Lost PLA Casting (LPC), and Rapid Sand Casting (RSC). This investigation examines the part which has various geometric features. Each casting route's procedure is described in detail; pattern development, slurry preparation and mould making. Comparison of RIIC with other RC processes is studied based on the cast specimen's dimensional accuracy and surface finish. According to the findings, RIIC is preferable in terms of smooth surface finish, whereas Direct Wax IC and LFC are superior in dimensional accuracy. The article also addresses, the shortcomings of RIIC are discussed in this article, as well as proposed methods to overcome them. [ABSTRACT FROM AUTHOR]

Metal quality must be improved in the additive production of workpieces. Monolithic workpieces of considerable size and mass with specified characteristics may be produced by layer-by-layer application of metal layers on the basis of plasma spraying. However, practically no research has been devoted to this topic. To create high-quality metal layers by this means, the metal particles must be as uniform as possible in terms of shape, size, velocity, and temperature. Satisfactory transfer of material also requires uniform parameters of the two-phase jet over the cross section. It is established that plasmatrons with a series of vortex chambers may be used to create two-phase jets with parameters specified over the cross section and hence to ensure controllable transfer of material from the disintegrating wire. Ensuring that the metal particles are uniform in size and shape, with a transfer coefficient of 0.95–0.97, is a precondition for the use of layer-by-layer plasma spraying in the additive production of metal workpieces. [ABSTRACT FROM AUTHOR]

In the present era, polystyrene foam is widely used in foundries for pattern making. Industries extensively use the steam molding routes for polystyrene foam pattern making. However, the molding method cannot produce complex geometries. Industries are using the machining route for pattern making to overcome these limitations. There is limited research carried out on expanded polystyrene foam machining. Patterns need smooth surfaces with minimum surface roughness to make good quality castings. Therefore, there is a need to predict the surface roughness and its affecting parameters for polystyrene foam machining. The present article discusses a new theory for foam machining. The preliminary experiments identified two cutting mechanisms, mechanism I (through bead cutting) and mechanism II (bead removal). A novel mathematical model for the surface roughness has been developed and experimentally validated. A close correlation between the predicted and experimental values of average surface roughness (Ra) is observed with an average error of 19.70%. The correlation analysis shows a 93.07% correlation between the predicted and experimental values. The proposed mathematical model has been segregated into two parts because of through bead cutting and bead removal. Observation shows, the model part due to bead removal contributes significantly more (approximately 90% for all experiments) to the surface roughness. Therefore, surface roughness can be improved by minimizing or avoiding bead removal. [ABSTRACT FROM AUTHOR]

The production of metal laminates from 308 Lsi and 30ХГСА steel by twin-arc surfacing is considered. Two walls are produced: one by twin-arc surfacing with a specific ratio of the materials; the other by alternating layers of each material. The products are subjected to chemical analysis and mechanical testing. [ABSTRACT FROM AUTHOR]

Build orientation is one of the most important process planning tasks in additive manufacturing (AM) since it directly affects the part quality, build time, cost etc. Many researchers have investigated the orientation optimization problem and proposed numerous solutions. However, former researches only focused on how to find an optimal orientation for one part, but none of the solutions was provided to solve the orientation optimization problem of Multi-part production, where a group of parts in the same build vat or chamber should be optimally-orientated simultaneously. This paper introduces a two-step solution to solve the problem. At first, a feature based method is used to generate a set of finite optimal alternative orientations for each part within a given part group to guarantee each part's individual build quality; then an improved genetic algorithm is applied to search for an optimal combination of part build orientations to minimize the total build time and cost at a global optimal level. A case study of orientating 16 parts simultaneously within a given build chamber is presented for demonstration. [ABSTRACT FROM AUTHOR]

An octree-based (numerical control) NC simulation (Oct-OAC) system developed for end milling has two major applications: (1) NC verification and (2) optimization of the cutting parameters, viz., spindle speed, N (s−1), and feed rate, f (ms−1). Oct-OAC has a geometric modeling module to simulate the geometry of material removal process. Every object in the machining environment such as cutter, instantaneous workpiece, swept volume, etc. is stored as octree, an inexact representation of solid. Using this module, one can predict the geometry of the material removed at any instant of time and update the geometry of the blank subsequently. Optimization of cutting parameters using Oct-OAC is achieved through optimization module using a mechanistic model for computation and prediction of the cutting forces at any instant. The basic input for this module is the geometry of the contact surface between the cutter and workpiece which comes from the geometric modeling module using an octree-based solid modeler. It is through this contact surface that the cutting forces are passed from the workpiece onto the cutter and vice versa. The mechanistic modeling module can predict the instantaneous cutting forces from the instantaneous contact geometry and other process parameters like material combination of cutter–workpiece, parameters defining cutter geometry, and current cutting parameters such as N and f. Using this prediction, it will modify the cutting parameters for maximizing the material removal rate. This way, the mechanistic modeling module does what an adaptive controller will do with the help of force sensing. Therefore, the NC program optimization done using the Oct-OAC system is actually off-line adaptive control. [ABSTRACT FROM AUTHOR]

