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Directed energy deposition (DED) process is recognized as an alternative technology to produce the complex-shape AISI 316L components. The critical production step in this technology is the optimization of process parameters that can directly affect the final properties of the components. To optimize the process parameters, the residual defects of specimens produced with different combinations of process parameters are evaluated, and the optimum condition is chosen. Therefore, the residual defects assessment is a vital step in finding the optimum process parameters; therefore, this evaluation should be carried out carefully. One of the main issues in the production of AISI 316L by DED process is oxidation during the process that should be considered besides the other defects such as porosity and cracks. However, the identification between the oxides and porosities is not an easy task, and so this study aims to provide more clear insight into the evaluation of pores and oxides in DED 316L samples. The outcomes of this work show that at the best process parameters suitable for a porosity-free sample, there are some oxides that can be misinterpreted as porosity and consequently deteriorate the mechanical properties of the dense sample.

Background: Cross-sectional measures of body mass index (BMI) are associated with cardiovascular disease (CVD) incidence, but less is known about whether weight change affects the risk of CVD. Methods: We estimated the effect of 2-y weight change interventions on 7-y risk of CVD (CVD death, myocardial infarction, stroke, hospitalization from coronary heart disease, and heart failure) by emulating hypothetical interventions using electronic health records. We identified 138,567 individuals with 45-69 years of age without chronic disease in England from 1998 to 2016. We performed pooled logistic regression, using inverse-probability weighting to adjust for baseline and time-varying confounders. We categorized each individual into a weight loss, maintenance, or gain group. Results: Among those of normal weight, both weight loss [risk difference (RD) vs. weight maintenance = 1.5% (0.3% to 3.0%)] and gain [RD = 1.3% (0.5% to 2.2%)] were associated with increased risk for CVD compared with weight maintenance. Among overweight individuals, we observed moderately higher risk of CVD in both the weight loss [RD = 0.7% (-0.2% to 1.7%)] and the weight gain group [RD = 0.7% (-0.1% to 1.7%)], compared with maintenance. In the obese, those losing weight showed lower risk of coronary heart disease [RD = -1.4% (-2.4% to -0.6%)] but not of stroke. When we assumed that chronic disease occurred 1-3 years before the recorded date, estimates for weight loss and gain were attenuated among overweight individuals; estimates for loss were lower among obese individuals. Conclusion: Among individuals with obesity, the weight-loss group had a lower risk of coronary heart disease but not of stroke. Weight gain was associated with increased risk of CVD across BMI groups. See video abstract at, .

Despite the extensive capabilities of Laser-Powder Directed Energy Deposition (LP-DED), compared to other metal additive manufacturing processes, the use of LP-DED in industry is still limited as a result of the limited knowledge on the relationships between the process parameters and mechanical behaviour. In this work, the quality of AISI 316L samples, produced by means of LP-DED and evaluated in terms of surface roughness, residual stresses and microstructure, is linked to the scanning strategy. The outcomes confirm that the deposition strategy plays a key role in the definition of the final properties of specimens.

In this work, 316L cubes were produced by Directed Energy Deposition (DED) process. To evaluate the effect of deposition patterns on the microstructure, mechanical performance and residual stress of 316L samples, two different deposition strategies are selected (67° and 90°). The general microstructure is revealed, and then the effect of deposition pattern on the microstructure of 316L alloy is evaluated through the Primary Cellular Arm Spacing (PCAS) analysis. The cooling rate in each sample is estimated according to the PCAS values. Interestingly, it is found that by increasing the rotation angle per layer, the PCAS value decreases as a consequence of increment in the cooling rate. On the other hand, in both cases, by increasing the distance from the substrate, due to the changes in cooling mechanisms, the cooling rate at first decreases and then at the last layers increases again. The phase composition analysis of 316L samples confirms the predictions that suggested the presence of residual δ-ferrite in the final microstructure. In fact, the final microstructure of samples is characterized by austenitic dendrites together with some residual δ-ferrite in the interdendritic regions. Moreover, the microstructural evaluations exhibit that during the DED process, some metallic inclusions are formed within the 316L samples that consequently deteriorates their mechanical properties. Tensile results show that the samples with 90° rotation per layer have a better mechanical performance such as slightly higher ultimate tensile strength and almost 35% higher elongation to fracture, mainly owing to their finer microstructure and slightly less oxide content. However, in both cases, the elongation of the 316L samples is lower than the typical elongation of this material produced via DED. This discrepancy is found to be as a result of higher inclusions contents in the samples produced in this work with respect to those of literature. Lastly, it is found that the residual stresses on the top surfaces are similar for both deposition patterns, although higher stress values are observed on the lateral surfaces of the cubes produce using the 90° rotation per layer.

