Manufacturing Process Parameters Research Articles

Simulation of the microstructure evolution during the extrusion of two industrial-scale AA6063 profiles

The microstructure of lightweight alloys is of a primary interest for manufacturing companies since it affects mechanical strength, crash, corrosion and esthetic properties. Numerical and experimental research activities are needed to investigate the relation between manufacturing process parameters and grain structure evolution in order to control the properties of the final component. In this context, aim of this work is the experimental investigation of the evolution of the microstructure in two different industrial-scale AA6063 aluminum alloy extruded profiles. Furthermore, a novel modeling of the AA6063 recrystallization behaviour is developed and implemented within the commercial FEM code Qform UK Extrusion®. The results of the numerical evaluations are then compared to the experimental data in order to assess the accuracy of the model. A good correlation between numerical predictions and experimental data is found for both profiles, thus proving the reliability of the proposed AA6063 recrystallization model.

A Complete System for the Autonomous Evaluation of Poly(alpha-methylstyrene) Mandrels

The success of inertial confinement fusion experiments hinges on the production of perfectly round spherical capsules placed at the center of an implosion. Some of the most common ablator materials are grown on poly(alpha-methylstyrene) (PAMS) mandrels. Human operator–based optical inspection of individual PAMS mandrels followed by a selection decision, is a labor-intensive process that suffers from operator dependence. General Atomics has developed a robotic system to handle and image these delicate PAMS mandrels and has implemented an autonomous method for evaluating shell quality. The selection criteria of acceptable mandrels has been standardized by employing visual defect characterization tools and associated machine learning algorithms. This work discusses the mechanical upgrades made to the robot cell for handling shells, the suite of software tools developed for a more complete evaluation of individual shells, and correlating defect statistics from entire batches to production data from the PAMS fabrication process parameters.

New figure of merit to compare josephson balanced comparators

The Josephson comparator, composed of two Josephson junctions in series, is the decision-making pair of the single flux quantum (SFQ) logic and also performs critical roles in superconducting analog-to-digital converter (ADC) as sampling elements. Its current resolution and speed determine the performance of these circuits. Balancing the inherent trade-off between the resolution and speed is an issue in optimizing a Josephson comparator. In this research, we propose the Normalized Speed Resolution Ratio (NSRR) to analyze the comprehensive performance of the Josephson comparator under various critical currents (Ic) and critical current densities (jc). Based on numerical simulations and results, we suggested an NSRR-based optimization criterion for the manufacturing process and design parameters of a Josephson comparator. Furthermore, a fitted value for the NSRR is determined by fitting our experimental data and the results of other research organizations. This reference value may be used to assess the complete performance of the Josephson comparator under different processes.

Material Quality Filter Model: Machine Learning Integrated with Expert Experience for Process Optimization

In the process of material production, the mismatch between raw material parameters and manufacturing processing parameters may lead to fluctuations in product properties and ultimately to unstable or unqualified product quality. In this paper, we propose the concept of the Quality Filter model for process optimization. The Quality Filter model uses the property prediction model as a surrogate model and integrates expert experience and process window constraints to construct a loss function. When raw material parameters are supplied, the suitable processing parameters can be automatically matched, and the processing fluctuation can be used to hedge the fluctuations in raw material, thus stabilizing the product quality and improving overall product properties. A trial production data set of 128 samples of wind power steel from a steel plant was used to test the model. We selected the ellipsoid discriminant analysis model with a classification accuracy rate of 82.81% as the surrogate model, which gives a highly interpretable visualization result. Finally, the results show that the properties of the samples that underwent the optimized process are improved.

