Abstract: Industrial Robots (IR) are currently employed in several production areas as they enable flexible automation and high productivity on a wide range of operations. The IR low positioning performance, however, has limited their use in high precision applications, namely where positioning errors assume importance for the process and directly affect the quality of the final products. Common approaches to increase the IR accuracy rely on empirical relations which are valid for a single IR model. Also, existing works show no uniformity regarding the experimental procedures followed during the IR performance assessment and identification phases. With the aim to overcome these restrictions and further extend the IR usability, this paper presents a general method for the evaluation of IR pose and path accuracy, primarily focusing on instrumentation and testing procedures. After a detailed description of the experimental campaign carried out on a KUKA KR210 R2700 Prime robot under different operating conditions (speed, payload and temperature state), a novel online compensation approach is presented and validated. The position corrections are processed with an industrial PC by means of a purposely developed application which receives as input the position feedback from a laser tracker. Experiments conducted on straight paths confirmed the validity of the proposed approach, which allows remarkable reductions (in the order of 90%) of the orthogonal deviations and in-line errors during the robot movements.
Abstract: Wire Arc Additive Manufacturing is based on a welding torch usually attached to a robotic arm with multiple degrees of freedom. Robot-based additive manufacturing allows non-planar and non-uniform thickness layers to be deposited where the slices have non-constant thickness. Thus, in addition to the motion settings, fine regulations of the welding parameters become necessary to obtain variable bead heights in the same slice. This paper aims to evaluate the user-accessible welding parameters’ influence on the deposited material’s dimensions during continuous Cold Metal Transfer (CMT) and its variant named CMT Cycle Step. In particular, the height and width of beads are investigated by varying the travel speed and the wire-feed rate (continuous CMT), as well as the size of the droplets by varying the number of CMT cycles and the wire-feed rate (CMT Cycle Step). In particular, the characterization of the material deposited during the CMT Cycle Step is not deeply studied in the literature. The experimental specimens are measured and the obtained values are numerically processed to yield empirical formulas that link the dimensions of the deposited material with the selected process parameters. The results show that CMT Cycle Step is more stable than continuous CMT, which confirms its higher suitability for accurate manufacturing.
Keywords: Bead Modeling | Cold Metal Transfer | Experimental characterization | Wire and Arc Additive Manufacturing
Abstract: The study of an automated system for intralogistics requires an important use of time and resources, starting from the input data analysis up to the definition of the technical solution. While many commercial tools are available for testing and optimizing the plant performance during the advanced design stages, little work has been done concerning the workflow to be followed at the pre-sales design phase. In this context, the present paper focuses on the definition of the best practices for the correct preliminary definition of a robotic cell for palletization. To simplify and speed up the pre-sales feasibility study and estimate the performance of the proposed robotic system, an engineering approach based on a simplified theoretical model is reported and integrated within a dynamic calculation table. As the main output, the proposed tool calculates the robot saturation which is a key index for the plant preliminary definition.
Keywords: Design Tool | Industry 4.0 | Palletizing Robotic System | Performance Definition | Pre-Sales Design
Abstract: Planar slicing algorithms with constant layer thickness are widely implemented for geometry processing in Additive Manufacturing (AM). Since the build direction is fixed, a staircase effect is produced, decreasing the final surface finish. Also, support structures are required for overhanging portions. To overcome such limits, AM is combined with manipulators and working tables with multiple degrees of freedom. This is called Robot-Based Additive Manufacturing (RBAM) and it aims to increase the manufacturing flexibility of traditional printers, enabling the deposition of material in multiple directions. In particular, the deposition direction is changed at each layer requiring non-uniform thickness slicing. The total number of layers, as well as the volume of the support structures and the manufacturing time are reduced, while the surface finish and mechanical performance of the final product are increased. This paper presents an algorithm for non-uniform planar slicing developed in Rhinoceros and Grasshopper. It processes the input geometry and uses parameters to capture manufacturing limits. It mostly targets curved geometries to remove the need for support structures, also increasing the part quality.
Abstract: Industrial Robots (IRs) are increasingly adopted for material subtraction or deposition functions owing to their advantages over machine tools, like cost-effectiveness and versatility. Unfortunately, the development of efficient robot manufacturing processes still faces unsolved issues related to the IRs poor positioning accuracy and to the tool path generation process. Novel engineering methods and tools are needed for CAD based programming of accurate paths and continuous robot motions to obtain the required manufacturing quality and tolerances. Within this context, to achieve smoothness along the tool path formed by linear G-code segments, the IR controllers’ approximation strategies, summarily reported in the manufacturer’s manuals, must be considered. The aim of this paper is to present the preliminary work carried out to identify the approximation algorithms of a Kuka IR when executing linear moves. An experimental study is conducted by varying the controller settings and the maximum translational velocity. The robot behavior has been acquired thanks to the controller tracing function and then processed to yield relations readily employable for the interpretation of G-Code commands and the subsequent generation of proper robot motion instructions. The obtained formulas allow to accurately predict the robot geometric path and kinematics within the corner transition between two linear segments.
Abstract: Augmented Reality (AR) is one of the leading technologies of the Industry 4.0 revolution, offering innovative interfaces to promote the diffusion of digital contents into industrial processes, thanks to flexible and robust solutions and cost-effective devices. In this context, this paper explores the adoption of AR in industrial logistics where several open issues still discourage its effective use in everyday scenarios. After a review of objectives, approaches and technics of AR integration in logistics operations, the paper presents a framework to identify goods in a warehouse, retrieve data relative to the package, display info to the user to drive operations. The approach aims at easing and speeding up the activity of the warehouseman to identify goods, check the relative information and to put each good on the correct shelf. A prototypal application was developed within the Unity platform and integrated with the company ERP system to manage data on the products and retrieve images of the identification labels. A real use case involving a primary company producing agricultural tractors is proposed to test usability of the prototype. Results showed that the developed application allows relevant benefits in terms of process effectiveness, error prevention, aiming at reducing the operator mental workload.
Abstract: Design For Assembly (DFA) aims at improving product design facilitating assembly phases via the application of evaluation metrics and design guidelines. However, DFA analyses are usually performed manually and the adoption of supporting tool is poor. This paper investigates the application of algorithms allowing to extract from CAD assembly models the required data to perform automated DFA analyses, thus providing a tool to support designers’ everyday works. In particular, attributes from geometric feature recognition algorithms, solids properties and assembly parts’ semantics are leveraged and mapped to the parameters required to accomplish DFA evaluations. The proposed approach is illustrated on a 3D printer for home use. At first, a manual DFA analysis has been performed on the product identifying product BOM, components properties, assembly cycle and times according to models in the literature. Then, the CAD model of the printer has been processed with some geometric algorithms to verify the possibility to extract the required data to be used as input to the DFA analysis. The test case has demonstrated the feasibility of the approach, even if some design considerations and improvement directions still need the critical evaluation of the designer.
Keywords: Assembly semantics | Design For Assembly | Feature recognition | Part recognition
Abstract: The work here presented is part of a wider research project aimed at extracting and using in industrial applications high level semantic information from 3D product models that are described by means of their boundary representation (B-rep). The specific focus of the paper is the recognition among the components of the CAD model of an assembly of those belonging to some categories of standard parts largely employed in mechanical industry. The knowledge of these components is crucial to understand the structure of mechanical products as they have specific meaning and function. Standard parts follow international standard in shape and dimensions, and also typical mounting schemes exist concerning their use in the product assembly. These distinctive features have been exploited as a starting point to develop a multi-step recognition algorithm. It includes a shape-based and a context-based analysis both relying on the geometric and topological analysis of a CAD model. As already anticipated by Voelcker in his visionary ability to anticipate open challenges, the shape of an object alone is not enough to understand its function. Therefore, context assessment becomes crucial to validate the recognition given by the shape-based step. It allows to uniquely recognize components in mechanical CAD models, by confirming correct results, refusing the false positives, as well as choosing the correct one when the assignment is multiple.
Keywords: 3D part recognition | Assembly analysis | CAD model processing | Standard part
Abstract: Nowadays, manufacturing plants are required to be flexible to respond quickly to customer demands, adapting production and processes without affecting their efficiency. In this context, Industrial Robots (IRs) are a primary resource for modern factories due to their versatility which allows the execution of flexible, reconfigurable, and zero-defect manufacturing tasks. Even so, the control and programming of the commercially available IRs are limiting factors for their effective implementation, especially for dynamic production environments or when complex applications are required. These issues have stimulated the development of new technologies that support more efficient methods for robot control and programming. The goal of this research is to identify and evaluate the main approaches proposed in scientific papers and by the robotics industry in the last decades. After a critical review of the standard IR control schematic, the paper discusses the available control alternatives and summarizes their characteristics, range of applications, and remaining limitations.
