An exploratory study for analyzing the energy savings obtainable by reshaping processes of sheet metal based components

Abstract Producing materials causes about 25% of all anthropogenic CO2 emissions. Reshaping could be one of the most efficient strategy to foster material reuse and lower the environmental impact due to material production. Sheet metal forming processes can be applied to reshape sheet metal based component. This research field is still almost unexplored and the actual environmental impact saving potential has not been quantified. The present paper aims at starting to cover this research gap, a modeling effort to quantify the environmental impact saving of reshaping is proposed. Primary energy demand for conventional recycling and reshaping are quantified and compared. Primary energy savings…

A gradient-based decomposition approach to optimize pressure path and counterpunch action in Y-shaped tube hydroforming operations

International audience; In tube hydroforming, the concurrent actions of pressurized fluid and mechanical feeding allows obtaining tube shapes characterized by complex geometries such as different diameters sections and/or bulged zones. Main process parameters are material feeding history (i.e., the punches velocity history), internal pressure path during the process, and (in T- or Y-shaped tube hydroforming) counterpunch action. What is crucial, in such processes, is the proper design of operative parameters aimed to avoid defects (for instance underfilling or ductile fractures). Actually, the design of tube hydroforming operations is mainly aimed to prevent bursting or buckling occurrence …

Shape distortion and thickness distribution during SPIF processes: experimental and numerical analysis

Single Point Incremental Forming (SPIF) is a quite new sheet forming process which offers the possibility to deform complex parts without dedicated dies using only a single point tool and a standard 3-axis CNC machine. The process mechanics enables strains much higher than traditional sheet forming processes, but particular attention must be given to the final part geometrical accuracy. In this paper the capabilities of a dedicated explicit numerical model are quantitatively analyzed on pyramid-shaped parts. In particular a comparison between experimental and numerical results is reported. Three different shapes at the varying of the stamping angle were considered and the final shape was ac…

Analysis of Energy Efficiency of Different Setups Able to Perform Single Point Incremental Forming (SPIF) Processes

Abstract Production processes, as used for discrete part manufacturing, are responsible for a substantial part of the environmental impact of products, but are still poorly documented in terms of environmental impact. The present paper proposes an energy analysis of single point incremental forming processes (SPIF). The electrical energy consumption of two different setups have been considered and compared. In particular the power demand of one of the most used machine tools architecture able to perform SPIF process, namely a CNC milling machine, has been measured. The obtained results have been compared with the ones obtained for an innovative high speed incremental forming processes perfo…

Energy and Resource efficient Forming Processes

On the springback prediction in 3d sheet metal forming processes

Life cycle energy and CO2 emissions analysis of food packaging: an insight into the methodology from an Italian perspective

Packaging is strictly connected to environmental issues as it is a product characterised by high material consumption rate; it is often transported over long distances and has a short life. Providing environmental analysis is, therefore, urgent to identify energy and resources efficient solutions. The paper, taking advantage of a real case study, presents a life cycle-based comparative analysis among three different food packaging systems. The paper compares the life cycle of tin steel, polypropylene and glass-based packaging of an Italian preserves producer. The analysis leads to the conclusion that, for the baseline scenario, polypropylene packaging represents the greenest solution, where…

Shape Distortion and Thickness Distribution during SPIF Processes: Expermental and Numerical Analysis

Single Point Incremental Forming (SPIF) is a quite new sheet forming process which offers the possibility to deform complex parts without dedicated dies using only a single point tool and a standard 3-axis CNC machine. The process mechanics enables strains much higher than traditional sheet forming processes, but particular attention must be given to the final part geometrical accuracy. In this paper the capabilities of a dedicated explicit numerical model are quantitatively analyzed on pyramid-shaped parts. In particular a comparison between experimental and numerical results is reported. Three different shapes at the varying of the stamping angle were considered and the final shape was ac…

On the Effectiveness of SPIF Process to Re-Form End-of-Life Components as Compared to Conventional Forming Approach

Manufacturing processes have a significant impact on global energy consumptions. The recovery of materials and functions for the implementation of the Circular Economy principle needs to be focused on either, by utilizing new techniques or the rethinking of old processes to rework End-of-life (EoL) components. Previous researches have shown Single Point Incremental Forming (SPIF) process as a good alternate for sheet metal EoL components reuse by their reshaping. In this article, the authors aim to study the effectiveness of the SIPF processes by comparing its reshaping performance with other, more conventional forming processes. An initial deep drawing process was performed to imitate alum…

Electrical energy analysis and potential environmental improvements of sheet metal punching processes

Discrete part manufacturing processes, in particular non-conventional production processes, are still poorly documented in terms of environmental footprint. Within the separating processes, sheet metal punching processes have not been analyzed yet from environmental point of view. The present paper aims to contribute to filling this knowledge gap. In particular, two different punching machine tool architectures were analyzed. Following the previously developed CO2PE methodological approach, power studies and a preliminary time study have been performed in order to understand the contribution of each sub-unit towards the total energy demand. The influence of the most relevant process paramet…

Environmental comparison between a hot extrusion process and conventional machining processes through a Life Cycle Assessment approach

Nowadays manufacturing technologies have to be evaluated not only for the technical features they can provide to products, but also considering the environmental perspective as well. As long as the technological feasibility of a given process is guaranteed, processes minimizing resources and energy consumption have to be selected for manufacturing. With respect to this topic, the research studies in the domain of metal processing technologies predominantly focus on conventional material removal processes as milling and turning. Despite some exceptions, many other non-machining technologies, such as metal forming processes, are still not well documented in terms of their energy and resource …

Internal pressure and material feeding optimisation in tube hydroforming

Design of complex sheet metal forming processes: a new computer aided progressive approach

The growing interest in sheet metal stamping processes, particularly in automotive industry, led to three main issues in this field: request of very complex shapes; growing interest in springback control; solution of multi-objective problems. This makes the design of the sheet metal stamping processes very difficult, since the number of both design variables and design objectives are progressively increased; therefore, proper design methodologies to reduce times and costs are highly required. In this paper, an innovative design approach able to manage and optimize complex stamping operations is proposed. In particular, a progressive design approach based on the integration between numerical…

