炭素生产控制系统网络化设计

现代企业要求生产统一，分散控制，集中管理将整个工厂作为一个系统实现其自动化，应用数字通讯网络技未，实现工厂信息纵向的透明通信，实现企业的最佳经济效益。在连城铝厂炭素生产中成功地进行了控制系统网络化设计。取得了较好的经济效益和社会效益。本文介绍了该控制系统的网络规划及目标；各层的网络结构搭建及特点。     

Development and operation of Digital Twins for technical systems and services

Digital Twins are new solution elements to enable ongoing digital monitoring and active functional improvement of interconnected products, devices and machines. In addition, benefits of horizontal and vertical integration in manufacturing are targeted by the introduction of Digital Twins. Using the test environment of smart factory cells, this paper investigates methodological, technological, operative, and business aspects of developing and operating Digital Twins. The following Digital Twin dimensions are considered in scientific and application oriented analysis: (1) integration breadth, (2) connectivity modes, (3) update frequency, (4) CPS intelligence, (5) simulation capabilities, (6) digital model richness, (7) human interaction, and (8) product lifecycle. From this, design elements for the development of Digital Twins are derived and presented.     

Diversified recycling strategies for high-end plastics: Technical feasibility and impact assessment

Waste Electrical and Electronic Equipment (WEEE) comprises a complex mix of engineering plastic grades often containing flame retardants. Whereas post-shredder recycling strategies are widely implemented, considerably higher economic and environmental returns can be expected based on information-rich dismantling scenarios. This paper therefore presents the results of an extensive technological feasibility study on diversified recycling strategies for a dismantling based approach. Results of mechanical and flammability tests as well as injection moulding trials are moreover presented to show the quality and potential of the recycling strategies. Subsequently, the environmental impact reduction potential is assessed using Life Cycle Assessment.     

On-machine and in-process surface metrology for precision manufacturing

On-machine and in-process surface metrology are important for quality control in manufacturing of precision surfaces. The classifications, requirements and tasks of on-machine and in-process surface metrology are addressed. The state-of-the-art on-machine and in-process measurement systems and sensor technologies are presented. Error separation algorithms for removing machine tool errors, which is specially required in on-machine and in-process surface metrology, are overviewed, followed by a discussion on calibration and traceability. Advanced techniques on sampling strategies, measurement systems-machine tools interface, data flow and analysis as well as feedbacks for compensation manufacturing are then demonstrated. Future challenges and developing trends are also discussed.     

Integration of product entropy and LCA to screen the potential environmental impacts of complex product systems at the end-of-life stage

Applying life cycle assessment (LCA) early in the development of technologies is essential to anticipate potential unforeseen environmental consequences. Modelling the lifecycle of a complex product is nevertheless challenging, as the data required is usually scarce. The approach presented in this paper integrates product entropy into end-of-life modelling for LCA. This enables anticipating the fate of a product after its end-of-use leading to a more realistic allocation of environmental impacts. The approach is demonstrated for the case study of recycling traction batteries with emerging traction battery cell chemistries.     

Designing assembly lines with humans and collaborative robots: A genetic approach

Human-robot collaboration represents a significant evolutionary step in manufacturing. A crucial point is to establish a proper task assignment to combine robot productivity with human flexibility. In this regard, this paper proposes a genetic algorithm to approach the Assembly Line Balancing Problem (ALBP) in the case of human-robot collaborative work. The aim is the minimization of: i) the assembly line cost, evaluated according to the number of workers and equipment on the line, including collaborative robots, ii) the number of skilled workers on the line, iii) the energy load variance among workers, based on their energy expenditures and thus on their physical capabilities and on the level of collaboration with robots.     

