Advances on Mechanics, Design Engineering and Manufacturing III

The precision of parts produced by Powder Metallurgy (PM) strongly depends on the careful design of PM process parameters. Among them, high sintering temperature is generally considered as detrimental for dimensional and geometrical precision, and therefore neglected in industrial production. Nevertheless, high sintering temperature would strongly improve mechanical characteristics of PM parts, so that the real influence of high sintering temperature on dimensional and geometrical precision is of great interest for PM companies. This study investigates the influence of sintering temperature (up to 1350 °C) on dimensional and geometrical precision of real parts. Dimensional changes on sintering and the effect of sintering temperature have been evaluated. Geometrical characteristics have been measured both in the green and in the sintered state, and the real influence of sintering temperature has been highlighted. As a conclusion, it has been demonstrated that the larger shrinkage due to the high sintering temperature is not detrimental with respect to the dimensional precision, being it reliably predictable. Moreover, the influence on geometrical characteristics is unexpectedly low. The encouraging results of this study convinced the main PM companies in Europe to further investigate the influence of high sintering temperature, as partners in a Club Project within the European Powder Metallurgy Association (EPMA).

Among Additive Manufacturing technologies, Wire and Arc Additive Manufacturing process is strongly dependent of deposition conditions such as welding parameters, substrate temperature, trajectory. In this research, geometry and temperature evolutions of single beads have been investigated according to process parameters modifications. For our experiment, a heating device have been used in order to control the substrate temperature from room temperature up to 400 °C. Considering the Cold Metal Transfer technology, welding parameters, Wire Feed Speed (WFS) and Travel Speed (TS), have been modified while keeping a constant ratio λ (WFS/TS). Results indicate that weld bead geometry, height (h) and width (w), is influenced by substrate temperature and welding parameters. It has been shown that substrate temperature, itself influenced by process parameters, tends to produce thicker and lower weld beads while it increases.

Additive Manufacturing has proven to be an economically and industrially attractive process in building or repairing parts. However, the major issue of this new process is to guarantee a mechanical behavior identical to the subtractive manufacturing methodologies. The work, presented in this paper, is centered on the Laser Wire Metal Deposition (LMD-w) method with the metallic alloy TA6V. Its working principle is to fuse a coaxial wire on a substrate with a laser as a heat source. To better understand the interaction between the input parameters (Laser Power, Wire Feed Speed and Tool Speed) and the clad geometry output variables (Height, Width and Contact Angle) and the substrate displacement, we have realized an experimentation. We printed 9 clads according Taguchi’s experimental design. Pearson correlation coefficient and Fisher test performed on the experimental measures showed as main result: Tool Speed is the parameter with the most significant influence on the output variables.

Abrasive water jet machining (AWJM) is an interesting solution for the production of shallow pockets in metal sheets made of titanium alloys. Indeed, it produces low cutting forces and heat generation and prevents deformation of these parts after machining. In addition, it has the advantage of only using two raw materials: sand and water. It is possible to generate pocket edges with an imposed geometry using AWJM, but it is necessary to tilt the axis of the jet. The material removal mechanism is then a function of the inclination angle. The presented study propose an improved model for modelling the pocket profile in TiAl6V parts. The experimental results shows that the model is efficient as the precision is around 5%.

The structural properties of cast aluminum parts are strongly affected by the solidification in the production process. The solidification dynamics determines the Secondary Dendrite Arm Spacing (SDAS), directly affecting the structural strength of the alloy. Simulation techniques enable the integrated design of chassis parts and their production equipment. However, in order to effectively predict the SDAS formation, the simulation models need to be investigated and calibrated. The present research investigates the SDAS formation models and identifies a robust relation to be used in Design by Simulation phases for AlSi7Mg0.3 parts.

Fatigue strengths of aluminium 2024-T351 open-hole specimens drilled by axial and orbital drilling processes are compared. Two drilling diameters (Ø) are studied: 6.35 mm and 9.53 mm. Surface integrity characterization tests are conducted in order to study the link between drilling processes, surface integrity and fatigue life. Fatigue test results show an increase of the fatigue life for specimens drilled by axial drilling for Ø = 9.53 mm and no significant difference in fatigue life between the two drilling processes for Ø = 6.35 mm. Surface integrity results show no impact of the roughness on the fatigue strength but a potential positive influence of the hole microhardness on the fatigue life.

Designed for aeronautical and automotive applications, the split sleeve cold expansion process is used to improve the fatigue life of bolted metallic parts. Although its application has been well tested on aluminum assemblies, hard metal applications are still being studied. This paper presents experimental results of double bolt joint assemblies under double shear fatigue tests after stacked split sleeve cold expansion. The behaviors of two sizes of assemblies with different degrees of expansion are investigated. S-N curves are the main indicators of this study but thermal aspects are also investigated to observe fretting in the specimens as bolts are preloaded. Bolt tension is a major parameter in assembly regarding fatigue life. Interference between those two phenomena is at the heart of this paper. The first results show that stacked cold expansion has a negative effect on mechanical performances, as it deteriorates the fatigue life of the assembly. However, an examination of these results provides a coherent explanation for the loss of performance that occurs.

Foam Additive Manufacturing (FAM) is the additive manufacturing process allowing parts to be obtained by depositing layers of polyurethane foam using a high-pressure machine. This inexpensive technology allows large parts to be produced in a reduced time. However, the quality of the parts produced by the FAM technique is greatly affected by the various thermal phenomena present during manufacturing and by the geometrical deviations of the layers due to the expansion of the PU foam. Numerical simulation remains an effective analytical tool for studying these phenomena. The aim of this work is to build a geometric and thermal model predictive of the FAM process by the finite element method, the final objective of which is to provide temperature maps throughout the manufacturing process and also to choose the best 3D printing strategy to have a model with constant cords and the smallest possible form deviation. The proposed model and the various simulation techniques used are detailed in this article. This model is developed under the finite element code Rem3D, and validated by experimental tests carried out on a FAM machinery or a robot, an example of which is detailed in this article.