Keywords: industrial robots | instruction streaming | open controller | robot control | robot programming | trajectory streaming
Abstract: Assembly sequence planning starting from CAD models turned out to be a relevant task in the industrial manufacturing field. To have a successful assembly sequence, the relations between the assembly's parts and the possible interferences during the assembly operations deserve to be investigated. In particular, the collision analysis is the phase in which the movement of each part along some directions is evaluated to assess if it is obstructed by any of the other parts, and according to which the precedence matrix is computed. A lot of work has been done to address the problem, however, existing algorithms need to be improved yet. Among the open issues, the following three result to be the most challenging: the combinatorial explosion of the problem complexity, the limited choice of the assembly directions, and the engineering meaning of parts that is not taken into account, or it is manually given in input by experts. In this paper, an automatic assembly sequence planning approach is introduced. The focus is on the collision detection and precedence analysis for engineering meaningful subassemblies, namely the axisymmetric. Information automatically extracted relying on geometric processing and engineering knowledge, such as parts features and semantic interpretation of mechanical components, is first exploited to identify the subassemblies and, then, to choose the feasible assembly direction, as well as to treat fasteners and deformable parts in a more realistic way. An industrial CAD model of a gearbox is selected as case study to illustrate the approach, also emphasizing the importance of axisymmetric subassemblies.
Abstract: Robot-Based Additive Manufacturing (RBAM) combines material deposition nozzles and robotic manipulators to increase the flexibility of cartesian/delta Additive Manufacturing (AM) systems. RBAM overcomes the traditional limit given by the planarity of the manufacturing layer and allows variable slice thickness to be realized. Also, RBAM enables the deposition of the material in multiple directions. In this context, volume decomposition algorithms are implemented to split a solid into several sub-volumes. Each sub-volume is sliced according to an optimal direction to perform support-free manufacturing and to avoid tool collisions. A novel algorithm for the volume decomposition of a given input geometry is presented. In particular, it allows several planar separation surfaces to be computed that are used to split a general input shape. The surfaces are defined by analyzing overhangs according to an initial slicing direction. The normal of the surfaces identifies the slicing direction of the related sub-volumes. The algorithm steps are iterated to reach the complete removal of overhangs. The approach is tested in some case studies to evaluate its applicability.
Abstract: The Servo-Mechanisms (SMs) mounted in industrial robots joints are a major source of positioning accuracy errors. To improve robots precision performance, researchers have been focusing on the development of novel SMs design and control strategies, which need extensive experimental analyses to tune their parameters. In this context, the scope of this paper is double: first, to present the novel experimental apparatus and methods designed to improve the accuracy of the transmission performance evaluation of high dynamics SMs and, secondly, to report and discuss the achieved experimental results. In the first part, a description of the test rig tuning operations is given, primarily focusing on the signals synchronization and on the elimination of the measuring errors caused by the mechanical transmission elasticity and the servomotor torque ripples. Then, control strategies for compensating the torque ripples and input speed errors are defined. It is shown that speed oscillations can be reduced of ≈70% when rotating the servomotor up to 2000 rpm, improving the measurement quality of the reducer performance. In the second part, a set of experiments is carried out to assess the combined effect of input speed and lubricant temperature on the reducer behavior. The system sensitivity to the variation of the input parameters is confirmed by the dynamic lost motion curves, whose mean value equals 16.8″ and 35.4″ when the reducer is operated at its minimum and maximum friction load respectively. At last, the extrapolated harmonic content is used to build a simple mathematical model of the reducer transmission error.
Keywords: Experimental methods | Lubricant temperature | Robot reducers | Servo-mechanisms | Test rig | Torque ripples | Transmission error
Abstract: Intelligent robotic manufacturing cells must adapt to ever-varying operating conditions, developing autonomously optimal manufacturing strategies to achieve the best quality and overall productivity. Intelligent and cognitive behaviors are realized by using distributed controllers, in which complex control logics must interact and process a wide variety of input/output signals. In particular, programmable logic controllers (PLCs) and robot controllers must be coordinated and integrated. Then, there is the need to simulate the robotic cells’ behavior for performance verification and optimization by evaluating the effects of both PLC and robot control codes. In this context, this work proposes a method, and its implementation into an integrated tool, to exploit the potential of ABB RobotStudio software as a virtual prototyping platform for robotic cells, in which real robots control codes are executed on a virtual controller and integrated with Beckhoff PLC environment. For this purpose, a PLC Smart Component was conceived as an extension of RobotStudio functionalities to exchange signals with a TwinCAT instance. The new module allows the virtual commissioning of a complete robotic cell to be performed, assessing the control logics effects on the overall productivity. The solution is demonstrated on a robotic assembly cell, showing its feasibility and effectiveness in optimizing the final performance.
Abstract: Focus of this work is the recognition of the standard parts contained in a CAD assembly model, with the aim of enhancing the model semantics. Standard parts are components typically used in mechanical industry, which have a specificc engineering meaning and follow international standards. In particular eight categories of standard parts are considered, i.e. screws, nuts, O-ring, washers, circlips,keys, studs and pins. The provided algorithm relies on the geometric and topological analysis of the CAD model parts. A part is assigned to one of the categories if it satisfies the geometric requirements extracted for that specific category, based on engineering knowledge and design rules. In addition, if a part is recognized as standard part, besides the class of membership, further information is provided as result, namely its engineering dimensions.
Keywords: Assembly Semantics | CAD Model Processing | Part Classification | Standard Part Detection | Type Recognition
Abstract: Compared to other additive technologies, Wire and Arc Additive Manufacturing (WAAM) offers high deposition rates, flexibility and a larger build volume as well as reduction of material waste. WAAM can be combined with a subtractive technology in hybrid robotic cells to further increase the application scope, thus producing products with improved surface finish where needed. However, there are some open issues that limit this process. So, the main goal of this paper is to review current research developments and provide a framework aimed at manufacturing parts by hybrid cells. A procedure is defined which moves from the evaluation of the designed shapes, their analysis to identify a proper manufacturing sequence until the elaboration of the instructions for the cell automaton controllers. Main WAAM issues are outlined to identify main research directions, and a test case is presented to highlight the process phases.
Keywords: Hybrid manufacturing | Process planning | Robotic cell | Wire and arc additive manufacturing
Abstract: The fourth industrial revolution is evolving the machines as well as the abilities of people working in the factories. Human roles and tasks are changing, moving from highly physical tasks to decision-making and high-precision activities, asking for different competencies and creating new types of interactions with machines. This paper reviews the design and engineering methods for the inclusion of human factors in modern companies. Human factor integration (HFI) can play a key role in the design of factories with a great impact on social aspects and global process sustainability. The paper proposes a systematic view of the main tools to design human-centered industrial processes, with a specific focus on manufacturing, and discusses trends to achieve and effective HFI.
Abstract: The fourth industrial revolution is characterized by flexible production systems that can respond to the demand for high variability and customization of the product. To maintain the efficiency of the production process, automated and flexible solutions are mandatory. This paper describes an approach to design Virtual Prototypes of robotic cells and support designer in the definition and simulation of the manufacturing system. The identified model is capable of replicating the performance of the cell under different aspects in a holistic manner: geometry, operating logic, performance, and physical behavior. The design approach is demonstrated on a robotic cell composed of two anthropomorphic robots for the flexible process of automatic assembly of mechanical parts. The resulting model proves to be straightforward, accurate and complete.
Abstract: Industry 4.0 is driving the revolution of manufacturing processes by combining innovative technologies and new interaction paradigms among systems and operators. In particular, the layout, tasks and work sequences of assembly lines are designed according to several transdisciplinary Design Principles (DPs), such as process efficiency, product quality, ergonomics, safety and operators' workload. A large variety of simulation software can be employed for evaluations. However, the related ability to assess multidisciplinary factors must be evaluated. The paper aims to provide a framework for guiding the assessment of simulation software in the context of Industry 4.0 assembly lines. Process requirements are first analyzed and mapped to select DPs, prioritized according to design goals by an analytical hierarchy process. Then, suitable simulation software is determined accordingly, and the virtual model is realized. Finally, the possibility of the software to provide meaningful elaborations for the selected DPs is assessed. The framework has been tested on a prototypal Industry 4.0 assembly line composed of automated logistic systems, cobots and systems to guide the execution of tasks. The line has been modeled in Siemens Process Simulate, analyzing the completeness and appropriateness of the functionalities of this software according to the defined DPs.