Analysis of influence of process parameters in ultrasonic assisted jet electrochemical manufacturing

Analysis of influence of process parameters in ultrasonic assisted jet electrochemical manufacturing

Study on Process Parameters of Aluminium Alloy Oscillating Laser Double-wire Additive Manufacturing

To improve the deposition efficiency and forming quality of laser fuse additive manufacturing, this paper combines the advantages of oscillating laser and double-wire additive manufacturing to realize oscillating laser double-wire additive manufacturing. The feasibility of the scheme is verified through experiments, and a corresponding three-dimensional simulation model is established. Through the comparison of experiment and simulation, the forming fit is good and the accuracy of the model is verified. Finally, the forming effects under different laser oscillating frequencies and oscillating amplitudes are studied through the simulation model. The results show that the appropriate oscillating amplitude can preheat the substrate and improve wettability. The laser oscillating frequency is inversely proportional to the forming width, and a high oscillating frequency can improve the forming effect.

Al 6061hybrid metal matrix composites with SiC & Al2O3 using stir casting: A review

In this decade, alloy series as well as composites of Aluminum have become a better choice for fabrication of aluminium matrix composites which possess wide range of applications due to excellent material properties. Present study is emphasized on fabrication of Al6061 as matrix and Sic&Al2O3 as reinforcements by stir casting method and impact of these reinforcements on performance on Al MMC. Attention will be given to fabrication technique, process parameters and reinforcements and effect on mechanical properties of Al MMC. Recent research studies describe that the stir-casting method is majorly adopted technique for fabrication and fit for casting Aluminum based Hybrid MMCs. The recent studies showed that the tribological and mechanical properties of the composites get improved by increasing the reinforcement’s percentage. Further hybrid composites showed improved material characteristics as compared to single reinforcement composites. In Future, the studies can focus on the casting of Al 6061 hybrid composites by using stir casting and evaluation of mechanical properties. These composites can find extensive use in automobile and aerospace engineering applications.

Effects of process parameters and loading direction on the impact strength of additively manufactured 18%Ni-M350 maraging steel under dynamic impact loading

The microstructural and damage evolution of 18%Ni M350 maraging steel fabricated by laser-based directed energy deposition (DED) process under dynamic impact loading are investigated in this study. The influence of additive manufacturing (AM) processing parameters, including laser power, powder feed rate, and energy area density (EAD) are discussed. The mechanical testing of the additively manufactured alloy was done using the split Hopkinson pressure bar (SHPB) system. The dynamic impact test was conducted using strain rates ranging from 100 to 4000 s−1. The test was conducted on cylindrical specimens (7 mm diameter and 8 mm long) with axes parallel to the build direction (Z-axis) and perpendicular (X- and Y-axis) to the build direction to evaluate the effects of loading directions on mechanical responses and microstructural evolution in the alloy under the impact loading conditions. The test results revealed that the materials processed using the lowest EAD parameters exhibit the greatest impact strength under dynamic impact loading for all directions. Specimens impacted along the build direction (Z-axis) exhibit a continuous drop in peak flow stress once the strain rates exceeded 2300 s−1 indicating the greatest susceptibility to thermal softening at high strain rates. Strain localization leading to the formation of adiabatic shear bands (ASB) was observed in some specimens. Cracks developed along the ASBs, while some AM-process-related defects, such as the lack-of-fusion, interacted with adiabatic shear bands, promoting cracking inside the shear bands. Despite possessing the highest impact strength, the materials produced by the lowest EAD parameters are the most susceptible to the development of adiabatic shear bands leading to cracking and fracture.

Experimental investigation of the effect of skin-pass rolling reduction ratio on corrosion behaviors of AISI 304 stainless steel sheet materials

This study was carried out in order to reveal the effect of reduction ratio, one of the parameters of the skin-pass rolling manufacturing process of sheet metal materials, on the corrosion behaviours. In this experimental study, AISI 304 stainless steel sheet material samples were subjected to skin-pass rolling process with different reduction ratios (0.5%, 2.0%, 4.2% and 7.2%). The corrosion behaviours of skin-pass rolled AISI 304 stainless steel sheet material samples in 3.5% chloride solution was determined by potentiodynamic polarization curves. The changes in the surfaces were evaluated together with the surface roughness measurements and microstructure images. It was concluded that the increase in skin-pass rolling reduction ratio increased the corrosion resistance. The arithmetic mean roughness (Ra) did not give sufficient results to prove the finding that corrosion resistance improves as the reduction increases. The change of valleys and peaks in the roughness profile of the skin-pass rolled samples before and after corrosion was found to be evidence that the increase in reduction ratio improves corrosion resistance. As the skin-pass rolling reduction ratio increased was determined in the microstructural images that the amount of oxide layer increased and this situation was clarified from x-ray spectroscopy (EDS) findings. Electrochemical measurements, surface roughness profiles, microstructure images, and EDS analyses were obtained with results that support each other.