Energy demand reduction of aluminum alloys recycling through friction stir extrusion processes implementation

Abstract Aluminum alloys are characterized by high-energy demands for primary production. Recycling is a well-documented strategy to lower the environmental impact of light alloys production. Despite that, conventional recycling processes are still energy-intensive with a low energy efficiency. Also, permanent material losses occur during remelting because of oxidation. Recently, several solid-state recycling approaches have been analyzed; in fact, by avoiding the remelting step both energy and material can be saved and, therefore, the embodied energy of secondary production can be substantially reduced. In this paper, the solid-state approach Friction Stir Extrusion (FSE) is analyzed for a…

Uncovering Technological and Environmental Potentials of Aluminum Alloy Scraps Recycling Through Friction Stir Consolidation

Conventional metal chips recycling processes are energy-intensive with low efficiency and permanent material losses during re-melting. Solid state recycling allows direct recycling of metal scraps into semi-finished products. It is expected that this process category would lower the environmental performance of metals recycling. Friction Stir Consolidation is a new solid-state technique taking advantage of friction heat generation and severe plastic deformation to consolidate chips into billets. In this research, the feasibility of Friction Stir Consolidation as aluminum chips recycling process is analyzed. Specifically, an experimental campaign has been carried out with varying main proces…

Optimisation of a tube hydroforming process by gradient techniques

A sustainability point of view on sheet metal forming operations: material wasting and energy consumption in incremental forming and stamping processes

Abstract Sustainability and sustainable production is nowadays a wide research field due the urgency of reducing environmental burdens of industrial production. Sustainable manufacturing issues are widely investigated too. In particular, due to the relevance such issues assume for automotive and aeronautical industry, the investigation of sheet metal forming processes sustainability is worth studying and, within this research fields, a certain lack of knowledge is still present. Many studies have been presented concerning the evaluation and reduction of environmental burdens in manufacturing. In this paper, the authors focus on sheet metal forming and aim to investigate both the efficient u…

Multi-material based functionally graded billets manufacturing through friction stir consolidation of aluminium alloys chips

New deal of Friction Stir Consolidation (FSC) is its evolution from Recycling technique towards Upcycling. In this paper, the potential of FSC to manufacture Functionally Graded billets is proved. Processing chips of two different aluminium alloys (AA7075, AA2011-T3), graded hardness distributions were obtained along the longitudinal direction of the manufactured billet. Material flow was analysed by EDX analyses and numerical simulations; mechanical properties were assessed through hardness measurements. The influence of material's position, mass fraction of each material and process parameters was considered. Results reveal that FSC offers a proper control in the design of billets with gr…

A Comparison between Three Meta-Modeling Optimization Approaches to Design a Tube Hydroforming Process

Computer aided procedures to design and optimize forming processes have become crucial research topics as the industrial interest in cost and time reduction has been increasing. A standalone numerical simulation approach could make the design too time consuming while meta-modeling techniques enables faster approximation of the investigated phenomena, reducing the simulation time. Many researchers are, nowadays, facing such research challenge by using various approaches. Response surface method (RSM) is probably the most known one, since its effectiveness was demonstrated in the past years. The effectiveness of RSM depends both on the definition of the Design of Experiments (DoE) and the acc…

Life Cycle Assessment of aluminum alloys chips recycling through single and multi-step Friction Stir Consolidation processes

Manufacturing scientists have to find new processes enabling energy and resource efficient circular economy strategies. Solid state recycling processes have proved to be environmentally friendly alternatives to recycle aluminum alloys process scraps like chips. In this paper the environmental characterization of a solid state recycling process named Friction Stir Consolidation (FSC) is presented. A full Life Cycle Assessment (LCA) comparative analysis is developed: the environmental performance of new and different variants of FSC processes and remelting based routes are quantified and compared to one another. Also, different scenarios are analysed to provide guidelines for the correct impl…

Integrated WAAM-Subtractive Versus Pure Subtractive Manufacturing Approaches: An Energy Efficiency Comparison

Over the last years, additive manufacturing (AM) has been gathering momentum both in the academic and in the industrial world. Besides the obvious benefits in terms of flexibility and process capabilities, the environmental performance of such processes has still to be properly analyzed. Actually, the advantages of additive manufacturing over conventional processes are not obvious. Indeed, different manufacturing approaches result in different amounts of involved material and in different processing energy demands. Environmental comparative analyses are hence crucial to properly characterize AM processes. In this paper, an energetic comparison between the emerging wire arc additive manufact…

Evaluating the material resource efficiency of secondary aluminium production: A Monte Carlo-based decision-support tool

The contamination of aluminium streams during the different life cycle stages by alloy mixing and/or accumulation of foreign elements, in combination with the limited melt purification options during remelting, represents an important limiting factor in recycling. Consequently, in secondary aluminium production, primary aluminium is used to dilute the concentration of the residual elements, and alloying elements are added to adjust the composition to the target alloy specifications. However, adding elements, for which their refinement in a subsequent recycling step is problematic, results in permanent down-cycling or ‘quality losses’. Hence, it is crucial to more efficiently control the com…

Analysis of stamping performances of dual phase steels: A multi-objective approach to reduce springback and thinning failure

The industrial interest on light weight components has contributed in the last years to a significant research effort on new materials able to guarantee high mechanical properties, good formability and reasonable costs together with reduced weights when compared to traditional mild steels. Among such materials advanced high strength steels (AHSS) such as transformations induced plasticity (TRIP) and dual phase (DP), and light weight alloys proved their usefulness in stamping of automotive components. As AHSS are concerned, one of the main drawbacks is related to springback occurrence. Many aspects have to be taken into account when springback reduction is investigated: material behavior iss…

Energy Efficiency of Sheet Metal Working Processes: Where do we stand today?/Energieeffizienz in Prozessen der Blechumformung – eine aktuelle Standortbestimmung