Keywords: Decision Support Tools | Design Principles | Industry 4.0 | Interactive Simulation for Engineering | Transdisciplinary Engineering
Abstract: Nowadays, robot-based additive manufacturing (RBAM) is emerging as a potential solution to increase manufacturing flexibility. Such technology allows to change the orientation of the material deposition unit during printing, making it possible to fabricate complex parts with optimized material distribution. In this context, the representation of parts geometries and their subsequent processing become aspects of primary importance. In particular, part orientation, multiaxial deposition, slicing, and infill strategies must be properly evaluated so as to obtain satisfactory outputs and avoid printing failures. Some advanced features can be found in commercial slicing software (e.g., adaptive slicing, advanced path strategies, and non-planar slicing), although the procedure may result excessively constrained due to the limited number of available options. Several approaches and algorithms have been proposed for each phase and their combination must be determined accurately to achieve the best results. This paper reviews the state-of-the-art works addressing the primary methods for the representation of geometries and the subsequent geometry processing for RBAM. For each category, tools and software found in the literature and commercially available are discussed. Comparison tables are then reported to assist in the selection of the most appropriate approaches. The presented review can be helpful for designers, researchers and practitioners to identify possible future directions and open issues.
Abstract: The fourth industrial revolution is promoting the Operator 4.0 paradigm, originating from a renovated attention towards human factors, growingly involved in the design of modern, human-centered processes. New technologies, such as augmented reality or collaborative robotics are thus increasingly studied and progressively applied to solve the modern operators’ needs. Human-centered design approaches can help to identify user’s needs and functional requirements, solving usability issues, or reducing cognitive or physical stress. The paper reviews the recent literature on augmented reality-supported collaborative robotics from a human-centered perspective. To this end, the study analyzed 21 papers selected after a quality assessment procedure and remarks the poor adoption of user-centered approaches and methodologies to drive the development of human-centered augmented reality applications to promote an efficient collaboration between humans and robots. To remedy this deficiency, the paper ultimately proposes a structured framework driven by User eXperience approaches to design augmented reality interfaces by encompassing previous research works. Future developments are discussed, stimulating fruitful reflections and a decisive standardization process.
Keywords: Augmented reality | Human factors | Human-centered design | Human–robot collaboration | Human–robot interaction | User eXperience
Abstract: Nowadays companies have to face a competitive market that requires small volumes with a high level of customisations. In this context, assembly quality and timeliness is crucial. To guarantee flexibility and personalization, manual operations still have a crucial role for a lot of manufacturing sectors, so that workers' conditions and ergonomics are important factors to achieve a better product quality and overall cost reduction. Ergonomics evaluation in manufacturing is a challenging and expensive activity that requires a transdisciplinary approach, to merge technical and social sciences to finally have a consolidated and reliable evaluation. This paper compared two digital human simulations tools offered by Siemens Tecnomatix: Jack and Process Simulate. They were applied on the same industrial case study, concerning the hood assembly of an agricultural machine, comparing results on ergonomics reports and usage time. Results confirmed the advantage of adopting a digital approach to predict the human effort and ergonomic risk related to a series of tasks. At the same time, they showed the major strengths and weaknesses of the two analysed tools and defined how they can be successfully adopted by companies. The paper finally provided guidelines to drive companies in choosing the best tool according to their needs.
Keywords: Digital human simulations | Digital manufacturing | Ergonomics | Human-centered design | Transdisciplinary engineering
Abstract: In recent years Human-Robot Collaboration (HRC) has become a strategic research field, considering the emergent need for common collaborative execution of manufacturing tasks, shared between humans and robots within the modern factories. However, the majority of the research focuses on the technological aspects and enabling technologies, mainly directing to the robotic side, and usually neglecting the human factors. This work deals with including the needs of the humans interacting with robots in the design in human-robot interaction (HRI). In particular, the paper proposes a user experience (UX)-oriented structured method to investigate the human-robot dialogue to map the interaction with robots during the execution of shared tasks, and to finally elicit the requirements for the design of valuable HRI. The research adopted the proposed method to an industrial case focused on assembly operations supported by collaborative robots and AGVs (Automated Guided Vehicles). A multidisciplinary team was created to map the HRI for the specific case with the final aim to define the requirements for the design of the system interfaces. The novelty of the proposed approach is the inclusion of typically interaction design tools focusing in the analysis of the UX into the design of the system components, without merely focusing on the technological issues. Experimental results highlighted the validity of the proposed method to identify the interaction needs and to drive the interface design.
Keywords: Human Factors | Human-Robot Collaboration | Human-Robot Interaction | Industrial Ergonomics | User eXperience
Abstract: The paper presents an interactive methodology partially inspired by Japanese Kaizen concept and applicable in several industrial contexts; its implementation starts when different circumstances arise, e.g. an analysis is carried out and some criticalities emerge. The proposed methodology aims at continuously improving processes under the environmental and economic perspectives. It is made up of eleven steps that leads the group from the issue identification to a new status, improved than the previous one, and improvable than the following. The case study describes an implementation of the methodology in an Italian medium company acting in the clothing sector, demonstrating its validity and efficacy. It was launched in the firm after energetic and environmental analyses outlined material, energy wastes and environmental impacts; they were tackled, and results show the methodology to be successful both from environmental and economic point of view.
Keywords: Energy analysis | Environmental sustainability | Kaizen | Life cycle assessment | Sustainable manufacturing | Waste reduction
Abstract: Product and process digitalization is pervading numerous areas in the industry to improve quality and reduce costs. In particular, digital models enable virtual simulations to predict product and process performances, as well as to generate digital contents to improve the general workflow. Digital models can also contain additional contents (e.g., model-based design (MBD)) to provide online and on-time information about process operations and management, as well as to support operator activities. The recent developments in augmented reality (AR) offer new specific interfaces to promote the great diffusion of digital contents into industrial processes, thanks to flexible and robust applications, as well as cost-effective devices. However, the impact of AR applications on sustainability is still poorly explored in research. In this direction, this paper proposed an innovative approach to exploit MBD and introduce AR interfaces in the industry to support human intensive processes. Indeed, in those processes, the human contribution is still crucial to guaranteeing the expected product quality (e.g., quality inspection). The paper also analyzed how this new concept can benefit sustainability and define a set of metrics to assess the positive impact on sustainability, focusing on social aspects.
Keywords: Augmented reality | Humancentered design | Model-based design | Product development | Quality inspection | Social sustainability
Abstract: Additive Manufacturing (AM) technologies have expanded the possibility of producing unconventional geometries, also increasing the freedom of design. However, in the designer’s everyday work, the decision regarding the adoption of AM for the production of a component is not straightforward. In fact, it is necessary to process much information regarding multiple fields to exploit the maximum potential of additive production. For example, there is a need to evaluate the properties of the printable materials, their compatibility with the specific application, redesign shapes accordingly to AM limits, and conceive unique and complex products. Additionally, procurement and logistics evaluations, as well as overall costs possibly extending to the entire life cycle, are necessary to come to a decision for a new and radical solution. In this context, this paper investigates the complex set of information involved in this process. Indeed, it proposes a framework to support and guide a designer by means of a structured and algorithmic procedure to evaluate the opportunity for the adoption of AM and come to an optimal design. A case study related to an ultralight aircraft part is reported to demonstrate the proposed decision process.
Keywords: Additive manufacturing | Design for additive manufacturing | Multi criteria decision‐making | Product design
Abstract: The Industry 4.0 framework is pushing the manufacturing systems towards a zero-defect production based on robot technologies. The increasing level of automation in the production lines is raising new challenges for designers that must face the latest requirements in terms of product quality and power consumption. Among the multitude of components of the industrial plants, Servo-Mechanisms (SMs) play a crucial role and govern important performance indices of both robots and automatic machines. During the execution of high dynamics tasks, the SMs performance is influenced by many factors, including motion law, acting load, temperature and degradation. The development of accurate models aiming at predicting and optimizing the SMs behavior may not be practicable without extensive experimental activities. Owing to these considerations, this work introduces a novel test rig for the accurate characterization of industrial SMs. The rig is designed by combining the advantages of the existing prototypes. It is equipped with high precision sensors and an active loading system that enable to test the SM in various working conditions. Also, the rig modularity facilitates the installation of newly commissioned components and the execution of static and dynamic experiments. The paper mainly focuses on the rig mechanical design and components selection criteria.