Hybrid manufacturing of mixed‐material bilayer parts via injection molding and material extrusion three‐dimensional printing

AbstractIn this paper, a hybrid manufacturing method combining the advantages of injection molding (IM) in terms of manufacturing efficiency and high precision with those of three‐dimensional printing (3DP) in terms of minimum waste and a high degree of freedom is described to produce mixed‐material bilayer tensile specimens. 3DP was first utilized to fabricate polylactic acid substrates with four varied geometries and two infill densities and an overmolding technique was employed to finish the manufacture using acrylonitrile butadiene styrene under two IM pressure. analysis of variance and scanning electron microscopy (SEM) were used to investigate the tensile properties and microstructures of the samples. The results showed that a greater tensile performance could be found in those specimens with greater infill density. Lower‐pressure overmolded specimens performed better than those with higher IM pressure. In addition, female joints outperformed male joints in the tensile performances of finished specimens. This study optimized the parameters for this hybrid manufacturing process for building mixed‐material parts and has potential applications in manufacturing, particularly manufacturing as a service.

A short review on SLM-processed Ti6Al4V composites

The advancements in computer-aided design, manufacturing, and additive manufacturing techniques attracted the researcher to apply various new methods with the unique combination of alloys and composites to design and develop complex parts. Among them the selective laser melting (SLM) process, a branch of additive manufacturing, and Ti6Al4V (Ti64) composite. Due to the better mechanical and corrosion resistance characteristics of Ti64 and its composites, they have been utilized for making various engineering parts related to jet engine fans of aero-engine, engine valves of automobiles, knee and hip joint endoprosthesis in the biomedical field, and corrosion resistance pipes in chemical industries. Also, more complex, net-shaped, and lattice-structured components can be fabricated by advancing the SLM process. The final quality of the parts manufactured from the SLM technique will depend on the fabrication process parameters followed. Many researchers have done research work on metal additive manufacturing by changing and optimizing the SLM process parameters such as laser power ( P), scanning speed ( v), hatch spacing ( d), and layer thickness ( h). Also, they have studied the effect of changes on the feedstock preparation, SLM process parameters, milling time of composite and post-heat treatment on the quality of Ti6Al4V composites. Therefore, a detailed review is needed to study the effect of the abovementioned parameters on the quality of metal additively manufactured parts through SLM. Hence, a short review is done on future challenges and opportunities of SLM-processed Ti6Al4V composites and reported in this article.

A modified approach on modeling-design-optimization procedure for cutting of pure titanium using wire electric discharge machining (WEDM)

The main goal of this study is to introduce a modified approach to the modeling-design-optimization triple procedure for cutting pure titanium. The manufacturing process is selected as wire electric discharge machining. To achieve a smooth cutting operation of the pure titanium plate (grade 2), the independent cutting parameters, peak current, pulse off time, pulse on time, spark gap voltage, wire feed, and wire tension are taken into consideration. Their effects on machining rate, surface roughness, dimensional deviation, and wire wear ratio are also examined. The mathematical model of the process is determined with the multiple nonlinear neuroregression approach. Stability study that measures the ability to realize the cutting parameters was conducted during the modeling phase. This type of step has not been used as a criterion for model determination before in modeling studies. Comparisons were accomplished with the traditional and nontraditional models, and it is shown that the nontraditional models’ accuracy was more reasonable. Besides, this study contains the design optimization of the manufacturing process parameters using modified version of different stochastic and derivative-free optimization methods: differential evaluation, random search, simulated annealing, and Nelder-Mead algorithm, (MDE, MRS, MSA and MNM) simultaneously.

