403 research outputs found

    CIRP Encyclopedia of Production Engineering

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    This high quality reference work has been written and reviewed by members of The International Academy for Production Engineering, also known as CIRP. This Academy is recognized worldwide to represent the highest standards in research on production engineering, which includes design, optimization, control, management of processes, machines, and systems. One key concept behind this Encyclopedia is that apart from covering fundamental concepts in the field of production engineering, it also closely follows recent developments and emerging concepts. In particular this renewed print edition covers a wide range of new topical entries such as Hybrid Processes, High Performance Grinding, Biomimetic Design, Cold Spray, Sheet-bulk Metal Forming, Ecodesign, Cyber Physical System, Nano Technology, or Geometrical Product Specification. The second edition also comprises reviewed entries from the first version, which have been updated to reflect new standards or developments. The target audience primarily comprises researchers, engineers, managers, graduate students, and many others whose day-to-day work gravitates around production engineering technologies in the global market

    Pancakes for a healthy diet: low-carb, prebiotic, gluten-free

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    The work aims to develop pancake recipes corresponding to the standards of a healthy diet by replacing traditional components with ingredients containing nutritional functional properties. Corn and rice flour are gluten-free and can be used to design gluten-free pancakes. Barley flour contains beta-glucans, a large amount of fiber, reduces the glycemic index of products, is useful not only for a healthy diet but also for people suffering from diabetes and obesity. Rye flour is low in calories, as millet flour contains dietary fiber, vitamins, and lowers cholesterol. Dietary fiber and inulin contribute to the regulation of intestinal microbiota. The results show the possibility of 100% replacement of wheat flour with other types of flour in the production of low-carb, prebiotic, and gluten-free pancakes. The water absorption capacity of flour, dough viscosity, humidity, texture of products, and sensory analysis of finished products were investigated. Replacing wheat flour with alternative types of flour can improve the nutritional value of products, increase the content of dietary fiber, and reduce the calorie content of pancakes

    Grinding and fine finishing of future automotive powertrain components

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    The automotive industry is undergoing a major transformation driven by regulations and a fast-paced electrification. A critical analysis of technological trends and associated requirements for major automotive powertrain components is carried out in close collaboration with industry – covering the perspectives of OEMs, suppliers, and machine builders. The main focus is to review the state of the art with regard to grinding, dressing, texturing and fine-finishing technologies. A survey of research papers and patents is accompanied by case studies that provide further insights into the production value chain. Finally, key industrial and research challenges are summarized

    Disturbance of the regenerative effect by use of milling tools modified with asymmetric dynamic properties

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    Milling processes are often limited by self-excited vibrations of the tool or workpiece, generated by the regenerative effect, especially when using long cantilevered tools or machining thin-walled workpieces. The regenerative effect arises from a periodic modulation of the uncut chip thickness within the frequencies of the eigenmodes, which results in a critical excitation in the consecutive cuts or tooth engagements. This paper presents a new approach for disturbing the regenerative effect by using milling tools which are modified with asymmetric dynamic properties. A four-fluted milling tool was modified with parallel slots in the tool shank in order to establish asymmetric dynamic characteristics or different eigenfrequencies for consecutive tooth engagements, respectively. Measurements of the frequency response functions at the tool tip showed a decrease in the eigenfrequencies as well as an increase in the dynamic compliance in the direction of the grooves. Milling experiments with a constant width of cut and constantly increasing axial depth of cut indicated a significant increase in the stability limit for the specific preparations of up to 69%

    EUSPEN : proceedings of the 3rd international conference, May 26-30, 2002, Eindhoven, The Netherlands

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    Effect of laser texturing on the performance of ultra-hard single-point cutting tools

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    This paper investigates the cutting performance and anti-adhesive properties of textured single point polycrystalline diamond (PCD) cutting tools in machining Aluminium 6082 alloys. The micro/nano textures were first milled using a fibre laser (1064 nm wavelength) at different power intensities, feed speeds and pulse durations, and finally characterised using scanning electron microscopy, white light interferometry and energy dispersive X-ray spectroscopy. The effect of different textures on the cutting performance was investigated in turning tests under dry cutting conditions. The test was stopped at regular lengths of cut to allow analysis of height of adhesion through 3D white light interferometry. The data processing of the cutting forces and the microscopical characterisation of the tested cutting tools enabled the evaluation of the effects of texture design, friction coefficient and adhesive properties. The results indicated that feed force in tools with grooves perpendicular to the chip flow direction (CFD) was more stable (20-40N) than the benchmark (6-41N). Similarly, the thrust force for tools with grooves parallel to CFD and grooves perpendicular to CFD showed a homogeneous trend fluctuating between 60N to 75N as compared to the benchmark (ranging between 73N to 90N). For texture depth in the order of 260 nm and post process roughness in the order of tens of nanometers a reduction of average friction coefficient (0.28±0.14) was reported when using lasered inserts with grooves parallel to the chip flow direction compared to the benchmark tools (0.34±0.26) corroborated by reduced stiction of workpiece material on the rake face. In machining via textured tools with grooves perpendicular to CFD, the cutting forces were reduced by 23%, and the surface quality of the machined workpiece was improved by 11.8%, making this geometry the preferred choice for finishing applications. Using grooves parallel to CFD reduced the cutting forces by 11.76%, adhesion by 59.36% and friction coefficient by 14.28%, however it increased the surface roughness of the machined workpiece, making this geometry suitable for roughing operations. For the first time, laser manufacturing is proposed as a flexible technique to functionalise the geometrical and wear properties of PCD cutting tools to the specific applications (i.e. roughing, finishing) as opposed to the standard industrial approach to use microstructurally different PCDs (i.e. grain size and binder%) based on the type of operation. </div