Keywords: Computer Aided Design | Design methods | High Precision Manufacturing | Industry 4.0 | Servo-Mechanism Test Rig
Abstract: Mechanical assemblies are very complex structures, made of many parts of various shapes and sizes with different usages. Consequently, it is challenging to manage them during all the manufacturing processes, from the design to the assembly and the recycling. Aiming to simplify the assembly structure and reduce the number of parts to deal with simultaneously, in literature many works exist on subassemblies identification starting from the CAD assembly model. However, the methods provided loose sight of many details associated with the parts, as well as the fact that the treated model represents a real mechanical assembly which respects precise engineering rules. At this regard, this work introduces a novel methodology to detect meaningful clusters in CAD assembly models. The logic applied relies on engineering knowledge, both of mechanical assemblies' components and of assembling techniques, and on the leveraging of the semantics of components. In particular, referring to general design rules, we have identified some heuristics to exploit to partition the assembly into different types of clusters, such as the symmetry along an axis and the presence of fasteners or welds. It results that the assembly's parts are meaningfully grouped, considering, at the same time, their shape, functionality, and type of contact.
Abstract: 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.
Abstract: 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%.
Abstract: Latest trends and developments in digital technologies have enabled a new manufacturing model. Digital systems can monitor, optimize and control processes by creating a virtual copy of the physical world and making decentralized decisions. This paradigm relies on the development of a digital counterpart, the Digital Twin, for each production resource taking part to the whole manufacturing process. Although real applications of Digital Twin may differ in technical and operational details, in the past years, a huge effort has been done in order to identify and define focal functionalities and properties, as well as main challenges for the practical implementation within real factories. This paper is intended to review and analyse principles, ideas and technological solutions of the Digital Twin vision for production processes focusing on the practical industrial implementation. The purpose of this document is therefore to summarize the current state-of-art on Digital Twin concepts, and to draw their up-to-date state for application and deployment in real industrial processes. Finally, future directions for further research are discussed.
Keywords: Digital twin | digital twin industrial architecture | industrial implementation | industry 4.0 | smart manufacturing
Abstract: In industrial manufacturing, both in the design and the production phase, the management of modern mechanical assemblies is becoming demanding due to their increasing complexity. The use of stable subassemblies concept constitutes a better alternative, which allows to independently treat smaller groups of the assembly's parts, also to achieve a parallel production. At this regard, several methods for automatic subassemblies identifi-cation, starting from the assembly CAD model, have been provided. However, most of the methodologies proposed rely on human intervention, especially in the model processing to make available essential data, while other details are ignored. After giving the definition of stable subassembly, this paper focuses on the application of stable subassemblies identification to industrial CAD models and highlights the issues arising. With the aim of ensuring a reliable CAD model analysis, starting point of the identification, the possible real engineering situations, both related to assembling methods and modelling techniques, are presented. Ap-proaches to algorithmically address them are then described, with the help of two examples of mechanical assemblies.
Abstract: Successful interaction with complex systems is based on the system ability to satisfy the user needs during interaction tasks, mainly related to performances, physical comfort, usability, accessibility, visibility, and mental workload. However, the "real"user experience (UX) is hidden and usually difficult to detect. The paper proposes a Transdisciplinary Assessment Matrix (TAS) based on collection of physiological, postural and visibility data during interaction analysis, and calculation of a consolidated User eXperience Index (UXI). Physiological data are based on heart rate parameters and eye pupil dilation parameters; postural data consists of analysis of main anthropometrical parameters; and interaction data from the system CAN-bus. Such a method can be adopted to assess interaction on field, during real task execution, or within simulated environments. It has been applied to a simulated case study focusing on agricultural machinery control systems, involving users with a different level of expertise. Results showed that TAS is able to validly objectify UX and can be used for industrial cases.
Keywords: Ergonomics | Human Factors | Human-centered design | User eXperience (UX) | Workload
Abstract: The use of computational methods in engineering design is a long-standing issue. Several mathematical approaches have been investigated in the literature to support the design optimization of engineering products. Most of them are focused on the optimization of a single structure, without considering a system of structures. The design of supports for electric lines requires tools for the management and sizing of a system of structures that interacts with each other under specific load conditions. This paper deals with a framework to support the design optimization of an overhead line using methods related to the theory of the Constraint Satisfaction Problem. The object-oriented model of a transmission line has been described and then implemented into a prototypical software platform. The parameters to be considered as variables are defined by the designer at the beginning of the optimization process. These variables are geometrical dimensions, poles locations, cable pre-tension, etc. The set of constraints is related to normative, climate conditions, datasheets, material limits, and expert knowledge. To demonstrate the effectiveness of this approach, a case study has been developed considering a variable number of constraints and parameters. In particular, the case study is focused on the design of a low-voltage sub-network between two distribution substations.
Abstract: Currently, design optimization is widely applied in civil and mechanical engineering. Optimization strategies are used to enhance the product performance and reduce the cost, lead time and environmental impacts related to the product lifecycle. In this context, evolutionary algorithms are used for determining the optimum solution in engineering problems. The design of complex products, such as those that are engineered to order, often requires the study of subproblems. Modularization is a common practice to reduce the complexity; however, the configuration practices are difficult to be applied in engineered to order products. As a solution, the integration of the optimization tools and model-based simulations is proposed to manage the complexity. However, even when a commercial software is available to support the parameter optimization, there may exist a lack of design tools that can be integrated with the product structure of an engineered to order product. This paper describes a design optimization approach that integrates a Constraint Satisfaction Problem (CSP) tool with model-based simulations in a collaborative design context. A platform tool is developed using the. NET and MiniZinc languages. The case study is focused on the design optimization of a 700-ton steel structure. In particular, the optimization analysis considers the mechanical behavior, weight, and cost reduction.
Keywords: Constraint satisfaction problem | Design optimization | Engineer-to-order | Oil & gas | Steel structures
Abstract: This paper presents a novel framework for manufacturing and cost-related knowledge formalization. This artefact allows industries to capitalize the knowledge of experienced practitioners in the field of manufacturing and assembly, so that it can be used by designers for quickly and analytically estimating the production costs of components during product development. The framework consists of the following: (i) a cost breakdown structure used for splitting out the manufacturing cost, (ii) a data model (cost routing) to collect the knowledge required to define a manufacturing process, (iii) a data model (cost model) for collecting the knowledge required to compute the manufacturing cost of each operation within a manufacturing process, and (iv) a workflow to define the manufacturing process. The proposed framework provides several advantages: (i) knowledge formalization of product manufacturing cost, (ii) knowledge sharing among design/engineering departments, and (iii) knowledge capitalization for decision-making process. The proposed framework is used to formalize the knowledge required for analytically estimating the manufacturing cost of open-die forged components. Results highlight that the framework addresses the most important requirements for a knowledge-based cost estimation system.
Abstract: Deburring operations are critical to automate when high quality is required, due to the unpredictable presence and variable thickness of burrs that necessitate singular optimized process planning. Industrial anthropomorphic manipulators could effectively perform high quality deburring operations, but still lack the intelligence needed to generate quality and time-optimal deburring cycles. This paper presents a novel architecture of Zero Defect intelligent deburring robotic cells. Vision systems and metrological sensors allow the identification of the burrs and the overall quality and pose of the workpiece, while a novel model-based supervisory control, based on a digital twin, automatically calculates the optimal sequence of operations and working parameters needed to achieve the desired quality, generating also the PLC and robot controllers validated code to perform each task. Finally, the prototype of the proposed Zero Defect intelligent deburring cell has been developed.
Keywords: Digital twin | Engineering methods | Industry 4.0 | Robotic manufacturing | Virtual prototyping | Zero defect manufacturing
Abstract: Additive Manufacturing (AM) technologies have greatly extended design possibilities and freedom. However, in the designer everyday work, the decision regarding the adoption of AM for some components is not straightforward. There is a need to evaluate the properties of the available materials, their compatibility with the specific application, redesign shapes accordingly to additive rather than subtractive or deforming processes, conceive merging components in unique complex multifunctional parts. Indeed, economic, procurement and logistics evaluations, possibly extended to the entire life cycle, are necessary to come to a decision for a new and radical solution. In this context, the paper investigates the complex set of information involved in the process to guide a designer in a structured assessment and evaluation of opportunities for the adoption of AM. The approach includes the analysis of the design requirements to evaluate the applicability of additive technologies. Selected design questions are presented as attention points to help designers in the decision-making process along with a metric to merge the answers in an overall compliance index. Finally, some test cases from the literature and industry are reported to validate the proposed decision process.