Electrochemical deposited (ECD) thick film copper on silicon substrate is one of the most challenging technological brick for semiconductor industry representing a relevant improvement from the state of art because of its excellent electrical and thermal conductivity compared with traditional compound such as aluminum. The main technological factor that makes challenging the industrial implementation of thick copper layer is the severe wafer warpage induced by Cu annealing process, which negatively impacts the wafer manufacturability. The aim of presented work is the understanding of warpage variation during annealing process of ECD thick (~20 µm) copper layer. Warpage has been experimental characterized at different temperature by means of Phase-Shift Moiré principle, according to different annealing profiles. A linear Finite Element Model (FEM) has been developed to predict the geometrically stress-curvature relation, comparing results with analytical models.

Wire arc additive manufacturing allows the production of metallic parts by depositing beads of weld metal using arc-welding technologies. This low-cost additive manufacturing technology has the ability to manufacture large-scale parts at a high deposition rate. However, the quality of the obtained parts is greatly affected by the various thermal phenomena present during the manufacturing process. Numerical simulation remains an effective tool for studying such phenomena. In this work, a new finite element technique is proposed in order to model metal deposition in WAAM process. This technique allows to gradually construct the mesh representing the deposited regions along the deposition path. The heat source model proposed by Goldak is adapted and combined with the proposed metal deposition technique taking into account the energy distribution between filler material and the molten pool. The effectiveness of the proposed method is validated by series of experiments, of which an example is detailed in this paper.

Expanded polystyrene foams are a petroleum-origin material that is usually used in some applications such as motorcyclist helmets. Despite it notably mechanical properties, it low density and its capability to absorb energy during an impact, it is necessary to find a renewable-origin substitute material. Thus, it has been studied the use of a sawdust and mycelium composite material under quasi-static and dynamic efforts. Sawdust is a waste material that has very small grains that are totally disaggregated so it has very low material properties. The use of oyster mushroom mycelium generates an internal structure that joins grains and, consequently, the resultant material has notably high mechanical properties. Then it has been compared the resultant properties (stress-strain curve, absorbed energy, decelerations, etc.) with the different densities EPS ones and it has been concluded that this composite material, despite it high density, it could be a suitable substitute material and in some cases it has better properties.

In this paper, a novel approach has been followed based on FEM simulation and Topology Optimization tools to locate and model the reinforcements inside the hull of a sailing dinghy. This process assumes that the inner volume included between the hull and the deck is, at the beginning of the simulation, filled with material; then a portion of this inner volume is eroded until a final free form shape of the reinforcements is obtained. A key point of this procedure is the definition of the optimization constrains because the final shape of the reinforcements must fulfill several requirements such as weight, stiffness and stress. At the end of the optimization procedure, the final shape of internal reinforcements consists of a truss-like web frame with a final weight equal to the 18% of the initial full body.

Additive Manufacturing (AM) technologies allow to produce functional parts with complex geometries that cannot be manufactured by conventional processes. However, the complexity of the product is increased and causes new constraints in the manufacturing process. Therefore, these new processes lead particularly to new needs in design methods. The objective of this paper is to explore and form an overall view of design methods, especially, robust design (RD) methods. Robust design is defined here as a methodology that enables to design a product with optimal performances and insensitivity to small variations of the inputs of the manufacturing process. In this contribution a state of the art of robust design methods applied to AM will be carried out.

Topological optimization (TO) is commonly used to design a part for additive manufacturing (AM), but rarely for entire systems including several parts. How can be optimized a mechanical system in which each optimized part changes the boundary conditions? A Design method called TOMS (Topological Optimization of a Mechanical System) has been developed to take into account the variation of the boundary conditions when optimizing parts. When the using TOMS method the loops are performed until the optimization converges. The object of this article is to propose a discussion on the quantification of this convergence based on a practical case study.

To implement the CAD platform-based approach of Design for Additive Manufacturing (DfAM) and validate it in a real case, an entire design optimization process of a Formula SAE front brake caliper has been performed, to be printed by Powder Bed Fusion (PBF) process. The DfAM consists in the use of a Ti6Al4V titanium alloy to better resist at high temperatures and a topology optimized shape allowed by the technology to save weight despite the density increase. Structural and thermal behavior has been discussed. DfAM process-specific techniques have been implemented for internal geometrical features and optimized shapes. The design for additive workflow is presented and finally the exploited design approach based on a CAD platform is synthesized.

Obstructive sleep apnea syndrome (OSAS) is a sleep disorder that causes pauses in breathing or periods of shallow breathing during sleep. Mandibular advancement devices (MADs) represent a non-invasive treatment for OSAS that has had the highest development in recent years. Nevertheless, literature has not primarily investigated the effects of mandibular advancement. This paper presents a finite element method numerical simulation model for evaluating the stress/strain distribution on the temporomandibular joint (TMJ) and periodontal ligaments caused by advancement devices used for the treatment of OSAS. Results highlight that the mandible lift phase generates significant stress values on TMJ, which cannot be neglected for extended usage of MADs. Furthermore, mandible molar teeth are more loaded than incisor ones.