Due to increasing energy and resource costs at the one hand and upcoming regulations on energy and resource efficiency at the other, a growing interest of machine tool builders to the environmental performance of their machine tools can be observed today. The last decade, academic as well as industrial research groups started to assess the energy demand of discrete part manufacturing processes and indicated a significant potential for improvement [1]. In contrast to conventional machining processes (e.g. milling, turning…), (sheet) metal forming processes are still less well documented in terms of their energy demand [2]. In consequence, potential energy efficiency improvement measures for …

An Intelligent Tool to Predict Fracture in Sheet Metal Forming Operations

One of the main issues in sheet metal forming operations design is the determination of formability limits in order to prevent necking and fracture. In fact, the ability to predict fracture represents a powerful tool to improve the production quality in mechanical industry. Many researchers investigated the problem here addressed, mainly studying forming limit diagrams (FLD) or developing fracture criteria which are able to foresee fracture defects for different processes. In this paper, the author present some early results of a research project focused on the application of artificial intelligence (AI) for ductile fracture prediction in sheet metal forming operations. The main advantage o…

Towards criteria for sustainable process selection: On the modelling of pure subtractive versus additive/subtractive integrated manufacturing approaches

Additive Manufacturing (AM) processes can be counted among the disruptive technologies that are capable of transforming conventional manufacturing routes. The ability to create complex geometries, the reduction in material scraps during manufacturing, and the light-weighting due to the think-additive redesign of the components represent the main points of strength of AM. However, for some applications (such as the production of metal components for the automotive and aerospace industries), the surface finishing and dimensional/geometrical part tolerancing that can be achieved via AM processes might not be adequate to satisfy the imposed product specifications, and finish machining operation…

Numerical Prediction Of Elastic Springback In An Automotive Complex Structural Part

A Pareto optimal design approach for simultaneous control of thinning and springback in stamping processes

One of the most relevant research issues in automotive field is focused on the reduction of stamped parts weight also increasing their strength. In this way, a strong research effort is developed on high strength steels which are widely utilized and they require a proper springback control. Springback reduction in sheet metal forming is a typical goal to be pursued which is conflicting with thinning reduction for instance. Thus, such problems can be considered as multi-objective ones characterized by conflicting objectives. What is more, nowadays, a great interest would be focused on the availability of a cluster of possible optimal solutions instead of a single one, particularly in an indu…

Microstructural, mechanical and energy demand characterization of alternative WAAM techniques for Al-alloy parts production

Abstract Additive manufacturing (AM) processes are gathering momentum as an alternative to conventional manufacturing processes. A research effort is being made worldwide to identify the most promising AM approaches. Within this category, wire arc additive manufacturing (WAAM) is among the most interesting, especially when large parts must be manufactured. In this paper, two different WAAM deposition techniques suitable for the deposition of Aluminum alloys, Cold Metal Transfer (CMT) and CMT mix drive, are analyzed and compared. With the aim of obtaining a clear picture concerning the two different techniques, microstructural analyses, mechanical property evaluation and electrical energy de…

A comparison between three meta-modeling optimization approaches to design a tube hydroforming process

Integration of gradient based and response surface methods to develop a cascade optimisation strategy for Y-shaped tube hydroforming process design

International audience; In the last years a strong research effort was produced in order to develop and design new forming technologies able to overcome the typical drawbacks of traditional forming operations. Among such new technologies, hydroforming proved to be one of the most promising. The design of tube hydroforming operations is mainly aimed to prevent bursting or buckling occurrence and such issues can be pursued only if a proper control of both material feeding history and internal pressure path during the process is performed.In this paper, a proper optimisation strategy was developed on Y-shaped tube hydroforming process which is characterized by a quite complex process mechanics…

An insight into the electrical energy demand of friction stir welding processes: the role of process parameters, material and machine tool architecture

The manufacturing sector accounts for a high share of global electrical energy consumption and CO 2 emissions, and therefore, the environmental impact of production processes is being more and more investigated. An analysis of power and energy consumption in friction stir welding processes can contribute to the characterization of the process from a new point of view and also provide useful information about the environmental impact of the process. An in-depth analysis of electrical energy demand of friction stir welding is here proposed. Different machine tool architectures, including an industrial dedicated machine, have been used to weld aluminum and steel sheets under different process …

A contribution on the optimization strategies based on moving least squares approximation for sheet metal forming design

Computer-aided procedures to design and optimize forming processes are, nowadays, crucial research topics since industrial interest in costs and times reduction is always increasing. Many researchers have faced this research challenge with various approaches. Response surface methods (RSM) are probably the most known approaches since they proved their effectiveness in the recent years. With a peculiar attention to sheet metal forming process design, RSM should offer the possibility to reduce the number of numerical simulations which in many cases means to reduce design times and complexity. Actually, the number of direct problems (FEM simulations) to be solved in order to reach good functio…

Numerical analysis for formability boundaries definition in sheet metal forming operations

Formability limits in sheet metal forming have been widely investigated through different approaches. The main aim of such approaches was to develop tools able to prevent or predict fracture occurrence in order to improve production quality. Forming limit diagrams (FLDs) and fracture criteria are probably the most utilised tools in this field; nevertheless, some drawbacks of such tools were demonstrated. In particular, forming limit curves are characterised by ineffective prediction capability if non linear deformation paths are taken into account. Moreover, the importance of stress paths was demonstrated in order to predict fracture, and forming limit stress diagrams are, nowadays, deeply …

On the Use of Artificial Neural Networks to Predict Ductile Fracture for Different Materials

The Role of re-design for Additive Manufacturing on the Process Environmental Performance

Abstract At present, economic and technological design criteria for products and processes should be matched with the minimization of environmental impact objectives. Manufacturing, material production, and product design are strictly connected stages. The choice of a production system over another could result in significant material and energy/resource savings, particularly if the component has been properly designed for manufacturing. In this scenario, Additive Manufacturing, which has been identified as a potential disruptive technology, gained an increasing interest for the creation of complex metal parts. The paper focuses on the tools, based on the holistic modelling of additive and …