Keywords: Additive manufacturing | Decision-making | Design for additive manufacturing | Design process
Abstract: The paper describes an approach for analyzing the use of a Laser-Guided Vehicle (LGV) in the context of the small and medium-sized enterprise. The use of LGVs is an efficient solution to provide more flexibility in the context of Just-In-Time production; however, the investment cost can limit this application. A methodology has been proposed in this work to analyze the technical feasibility of using an LGV in the manufacturing industry of customized products. The test case focuses on the study of a laser-guided system to optimize the handling of molds for customized production. In this scenario, an LGV is proposed to substitute manual carts used for moving molds from the warehouse to the injection machines. The traditional path included an intermediate station for pre-heating the molds in hot-air ovens. The proposed solution includes the study of an induction heating system on the LGV to optimize time and energy consumption.
Keywords: Customized production | Laser Guided Vehicle | Life Cycle Cost | System modeling
Abstract: The design of Engineer-To-Order products needs tools and methods for reducing time and cost during the phase of the quotation preparation. Modularization is one of the more applied design methods for ETO systems; however, it is necessary to integrate traditional tools with practices of design optimization to improve the development of a proposal. Even if commercial design tools for modeling specific types of engineering systems are available, the application of design optimization is still based on the use of tools not integrated with each level of the design phases. Moreover, these tools often require software customization. The integration of geometrical modeling, simulations, analysis, and optimization concerns the interaction between different tools. This paper describes an approach to support the Multi-Object Optimization related to the design of complex ETO systems with a focus on the oil & gas context. In this context, Genetic Algorithms and Constraint Satisfaction Problems are introduced as tools to support the design optimization of steel structures. The approach includes the employment of different and integrated tools throughout the design phases. This paper also shows a collection of tools to support the different levels for the design of different ETO products during the preparation of an offer related to proposal submission.
Keywords: Design optimization | Design tools and methods | Engineered-To-Order | Oil & gas
Abstract: Target pricing is a methodology to develop competitive products by determining the target price from market analyses. To guarantee the right profit margin, target cost is a direct consequence of target price. In this situation, the manufacturing cost estimation at the design phase becomes an essential task. The paper presents a framework for collecting knowledge required for estimating manufacturing cost of components. The framework consists of: (i) a cost breakdown structure used for splitting manufacturing costs, (ii) a data model for collecting that knowledge required for defining manufacturing processes, (iii) a data model for the collecting that knowledge required for computing the manufacturing cost of each operation within a manufacturing process and (iv) a workflow for analytically estimating cost of components. The framework has been mainly conceived for managing components realized through forming and shaping processes. The result presented in this paper guarantee the following benefits: (i) knowledge elicitation on product manufacturing cost, (ii) knowledge sharing among design/engineering departments, and (iii) knowledge capitalization for decision-making process.
Keywords: Design for manufacturing | Design to Cost | Knowledge management | Manufacturing cost estimation
Abstract: Nowadays, the contribution of the CAD modeling is not yet well exploited into the design of overhead lines. Even if some commercial tools are available, they are very similar to configuration tools with design rules related to reference normative. Sometimes, if 2D/3D CAD tools are employed, they are viewers or customized versions with specific features for the design of overhead lines. This situation limits the interoperability between the design of overhead lines and traditional software employed in the design of civil structures and infrastructures. Moreover, an information modeling approach is still lacking in current tools for the management of additional data about maintenance, cost, etc. In the context of overhead lines, the paper aims at showing an information modeling approach with a platform software which includes a configuration tool, a CAD module, an analytical-based solver, a costing tool, and a Finite Element Method solver. The CAD module is employed to define a 3D model including, as tag-objects, a set of information regarding the lifecycle design of overhead lines. Finally, a Finite Element Model solver enhances a second level of validation and enables advanced simulations.
Keywords: Computer-aided design | Configurations | Finite Element Model | Information Modeling | Overhead lines
Abstract: Nowadays, the development of Internet of Things (IoT) technologies have been enhancing the factory digitalization with several advantages in terms of production efficiency, product quality, and cost reduction. This opportunity encourages the implementation of digital twins related to physical systems for controlling the production workflow in real time. Firstly, the paper studies the enabling technologies for supporting the defect analysis in the context of Industry 4.0 for mechanical workpieces. Secondly, the approach aims to study the integration between the CAD geometry and the quality check process for the inspection planning. A Knowledge-Based tool has been proposed to support the configurations of the quality control chain for each CAD geometry. The test case is focused on the fragmented production of customized gearbox parts.
Keywords: Gearbox | Industry 4.0 | Knowledge Base | Machine Vision | Quality Control
Abstract: The ever-increasing competitiveness, due to the market globalization, has forced the industries to modify their design and production strategies. A key point is the development of products that fulfil the individual customer needs as close as possible. ETO companies manufacture new products according to the customer technical requirements given in the request for proposal. Computational Design Synthesis is the research area focused on activities to automate the design phase in the production of products such ETO structures. In this context, Knowledge Based Engineering applications are usually applied to automate design routines and to implement a multidisciplinary product design. Knowledge should be elicited and formalized, so that it can allow the past cases retrieval and the connection between customer specifications and the product configuration tasks. This paper proposes an approach for the rapid definition of the product structure related to a ETO product, including the early cost evaluation in configurations. The research scope aims at defining a framework to support the knowledge repository, which is the Knowledge Based used to design new products and estimate their costs.
Abstract: In recent years, long distance learning has become more and more popular. Web based technologies, that allow the sharing of information in real time, as well as the development of Learning Management Systems, provide the required technological support to implement long distance courses. However, long distance learning is characterized by a completely different relationship between teacher and student, in respect to the traditional teaching approach. It is then important to understand if this difference can affect the students learning outcomes. In this paper the comparison is presented between the summative assessment of two separated groups of students, attending an engineering drawing course, that is part of the curriculum for the bachelor degree in mechanical engineering. One group attended the course in a traditional form, while the second group attended the course in remote. The aim of the study is to verify if significant differences exist between the two groups of students, in terms of learning outcome. The identification of such differences is the premise to develop appropriated teaching strategies, aimed to overcome possible deficiencies related to the teaching approach.
Abstract: Nowadays, Knowledge-Based systems are widespread decision-making tools applied in product design and manufacturing planning. The series production requires agile and rapid decision-making methods to support actions in manufacturing lines. Therefore, agent-based tools are necessary to support the detection, diagnosis, and correction of accidental production faults. The context of Industry 4.0 has been enhancing the integration of sensors in manufacturing lines to monitor production and analyze failures. The motivation of the proposed research is to study and validate decision theory methods to be applied in smart manufacturing. This paper shows a Knowledge-Based approach to support action decision-making processes by a Bayesian network model. The proposed method aims at solving production problems detected in the manufacturing process. In particular, the focus is on the automatic production of cooker hoods. A case study describes how the approach can be applied in the real-time control actions, after a problem in quality is detected.
Keywords: Bayesian Network | Cooker Hoods | Industry 4.0 | Knowledge Base
Abstract: Molding is one of the most widely used processing technologies in manufacturing. Among typical molding parameters, the mold temperature is a critical one for the quality of the molding process. A solution to this issue can be the employment of induction heating which, through a high-frequency electromagnetic field, produces eddy currents and a consequent rapid heating of the material into the cavity of the mold. The necessity to maintain the mold walls at the operative temperature makes the induction heating to be one of the most efficient non-contact means of heating. In fact, induction heating is characterized by quickness, efficiency, and energy saving; however, the design and the sizing of an induction heating system is complex due to different parameters involved in the electromagnetic and thermal phenomena. In this context, the paper aims to define a methodology to support engineers in the design and sizing of an induction heating system for molds, taking as case study a mold for composite parts. A model-based approach is proposed to analyze and simulate the mold heating, considering three different levels of modelling: Analytical (0D), Finite-Difference Methods (2D) and Finite Element Methods (3D). The Analytical approach investigates the solution of the physical equations applied to the volume of the material involved. Instead, the Finite-Difference approach (2D) solves the heat transfer problem by discretizing the domain and by solving for temperature at discrete points. Finally, the Finite Element method (3D) solves partial differential equations on a 3D discretized domain.