The valve train plays a major role in the performance of internal combustion engines by controlling the combustion process and it is therefore one of the key aspects for increasing the efficiency of combustion engines. Considering the dynamics, the spring force must be high enough to reliably close the valve preventing from seating bouncing due to surge modes after the valve closure. On the other side, the spring force should be kept as low as possible in order to reduce the engine friction losses and consequently the fuel consumption. In the high-performance engines, the valve springs have to be designed and optimized for sustaining higher stresses with compact dimensions leading to critical material and manufacturing processes. This requires a reduction of moving masses and a strong focus on design and process optimization of the coil springs for reducing the mechanical load and the friction losses at low engine speed. At the same time, valve train should be reliable at high engine speed. The calculation of stresses and contact forces for moving parts under dynamic load is essential for durability analysis. A method to calculate the contact of moving masses is described and proposed to justify valve motions experimental results. To fully understand the failure mechanism of test bed reliability trials, the dynamic stresses have been calculated modeling the real springs’ shape. The contact forces have been reproduced considering the coil clash effects and the dynamic behavior of the flexible spring.

Traditional analytical methods are approximate and need to be validated when it comes to predict the tensional behavior of thread coupling. Numerical finite element simulations help engineers come up with the optimum design, although the latter depends on the constraints and load conditions of the thread couplings which are often variable during the system functioning. The present work illustrates a new method based on Radial Basis Functions Mesh Morphing formulation to optimize the stress concentration in thread couplings which is subject to variable loads and constraints. In particular, thread root and fillet under-head drawings for metric ISO thread, which are the most commonly used thread connection, are optimized with Radial Basis Functions Mesh Morphing. In metric ISO threaded connection, the root shape and the fillet under the head are circular, and from shape optimization for minimum stress concentration it is well known that the circular shape becomes seldom optimal. The study is carried out to enhance the stress concentration factor with a simple geometric parameterization using two design variables. Radial Basis Functions Mesh Morphing formulation, performed with a simple geometric parameterization, has allowed to obtain a stress reduction of up to 12%; some similarities are found in the optimized designs leading to the proposal of a new standard. The reductions in the stress are achieved by rather simple changes made to the cutting tool.

This paper proposes the analysis of the tolerances (values, types, datum) and their effects on a mechanical assembly, as a high-performance car engine, by means of a Computer-Aided Tolerancing software. The 3D tolerance stack-ups are investigated to assess the fulfillment of the functional requirements as well as the performance specifications of the assembly. Moreover, after identifying the tolerances that mainly affect the product variability, we finally propose some corrective actions on the tolerances and assess their functional allocation, tightening or relaxing their values, ensuring assemblability and cost reduction.

Product design is a process developed by specialized profiles such as designers or engineers. For this reason, most of product design and/or manufacturing methods developed are aimed at experienced professionals. However, in the current social and technological context, we observe that the number of prosumers, users who partially produce the products they consume, is increasing. These users are involved in design, manufacturing or assembly phases of the product to obtain final results that respond to specific needs and desires. Given this emerging trend, we wonder if there are methodologies focused on these users in particular, both in the academic field and in practice. This work aims to clarify this issue through a review of research papers and real cases. The results obtained differentiate between the methodologies that have been defined in the academic field and those that have not been compiled but whose repeated use has agreed its application and existence in practice. The methodologies identified are analyzed in two tables that summarize how they are applied and what their main objective is. The results and conclusions offer both the scientific community and the prosumers a series of product design and manufacturing methods focused on non-specialized profiles.

The concepts of solutions resulting from the inventive design process measures are generally described in a declarative manner, which does not allow having a shareable formal or visual representation between partners of the project. In addition, the absence of a model does not allow evaluation and compare competing concepts. In this paper, most relevant work regarding inventive design solution concept presented along with potential merits and demerits and highlighted the need of a systematic method to evaluate behavioral performance of solution concepts.

Whereas energy mainly comes from main national power plants, distributed energy resources and storage technologies would allow local territories to choose their energy sources and increase their autonomy. This paper presents a decision-support tool that propose to find new system architecture based compromises between economic, technical and environmental objectives. Based on a systemic approach, it takes into account a broad range of technologies and assesses multi-scale territories thanks to a physical modelling. Numerical simulations show the influence of different parameters on the ability of a system to balance power demand.

The open-source-software movement that emerged in the late 90s has recently extended to hardware. In this paper, we try to better understand how the reuse of design solutions facilitates company-community collaboration. On the one hand, based on existing research studies, we analyze three fundamental questions - 1) who wants to reuse a design? 2) Why do they want to reuse a design?, and 3) How do they reuse a design? - from a company perspective and a community perspective. On the other hand, we identified that companies and communities must create a common understanding of the design problems and solution and they could benefit in reusing design artifact to speed up the development time and improve the quality and transferability of the results. However, this research shows that companies and communities don’t use the same type of tools and methods to reuse design knowledge which may cause some problems for collaboration [2].

University students spend most of their time in a sitting position. Prolonged sitting on ill-fitted furniture and the resulting lousy posture is making students having different musculoskeletal disorders and is strictly related to students learning outcomes. This study aims to improve postural comfort of chairs placed inside the Science & Technology Library at the University of Salerno. A previous study about these library chairs showed that the lumbar area was the most suffering part while perceived (dis)comfort was dependent on time. Based on this, an ergonomic redesign and, consequently, manufacturing of the chair has been done. A perceived-comfort comparison between the library chair and the redesigned one has been performed. A statistical sample of 28 healthy students performed a 20-min experiment two times, alternatively on the library chair and the redesigned one. The 20-min experiment was divided into two 10-min tasks (“Reading & Writing” and “Laptop use”) to simulate a study day. The participants’ postures were acquired non-invasively using cameras and processed by Kinovea; questionnaires were used to rate the perceived subjective (dis)comfort. A procedure for improving an existing product through a comfort-driven redesign is proposed. Results showed the redesigned library chair lead on increasing postural comfort (particularly in the lumbar area) thanks to the new design and modifications.