This work deals with Directed Energy Deposition (DED) that is a process in which the material is delivered directly into the melt pool. Several kinds of nozzle have been developed and used ...

We describe an analysis system for some of the most important methods of metal welding, based on the acquisition, study and comparison of the atomic emission spectra (in the range from 250 nm to 830 nm), hyperspectral imaging between 600 nm and 950 nm wavelengths and microstructural analysis. The radiometric measurement system acquires information while the welding process is in progress and acquired data are then compared with those resulting from the subsequent microstructural analysis. It is known that the process parameters like, for example, the source power or its speed over the parts during welding, significantly affect the mechanical properties and quality of the resulting junction like hardness, porosity, presence of cracks or other damages and so on. On the other hand, these properties and, above all, the changes in the joint features due to unwanted variations in the process parameters or in the materials being welded, can be inferred by studying the microstructure. In this sense, a proper correlation between the in situ spectral analysis and the microstructural properties is of paramount importance for controlling and adjusting the parameters during the process. In line with the requirements of Industry 4.0, the system described is a study of the application of metrology in a production line, designed to increase information about the production parameters of mechanical industry without increasing costs and limiting the complexity of additional installations. In this paper we report a series of experiments performed using LASER and TIG welding systems applied to different metals. The comparison between the welding conditions acquired by the optical systems and the methods of structural analysis are the basis of a project to improve production systems and their automation.

Project FreeWheel “Lifecycle-reconfigurable Smart Mobility Platform to enable autonomous and cost-effective personalized solutions for social inclusion of disabled and elderly while leveraging AM technologies” (Grant Agreement number 768908) is a four year project started on October the 1st 2017. The project has the main objectives of: Promoting social inclusion of disabled and elderly by developing a smart mobility platform based on a reconfigurable autonomous unit to ease individual mobility in urban environment. Satisfying the need of customization both for the disabled and for the unit by implementing a modular reconfigurable concept based on standard low-cost modules and on ultra-customized interfaces to be produced by additive manufacturing. Making affordable the lifecycle cost of the above-mentioned mobility service/product by implementing an innovative business model. The project is structured in nine work packages This report focuses on the activities already undertaken within work package (WP) 2 identifying the main results achieved and transferred to the whole project; it also documents the activities started in WP3 on FreeWheel product design and in WP9 on communication, dissemination and exploitation. A short description of activities expected within the next year for the WPs active or to be initiated is also provided.

This document reports briefly on the overall progress progress of project FreeWheel at month 6, specifying also technical, administrative and financial progress.

Directed Energy Deposition (DED), which is an additive manufacturing technique, involves the creation of a molten pool with a laser beam where metal powder is injected as particles. In general, this technique is employed to either fabricate or repair different components. In this technique, the final characteristics are affected by many factors. Indeed, one of the main tasks in building components by DED is the optimization of process parameters (such as laser power, laser speed, focus, etc.) which is usually carried out through an extensive experimental investigation. However, this sort of experiment is extremely lengthy and costly. Thus, in order to accelerate the optimization process, an investigation was conducted to develop a method based on the melt pool characterizations. In fact, in these experiments, single tracks of Ti-6Al-4V were deposited by a DED process with multiple combinations of laser power and laser speed. Surface morphology and dimensions of single tracks were analyzed, and geometrical characteristics of melt pools were evaluated after polishing and etching the cross-sections. Helpful information regarding the selection of optimal process parameters can be achieved by examining the melt pool features. These experiments are being extended to characterize the larger blocks with multiple layers. Indeed, this manuscript describes how it would be possible to quickly determine the layer thickness for the massive deposition, and avoid over or under-deposition according to the calculated energy density of the optimum parameters. Apart from the over or under-deposition, time and materials saving are the other great advantages of this approach in which the deposition of multilayer components can be started without any parameter optimization in terms of layer thickness.

In order to improve the process efficiency of a direct energy deposition (DED) system, closed loop control systems can be considered for monitoring the deposition and melting processes and adjusting the process parameters in real-time. In this paper, the monitoring of a new deposition nozzle solution for DED systems is approached through a simulation-experimental comparison. The shape of the powder flow at the exit of the nozzle outlet and the spread of the powder particles on the deposition plane are analyzed through 2D images of the powder flow obtained by monitoring the powder depositions with a high-speed camera. These experimental results are then compared with data obtained through a Computational Fluid Dynamics model. Preliminary tests are carried out by varying powder, carrier, and shielding mass flow, demonstrating that the last parameter has a significant influence on the powder distribution and powder flow geometry.