On the Moving Least Squares (MLS) approximation effectiveness in a T-Shaped tube hydroforming design

Single point incremental forming: An assessment of the progress and technology trends from 2005 to 2015

The last decade has seen considerable interest in flexible forming processes. Among the upcoming flexible forming techniques, one that has captured a lot of interest is single point incremental forming (SPIF), where a flat sheet is incrementally deformed into a desired shape by the action of a tool that follows a defined toolpath conforming to the final part geometry. Research on SPIF in the last ten years has focused on defining the limits of this process, understanding the deformation mechanics and material behaviour and extending the process limits using various strategies. This paper captures the developments that have taken place over the last decade in academia and industry to highlig…

Process parameters calibration in 3D tube hydroforming processes

In tube hydroforming the concurrent actions of pressurized fluid and mechanical feeding allow to obtain tube shapes characterized by complex geometries such as different diameters sections and/or bulged zones. What is crucial in such processes is the proper design of operative parameters aimed to avoid defects (for instance shape defects or ductile fractures). The main process parameters are material feeding history (i.e. the punches velocity history) and internal pressure path during the process. In more complex three dimensional processes, also the action of a counterpunch is generally useful to reduce thinning in particular in expansion zones of the tube (i.e. T or Y shaped tubes). The g…

Energy and CO2 life cycle inventory issues for aluminum based components: The case study of a high speed train window panel

Abstract As materials production and transport are two relevant sectors in terms of global environmental impact, over the last years environmental impact analyses (mainly life cycle based analyses) of material replacing strategies in means of transportation were developed. Life cycle approach allows to consider the light-weighing benefit without neglecting the environmental impact of material production. In the present research energy and CO2 emissions life cycle analysis of a real case study is presented. Industrial data, experimental measurements and literature analysis were used to develop the life cycle analysis of an aluminum window panel to be assembled on an Italian high speed train.…

Guidelines to compare additive and subtractive manufacturing approaches under the energy demand perspective

In order to characterise the environmental performance of additive manufacturing (AM) processes, comparative analyses are required. Different manufacturing approaches (such as additive and subtractive ones), besides adopting different equipment, use different kinds and amounts of material. Therefore, the material-related flow has to be followed throughout the entire product life. Differences in environmental impact arise at each step of the life cycle: material production, manufacturing, use, disposal, and transportation. A life cycle-based methodology able to take due account of all the factors of influence on the total energy demand for the production of metal components is given in this …

Multi Stage Strategies for Single Point Incremental Forming of a Cup

A five stage forming strategy for Single Point Incremental Forming of a circular cylindrical cup with a height/radius ratio of one is presented. Geometrical relations are discussed and theoretical strains are calculated. The influence of forming direction (upwards or downwards) is investigated for the second stage comparing explicit FE analysis with experiments. Good agreement is found between calculated and measured thickness distribution, overall geometry and strains. Using the proposed multi stage strategy it is shown possible to produce a cup with a height close to the radius and sides parallel to the symmetry axis in about half of the depth.

Moving Least Squares Innovative Strategies For Sheet Forming Design

In the last years a great interest in optimization algorithms aimed to design forming processes was demonstrated by many researches. Proper design methodologies to reduce times and costs have to be developed mostly based on computer aided procedures. Response surface methods (RSM) proved their effectiveness in the recent years also for the application in sheet metal forming aiming to reduce the number of numerical simulations. Actually, the main drawback of such method is the number of direct problem to be solved in order to reach good function approximations. A very interesting aspect in RSM application regards the possibility to build response surfaces basing on moving least squares appro…

Sustainability for 3DP Operations

Sustainability is an essential consideration in manufacturing, and within this chapter a detailed appraisal is given to sustainability for 3D printing. An in-depth review of existing research is provided, and a cradle-to-grave assessment technique is shown to assess the environmental impact of 3D printed part.

Single Point Incremental Forming: analysis of sustainability of the process through an experimental approach

In literature, manufacturing processes have been studied with different approaches, but a lack of knowledge on the analysis of the energy required is still present. The aim of this paper is to carry out energy analysis on Single Point Incremental Forming process. Accordingly, a wide experimental investigation was executed by taking into account different process parameters (i.e. tool depth step, punch velocity and product shape). The total energy consumption was monitored during all the experiments and properly weighted with respect to the deformation energy, required to execute the process. A sensitivity analysis was also carried out to highlight the conditions which allow to save energy r…

A NEW PROGRESSIVE DESIGN METHODOLOGY FOR COMPLEX SHEET METAL STAMPING OPERATIONS: COUPLING SPATIALLY DIFFERENTIATED RESTRAINING FORCES APPROACH AND MULTIOBJECTIVE OPTIMIZATION

The growing interest in sheet metal stamping processes, particularly in the automotive industry has led to three main issues in this field:*request of very complex shapes; *growing interest in springback control; *solution of multi-objective problems. These issues make a sheet metal stamping processes design very difficult and proper design methodologies to reduce times and costs are highly required. In this paper, a computer aided approach aiming to satisfy the mentioned issues is proposed. In particular, a progressive design approach based on the integration between numerical simulations, Response Surface Methodology (RSM) and Pareto optimal solutions search techniques was applied in orde…

Tecniche di ottimizzazione multi-obiettivo e metodologie di supporto alle decisioni per la progettazione di processi di stampaggio di lamiere

An energy efficiency analysis of Single Point Incremental Forming as an Approach for Sheet Metal Based Component Reuse

Abstract Producing materials causes about 25% of all anthropogenic CO2 emissions. Metals play a significant role, steel and aluminum account for 24% and 3% of worldwide material related emissions respectively. Fostering resources efficiency strategies in the field of sheet components could lead to a significant environmental impact reduction. Reshaping could be one of the most efficient strategy to foster material reuse and lower the environmental impact due to material production. Specifically, for aluminum recycling, the overall energy efficiency of conventional route is very low and, more importantly, permanent material losses occur during re-melting because of oxidation. The present pap…