This study proposes the realization of a device with a pure cubic stiffness mechanism to suppress a wide range of vibrations, which is known as the Nonlinear Energy Sink. Deciding how to construct a light, reliable NES device is always a challenge. According to our design, the device can counterbalance the undesirable linear stiffness that emerges from the intrinsic property of a variable pitch spring. Our goal is to reduce the mass of the spring while keeping the same cubic stiffness. Through the multifaceted analysis of the nonlinear constraint, we try to explore the full potential of NES device to reduce its mass. Meanwhile, a global search method, Multi Start, is applied by repeatedly running a local solver. Finally, a new design with different variable pitch distribution is proposed.

Generative design (GD) is a new way of designing products that respond to the current characteristics of the 4.0 industry era. It allows the customization of designs and helps to minimize process times and material quantities. In the case study, two parts of the transmission system of a skateboard have been designed using GD of Solid Edge ST10. The design has been customized for 67 kg users who will use the skateboard for riding and not for jumping or doing tricks. On the other hand, the aim was to minimize the weight and the use of material for its manufacture. Once the initial solid is defined, the software generates specific designs for different levels of mass reduction or product quality. An axle with a mass reduction of 70% from the initial solid and a base with reduction of 60% have been proposed. The GD more than an alternative is a requirement to respond to the demands of the 4.0 industry in which customization and cost reduction are one of the fundamental pillars. This type of design, at the same time, forces to adapt the manufacturing processes so that it is necessary to manufacture in additive manufacturing (AM) machines.

Companies awareness of the impact generated by its products increases and motivates them to develop initiatives to improve their sustainability. In this work, a methodology consisting of three main phases: sustainability assessment, redesign process and comparison of designs, is proposed to obtain more sustainable product designs. Methodology is based on the Life Cycle Sustainability Assessment (LCSA) approach, which is applied to simultaneously evaluate environmental, economic and social aspects. In the case study the sustainability improvement of the furniture of a clothing retail store is addressed. A set of indicators are considered to evaluate the sustainability performance of both initial design and redesign. The study concludes that the application of different sustainability strategies allows a significant enhancement of the environmental and economic indicators.

As society and regulations demand more ecological materials, we must focus on finding new properties in potential candidates that make them really feasible and open up new possibilities. A new methodology is established to reach that goal, based on already existing ones, but with a broader vision; more focused on the use, and not solely on the product. To put it into practice, it’s been applied on Luffa Cylindrica, a plant with interesting properties. A volumetric, mechanical and perceptual characterization of it has been carried out, so that we can create new concepts specially linked to that. One of these paths has been fully developed to the point of getting a physical prototype, while more complex ones have been suggested. The stated methodology may be used as a flexible guide to find new materials not only more environmentally-friendly, but better than what’s stablished.

Automotive sector is crucial for the economic and social system. Conversely, it also plays an important role in the global emissions balance with strong consequences on the environment. Currently the Research world is engaged in the reduction of the emissions, especially in order to contrast the Climate Change and reduce toxicity on humans and the ecosystem. This study presents a comparative Life Cycle Assessment, Well-to-Wheel, between the most common technology used in the automotive sector, i.e. the traditional petrol Internal Combustion Engine and the full Battery Electric Vehicle. The different configurations have been analysed within 17 different impact categories in terms of climate change, human health, resourced depletion and ecosystems. The Well-to-Wheel approach allows to focus the attention on the use stage of the vehicle, considering the local effects due to the direct emissions in high density urban zones and it mitigates the dependence of usage hypotheses, different scenarios and intrinsic differences between the various models of cars in circulation.

Product eco-design includes several methodologies aimed at supporting companies in the development of sustainable products. Currently, this theme is assuming an important role in both the academia and industry worlds due to the increasing attention to environmental problems and the need for a transition toward circular economy business/organizational models. In this context, the present paper focuses on the industrial sector of espresso coffee machines manufacturing which has several unexploited potentialities. The analysis of the sector specificity (internal and external contexts), as well as of the product lifecycle allowed to define an eco-design framework to guide companies involved in the design and production of espresso coffee machines. Effective eco-design strategies should include the combined use of specific methods, tools and metrics to manage all the most important lifecycle phases (beginning of life, middle of life, end of life) during the design activities in order to set preventive actions that avoid future potential environmental impacts. Only in this way, the environmental and economic benefits of the circular economy paradigm (e.g. remanufacturing/reuse of selected components) can be practically exploited in real industrial contexts. The presented case studies confirmed that the application of design for disassembly rules positively contributes to increase the product performances during maintenance and end of life, while a re-design oriented to component modularity could be a key strategy to pursue remanufacturing for boilers, a key and expensive component included in espresso coffee machines.

Spine surgery is based, nowadays, on the use of cutting-edge instruments that optimize the intervention processes in the operating room, with advantages that affect the patient himself. Among these, rapid prototyping is configured as a first-rate tool, thanks to its ability to detail the diagnostic treatment according to the specific pathological case under examination. An example of this technology is represented by the generation of a drilling template, to assist the surgeon in identifying the optimal direction of insertion of the pedicle screws, capable of significantly reduce intervention times, in addition to the inevitable exposure of the patient to ionizing radiation, to which he is subjected during a normal arthrodesis intervention procedure. The design of a drilling guide requires, however, a particular attention in identifying the undercuts present on the vertebral surface, those areas of the spinous process which, reported inside the cavity of the template, involve complications at the time of extraction. In parallel, it is vitally important to carry out an evaluation of its stability during its use. In this article, starting from the analysis of the interferences present during the insertion of the template, a semi-automatic correction model is proposed for the generation of a new profile of the same, which facilitates its extraction without causing injury to the vertebral regions involved from the contact with the mask.

