Search results for "Process"
showing 10 items of 22310 documents
A comparative assessment of energy demand and life cycle costs for additive- and subtractive-based manufacturing approaches
2020
Abstract The applicability domain of Additive Manufacturing (AM) processes, apart from technological and quality results, relies on environmental and cost performance. These aspects still need to be better understood. To this aim, comparative analyses with conventional manufacturing routes are needed. In this paper, empirical cost and energy requirement models are suggested to assess subtractive- (machining) and additive- (Electron Beam Melting) based manufacturing approaches for the production of Ti-6Al-4V components. A life-cycle perspective is adopted, and all the steps from the input material production to the post-AM processing operations and the use phase are included. The analyses ha…
An Additive Model to Predict the Rheological and Mechanical Properties of Polypropylene Blends Made by Virgin and Reprocessed Components
2021
In this work, an additive model for the prediction of the rheological and mechanical properties of monopolymer blends made by virgin and reprocessed components is proposed. A polypropylene sample has been reprocessed more times in an extruder and monopolymer blends have been prepared by simulating an industrial process. The scraps are exposed to regrinding and are melt reprocessed before mixing with the virgin polymer. The reprocessed polymer is, then, subjected to some thermomechanical degradation. Rheological and mechanical experimental data have been compared with the theoretical predictions. The results obtained showed that the values of this simple additive model are a very good fit fo…
Numerical Study about the Influence of Wall Angle about Main Strains, Thickness Reduction and Forces on Single Point Incremental Forming Process
2016
Abstract The current paper aims to study, using numerical simulation, the influence of the wall angle on the single point incremental forming process. For the analysis there has been used the LS-Dyna software and three explicit dynamic analyses were run for three parts with wall angles of 450, 550 and 650. The factors taken into account are the main strains, the thickness reduction and the forces on three directions. The material data introduced into the simulation were determined based on an uniaxial traction test on an Instron 5587 testing machine and the Aramis system was used as optical extensometer.
The use of exploratory experimental designs combined with thermal numerical modelling to obtain a predictive tool for hybrid laser/MIG welding and co…
2011
Abstract While hybrid laser welding and coating processes involve a large number of physical phenomena, it is currently impossible to predict, for a given set of influencing factors, the shape of the molten zone and the history of temperature fields inside the parts. This remains true for complex processes, such as the hybrid laser/MIG welding process, which consists in combining a laser beam with a MIG torch. The gains obtained result essentially from the synergy of the associated processes: the stability of the process, the quality of the seam realized, and the productivity are increased. This article shows how, by means of a reduced number of experiments (8), it is possible to predict th…
Effect of active heating and cooling on microstructure and mechanical properties of friction stir–welded dissimilar aluminium alloy and titanium butt…
2019
A butt joint configuration of AA6061–pure Ti was welded using friction stir welding (FSW) with an assisted cooling and heating conditions, aiming to attain a flawless joint. Cooling-assisted friction stir welding (CFSW) was carried out with a different cooling medium such as CO2, compressed air and water at controlled flow rate. However, heating-assisted friction stir welding (HFSW) was performed with heating source of GTAW torch just before FSW tool at different current density. Prepared specimens were subjected to optical microscopy (OM), scanning electron microscopy (SEM) and electrodischarge spectroscopy (EDS) for microstructural characterizations. The tensile strength and microhardness…
Residual stress measurement in innovative friction stir welding processes
2017
In recent years, important innovations have been introduced in Friction Stir Welding (FSW) technology such as, for example, the Laser assisted Friction Stir Welding (LFSW) and in-process Cooled Friction Stir Welding (CFSW). Residual stresses have a fundamental role in welded structures because they affect the way to design the structures, fatigue life, corrosion resistance and many other material properties. Consequently, it is important to investigate the residual stress distribution in FSW where, though the heat input is lower compared to traditional welding techniques, the constraints applied to the parts to weld are more severe. The aim of the present work is to verify the capabilities …
A new approach to simulate coating thickness in cold spray
2020
Abstract In the process of cold spray on complex components, the coating thickness is an important indicator to monitor and control. Current methods such as destructive tests or direct mechanical measurements can only be performed after spraying. Besides, these methods lead to production shutdown and additional costs . This article presents a novel approach predicting coating thickness for components with complex curved surfaces, especially in the case of shadow effects. Firstly, a three-dimensional geometric model of the coating profile based on Gaussian distribution was developed. In addition, the relative deposition efficiency (RDE) resulting from the different robot kinematic parameters…
High-temperature in-process inspection followed by 96-h robotic inspection of intentionally manufactured hydrogen crack in multi-pass robotic welding
2021
Abstract This investigation introduces two new techniques to quantitatively address the challenging problem of understanding Hydrogen Induced Cracking (HIC) in welding processes. The first technique is a novel procedure to create a known and controlled HIC in a welded sample. The second is an in-process monitoring technique to measure the initial formation and subsequent growth of the HIC in a multi-pass weld whilst being compatible with the high temperatures associated with the welding process. The HIC was initiated using a localised quenching method of the weld and its character was verified using both macrograph and microscopic investigations. During HIC initiation and growth, the sample…
Considerations Regarding the Industrial Implementation of Incremental Forming Process
2019
Incremental forming is a promising manufacturing process which allow the user to obtain sheet metal parts, in a flexible manner, without the use of a die. However, the industry is still reluctant to apply the process on an industrial scale. Several drawbacks of the process which hinder its industrial implementation are reviewed in the paper. Among them, the low accuracy of the parts and the low productivity of the process are considered. The lack of dedicated technological equipment and specific CAM software tools are also seen as major drawbacks. Moreover, the lack of any analytical tools to predict the plastic behaviour of the processed part and to predict the moment when it loses its int…
Influence of Process Parameters on the Product Integrity in Friction Stir Extrusion of Magnesium Alloys
2016
Friction Stir Extrusion is an innovative direct-recycling technology for metal machining chips. During the process a specifically designed rotating tool is plunged into a cylindrical matrix containing the scraps to be recycled. The stirring action of the tool prompts solid bonding related phenomena allowing the back extrusion of a full dense rod. This process results to be particularly relevant because allows the reuse of the scrap without any previous treatment. Experiments have been carried out in order to investigate the influence of the process parameters on the extrudes quality and a numerical model has been developed in order to simulate the evolution of the material flow.