Abstract: Nowadays, Building Information Modeling (BIM) is a common design approach to support the life cycle of projects in the field of Architecture Engineering Construction (AEC). New constructions’ projects require a BIM modeling to provide digital information within a 3D digital mockup. The main target is to reduce time and cost related to the elaboration of additional and not integrated documentation. This issue is also common in projects focused on the renovations of existing buildings. In fact, the BIM approach provides tools to improve interoperability between different software to integrate analysis and simulations within the architectural representation. The renovation projects require reverse engineering tools and methods for the 3D modeling of existing structures. One of the issues concerns the digital photogrammetric survey of glass surfaces. This paper proposes a design approach to support BIM phases for already existing structures with a test case focused on a hallway with a continuous glass wall.
Abstract: This paper defines a systematic workflow for production cost estimation of sheet metal stamped components. The approach represents a solution toward the adoption of Design to Cost methods during early product design. It consists in a sequence of steps that, starting from a 3D CAD model with annotations (material, roughness and tolerances) and production information (batch and production volume) leads to the manufacturing cost through an analytic cost breakdown (raw material, stamping and accessory processes, setup and tooling). The calculation process mainly consists in a first step where geometric algorithms calculate the sheet metal blank (dimensions, shape, thickness) and specific product features (e.g. flanges, louvers, embossing, etc.). The following steps allow to calculate the raw material, the stamping process and the process-related parameters, which are the manufacturing cost drivers (e.g. press, stamping rate/sequence/force and die dimensions/weight). The manufacturing cost is the sum of the previous calculated items. Testing the approach for three different components, the average absolute deviation measured between the estimated and actual cost was less than 10% and such a result looks promising for adopting this method for evaluating alternative design solutions.
Keywords: Cost estimation | Design to cost | Feature recognition | Sheet metal stamping
Abstract: In the era of the fourth industrial revolution the efficient sharing and exploitation of information are key success factors for companies. In order to maintain competitiveness and to answer to the requests for highly customized products, shoe last producers need to innovate their processes, by adopting digital technologies. The present paper proposes an innovative integrated approach for shoe last design and manufacturing. The process is enabled by CAD/CAM technologies, which allow to integrate the design and manufacturing phases, and by haptic technologies, which allow to interact with the virtual models to simplify the successive planning and manufacturing operations. The final aim is to support traditional companies in the implementation of the Industry 4.0 paradigm. The test case about marking operation confirms that the adoption of the proposed approach leads to a sensible improvement in the company operational efficiency, thanks to the reduction in the number of repetitive tasks.
Keywords: CAD/CAM technologies | Haptic interface | Industry 4.0 | Shoe last design
Abstract: Nowadays, product configuration and optimization are very important topics in several industrial applications such as the manufacturing of Engineered-to-order (ETO) products, where there is a fierce increase in market competition. The product configuration allows past design solutions to be reused and new product variants to be defined and pre-designed. However, the delivery of new configurations of products requires a technical feasibility analysis before closing the contract of the order with the customer. There is a lack of commercial tools which can support the designer from the early configuration phase to the product optimization with the automatic generation of geometric models and simulations. While traditional software tools can be used for the product configuration, with automation in the CAD modeling, other ones can combine optimization algorithms with numerical simulations. However, the combination of all these design levels requires the development of a dedicated platform tools. The research aims to reduce time and cost related to the early design phase of an oil & gas system, focusing on gas turbine ducts. The paper proposes a methodological approach to integrate the design optimization with the product configuration using Model-Based simulations to verify the technical feasibility and to optimize the product design. As a test case, the early design of a gas turbine chimney is proposed.
Keywords: Model-Based simulation | oil & gas | Product configuration | Product optimization | Virtual prototyping
Abstract: Sustainability and cost optimization are actually the main drivers of product and system design in modern companies. However, cost assessments are usually carried out at the end of the design process to check the validity of the decisions already taken. Therefore, when targets are not achieved, numerous time-consuming iteration loops are necessary to optimize the initial solution. The paper situates in a research aimed at merging functional-based and design-to-cost approaches to propose a CAD-based platform able to assess new product variants from the earliest stages by configuring and assessing feasible design solutions. In particular, an approach is proposed for dealing with dependencies among design parameters in order to support the designer in a rapid definition of valid solutions and optimise them. The approach is described and then applied on an industrial test case, a bridge-crane design process.
Abstract: Nowadays, several consumer goods are sold with an energy label which provides energy information about consumption, efficiency, noise, and performance. These labels are regulated by local energy policy and governments. Because of this, customers are becoming increasingly aware about the energy efficiency and consumption of products such as household appliances. In Europe, several household appliances are involved in the European Energy Labelling Directive. Therefore, the manufacturers are paying attention to Ecodesign tools and methods to support the development of eco-innovation and sustainable products. In this context, the paper proposes a design methodology to support the development of efficient cooker hoods using an approach based on a constraints satisfaction problem model. The scope of the proposed research is to reduce the time-to-market of household appliances considering the energy efficiency optimization from the early design phases to the embodiment design. A Case Based Reasoning is also implemented to define a pre-configured model of product before the CSP optimization. The CSP model has been developed as an analytical system, which can predict the energy label achieved by a final prototype of a cooker hood. The interaction of such tools can fill the gap between traditional design methods and eco-innovation approaches, in order to support the designer in the decision-making activity. The test case shows a cooker hoods optimization based on a CSP tool, developed using a programming framework based on Gecode platform.
Keywords: Case-based reasoning | Constraints satisfaction problem | Design optimization | Ecodesign | Energy label | Virtual prototyping
Abstract: In several application contexts, virtual solid models require to integrate portions of polygonal meshes with synthetic models, designed by traditional parametric/analytical multipatches systems. The paper reports the research aiming at covering the theoretical and numerical aspects connected with an extended geometric solid modeling system, focusing on the B-Rep models and introducing the new paradigm of Extended B-Rep (EB-Rep), which is able to integrate mesh-faces as part of a B-rep model. This paradigm introduces a notion of continuity between parametric and discrete representations, regularized Boolean Operations, a join operator and an approach to represent a valence semi-regular mesh as an EB-Rep structure. A prototype of the geometric solid modeling kernel has been realized and tested in the OpenCascade library environment.
Abstract: Feature-based modeling and feature recognition algorithm are state of the art technologies, mainly used to favor the integration and exchange of data between design and manufacturing phases. This paper aims to investigate the possibility to extend the use of the feature recognition as a means for the prevention of ergonomics issues during the manual assembly phase, such as Work-related Musculo-Skeletal Disorders (WMSDs). Starting from the features analysis of a 3D product model, the proposed five steps method allows preventively identifying potential ergonomics issues. The main novelty of this study is related to the correlation between design tools, product virtual representations (e.g. 3D models), assembly and ergonomics aspects. Results obtained with two case studies, a cooker hood and a tool-holder carousel, confirm the usefulness of the proposed method in helping designers to prevent potential ergonomics issues for operators involved in the assembly phase.
Abstract: Design optimization is a common practice in industry. Different mathematical algorithms have been developing to support the optimization in engineering design. The integration between optimization methods and simulations is an interesting issue in engineering design. A typical optimization workflow can include simulation steps; however, the Virtual Prototyping analysis is more time-consuming than analytical calculations. The study of Constraints Satisfaction Problems is a mathematical topic which can be applied for solving engineering issues in design. The strength of this approach is the velocity on searching the satisfied solutions. This paper proposes a design methodology which considers the use of CSP models and calculation tools to optimize the sizing of columns and beams in the design of a steel structure. The calculation tools regard analytical models and numerical analysis. While the analytical approach regards the computing of cost and weight, the numerical analysis is used to verify and check the engineering performance in terms of deformation and stress state. A customized application, based on MiniZinc platform, has been developed and proposed to solve the CSP model for a test case steel structure. The CSP problem has been limited to the calculation of analytical constraints such as cost and weight. Finally, the resultant set of solutions has been evaluated using numerical solution to complete the optimization analysis.
Abstract: Nowadays, different commercial tools are available to support engineers during optimization tasks in engineering design; however, many researches have been still studying tools and methods to improve the design process and overcome some limits related to configuration and design optimization. This paper proposes a methodological approach to highlight how a CSP analysis can support the first phase of an optimization analysis, to reduce the design space of solutions to be investigated and subsequently optimized. A test case shows a CSP study applied to steel structures for oil & gas applications.