Laryngoscopes are used as diagnostic devices for throat inspection or as an aid to intubation. Their blade must be geometrically compatible with patients’ anatomy to provide a good view to doctors with minimal discomfort to patients. For this reason, this paper was aimed to investigate the feasibility of producing customized blades.The customizable blade model was developed following a feature-based approach with eight morphological parameters. The thickness of such a blade was determined through numerical simulations of ISO certification tests, where the finite element mesh was obtained by morphing a ‘standard’ mesh.The following procedure was applied: the model was built from the selected parameters; the blade was tested in silico; finally, the blade was produced by additive manufacturing with an innovative biodegradable material (Hemp Bio-Plastic® -HBP-) claimed to feature superior mechanical properties. The procedure evidenced that the mechanical properties of current biodegradable materials are unsuitable for the application unless the certification norm is revised, as it is expected.

This paper focuses on finger force magnitude analysis during stiffness discrimination task. In the frame of their Study and research work MS students from the Université Grenoble Alpes specially designed an experimental bench allowing to simulate a pseudo-haptic spring. Then, a series of stiffness discrimination tests between reals springs and a pseudo-haptic spring were performed. Finger pressing forces and students’ (subjects’) perception of spring stiffness were recorded and analyzed. The analysis of psychometric curves indicates that subjects underestimate the simulated stiffness of the pseudo-haptic spring. The results also indicate that the peak of finger force applied on pseudo-haptic spring increases as the simulated stiffness increases. Moreover, it was found that the relationships between the logarithm of stiffness and the finger force were linear for the real springs and the pseudo-haptic spring. Pseudo-haptics effect being provided by specially designed isometric force feedback device, the results of this study may be useful for computer-based rehabilitation tasks designed for motor disorder patients with muscle deficiency associated with limited joint movement range or for injured athletes in the process of rehabilitation.

In this paper, a tool able to support the sailing yacht designer during the early stage of the design process has been developed. Quadratic and cubic Rational Bézier curves have been selected to describe the main curves defining the hull of a sailing yacht. The adopted approach is based upon the definition of a set of parameters, say the length of water line, the beam of the waterline, canoe body draft and some dimensionless coefficients according to the traditional way of the yacht designer. Some geometrical constraints imposed on the curves (e.g. continuity, endpoint angles) have been conceived aimed to avoid unreasonable shapes. These curves can be imported in any commercial CAD software and used as a frame to fit with a surface. The algorithm and the related Graphical User Interface (GUI) have been written in Visual Basic for Excel. To test the usability and the precision of the tool, two sailboats with different characteristics have been replicated. The rebuilt version of the hulls is very close to the original ones both in terms of shape and dimensionless coefficients.

In ISO Geometrical Product Specifications and Verification Standards (GPS) [1], partition is one of the fundamental operations used to obtain ideal or non-ideal features of a product. The operation of partition produces independent geometrical features by decomposing the object. A curvature-based CAD mesh partitioning framework is proposed in this paper. The framework combines several key steps including curvature-based attribute calculation, local shape type refinement, region growing, slippage analysis and statistical modeling. The partitioned features are classified into seven invariance classes of surface in the context of ISO GPS. A case study shows that not only appropriate partitioning but also accurate invariance class recognition for GPS are achieved by the proposed framework.

Stochastic lattice structures are very powerful solutions for filling three-dimensional spaces using a generative algorithm. They are suitable for 3D printing and are well appropriate to structural optimization and mass distribution, allowing for high-performance and low-weight structures. The paper shows a method, developed in the Rhino-Grasshopper environment, to distribute lattice structures until a goal is achieved, e.g. the reduction of the weight, the harmonization of the stresses or the limitation of the strain. As case study, a cantilever beam made of Titan alloy, by means of SLS technology has been optimized. The results of the work show the potentiality of the methodology, with a very performing structure and low computational efforts.

The aim of this work is to implement a new process for the design and production of orthopaedic devices to realize entirely by Additive Manufacturing (AM). In particular, a generative algorithm for parametric modelling of flexible structures to use in orthopaedic devices has been developed. The developed modelling algorithm has been applied to a case study based on the design and production of a customized elbow orthosis made by Selective Laser Sintering. The results obtained have demonstrated that the developed algorithm overcomes many drawbacks typical of traditional CAD modelling approaches. FEM simulations have been also performed to validate the design of the orthosis. The new modelling algorithm allows designers to model flexible structures with no deformations or mismatches and to create parametric CAD models to use for the production of orthopaedic devices through AM technologies.

Thanks to the great diffusion of additive manufacturing technologies, the interest in lattice structures is growing. Among them, minimal surfaces are characterized by zero mean curvature, allowing enhanced properties such as mechanical response and fluidynamic behavior. Recent works showed a method for geometric modeling triply periodic minimal surfaces (TPMS) based on subdivision surface. In this paper, the deviation between the subdivided TPMS and the implicit defined ones is investigated together with mechanical properties computed by numerical methods. As a result, a model of mechanical properties as a function of the TPMS thickness and relative density is proposed.

This study compares two techniques of reconstruction and representation of the anterior and posterior surfaces of the human cornea, both for healthy and for keratoconus eyes, in a CAD software environment using raw tomographic data, by two different methods: a mesh model (obtained from a grid of points) and a NURBS surface model. After reconstruction, a morpho-geometric analysis was made, and several parameters were defined and measured in a set of 100 healthy eyes and 61 keratoconus eyes, detecting the statistical analysis significant differences between methods for both groups. Mesh method proved to be more accurate, but less eyes could be modelled. Volumetric and surface measurement values showed a total equivalence between both methods, so these would be the ones to use when modelling eyes for keratoconus detection and characterization purposes.