A Review on Process Parameters of Additive Manufacturing

A Review on Process Parameters of Additive Manufacturing

Predictions of Additive Manufacturing Process Parameters and Molten Pool Dimensions with a Physics-Informed Deep Learning Model

Predictions of Additive Manufacturing Process Parameters and Molten Pool Dimensions with a Physics-Informed Deep Learning Model

Development of the Al12SiCuFe Alloy Foam Composites with ZrSiO4 Reinforcements at Different Foaming Temperatures

Lightweight aluminum composite is a class of foam material that finds many applications. These properties make it suitable for many industries, such as the transportation, aerospace and sports industries. In the present work, closed-cell foams of an Al-Si12CuFe alloy and its composite are developed by a stir casting process. The optimization of the foaming temperature for the alloy and composite foams was conducted in terms of the ligament and node size of the alloy and also the volatility of the zircon with the melt, to provide strength to the cell walls. CaCO3 as a blowing agent was homogeneously distributed in the molten metal without adding any thickener to develop the metal foam. The decomposition rate of CaCO3 is temperature-dependent, which is attributed to the formation of gas bubbles in the molten alloy. Cell structure, such as cell size and cell wall thickness, is controlled by manufacturing process parameters, and both the physical and mechanical properties are dependent on the foam cell structure, with cell size being the major variable. The results show that the increase in cell wall thickness with higher temperature leads to a decrease in cell size. By adding the zircon to the melt, the cell size of the composite foam first increases, and then the thickening of the wall occurs as the temperature is increased. The uniform distribution of the blowing agent in molten metal helps in the formation of a uniform cell structure. In this work, a comparative structural study of alloy foam and composite foam is presented regarding cell size, cell shape and foam stability at different temperatures.

The Characteristic Microstructures and Properties of Steel-Based Alloy via Additive Manufacturing

Differing from metal alloys produced by conventional techniques, metallic products prepared by additive manufacturing experience distinct solidification thermal histories and solid-state phase transformation processes, resulting in unique microstructures and superior performance. This review starts with commonly used additive manufacturing techniques in steel-based alloy and then some typical microstructures produced by metal additive manufacturing technologies with different components and processes are summarized, including porosity, dislocation cells, dendrite structures, residual stress, element segregation, etc. The characteristic microstructures may exert a significant influence on the properties of additively manufactured products, and thus it is important to tune the components and additive manufacturing process parameters to achieve the desired microstructures. Finally, the future development and prospects of additive manufacturing technology in steel are discussed.

Experimental investigation on 3D printed lightweight sandwich structures for energy absorption aerospace applications

One of the ongoing challenges in aeronautics is the development of increasingly lighter structures. This has become a crucial goal because structural lightening means improving aircraft performance in terms of speed, manoeuvrability, fuel efficiency, and at the same time reducing manufacturing and service costs. The aerospace industry continues to focus more and more on this goal and every improvement in technology and materials can bring significant advantages in performance, efficiency, and safety of aircraft. The present work is part of this framework, as it analyses the feasibility of achieving very high weight reduction in sandwich panels using a new manufacturing approach. It introduces an experimental limited sensitivity analysis on the mechanical responses of composite sandwich structures for shock-absorption applications lightened by appropriately setting a specific additive manufacturing process parameter: the infill value. The investigated sandwich structures are characterised by a core Designed for Additive Manufacturing (DfAM) in order to maximise their performance in terms of energy-to-weight ratio and damping of impact loads. The material chosen for the inner part of the sandwich structure (core and internal face sheets) is polypropylene (PP) while the external face sheets are in Carbon Fibre Reinforced Polymers (CFRP).By comparing the post-impact responses at 20 J impact of three sandwich configurations with the same external shape but different material layer densities related to different setting of the infill parameter in the frame of the printing process, the work proves that this approach leads to lightening of this specific sandwich structures by up to 28% and at the same time improves their structural effectiveness in terms of energy absorption characteristics.The comparison was made by relating specific absorption indices, force-time and force-displacement graphs and CT scans.