Manufacturing strategies for efficiency in energy and resources use: The role of metal shaping processes

Abstract Manufacturing sector nowadays has to deal with the global need to reduce the environmental impact of human activity. As manufacturing accounts for a significant portion of the global CO 2 emissions, scientific research should be addressed to understand the environmental impact of manufacturing processes and, in the meantime, to take advantage of their full potential in reducing the overall CO 2 emissions. The present review paper aims at describing the role of metal shaping processes in reducing the environmental impact across different stages of metal components life. Actually, an increased consciousness concerning both the environmental performances of manufacturing processes and…

On the sustainability evaluation in sheet metal forming processes

In sheet metal forming processes there is still a lack of knowledge in the field of environmental sustainability mainly due to the need of a proper modeling of issues and factors to be taken into account. Such topic is, nowadays, a urgent and remarkable issue in manufacturing and the main concerns are related to more efficient use of materials and energy. What is more, the estimation of environmental burdens of forming technologies is very complex to be accomplished since it is essentially process-dependent. This means that when comparing, for instance, a traditional forming process with an innovative one, there are some peculiar aspects to be considered; actually, processes can be rather d…

Measuring of Geometrical Precision of Some parts Obtained by Asymmetric Incremental Forming Process After Trimming

Asymmetric Incremental Forming exalts the advantages of Incremental Forming process since no dies are strictly necessary. In this way complex geometries may be manufactured with a very simple clamping equipment. On the other hand, this characteristic determines some intrinsic drawbacks which penalise its industrial suitability; first of all, the dimensional control of the manufactured part is a still open point for researchers all over the world. Several approaches have been already proposed in the last years to solve the problem, resulting only in partial solutions. At the same time, up to now, the numerical simulation did not supply significant aid to the designers, due to the problem com…

A novel linear friction welding based approach for sheet-bulk joining

In the last decades, the development of new, flexible manufacturing processes caused the increase of the demands for highly customized complex functional parts in many industrial fields. The peculiar design of these components often overcome conventional sheet metal and bulk metal forming processes capabilities. In order to face this issue, new hybrid techniques, capable of exploit key advantages of different processes, have to be developed. In this paper, a novel approach based on the Linear Friction Welding process is proposed to obtain sheet-bulk joints. The feasibility of the technique on high specific strength alloys is investigated through an experimental campaign.In the last decades,…

Geometrical deviation of end-of-life parts as a consequence of reshaping by single point incremental forming

AbstractPutting in place circular economy strategies is an urgent challenge to face. In this scenario, manufacturing processes play a relevant role as efficient material reuse enabler. Scientists have to make an effort either to find new process or to rethink old process to reprocess end-of-life (EoL) component to recover both material and functions. In this paper, single point incremental forming (SPIF) process is used for reshaping sheet metal EoL components. The entire process chain was replicated including both deep drawing process (to imitate the end-of-life component) as well as SPIF operations (to obtain the reshaped components). The geometrical deviation as a consequence of SPIF ope…

INTERNAL PRESSURE AND COUNTERPUNCH ACTION DESIGN IN Y-SHAPED TUBE HYDROFORMING PROCESSES: A MULTI OBJECTIVE OPTIMISATION APPROACH

In sheet metal forming most of the problems are multi-objective problems, generally characterised by conflicting objectives. A classical approach to investigate such kind of problems is focused on a combination of multiple objectives into a unique objective function to be optimised. Actually, in metal forming processes optimisation two main phases have to be developed in order to reach an optimal solution: the former is the modelling phase (definition of the design variables and objective function) and the latter concerns the computational aspect (numerical simulations or experiment to be developed). In this paper, an integration between numerical simulations, response surface methodology a…

Environmental modelling of aluminium based components manufacturing routes: Additive manufacturing versus machining versus forming

Abstract Additive Manufacturing represents, by now, a viable alternative for metal-based components production. Therefore the designer, often, has to select among three options at process design stage: subtractive, mass conserving, and additive approaches. The selection of a given process, besides affecting the manufacturing step impact, influences significantly the impact related to the material production step. If the process enables a part weight reduction (as the Additive Manufacturing approaches do) even the use phase is affected by the manufacturing approach selection. The present research provides a comprehensive environmental manufacturing approaches comparison for components made o…

Aluminium sheet metal scrap recycling through friction consolidation

Abstract In the last decades, several direct-recycling techniques have been developed and investigated in order to avoid material remelting, typical of the conventional aluminum alloys recycling processes. Moreover, the remelting step for aluminum recycling is affected by permanent material losses. Solid-state recycling processes have proven to be a suitable strategy to face such issues. Friction Consolidation is an innovative solid state-recycling technology developed for metal chips. During the process, a rotating die is plunged into a hollow chamber containing the material to be processed. The work of friction forces decaying into heat soften the material and, together with the stirring …

Fracture Prediction in sheet metal forming operations: an artificial neural networks based approach

Experimental validation of optimisation strategies in hydroforming of T-shaped tubes

For three dimensional tube hydroforming operations (i.e. T or Y shaped tubes) the calibration of both material feeding history and internal pressure path during the process is crucial and many approaches to such optimization were presented; the authors developed some procedures to optimize pressure paths and punch velocity histories with the application of an integrated method FEM - Gradient based optimization tools. In this paper, an experimental validation campaign of the utilized optimization strategies is presented with the aim to assess the effectiveness of the developed procedures. An optimization procedure (gradient based techniques) was applied on the process parameters leading to t…

Friction stir extrusion to recycle aluminum alloys scraps: Energy efficiency characterization

Abstract Solid state recycling refers to a group of processes allowing direct recycling of metals scraps into semi-finished product. Their main advantage lies in avoiding the molten state of the material which badly affects the environmental performance of the conventional (remelting based) recycling routes. It is expected that such process category would lower the environmental performance of metals recycling. In this paper, the friction stir extrusion process for aluminum alloy AA 2050 wire production is analyzed under the primary energy demand perspective. The process electrical energy demand is quantified with varying process parameters. An empirical modelling approach was applied and a…