In this paper, due to the importance of maintaining a secure grip with the control hand in kayaking, a simple three phase process is presented for the massive development of personalized grips which allow the improvement of this handgrip. This process consists of obtaining the 3D geometry of the paddler's handgrip by using Reverse Engineering (RE) tools, designing the grip from the obtained 3D geometry by using Computer Aided Design (CAD) tools and manufacturing the grip by using Additive Manufacturing (AM) tools. Therefore, this paper shows that the RE, CAD and AM tools available today allow the customization of products for many applications.

The article discusses the design of an acquisition system for the 3D surface of human arms. The system is composed by a 3D optical scanner implementing stereoscopic depth sensors and by an acquisition software responsible for the processing of the raw data. The 3D data acquired by the scanner is used as starting point for the manufacturing of custom-made 3D printed casts. Specifically, the article discusses the choices made in the development of an improved version of an existing system presented in [1] and presents the results achieved by the devised system.

This paper addresses the way a simulated annealing-based fitting strategy can be enhanced by leveraging a sensitivity analysis able to characterize the impact of the variations in the parameters of a CAD model on the evolution of the deviation between the CAD model itself and the point cloud of the digitized part to be fitted. The principles underpinning the adopted fitting algorithm are briefly recalled. The applied sensitivity analysis is described together with the comparison of the resulting sensitivity evolution curves with the changes in the CAD model parameters imposed by the simulated annealing algorithm. This analysis suggests several possible improvements that are discussed. The overall approach is illustrated on the fitting of single mechanical parts but it can be directly extended to the fitting of parts’ assemblies. It is particularly interesting in the context of the Industry 4.0 to update digital twins of physical products and systems.

Graphical tools for firefighters in emergency interventions have been proven to be very effective. Particularly, paper-based operational guides and digital guides with 360º images were already assessed during the drills developed, during a training program in a real, but obsolete and not in use, hotel. The obtained results were considered very interesting, being part of the study previously published by this research team. In the previous study, three different methods (two of them based on graphical contents) were compared in order to communicate the features of a building to firefighters, five minutes before starting a victim rescue during the drills of the mentioned live fire training program. These good results encouraged us to continue the development of the digital guides and this paper describes the first one created for a real building, placed in Zaragoza (Spain), which is in use nowadays. In this study, two versions of the digital guide are presented, one based on a PDF file and another one implemented with online 360º images.

Nowadays, the use of renewable energies and electric vehicles has become particularly relevant in order to lower the high pollution levels surrounding our cities. The design of a photovoltaic canopy for charging electric vehicles is a highly promising combination that can be set up in urban areas. To favour installing them in different places, this communication provides details of the technico-functional aspects that have been considered to design and fit them, along with other aesthetic and user-centred aspects that help stimulate our society to use such infrastructures.

User Centered Design approach is used in many sectors and appropriated by many design teams to defend principles of products adapted to the final users. In the Architectural and Industrial Design disciplines, architects and designers defend principles that could be able to create spaces, public areas or innovated products that are closer as possible as the user behavior. The issue is still the complexity of the user perception and the variability of its interpretation of the environment. The research method used in this research is to combine Universal Design and Usability approaches to be able to extract one first list of principles. The combination of this list with the five human sensorial systems identified in the literature give the structure of a tool that can be proposed to projectists like architects and industrial designers to better consider user perception during the designing process. The result of the research is the proposition of a software coupled with a user friendly interface dedicated to architects and industrial designer. It has the aim to simplify the organization of the early phases of the design process, taking into account designers and architects design priorities and integrating the final user specific sensorial situation.

SPES (Selective Production of Exotic Species) is a large facility, currently under advanced construction at the INFN-LNL (Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro) for the production of Radioactive Ion Beams (RIBs). Coordinated efforts are being dedicated to the development and upgrading of both the accelerator complex and the up-to-date experimental set-ups. This paper describes a work of upgrading as far as the inspection and maintenance of the system is concerned, and it deals with human-centered design methods to reduce the time spent in the radioactive environment of the facility during ordinary maintenance operations and to simplify them, also considering stress conditions of the operator and the mandatory wearable radiation protection devices (such as tracksuit, gloves, oxygen tank mask) which make simple operations difficult.

This paper presents a new smart web platform for plastic injection molds for use in industry 4.0 environments. The new platform requires as its only input the CAD model of the plastic part in a discrete format, the accuracy of the analysis, the thermoplastic material of which the part will be manufactured and the number of parts to manufacture per year. Using this information and through a fully automated process based on hybrid algorithms developed by the authors the smart platform generates an extended CAD model of the mold with additional expert information useful for industry 4.0 environments. In this way, it is possible to design a mold with uniform heat transfer, balanced ejection and a uniform filling phase of the mold cavity. The presented platform differ from other applications for mold designing in that the resulting mold meets all the geometric, functional and technological requirements of mold designing without needing CAE simulation software for its validation. The presented platform is considered as the first smart platform that does not require the interaction of the designer in the process of dimensioning and designing the different subsystems that compound the mold, being a tool to reduce time and costs in the initial phases of plastic part design and with the ability to integrate into a flexible manufacturing environment 4.0.

In order to have a full control on their processes, companies need to ensure real time monitoring and supervision using Key Performance Indicators (KPI). KPIs serve as a powerful tool to inform about the process flow status and objectives’ achievement. Although, experts are consulted to analyze, interpret, and explain KPIs’ values in order to extensively identify all influencing factors; this does not seem completely guaranteed if they only rely on their experience. In this paper, the authors propose a generic causality learning approach for monitoring and supervision. A causality analysis of KPIs’ values is hence presented, in addition to a prioritization of their influencing factors in order to provide a decision support. A KPI prediction is also suggested so that actions can be anticipated.