Initial transient phase and stability of annular laser beam direct wire deposition

In this paper the stability of the annular laser beam (ALB) direct wire-deposition process, which enables process symmetry and a well-defined ALB workpiece irradiation proportion (WIP) and related energy input onto the workpiece and the wire surface is considered. Various initial process phase strategies with respect to different initial wire-end positions and WIPs were analysed based on the process visualization and outcome, and the melt pool temperature. It was shown that in addition to a precise synchronization of the mutually time-dependent ALB power, wire and workpiece feeding velocity, the fastest and the most robust transition into a stable stationary process could be achieved with the initial position of the wire-end on the workpiece surface. Additionally, the WIP was shown to have a strong and nonlinear influence on the process stability.     

Pre-compensation of servo tracking errors through data-based reference trajectory modification

This paper presents a new dynamic error compensation approach with novel data-based closed-loop tuning scheme to enhance tracking accuracy of machine tool feed-drives. Both servo dynamics and friction disturbance induced positioning errors are pre-compensated by modifying the reference trajectory. Velocity and acceleration profiles of reference trajectory are modulated to achieve perfect tracking. Reference position profile is modified based on the pre-sliding friction regime to eliminate quadrant glitches. Optimal error compensation is achieved by a digital trajectory pre-filter whose parameters are tuned automatically by making on-the-fly iterative adjustments. Effectiveness of proposed compensation approach is validated experimentally in multi-axis feed-drive systems.     

Allocation of assembly tolerances to minimize costs

The cost and quality of an assembly depend on the processes used to manufacture its components. The specific processes and process settings are often dictated by the tolerances on the components. One long-standing challenge is allocating the assembly tolerance to components. Many methods have been proposed, most of which endeavor to minimize cost. We propose a tolerance allocation method that minimizes cost by jointly considering process variation and tolerance specifications. A cost model including processing cost, scrap cost, and quality loss is employed. The cost is minimized by a heuristic strategy. An overrunning clutch assembly case study is used to evaluate the method.     

Fabrication of optical freeform molds using slow tool servo with wheel normal grinding

Precision molding is recognized as the most appropriate technology for the mass production of glass freeform optics. However, difficulty arises when fabricating freeform molds with sub-micron form accuracy and nanometre-scale surface finish. A novel wheel normal grinding approach with fillet-end grinding wheel based on slow tool servo is proposed to ensure that the wheel errors are not transferred to mold surface and, thus, that the required machining accuracy is achieved. The wheel path generation strategy and the corresponding wheel truing method are presented. A toric tungsten carbide mold is ground to experimentally verify the validity of the proposed method.     

Visualization of electro-physical and chemical machining processes

This paper aims to visualize spatio-temporal phenomena in electro physical and chemical processes in order to understand machining mechanisms and to achieve a technological breakthrough. In situ measurement methods to visualize the time evolution of stress, strain, temperatures, fluid velocities, and species density distributions, together with 2D or 3D images of the workpieces being processed are summarized. Applications of these methods to fundamental studies on electrical discharge machining, electrochemical machining, laser processing and additive manufacturing are introduced. Signal recording and processing technologies and real time monitoring enabling closed-loop feedback control are also discussed.     

Models and modelling for process limits in metal forming

Modelling of metal forming processes is an essential task of production engineering. Due to the latest technological developments, a huge variety of models is already available and extending continuously. Thus, it is important to find a suitable model. This paper gives an overview on the common classification and characterization of modelling and models in metal forming, as well as introduces a model selection procedure. Based on this classification, various relevant process limits for metal forming are investigated regarding existing models. The conclusion of the paper shows open topics as well as upcoming challenges in modelling process limits in metal forming.     

Investigation of novel trochoidal toolpath strategies for productive and efficient directed energy deposition processes

Directed energy deposition (DED) is an additive manufacturing technology where a moving energy source creates a meltpool on the surface of a substrate into which feedstock material is deposited to form the final part geometry. Maintenance of the meltpool during deposition requires very high intensity energy flux to overcome thermal losses to the surroundings and substrate. Trochoidal toolpaths are investigated using numerical simulation and DED experiments as a means of increasing the efficiency of the DED process. Trochoidal laser motion during DED was found to increase the material addition rate by 17% and powder catchment efficiency by 15%.     