Energy consumption analysis of robot based SPIF

Part of: Seliger, Günther (Ed.): Innovative solutions : proceedings / 11th Global Conference on Sustainable Manufacturing, Berlin, Germany, 23rd - 25th September, 2013. - Berlin: Universitätsverlag der TU Berlin, 2013. - ISBN 978-3-7983-2609-5 (online). - http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-40276. - pp. 131–136. Production processes, as used for discrete part manufacturing, are responsible for a substantial part of the environmental impact of products, but are still poorly documented in terms of environmental impact. A thorough analysis of the causes affecting the environmental impact in metal forming processes is mandatory. The present study presents an energy consumption anal…

Design of sheet stamping operations to control springback and thinning: a multi-objective stochastic optimization approach

Abstract The aim of this paper is to develop a design tool for stamping processes, which is able to deal with the scattering of the final part quality due to the inner variability of such operations. Such variability is one of the main drawbacks for a robust process design. It results in a scattering of the most significant process results and depends on several parameters. The so called noise factors greatly influence final result variability, which often means rejecting parts and anyway achieving final properties different from the specified ones. The process investigated in the paper is an S-shaped U-channel stamping operation carried out on a lightweight aluminum alloy of automotive int…

A gradient based approach for the design of the shape of the blank in deep drawing of rectangualr boxes

Optimisation strategies to determine process parameters in tube hydroforming

Influence of Material-Related Aspects of Additive and Subtractive Ti-6Al-4V Manufacturing on Energy Demand and Carbon Dioxide Emissions

Summary The additive manufacturing of metal parts represents a promising process that could be used alongside traditional manufacturing methods. The research scenario in this field is still largely unexplored, as far as the technological solutions adopted to integrate different processes are concerned and in terms of environmental and economic impact assessment. In this article, an electron beam melting (EBM) process and a machining process have been analyzed and compared using a cradle-to-grave life cycle–based approach. The production of components made of the Ti-6Al-4V alloy has been assumed as a case study. The proposed methodology is able to account for all of the main factors of influ…

Tuning Decision Support Toolsfor Environmentally Friendly Manufacturing Approach Selection

Awareness about the environmental performance of manufacturing approaches has arisen. Comparative analyses of different manufacturing approaches as well as decision support methods should be developed in the field of metal shaping processes. The present paper aims at tuning a decision support tool for identifying when mass conserving approaches (forming based) are actually preferable over machining processes for manufacturing aluminum based components. A full LCA is developed for comparing the environmental performance of forming and machining approaches as the batch size and geometry complexity hang. The impact of the used metric on the comparative results is analyzed. Results reveal that …

A comparative assessment of energy demand and life cycle costs for additive- and subtractive-based manufacturing approaches

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…

Deep Drawing Process Design: A Multi Objective Optimization Approach

In sheet metal forming most of the problems are multi objective problems, generally characterized by conflicting objectives. The definition of proper parameters aimed to prevent both wrinkles and fracture is a typical example of an optimization problem in sheet metal forming characterized by conflicting goals. What is more, nowadays, a great interest would be focused on the availability of a cluster of possible optimal solutions instead of a single one, particularly in an industrial environment. Thus, the design parameters calibration, accomplishing all the objectives, is difficult and sometimes unsuccessful. In order to overcome this drawback a multi-objectives optimization procedure based…

On the Effectiveness of Numerical Prediction of Elastic Springback: An Industrial Case Study

On the springback prediction in industrial air bending sequences

On the Sustainability Evaluation in Sheet Metal Forming Processes

In sheet metal forming processes there is still a lack of knowledge in the field of environmental sustainability mainly due to the need of a proper modeling of issues and factors to be taken into account. Such topic is, nowadays, a urgent and remarkable issue in manufacturing and the main concerns are related to more efficient use of materials and energy. What is more, the estimation of environmental burdens of forming technologies is very complex to be accomplished since it is essentially process-dependent. This means that when comparing, for instance, a traditional forming process with an innovative one, there are some peculiar aspects to be considered; actually, processes can be rather d…

Sustainability issues in sheet metal forming processes: an overview

Abstract Environmental sustainability in manufacturing is nowadays an urgent and remarkable issue and the main concerns are related to more efficient use of materials and energy. In sheet metal forming processes there is still a lack of knowledge in this field mainly due to the need of a proper modelling of sustainability issues and factors to be taken into account. The aim of this paper is mainly to underline the state of the art from a forming point of view about the sustainability contributions offered in any phase of a product life cycle. Actually, a lack in terms of comprehensive contributions is present in the technical literature, thus, the authors try to give a sort of holistic visi…

Statistical tools and artificial intelligence approaches to predict fracture in bulk metal forming

PROCESSI DI FORMATURA DI LAMIERE IN ACCIAIO ALTORESISTENZIALE: LA TEMPERATURA COME PARAMETRO DI PROCESSO

A novel approach to enhance mechanical properties during recycling of aluminum alloy scrap through friction stir consolidation

Solid state recycling (SSR) is a new approach for making metals recycling more efficient with respect to remelting-based approaches. Friction stir consolidation (FSC) is a new solid-state process that is employed to recycle metallic scraps. Until now, a single-step FSC process was applied to recycled metal chips. During the single-step approach, critical processes parameters, especially processing time and rotational speed, are considered vital to control the quality and mechanical properties of the billet. However, the effectiveness of process parameters is highly restricted by challenging masses of recycling chips and machine competency. The present study first highlights the issues of th…

A sensitivity analysis on artificial neural networks fracture predictions in sheet metal forming operations

Ritorno elastico in processi di formatura della lamiera

A multi-objective Pareto design approach for simultaneous control of thinning and springback in complex stamping operations.