The objective of this research is to set the ground for new research to measure the impact of Industry 4.0, by combining two types of analysis, that of the performance, and that of the human behaviors, using experiments with digital instruments. A preliminary test, then a first experiment focusing on standardization of operational processes are presented showing promising results to understand how operational and human performance are impacted by the Industry 4.0. This study serves as a first step to a larger research project about productivity measurement of Industry 4.0 transformation.

The level of industrial performance is a vital issue for any company wishing to develop and acquire more market share. This article presents a novel approach to integrate intelligent visual inspection into “MES” control systems in order to gain performance. The idea is to adapt an intelligent image processing system via in-situ cameras to monitor the production system. The images are thus analyzed in real time via machine learning interpreting the visualized scene and interacting with some features of the MES system, such as maintenance, quality control, security, operations, etc. This novel technological brick, combined with the flexibility of production, contributes to optimizing the system in terms of autonomy and responsiveness to detect anomalies, already encountered, or even new ones. This smart visual inspection system is considered as a Cyber Physical System CPS brick integrated to the manufacturing system which will be considered an edge computing node in the final architecture of the platform. This smart CPS represents the 1st level of calculation and analysis in real time due to embedded intelligence. Cloud computing will be a perspective for us, which will represent the 2nd level of computation, in deferred time, in order to analyze the new anomalies encountered and identify potential solutions to integrate into MES. Ultimately, this approach strengthens the robustness of the control systems and increases the overall performance of industrial production.

[Context] In manufacturing industries, the design of a product needs to comply with many design rules. These rules are essentials as they help industrial designers to create high quality design in an efficient way. [Problem] However, the management of an ever-increasing number of design rules becomes a real problem, especially for new designers. Even if there exists some knowledge management tools for design rules, their capabilities are still limited and many companies continue to store their design rules in unstructured documents. Nowadays, design rule application is still a difficult task that needs a circular validation process between many expert services in a manufacturing company. [Proposition] In this paper, we will analyze the main existing approaches for design rules application from which we will demonstrate the need of a new approach to improve the current state-of-the-art practices. To minimize rule application impact on the design process, we propose to develop a Context-Aware Design Assistant that will perform design rule recommendation on the fly while designing using computer-aided technologies. Our Design Assistant relies on the modelling of the design rules and the design context in a single knowledge graph that can fuel a recommendation engine. [Future Work] In future work, we will describe the technical structure of the Context-Aware Design Assistant and develop it. The potential outcome of this research are: a better workflow integration of design rules application, a proactive verification of design solutions, a continuous learning of design rules, the detection and automation of design routines.

The rise of new technologies has led to a growth in the number of 3D models. They can come from various source, hence they are heterogeneous and complex. The level of 3D data access is often a function of the user’s expertise since the 3D data are often registered to different file formats. Some file formats do not show the data tree, as IGES. For using information inside a 3D model, that does not show a data tree, each company adopts his own system that will allow him to access easily to 3D model in order to exploit the hidden knowledge within the models. In this article, we are going to speak about technologies that helps user to exploit and knowledge coming from different file formats. In addition, we are going to present a system named VAQUERO that uses ontology to access, store and share knowledge coming from 3D models.

Manufacturing industry data are distributed, heterogeneous and numerous, resulting in different challenges including the fast, exhaustive and relevant querying of data. In order to provide an innovative answer to this challenge, the authors consider an information retrieval system based on a graph database. In this paper, the authors focus on determining the essential functions to consider in this context. The authors define a three-step methodology using root causes analysis and resolution. This methodology is then applied to a data set and queries representative of an industrial use case. As a result, the authors list four major issues to consider and discuss their potential resolutions.

The paper provides a method to acquire, process, and represent DfMA rules to help designers and engineers in the development of mechanical products compliant with manufacturing and assembly technology. This research work wants to define a general method able to link DfMA design guidelines (knowledge engineering) with geometrical product features that are available by the investigation of the 3D model. Numerical parameters of design features are related to design guidelines for the identification of manufacturing and assembly issues within the analysis of the 3D model.

Since 2002, the University of the Basque Country (UPV/EHU) has supported several teaching experiences related to the so-called Life Cycle Thinking or Ecodesign in collaboration with local Institutions. The kick off was the Ecodesign Learning Center aiming to promote environmental education at the Faculty of Engineering in Bilbao. In this framework, the last effort has been the implementation of a Master’s Degree entitled Circular Economy: Business Application. This course has been successfully implemented in the 2019–2020 academic year and has been specifically designed to provide training in circular economy for people with backgrounds as varied as product manufacturing engineering, environmental engineering or economics. These studies are aimed to become a European reference in its goal of promoting circular economy, life cycle thinking, ecodesign and sustainable development. This paper analyzes the learning issues and characteristics of this Master's degree placing a special emphasis on its novel competencies and learning outcomes for our society. It can be concluded that the Master's degree is a pioneering teaching experience, being the forefront of Circular Economy Education in Southwestern Europe.

The economic environment demands companies to be able of innovating and presenting new products and technologies. However, current industrial environments are composed of big established companies, small or medium family businesses and regional clusters. This business map does not comply with the dynamism required for detecting needs and proposals in form of new products that meet the current customer requirements. The creation of start-ups in the field of engineering is considered as a possibility to cover a growing market in designing high technological products. However, despite the importance and economic impact of the start-ups for less industrialized environments the courses in the engineering field do not include activities that contextualize theoretical knowledge and entrepreneurship. The paper presents the results of creating an entrepreneurial environment focused on the student as entrepreneurial unit. In this context, a series of new activities based on new design proposals have been developed on the basis of new technical solutions for industrial companies. The new designs have been presented as minimum viable products. The technical knowledge required for making the new designs has been complemented with entrepreneurial training. The results show an increase in students' willingness to create small companies based in new products as an employment option at the end of their studies.