    A novel approach towards a lubricant-free deep drawing process via macro-structured tools

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    In today’s industry, the sustainable use of raw materials and the development of new green technology in mass production, with the aim of saving resources, energy and production costs, is a significant challenge. Deep drawing as a widely used industrial sheet metal forming process for the production of automotive parts belongs to one of the most energy-efficient production techniques. However, one disadvantage of deep drawing regarding the realisation of green technology is the use of lubricants in this process. Therefore, a novel approach for modifying the conventional deep drawing process to achieve a lubricant-free deep drawing process is introduced within this thesis. In order to decrease the amount of frictional force for a given friction coefficient, the integral of the contact pressure over the contact area has to be reduced. To achieve that, the flange area of the tool is macro-structured, which has only line contacts. To avoid the wrinkling, the geometrical moment of inertia of the sheet should be increased by the alternating bending mechanism of the material in the flange area through immersing the blankholder slightly into the drawing die

    Investigation into vibration assisted micro milling: theory, modelling and applications

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    PhD ThesisPrecision micro components are increasingly in demand for various engineering industries, such as biomedical engineering, MEMS, electro-optics, aerospace and communications. The proposed requirements of these components are not only in high accuracy, but also in good surface performance, such as drag reduction, wear resistance and noise reduction, which has become one of the main bottlenecks in the development of these industries. However, processing these difficult-to-machine materials efficiently and economically is always a challenging task, which stimulates the development and subsequent application of vibration assisted machining (VAM) over the past few decades. Vibration assisted machining employs additional external energy sources to generate high frequency vibration in the conventional machining process, changing the machining (cutting) mechanism, thus reducing cutting force and cutting heat and improving machining quality. The current awareness on VAM technology is incomplete and effective implementation of the VAM process depends on a wide range of technical issues, including vibration device design and setup, process parameters optimization and performance evaluation. In this research, a 2D non-resonant vibration assisted system is developed and evaluated. Cutting mechanism and relevant applications, such as functional surface generation and microfluidic chips manufacturing is studies through both experimental and finite element analysis (FEA) method. A new two-dimensional piezoelectric actuator driven vibration stage is proposed and prototyped. A double parallel four-bar linkage structure with double layer flexible hinges is designed to guide the motion and reduce the displacement coupling effect between the two directions. The compliance modelling and dynamic analysis are carried out based on the matrix method and lagrangian principle, and the results are verified by finite element analysis. A closed loop control system is developed and proposed based on LabVIEW program consisting of data acquisition (DAQ) devices and capacitive sensors. Machining experiments have been carried out to evaluate the performance of the vibration stage and the results show a good agreement with the tool tip trajectory simulation results, which demonstrates the feasibility and effectiveness of the vibration stage for vibration assisted micro milling. The textured surface generation mechanism is investigated through both modelling and experimental methods. A surface generation model based on homogenous matrices transformation is proposed by considering micro cutter geometry and kinematics of vibration assisted milling. On this basis, series of simulations are performed to provide insights into the effects of various vibration parameters (frequency, amplitude and phase difference) on the generation mechanism of typical textured surfaces in 1D and 2D vibration-assisted micro milling. Furthermore, the wettability tests are performed on the machined surfaces with various surface texture topographies. A new contact model, which considers both liquid infiltration effects and air trapped in the microstructure, is proposed for predicting the wettability of the fish scales surface texture. The following surface textures are used for T-shaped and Y-shaped microchannels manufacturing to achieve liquid one-way flow and micro mixer applications, respectively. The liquid flow experiments have been carried out and the results indicate that liquid flow can be controlled effectively in the proposed microchannels at proper inlet flow rates. Burr formation and tool wear suppression mechanisms are studied by using both finite element simulation and experiment methods. A finite element model of vibration assisted micro milling using ABAQUS is developed based on the Johnson-Cook material and damage models. The tool-workpiece separation conditions are studied by considering the tool tip trajectories. The machining experiments are carried out on Ti-6Al-4V with coated micro milling tool (fine-grain tungsten carbides substrate with ZrO2-BaCrO4 (ZB) coating) under different vibration frequencies (high, medium and low) and cutting states (tool-workpiece separation or nonseparation). The results show that tool wear can be reduced effectively in vibration assisted micro milling due to different wear suppression mechanisms. The relationship between tool wear and cutting performance is studied, and the results indicate that besides tool wear reduction, better surface finish, lower burrs and smaller chips can also be obtained as vibration assistance is added

    Advances in Robotics, Automation and Control

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    The book presents an excellent overview of the recent developments in the different areas of Robotics, Automation and Control. Through its 24 chapters, this book presents topics related to control and robot design; it also introduces new mathematical tools and techniques devoted to improve the system modeling and control. An important point is the use of rational agents and heuristic techniques to cope with the computational complexity required for controlling complex systems. Through this book, we also find navigation and vision algorithms, automatic handwritten comprehension and speech recognition systems that will be included in the next generation of productive systems developed by man
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