Abstract In sheet metal forming operations design, optimization problems have to be solved in order to reach optimal process conditions. In these problems, there are some crucial issues to be taken into account: - most of the problems are multi objective problems, generally characterized by conflicting objectives: the definition of proper parameters aimed to prevent both springback and fracture is a typical example of an optimization problem in sheet metal forming characterized by conflicting goals; - in an industrial environment a great interest would be focused on the availability of a cluster of possible optimal solutions instead of a single “almost optimal” solution. Taking into account…

Study of the implementation of SPIF as a Reshaping strategy in terms of formability and accuracy performance

The adaption of circular economy strategies has become increasingly necessary in current times. Researches need to be addressed on finding alternative processes or the modification of the existing processes in order to reprocess End-of-Life (EoL) components and consequently recover both materials and their functions. This research paper focuses on the use of single point incremental forming (SPIF) process for the Reshaping of sheet metal EoL components. Uniaxial and biaxial pre-straining was performed on AA5754 sheets to imitate an end-of-life component, and SPIF operations were carried out so as to obtain reshaped components. In previous works, the authors have proven the technical feasibi…

Analysis of Electrical Energy Demands in Friction Stir Welding of Aluminum Alloys

Abstract Manufacturing processes, as used for discrete part manufacturing, are responsible for a substantial part of the environmental impact of products. Despite that, most of metalworking processes are still poorly documented in terms of environmental footprint. To be more specific, the scientific research has well covered conventional machining processes, concerning the other processes there is a lack of knowledge in terms of environmental load characterization instead. The present paper aims to contribute to fill this knowledge gap and an energetic analysis of Friction Stir welding (FSW) is presented. Following the CO2PE! methodological approach, power studies and a preliminary time stu…

Optimal design of flax fiber reinforced polymer composite as a lightweight component for automobiles from a life cycle assessment perspective

The present study combines the generalized rule-of-mixture (ROM) model and the Ashby material selection method for the life cycle assessment (LCA) of flax fiber reinforced polymers (FRPs) and glass FRPs (GFRPs). The ROM model allows life cycle environmental impact predictions according to specific parameters of flax FRPs such as fiber format, volume fraction, manufacturing technique, and load-bearing capacity. The comparisons applied in this study are constructed on two common composite structures: mat panels and injection molded struts with equal stiffness and strength as the design criteria. On the one hand, the parametric LCA predicts that the equal strength design criterion for flax FRP…

Outlining the Limits of Friction Stir Consolidation as Used as an Aluminum Alloys Recycling Approach

Friction stir consolidation (FSC) is a solid-state process that recycles metal scraps economically and eco-friendly compared to the conventional melting method. The process parameters especially processing time and rotational speed, have a crucial role in achieving a sound disc during FSC. The current study answers the research question of how far these process parameters can be effective when the mass of chips to be recycled increases. In specific, an experimental setup was analyzed that was previously identified as challenging for recycling 20 g chips of aluminum alloy AA 2024-O. Rotational speed was set doubled, and processing time was increased up to 1.5 times of their initial values. T…

Optimization methods for complex sheet metal stamping computer aided engineering

Nowadays, sheet metal stamping processes design is not a trivial task due to the complex issues to be taken into account (complex shapes forming, conflicting design goals and so on). Therefore, proper design methodologies to reduce times and costs have to be developed mostly based on computer aided procedures. In this paper, a computer aided approach is proposed with the aim to offer a methodology able to solve very complex sheet metal stamping processes, in particular a progressive design approach based on the integration between numerical simulations and optimization methodologies is presented. In particular, Response Surface Method, Moving Least Squares approximation and Pareto optimal s…

Re-forming end-of-life components through single point incremental forming

Abstract Applying Circular Economy strategies is mandatory to face material demand while minimizing the environmental impact. Manufacturing processes are to be thought as means to enable material/component reuse strategies. This paper presents the suitability of Single Point Incremental Forming (SPIF) to re-form End-of-life sheet metal components. Deep drawing followed by SPIF process on aluminium alloys were carried out to simulate reforming processes chain. The resulting thinning and strain distributions were experimentally analysed for different configurations. The research proves that the local action and enhanced formability nature of SPIF allow non-homogeneously thinned and reduced fo…

Influence of Material-Related Aspectsof Additive and Subtractive Ti-6Al-4VManufacturing on Energy Demandand Carbon Dioxide Emissions

The additive manufacturing of metal parts represents a promising process that could beused alongside traditional manufacturing methods. The research scenario in this field isstill largely unexplored, as far as the technological solutions adopted to integrate differentprocesses are concerned and in terms of environmental and economic impact assessment.In this article, an electron beam melting (EBM) process and a machining process have beenanalyzed and compared using a cradle-to-grave life cycle–based approach. The productionof components made of the Ti-6Al-4V alloy has been assumed as a case study. Theproposed methodology is able to account for all of the main factors of influence on energydem…

On the use of artificial intelligence tools for fracture forecast in cold forming operations

Abstract The design of cold forming processes requires the availability of a procedure able to deal with the prevention of ductile fracture. In fact, the ability to predict fracture represents a powerful tool to improve the production quality in mechanical industry. In this paper, artificial intelligence (AI) techniques are applied to ductile fracture prediction in cold forming operations. The main advantage of the application of AI tools and in particular, of artificial neural networks (ANN), is the possibility to obtain a predictive tool with a wide applicability. The prediction results obtained in this paper fully demonstrate the usefulness of the proposed approach.