Abstract: Modular product design is an efficient strategy to let manufacturing companies meet the customers' requirements by offering a wide variety and customization of products and significantly saving time and cost during engineering and production (Fei et al., 2011). Despite numerous approaches for function modeling and modular product design (Srinivasan et al., 2012; Eckert, 2013; Vermaas, 2013) that have been developed in the last decades, carrying out an efficient product variants' design process is still an open issue for many manufacturing companies. The proposed approaches offer numerous ways to model information about product functionality, but each approach is useful and particularly well suited for different applications and domains (Summers et al., 2013). The present research compares the existing approaches for product variants design and defines a function-based model to support product design and redesign according to a modular framework, merging qualitative technical issues with business-oriented evaluation. Such a framework has been used to develop a multiuser IT platform, composed of a knowledge-based engine and four different tools to support designers and engineers in product variants creation, management, and configuration, from product functional modeling to cost estimation and life cycle assessment. The proposed model has been tested on industrial cases in the context of household appliances. Experimental results demonstrates that, after a preliminary context analysis and a proper knowledge base creation, such a model supports a more conscious decision-making and promote collaboration within an interdisciplinary design team. Finally, the case study shows the necessity, but in the meanwhile the insufficiency, of a functional decomposition as the only representation viewpoint.
Keywords: Computer-Aided Design | Design Methods | Function Modeling | Product Family and Platform | Product Modeling
Abstract: PMI annotations are widely used to support the Model Based Design within modern companies. In particular, the introduction of digital annotations marks the transition from the 2D drawings to the 3D representation in many manufacturing and design companies. However, today the implementation of the PMI technology presents some limits, such as the lack of functions to generate structure templates to be applied to similar CAD models. The proposed approach aims to overcome the limits of traditional tools which are not able to add a PMI annotation’s structure from one model to another one. The paper describes a method to reuse digital PMI annotations in a new model during the design phase, where the annotations are inherited from similar CAD documents. The proposed approach is based on two levels of geometric analysis: the searching of similar template models from an XML database, and the identification of the related geometric entities, which are used as associated objects for the definition of 3D annotations. The test case is focused on the automatic generation of PMI annotations for exhaust duct items used in oil & gas applications. The proposed tool has been developed within a software program called Duct Designer, which is used for the CAD automation of duct items. Particularly, the test case enhances the retrieval and reuse of sizing schemes from previous 3D models in order to obtain an automatic rebuilding of the geometric annotations.
Keywords: Digital annotations | Model-based definition (MBD) | Oil & gas | Product manufacturing information (PMI)
Abstract: Sustainability is becoming one of the main drivers of the modern product and system design. However, sustainability assessments are usually carried out at the end of the design process to check the validity of the decisions already taken. As a consequence, when targets are not achieved, numerous time-consuming iteration loops are necessary to optimize the initial solution. The paper merges functional-based and design-to-cost approaches to propose a CAD-based platform able to assess product lifecycle costs and impacts from the earliest design stages by configuring and assessing feasible design solutions. It considers both economic expenses and environmental impacts during all phases of product lifecycle on the basis of the company knowledge.
Abstract: Maritime vessels have long service life and great costs of building, manning, operating, maintaining and repairing. Making a consistent lifecycle model among the different vessel typologies, repeatable with the same level of detail and comparable for the implementation of decision-making strategies, remains an open question. This paper aims to define a suitable lifecycle model in the context of maritime vessels to cope with the current limitations of ad-hoc and fragmented methods. The model considers the main aspects involved in the vessel lifecycle such as building materials, manufacturing and assembly, maintenance/service, operational activities, use, etc. The model provides a common structure for the lifecycle assessment (LCA) and lifecycle cost analysis (LCCA) including the way to retrieve and to collect the data necessary for the analysis starting from the available project documentation and the design models. The method is flexible and it is able to cover a large variety of maritime vessel typologies. As example, a luxury yacht has been analysed using the developed method, demonstrating the applicability of the proposed model in one of the most critical vessel typology.
Abstract: Cost estimation is a critical issue for many companies concerning both offers generation and company strategic evaluations. In this paper, a framework for early cost estimation has been proposed to some firms for an assessment of its main features. The aim of the industrial survey is to promote a discussion on the needs and the expectations regarding cost estimation in order to obtain feedbacks to be addresses in the implementation of a software tool. Gather data has led to a ranking of the main characteristics the tool should have.
Keywords: CAD | Design to Cost | Early cost estimation | Knowledge-based engineering | PLM | Product configuration
Abstract: An innovative method of tool wear assessment, based on the digitization of the cutting tool performed by a piezoelectric 3D scanner and on the analysis of the surfaces of a 3D model generated using the Reverse Engineering technique, has been developed. To this purpose, face milling experiments were carried out under dry cutting condition on AISI 420 B stainless steel using inserts in cemented carbide, with a two-layers coating (TiN and TiAlN). The time dependence of the insert wear was analysed by interrupting milling at predetermined time values. The proposed approach has been validated by comparing the output provided by the reverse engineering method to that measured experimentally by analysing the worn insert images obtained using a stereo microscope. An excellent agreement between the results given by the two different methodologies has been found. The worn tools have also been analysed using the scanning electron microscopy technique in order to understand the wear mechanisms operating during dry milling.
Abstract: Cost Estimation for offer generation in ETO companies is a critical and time-consuming activity that involves technical expertise and a knowledge base. This paper provides an approach to acquire and formalize the design and manufacturing knowledge of a company. The method has been described as a sequence of steps, which moves from the data acquisition of the past projects to the definition of a cost function based on dimensioning parameters. This approach has been experimented on a family of cranes for plants in collaboration with an industrial partner.
Keywords: Cost estimation | DSM | Engineer To Order | Functional requirements | Knowledge formalization
Abstract: Despite of the widespread of annotated 3D virtual models, it is still important to produce engineering drawings for a correct communication among the people of the design and manufacturing chain. Automatic drafting through meta drawing definitions, called Drafting Schemes, is proposed in this paper to save time when drawing becomes a repetitive task. The approach produces drafts with a predetermined content in terms of views arrangement and dimensioning strategy, and guarantees robust results to the variations of the input geometry. In fact, the geometrical entities referenced by the generated dimensions are retrieved through dedicated search algorithms based on recognition of geometric features of the input model. The approach has been implemented and tested on a family of gear motors showing feasibility and good results in terms of drafting time savings.
Keywords: Design Automation | Drafting | Feature Recognition | Knowledge Based Systems
Abstract: Design intent representation is a well-known issue in the MCAD domain, and is related to the readability, alterability, and usability of CAD models. The recent widespread introduction of functionality and commands in modern CAD systems, aimed at facilitating explicit modeling, introduces not only a new modeling paradigm supplementary to the feature-based approach, but also a new perspective on how the design intent can be captured and represented. Taking into account the traditional method of communicating design intent with functional dimensioning in mechanical drawings, in this paper a novel approach is presented, aimed at translating this traditional design intent representation from 2D into 3D. Objectives are directed towards the specification and implementation of dimensioning correspondence mapping and the identification as well as examination of shortcomings in current systems. This should help direct future improvements aimed at supporting 3D dimensioning within 3D explicit modeling systems.
Abstract: Patients affected by serious foot pathologies often require special orthotics to stand and walk correctly. Skilled operators obtain such insoles on the basis of manual procedures and following the prescriptions of orthopaedic technicians. The process is handicraft and time consuming. The paper presents a virtual prototyping approach which is based on dedicated foot scanners, CAD-based design tool and milling machines to obtain the bespoke footwear orthotics. The major contribution is a geometric procedure to design complex insole shapes starting from the foot scan and highly customized shoe lasts which are required in case of important deformities. The approach has been tested on several patients thanks to the collaboration with a partner insole producer and some orthopaedic centers. Patients have generally reported positive feedbacks on the comfort and functionality of the insoles.
Abstract: Web-enabling technologies represent the next generation of design environments to design and manufacture complex systems, such as them characterizing contract furniture. In the context of web applications to facilitate and support teamwork in collaborative product development, the paper presents a CAD-based infrastructure for the 3D visualization of co-designed solutions, the on-line customization of furniture items and the creation of a shared relational database of products, architectural scenes and knowledge-based rules guiding configuration. A double-level geometry is presented to manage 3D web representation and product structure. A use case is adopted to show main platform functionalities and possible advantages for the extensible contract furniture cluster.