To achieve a green label, white'R island must fulfil a number of crucial criteria related to production methods, materials, recycling and energy efficiency. The environmental assessment of the product must be undertaken considering its entire life cycle, providing certifiable and not misleading results of its environmental sustainability. The WEATool is basically a simple database in form of MS excel spreadsheet able to collect different kind of information and elaborate it to produce the environmental data required.

In order to certify the positive environmental impact emerging from white’R results, a procedure to apply for a Green Labelling was defined and applied (ISO14020 Environmental Labels and Declarations—General Principles: http://www.iso.org/iso/catalogue_detail?csnumber=34425, [1]): Product Description for white’R Island white’R island lifecycle description Preliminary prediction of white’R KPIs Choice between mono/multi criteria and third party/self-certificate Eco label Assessment of white’R KPIs Scenario selection and white’R island optimization to maximise KPIs Certification of environmental performance Achievement of white’R Green Label At this stage of the project, the first 4 steps of white’R green labelling methodology have been progressed and type III environmental declaration was chosen. At the end of the project, it will be possible facing a Life Cycle Assessment to achieve an Environmental Product Declaration (EPD) (http://www.environdec.com/, [2]) To that purpose, all the data necessary for the achievement of an EPD are being collected/calculated and a first draft of the EPD document is being progressed.

The purpose of the analysis is to identify the main variables that affect the production efficiency of the white’R island. In order to provide a detailed framework of the machine performances, a life cycle assessment study was undertaken, by collecting relevant information within a tool, in the form of MS Excel spreadsheet, properly developed and named White’R Energy Assessor Tool (WEATool) and thus handled to calculate a preliminary estimation of the energy consumption of the machine. The WEATool defines the white’R performance using a list of KPIs, very significant parameters that examine the economic, energy and environmental features of the island. The WEATool can be used during the design phase to provide a preliminary evaluation of the environmental impact; during the production planning such as a decision making tool to reduce the energy consumption and the production costs; and finally, during the demonstration phase to collect the data of the measurement campaign.

In new vehicles development weight reduction is one of the most important driving force often conflicting with other missions which would require additional mass (crashworthiness, comfort, etc). The use of HSS, especially new grades with very high strength and good formability is the most competitive way to reduce weight. Nevertheless some limitations come from manufacturing HSS: springback, residual stresses, weldability should be taken into account in product development in order to avoid an expensive set up phase in the press shop and in the body shop. This paper focus on the recent experience achieved by Fiat in introducing HSS up to reach a share higher than 60% in weight applying and developing new methodologies to solve in the design phase any criticality arising from the use of this material.

In order to certify the positive environmental impact emerging from white'R results, a procedure to apply a specific Green Label was defined.

Thanks to the recent affirmation of the active fiber lasers, remote laser welding of zinc coated steels is under investigation with a particular emphasis on the overlap joint geometry. Due to the high power and high beam quality offered by these lasers, the remote laser welding process has become more practicable. However laser welding of lap zinc coated steels is still problematic because of the violent vaporisation of zinc. The presence of a gap between the plates allowing vapour degassing has been proven to avoid defects due to zinc vaporization. On the other hand variation in the gap value can lead to the welding defect formation. Therefore constant gap values should be ensured and deviation from the reference gap value has to be monitored during the execution of the welding process. Furthermore, the on-line monitoring of the gap values between the plates can be helpful for the on-line quality control of the welding process. The paper proposes a new monitoring solution for the measurement of the gap in remote fiber laser welding of overlapped zinc coated steels. In this solution, referred as Through the Optical Combiner Monitoring (TOCM) , the optical emissions from the welding process are directly observed through the optical combiner of the fiber laser source with spectroscopic equipment. The TOCM solution presented in the paper is integrated in an IPG YLS 3000 fiber laser source whose beam is deflected and focused by means of an El.En. ScanFiber scanning system with an equivalent focal length of 300 mm. After the definition of the right welding process conditions, spectroscopic tests are exploited to evaluate the optical emission from the welding plasma/plume. Acquired spectra are then analysed with multivariate data analysis approach in order to ensure gap monitoring. Results showed that with the proposed method it is possible to evaluate not only the gap between the plates but also the location inside the weld at which the variation occurs. Furthermore, the relationship between the gap variation and local changes in the acquired spectra is given.