Enhancing Mechanical Properties of 3D Printing Metallic Lattice Structure Inspired by Bambusa Emeiensis.

Metallic additive manufacturing process parameters, such as inclination angle and minimum radius, impose constraints on the printable lattice cell configurations in complex components. As a result, their mechanical properties are usually lower than their design values. Meanwhile, due to unavoidable process constraints (e.g., additional support structure), engineering structures filled with various lattice cells usually fail to be printed or cannot achieve the designed mechanical performances. Optimizing the cell configuration and printing process are effective ways to solve these problems, but this is becoming more and more difficult and costly with the increasing demand for properties. Therefore, it is very important to redesign the existing printable lattice structures to improve their mechanical properties. In this paper, inspired by the macro- and meso-structures of bamboo, a bionic lattice structure was partitioned, and the cell rod had a radius gradient, similar to the macro-scale bamboo joint and meso-scale bamboo tube, respectively. Experimental and simulated results showed that this design can significantly enhance the mechanical properties without adding mass and changing the printable cell configuration. Finally, the compression and shear properties of the Bambusa-lattice structure were analyzed. Compared with the original scheme, the bamboo lattice structure design can improve the strength by 1.51 times (β=1.5). This proposed strategy offers an effective pathway to manipulate the mechanical properties of lattice structures simultaneously, which is useful for practical applications.

Analysis of Ancient Slag Inclusion-Metal Systems as a Method to Disclose Processing Thermo-chemical Parameters: The Case Study of a Medieval Lombard Steel Bar from Northern Italy

An archaeometallurgical characterization of a VI to VII century Lombard steel bar from Ponte di Val Gabbia I site (northern Italy) was performed to reconstruct its manufacturing process and extract processing thermochemical parameters (i.e., temperature and oxygen chemical potential) from the slag inclusion-metal systems. Metallographic observations by optical microscopy and Vickers microhardness measurements indicated that the steel bar was forged from a heterogeneous steel lump, most probably an iron bloom, which was cooled in the air after the forging process. The chemical composition of non-metallic inclusions was determined by scanning electron microscopy coupled with X-ray dispersive spectroscopy. A multivariate statistical analysis of the smelting-derived non-metallic inclusions chemistry allowed to conclude that the steel bar was obtained by the direct or bloomery method. Under the hypothesis of local near-equilibrium conditions for the slag inclusion-metal systems, a thermodynamic-based strategy was adopted to estimate the firing conditions in the bloomery furnace in terms of both temperature and oxygen chemical potential of the reducing gas atmosphere. In particular, the computed temperatures are in the range of 1003 °C to 1171 °C, whereas the values of oxygen chemical potential vary between − 447.47 and − 385.79 kJ/mol.

Current Achievements in Flexible Piezoelectric Nanogenerators Based on Barium Titanate

Harvesting ambient mechanical energy at the nanometric scale holds great promise for powering small electronics and achieving self-powered electronic devices. The current review is focused on kinetic energy harvesters, particularly on flexible piezoelectric nanogenerators (p-NGs) based on barium titanate (BaTiO3) nanomaterials. p-NGs based on nanotubes, nanowires, nanofibres, nanoplatelets, nanocubes or nanoparticles of BaTiO3 fabricated in vertical or lateral orientation, as well as mixed composite structures, are overviewed here. The achievable power output level is shown to depend on the fabrication method, processing parameters and potential application conditions. Therefore, the most widely studied aspects, such as influence of geometry/orientation, BaTiO3 content, poling process and other factors in the output performance of p-NGs, are discussed. The current standing of BaTiO3-based p-NGs as possible candidates for various applications is summarized, and the issues that need to be addressed for realization of practical piezoelectric energy harvesting devices are discussed.