Subtractive manufacturing [computer numerical controlled (CNC) machining] has high quality geometric and material properties but is slow, costly, and infeasible in some cases. On the contrary additive manufacturing (rapid prototyping) has total automation but compromises quality. A hybrid layered manufacturing process presented in this study combines the best features of both these approaches. It uses arc weld deposition for building near-net shapes, which are subsequently finish machined. Time and cost savings of this process can be attributed to reduction in NC programming effort and elimination of rough machining. It is envisioned as a low cost retrofitment to any existing CNC machine for making metallic objects without disturbing its original functionalities. Near-net shape building and finish machining happening at the same station is the unique feature of this process. A customized software generates the NC program for near-net shape building. The intricate details of integrating arc welding unit with a CNC milling machine are presented in this paper. [ABSTRACT FROM AUTHOR]

User-friendliness such as ease of creation and modification and system-friendliness such as space and time complexities, accuracy etc. are two important criteria for the selection of a solid representation scheme. No single solid representation scheme fully meets all the requirements of user-friendliness and system-friendliness. Hence, any practical CAD/CAM system maintains the geometry of the objects in more than one solid representation scheme simultaneously. Therefore, it is often required to convert one solid representation scheme to the other. The authors have developed a volumetric NC simulation system in which the instantaneous blank is represented as an octree as its space and time complexities are independent of the number of NC blocks. However, since octree does not lend itself readily for operations such as arbitrary transformations, rendered display etc., it is not directly usable for downstream applications such as animated display, verification and optimization. Boundary representation is suitable for these downstream applications. Therefore, it is required to convert octree of the instantaneous blank into BRep. An efficient algorithm for this conversion is presented in this paper. This algorithm essentially splits the octree into three quadtrees that store the geometry along the three principal directions. This algorithm is fast as it involves only tree-traversals. [ABSTRACT FROM AUTHOR]

The kinetics of ruthenium(III)-catalyzed oxidation of several arylthioacetic acids by Ce(IV) have been studied. The proposed mechanism involves the formation of a 1∶1 complex between Ru(III) and arylthioacetic acid, which then reacts with Ce(IV). [ABSTRACT FROM AUTHOR]

Anamolous Course of Carotid Artery is one of the rarest of the rare anamoly, we describe one such case of anamolous Course of Right Common Carotid Artery. [ABSTRACT FROM AUTHOR]

Tuberculosis (TB) abdomen presenting as gluteal abscess is very rare and difficult to diagnose in the absence of high index of suspicion; ruling out the possibilities of other diagnosis by means of suitable investigations is the only way to arrive at this diagnosis in an immuno-competent patient. We report an interesting case of TB abdomen presenting as gluteal abscess in a 27-year-old young female patient, who is otherwise hale and healthy. [ABSTRACT FROM AUTHOR]

Investment Casting (IC), using the wax pattern, produces metal parts with a high surface finish and complex geometries within acceptable tolerances. However, removing the wax patterns can have processing challenges, such as thermal expansion during wax melting for pattern removal leading to shell cracking defects, the release of hydrocarbons from melting wax, and the burnt residue from this process. To overcome these challenges, it has been proposed to replace wax with ice as a pattern material. Ice has an inherent benefit of reduction of volume during its phase change from solid to liquid. It helps to reduce cracking due to expansion. Rapid Freeze Prototyping (RFP) and Freeze Cast Process (FCP) can produce the ice pattern. In the process of Rapid Ice Investment Casting (RIIC), the ice pattern is invested with a low-temperature ceramic slurry to make ceramic shells for metal casting. Sublimation is used for ice pattern evacuation at sub-zero conditions using a vacuum. Estimating various properties like time for total sublimation, concentration gradient, and energy usage are vital for process characterization and optimization. A diffusion-based mathematical model has been proposed and experimentally verified to sublimate the ice patterns in this research. Experimental results show a close correlation (96.74%) with the theoretical model. The demonstration of ice investment casting has been carried out, and it reported close dimensional accuracy. [ABSTRACT FROM AUTHOR]