Abstract: Purpose-High pressure die casting is a widely used industrial process to manufacture complex-shaped products in light alloys. Virtual prototyping techniques, especially numeric-based simulations of the casting process, allow the die filling process to be evaluated and help faster optimization of the gating system, which is the most critical element of the mould. The purpose of this paper is to present a four step approach to design optimal moulds taking advantage of the simulation tools. Design/methodology/approach-No formalized method to design an optimal gating system is available yet and the majority of the studies aim to optimize existing geometries or to choose from alternative solutions. Rather than optimizing the geometries of predefined designs by running attempt trials, the proposed approach defines a procedure to position cavities, gating systems and, finally, to determine the whole mould geometry. Findings-The approach is demonstrated through three different industrial applications. The design of a six-cavity mould for gas cooking burners is reported at first. Then, two test cases, a cup and a radiator, are reported for showing different arrangements of the gating system. The reached quality of the mould design has been assessed using metallographic analyses of the casts. Originality/value-The design of a mould is strictly correlated to its product and mainly based on a trial-and-error approach. Numerical simulations offer a powerful and not expensive way to study the effectiveness of different die designs and filling processes. The paper proposes a structured approach for the definition of the gating system. It ultimately leads to improvements in both product quality and process productivity, including more effective control of the die filling and die thermal performance.
Keywords: Gating system | High pressure die casting | Numerical simulation | Paper type Research paper | Shape optimization
Abstract: The market globalization pushes for ever new products in order to reach new niches. In the household appliances field, the marketing specialists daily configure new combinations of numerous functional and product requirements seeking new product definitions. Each novel combination requires an assessment of technical and economic feasibility by the design departments. This paper proposes a method for a preliminary validation of new configurations at the marketing stage. Indeed a tentative Bill of Materials (BOM) and a cost of the product are obtained. A knowledge base is derived by eliciting the requirement compatibilities from existing products. The approach is matrix based and it analyzes recurrent dependencies between requirements and components variants to determine which parts are most likely to appear in the BOM. Then, the knowledge base is integrated with rules that are input by experienced designers through a simple syntax. The approach has been tested moving from the requirements of some instances of a family of cookers, and comparing the results obtained from the application of the method with the actual product BOM.
Keywords: Bill of materials | Configuration | Design requirements | Knowledge management
Abstract: Virtual prototyping lacks of application in SME due to the costs of software systems and the necessity of skilled operators. The aim is to improve dripper emitters design process reducing costs. A knowledge base is presented to gather data on products behaviour in terms of experimental data and simulation results for a set of meaningful test cases. Input design parameters were linked to performance indices on the base of the correlations emerged in the analysis. Specifications for a new product can be used to extract similar cases and to define a possible solution in terms of a combination of them.
Keywords: Design of experiments | Drip emitters | Knowledge based engineering | Virtual prototyping
Abstract: Updating products requires design activities, virtual and physical prototyping of new solutions, test and validation steps. If problems are detected at any of these stages, they cause iterations, waste of time and resources. A change propagation method is initially described as a way to facilitate the introduction of product changes. The approach relies on a multilevel product representation, the modelling of the component dependencies, algorithms to compute the propagation of some desired changes. Outputs are represented by the list of the affected components and indices indicating the impact on the product requirements. The method has been applied in the whole redesign process of a standard product like the fridge. Modifications must be usually released under time constraints. In this context, the outputs of the proposed method are an useful support to reduce iterations and resources waste. The experimentation has been based on case studies assigned to two groups of designers working with and without the tool. It has resulted that designers become more aware of the implications of the engineering changes, they are allowed of better decisions and the whole process becomes shorter.
Abstract: Flexibility is the main keyword in order to face the rapid changing market requirements. Companies need methods and tools in order to implement flexibility over the whole product development process, from ideation to manufacturing. The proposed approach goes towards the concretization of the lean product design concept. It can be achieved if design alternatives and product modifications can be rapidly evaluated in terms of feasibility. resources. cost and time. The approach is based on a multilevel representation of the product structure. where functions. modules. assemblies and components are strictly interrelated. The complex representation requires suitable software tools in order to model and visualize the entire structure and support the easy user navigation. On the other hand it is necessary to define rules and operators to interact with the structure in order to make product changes and evaluate the possible impact. Finally. this system has to be integrated within the product development flow for exchanging data and information with CAD, PLM and ERP tools. In this paper the general approach is defined and the preliminary software solution is described.
Abstract: Quality of service, in terms of improvement in patient satisfaction, is an increasingly important objective in all medical fields, and is especially imperative in orthodontics due to the high numbers of patients treated. Information technology can provide a meaningful contribution to bettering treatment processes, and we maintain that systems such as CAD, CAM and CAE, although initially conceived for industrial purposes, should be evaluated, studied and customized with a view to use in medicine. The present study aims to evaluate Reverse Engineering (RE) and Rapid Prototyping (RP) in order to define an ideal chain of advanced technological solutions to support the critical processes of orthodontic activity.
Abstract: In this work we focus our research on the product design related aspects; currently we deal with modularity, product architecture and change propagation issues along the design process. In order to apply abstract concepts to design practise different approaches and tools have been proposed; anyway presently concrete software solutions and applications examples are still lacking. Companies modify their products for a number of reasons and rarely start from new ideas when designing. Due to the lack of suitable tools and methodologies designers are not aware of modifications impacts and propagations when trying to change or update a product. In this paper we present our research efforts in developing a methodology and the related software tool to support change management during the product redesign. It is conceived as guiding tool based on a product multilevel representation: from functional contents to implementation design; currently the designer can obtain a complete presentation of the product parts characteristics and their relations. In this way the resulting graphical model becomes a company tacit knowledge repository about the product. Operational functionalities are provided to support the designer during his activities. This work has been carried out and tested on the redesign process of a washing machine in collaboration with an Italian company, leader in house working appliances.
Abstract: Repairing severe human skull injuries requires customized cranial implants. Trauma, cranial tumors, infected craniotomy bone flaps and neurosurgical external decompression are the main causes for large cranial defects. The success of the reconstructive cranial surgery depends on diverse aspects regarding the preoperative evaluation of the defect, the design and manufacturing of the implant and the execution of the operation. Currently, the design of membranes is mainly a manual work, even with the use of CAD facilities, and results in a time-consuming and user-dependent skull reconstruction. This paper presents an automated design methodology for custom-made cranioplasty plates in a PHANToM®-based haptic environment and the possibility to manufacture the same using Solid Freeform Fabrication technologies.
Abstract: Designing a new product, in most cases, means a modification of an existing one. Both adopting known solutions in different products, that inserting new technological processes into a consolidated context, the most design effort must be dedicated to the early evaluation of the impact of needed engineering changes to achieve the final result, in terms of cost, quality and time. Such activity is particularly strategic in the modular product development. The aim of our research work is to develop a method and the related tools that enable designers to easily represent the product platform, to structure the relations between modules defined at different levels of detail and, hence, to simulate, analyze and evaluate the modifications impact during the new product variant definition phase. A multi-level product structure able to represent the product informative content at different levels of detail is presented.
Abstract: The paradigm of Mass Customisation (MC) is today fundamental for the European fashion industry. Footwear industry is still labour intensive and companies need solution to reduce costs and remain competitive in the global market. In particular, specialized companies that produce customized medical shoes prescribed for people with feet malformations deal with small batches or unique pairs. This work presents some approaches and low-cost solutions related to foot measurement and CAD data elaboration for facilitating the diffusion of "made-to-measure" products. An integrated process made of hardware devices and customized software is explored and described aiming to increase production efficiency and reduce costs.
Keywords: 3D design tools | 3D foot measurement | Mass customization | Personalised shoes
Abstract: The present work focuses on the study of a method to acquire and formalise the design knowledge in a way usable for implementing a knowledge-based software system to support the NPC. The approach is based on the representation of corporate knowledge within a structured framework where market requirements, product specifications and functional aspects are interrelated. A hierarchical multi-level DSM structure allows representing such knowledge in a rationale manner. This paper presents the methodology to formalize the product knowledge, the used structure to define the specifications for implementing the knowledge-based product configuration system and, finally, a practical example to illustrate our proposed framework.
Abstract: Time Compression Technologies (TCT) are strongly widening their application fields, particularly in not traditional sectors, such as archaeology, jewellery, architecture and so on. The biomedical domain, especially orthodontics, is one of the most interesting. The design and positioning processes of corrective dental appliances consist of phases which can strongly benefit from Reverse Engineering (RE) and Rapid Prototyping (RP) techniques in terms of quality and time reduction. In these last years new systems have been developed to support the operator work but, unfortunately these technologies are still not largely used in orthodontic laboratories. In this context, the present paper, facing the problem of critical activities identification in corrective treatments orthodontic practice, proposes a low cost and easy to use technical solution in order to support orthodontists for a rapid and accurate positioning of vestibular and lingual brackets. In particular a new CAD (Computer Aided Design) software system to support the dental appliances design process has been implemented.
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