La sharing mobility è un approccio alla mobilità sostenibile dal punto di vista dell’impatto ambientale? Alcune considerazioni basate su un’analisi empirica

L'influenza della sharing mobility sulla sostenibilità ambientale non è stata ancora pienamente compresa. Da un lato la sharing mobility consente ai consumatori di assumere comportamenti che portano ad una riduzione delle emissioni di CO2 grazie, per esempio, alla minore produzione di automobili (riduzione dell’acquisto di auto) e alla riduzione dei chilometri percorsi dalle auto (condivisione della corsa e maggiore tasso di occupanti per veicolo). D'altra parte, l'implementazione della sharing mobility porta ad effettuare un numero maggiore di viaggi in automobile. Infatti, un certo numero di chilometri che vengono percorsi oggi dalle auto condivise, erano percorsi prima con mezzi di trasp…

Deep drawing process parameter design: a multi objective optimization approach

Manufacturing processes as material and energy efficiency strategies enablers: The case of Single Point Incremental Forming to reshape end-of-life metal components

Abstract Making materials consumes about 21% of the global energy demand; concerning metals production, it accounts for about 8% of total global energy consumption. Circular economy strategies such as longer life, more intense use, repair, product upgrades, modularity, remanufacturing, component reuse, and open/closed-loop recycling are strategies to put in place urgently to reduce the environmental impact of raw material production. Although recycling of metals is the most used strategy and is being improved in terms of efficiency, it is mandatory moving towards more virtuous circular economy strategies, such as product/component reuse. In this paper a novel reuse strategy for sheet metal …

Numerical prediction of elastic springback in automotive complex parts

Prevedere la frattura duttile nello stampaggio a freddo

A methodology for evaluating the influence of batch size and part geometry on the environmental performance of machining and forming processes

Metallic material processing plays a significant role in terms of global environmental impact. As a result, energy- and resource-efficient strategies in the metal shaping technology domain need to be identified urgently. Recently, the scientific world has been paying more and more attention to the environmental impact analysis of manufacturing processes. Despite this increased attention, the state of the art in the domain of environmental impact analysis of metal shaping processes is still characterized by gaps in knowledge and in methodologies. In particular, metal forming processes are still not well documented, in terms of their environmental impact, and there is a lack of systematic and…

Assessment of Cost and Energy Requirements of Electron Beam Melting (EBM) and Machining Processes

Additive Manufacturing is under the spotlight as potential disruptive technology, particularly for the production of complex-shaped structural metallic components. However, the actual AM process capabilities present some limitations in achieving the strict part quality requirements imposed by the aerospace and automotive sectors. Therefore, the integration of AM and conventional manufacturing represents an emerging scenario to be investigated. In this paper, a pure machining process and a hybrid production route (based on EBM and finish machining) are compared. The influence of material usage-related factors on costs and energy demand is discussed. The results prove that, despite precise pr…

Environmental Comparison between a Hot Extrusion Process and Conventional Machining Processes through a Life Cycle Assessment Approach

Nowadays manufacturing technologies have to be evaluated not only for the technical features they can provide to products, but also considering the environmental perspective as well. As long as the technological feasibility of a given process is guaranteed, processes minimizing resources and energy consumption have to be selected for manufacturing. With respect to this topic, the research studies in the domain of metal processing technologies predominantly focus on conventional material removal processes as milling and turning. Despite some exceptions, many other non-machining technologies, such as metal forming processes, are still not well documented in terms of their energy and resource …

Subtractive versus mass conserving metal shaping technologies: an environmental impact comparison

The scientific studies in the domain of environmental sustainability of metal processing technologies predominantly focus on conventional material removal processes, as milling and turning. Despite some exceptions, many other non-machining technologies, such as metal forming processes, are still not well documented in terms of their energy and resource efficiency. Moreover, to properly evaluate the environmental impact of a given process, a standing-alone approach is no longer sufficient. In order to offer a valuable contribution in the domain of metal shaping sustainability, the present paper proposes a thorough methodology entailing to compare, from the environmental point of view, two tr…

A comprehensive analysis of electric energy consumption of single point incremental forming processes

Abstract Production processes, as used for discrete part manufacturing, are responsible for a substantial part of the environmental impact of products, but are still poorly documented in terms of environmental impact. The present paper proposes a comprehensive energetic analysis of Single Point Incremental Forming Processes (SPIF). The three most commonly used machine tool architectures able to perform SPIF operations have been taken into account: a CNC milling machine, a six-axes robot as well as the dedicated AMINO machine tool were analyzed from an electrical energy consumption point of view. For all the setups, a working cycle time study and power study were performed. Moreover the cont…

Benchmarking the sustainable manufacturing paradigm via automatic analysis and clustering of scientific literature: A perspective from Italian technologists

Abstract The number of scientific papers in the field of Sustainable Manufacturing (SM) shows a strong growth of interest in this topic in the last 20 years. Despite this huge number of publications, a clear statement of the profound meaning of Sustainable Manufacturing, or at least a strong theoretical support, is still missing. The 6R framework seems to be a first attempt to rationalize this issue, as it is an axiomatic identification of its true nature. Recognizing the pursuing of one or more of the Reduce-Recycle-Reuse-Recover-Redesign-Remanufacture principles allows users to identify if any manufacturing action is in the right direction of sustainability. In the paper, the authors spec…

On the impact of recycling strategies on energy demand and CO2 emissions when manufacturing Al-based components

Abstract The industrial world is facing the challenge of reducing emissions by means of energy- and resource-efficient manufacturing strategies. In some cases, the exerted emissions and the energy demands related to conventional manufacturing processes are not as intensive as those required to extract and produce the raw materials of which the workpieces are made. Therefore, the consciousness of the impact of material usage and the eco-informed choice of the end-of-life scenarios are both needed in view of sustainable development. Aim of this paper is to offer a contribution to a better understanding of the environmental impact of forming and machining processes, for the production of Al-ba…

Electric energy consumption analysis of SPIF processes

Manufacturing processes, as used for discrete part manufacturing, are responsible for a substantial part of the environmental impact of products, but are still poorly documented in terms of environmental footprint. A thorough analysis on the causes affecting the environmental impact in metal forming processes, especially the innovative but very energy intensive sheet metal forming technologies required to form light-weight products, is nowadays necessary. Therefore, this paper presents an energy consumption analysis, including a power and time study, of Single Point Incremental Forming (SPIF) processes. First, the influence of the most relevant process parameters (e.g. feed rate, step down)…

Materiali innovativi nella lavorazione di formatura delle lamiere nel settore automobilistico