Sink electrical discharge machining of hydrophobic surfaces

The phenomenon of hydrophobicity observed in such surfaces as lotus leaves is typically manifest by hierarchical structures on low-energy surfaces. Sustained interest in fabricating hydrophobic surfaces has resulted in a myriad of processes, which are but limited by their largely referring to soft materials and/or involving multiple process steps. The present work explored the application of electrical discharge machining (EDM) for the single-step manufacture of durable, metallic hydrophobic surfaces. Simple sink EDM in a hydrocarbon dielectric, with no special process kinematic or tooling requirements, is demonstrated to rapidly generate surfaces that are intrinsically water repellent, with contact angles approaching 150°.     

Multi-material laser direct writing of aerosol jet layered polymers

We describe a novel multi-material polymer layer creation principle and deposition strategy based on aerosol jetting. In a multiple atomizer set-up, acrylates and methacrylates comprising a hardness of 25–80 ShoreD are deposited in a layer based process with a resolution range of 7.4–548.3 μm. The materials are transformed into droplets independently and enable the deposition of pure materials as well as mixed compositions. UV lasers create lateral structures with typical resolutions below 20 μm. The additive manufacturing process is experimentally verified using applications in the field of novel hardness level individualized in-ear hearing devices.     

Design and management of manufacturing systems for production quality

Manufacturing companies are continuously facing the challenge of operating their manufacturing processes and systems in order to deliver the required production rates of high quality products, while minimizing the use of resources. Production quality is proposed in this paper as a new paradigm aiming at going beyond traditional six-sigma approaches. This new paradigm is extremely relevant in technology intensive and emerging strategic manufacturing sectors, such as aeronautics, automotive, energy, medical technology, micro-manufacturing, electronics and mechatronics. Traditional six-sigma techniques show strong limitations in highly changeable production contexts, characterized by small batch productions, customized, or even one-of-a-kind products, and in-line product inspections. Innovative and integrated quality, production logistics and maintenance design, management and control methods as well as advanced technological enablers have a key role to achieve the overall production quality goal. This paper revises problems, methods and tools to support this paradigm and highlights the main challenges and opportunities for manufacturing industries in this context.     

Predictive simulation of damping effects in machine tools

A predictive simulation of the different damping effects in machine tools is required to optimize the dynamic behavior and thus increase their performance and working accuracy. Previously, holistic optimization based on damping was not possible due to non-predictive damping models and the lack of adequate modeling approaches. This paper presents a modeling approach, which allows the efficient simulation of the dynamic behavior. By applying this procedure and suitable damping and friction models, the dynamic behavior of a four-axes machining center was simulated with high accuracy – FRAC values above 95% were achieved.     

A new one-phase material model for the numerical prediction of critical material flow conditions in thixoforging processes

Thixoforging allows one-step forming processes of near-net shape components having excellent mechanical properties. However, the high sensitivity of thixoforging regarding process conditions requires precise modelling and determination of process related parameters. At the same time, simple numerical design proves challenging because of the inaccuracy of existing one-phase material models regarding the shear thinning flow behaviour of semi solid metals. Consequently, this paper deals with the development of a new one-phase material model providing a more precise simulation of materials’ shear rate dependency. By using this model, simulations could be performed, which allowed the prediction of solidification and flow-related component defects.     

An agile model for the eco-design of electric vehicle Li-ion batteries

Numerous design choices need to be made at several levels when designing high-tech products: technology, processes, architecture, components, materials… and these choices need to be made in relation to the product life cycle with the corresponding experts for each stage of the life cycle. At the same time, to ensure product sustainability, a specific focus on the future potential environmental impacts is highly recommended. In this research, an agile model is proposed to help designers make decisions while monitoring environmental performance indicators of high-tech solutions. The concept of Critical Product Life Cycle Parameters had to be introduced to facilitate the eco-design of the final product. The approach is illustrated by the Electric Vehicle Li-Ion Batteries case study.