Teaching product design is not a trivisal task. Considering the experience done along 20 years of teaching at master level class in mechanical engineering it is possible to take stock. The model followed is Project-Based Learning and this method can be licensed as the model that gives greater satisfaction to all attendees. Students give high score to the survey organized by university at the end of the course to assess didactic validity. Also, teachers have many stimuli when discussing with students the activities proposed. The course is based on the development of an industrial product that solves a problem, eventually posed by industry or emerged by customers. Based on the course schedule, the different phases of product development put in evidence the steps that require divergent thinking and those where it is necessary to employ convergent thinking. A case study allows explaining all the phases of product design.

This paper presents the results of a survey carried out with students enrolled in the first two years of the BS in Engineering at three Italian university locations. The study is part of a wider range of methods, tools and aids for the improvement of teaching and learning of technical drawing at university level developed by the University of Brescia, Udine, and Cassino and Southern Lazio. In particular, this work analyses the results of questionnaires related to the basic technical drawing outcomes, taking inspiration from previous research work in this field. What emerges is a positive picture that shows students’ interest in 3D CAD modeling topics such as part or assembly construction, but also their interest in more traditional subjects like sketching and dimensioning.

This paper presents a parametric cost model for estimating the raw material cost of components realized employing the investment casting process. The model is built using sensitivity analysis and regression methods on data generated by an analytic cost model previously developed and validated by the same authors. This is the first attempt of developing a parametric cost model for investment casting based on activity-based costing. The proposed cost model accounts component volume, material density and material price. The error in estimating the raw material cost for components whose volume is within the common range of investment casting is around 11%.

We propose that a systems engineering methodology may be applied in an effective interactive design environment for lifecycle cost estimation and value optimization in the context of a manufacturing enterprise. In order to optimize a product design for value, engineering and manufacturing businesses need to be able to estimate accurately product lifecycle costs during the early design phases of its development, because this is when the majority of these costs are determined. Systems engineering defines realizing value as meeting stakeholder requirements and emphasizes formalizing these in order to link coherently the individual estimated costs of a design to the needs it fulfils. Furthermore, formalized requirement and design parameters are suitable for modelling and simulation, and we envision a systems model implemented within existing knowledge-based engineering tools embedded in a design environment. The results of this model may support design decisions, as well as reinforce systems engineering analyses in evaluating processes for value chain simulations.

Industry 4.0 is an ubiquitous term that suggests significant impacts on the productivity and flexibility of production systems. But to what extent do the various technologies associated with Industry 4.0 contribute to enhance autonomy of operational teams by helping them make better and faster decisions, particularly in the context of Lean production system? This paper proposes a model of different types of autonomy in the decision-making process, depending on whether or not the steps in the decision-making process are enhanced by technologies. This model will be tested afterwards in a use case implemented in a learning factory offering Lean management training before being tested in a real production unit.

The design of medical devices is challenging, due to strict geometry specifications and criteria belonging to several disciplines. The aim of this paper is to provide a design methodology which seems to lack in the literature of design of biomedical devices. In particular, the case study proposed in this paper concerns with the design of Bone-Biopsy (BB) needle devices. Following the design process of Pahl and Beitz, a functional analysis is carried out, to point out the interfaces between parts of existing BB needles. A morphology matrix is used to generate alternatives for the cannula holder, the core part of the product. Generated alternatives have been ranked and scored by means of the Pugh’s Controlled Convergence method according to the decision makers' opinions. In this work, the design peculiarities related to the BB needles which have been pointed out could be extended for guiding the design of other biomedical devices.

In recent years, many changes have been taking place within the construction sector which is much more prone to innovate than in the past. New forms of processes are emerging with the introduction of digital technologies. This article aims to shed light on recent scientific advances that link Industry 4.0 to this sector. To this end, a review of articles published over the past 10 years reporting experiences and gains from 4.0 technologies applied to construction was conducted. It turns out that recent technological developments have brought new functionalities and new perspectives to companies. Some of these were not initially claimed with the sole deployment of a BIM approach. These new opportunities have ultimately raised questions as to whether and how they could impact the speed at which a digital transformation of the sector could take place.

Smart tightening development is part of the Industry 4.0 transformation with the introduction of smart tools, and preload in bolted assemblies is of major interest in today’s aircraft manufacturing process. So far, it has been difficult to estimate the importance of each parameter for tightening process quality, mainly because of the large number of combinations and configurations that exist.The present work aims at evaluating the effects and the interactions between different parameters that have to be taken in consideration in future torquing strategy. Many experimental tests have been conducted on an Automatica test bench using a Taguchi strategy and an analysis of the first main results is now presented, highlighting the complexity of the phenomena studied.All these points will help us to better understand tightening, so as to improve performance during installation, maintenance and repair.

Reconfigurable Manufacturing Systems (RMS) have gained importance in the current context of increasing high variety demand, Mass Customization (MC) and market instability, due to their ability of being quickly modified to adjust their production capacity to attain sudden fluctuations in market demands as well as to accommodate operations of new products. RMS can be configured at system and machine levels. Many papers have described the RMS configuration as combinatorial optimization problems and proposed several techniques to optimize them in terms of different responses of interest. This paper presents a literature review that seeks to understand how RMS configuration has been addressed in terms of configuration level, optimization problem modelling and techniques applied to solve it. This work aims to assist researchers working on RMS configuration to identify trends and new research opportunities.