| 1. |
- Agic, Adnan, 1967-, et al.
(författare)
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Experimental analysis of cutting edge effects on vibrations in end milling
- 2019
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 24, s. 66-74
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Tidskriftsartikel (refereegranskat)abstract
- The ability to minimize vibrations in milling by the selection of cutting edge geometry and appropriate cutting conditions is an important asset in the optimization of the cutting process. This paper presents a measurement method and a signal processing technique to characterize and quantify the magnitude of the vibrations in an end milling application. Developed methods are then used to investigate the effects of various cutting edge geometries on vibrations in end milling. The experiments are carried out with five cutting edge geometries that are frequently used in machining industry for a wide range of milling applications. The results show that a modest protection chamfer combined with a relatively high rake angle has, for the most of cutting conditions, a reducing effect on vibration magnitudes. Furthermore, dynamics of a highly positive versus a highly negative cutting geometry is explored in time domain and its dependency on cutting conditions is presented. The results give concrete indications about the most optimal cutting edge geometry and cutting conditions in terms of dynamic behavior of the tool.
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| 2. |
- Beglarzadeh, B., et al.
(författare)
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Modelling and indirect measurement of machine tool equivalent joint compliances
- 2021
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 35, s. 882-895
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Tidskriftsartikel (refereegranskat)abstract
- Machine tools require high geometric accuracy and stiffness. Both of these characteristics affect the radius of a radially loaded circular test. By using various loads, the machine's volumetric compliance can be studied as a function of position, orientation, and load. Further processing of the data using a kinematic and compliance model of the machine allows the equivalent joint compliances to be estimated. This model also allows to produce the characteristic patterns of loaded telescopic double ball bar readings associated with each compliance term. The compliance model contains numerous superfluous and confounded terms that are pruned from the model. The analytical model is then used to produce a numerical identification Jacobian that is further applied to estimate the compliances from test data gathered at various force levels. By using all force data at once global compliance values are estimated whereas using only adjacent force level data allows observing the change in compliance with force. The new nomenclature is introduced where each compliance term has three subscripts. The first subscript is the direction of the displacement, the second subscript is the applied force direction, and the third subscript is the relevant joint or axis. The dominant compliances are the X-axis on-axis compliance CXXX (confounded with the lateral compliance of the Y-axis CXXY) and CYYY (confounded with CYYX). It is observed that as the load increases from 76 to 706 N (by increments of 126 N), the dominant compliances increase by around 5%. Type A uncertainties of the calculated compliances are estimated from repeated measurements and are found to be relatively small. Some non-dominant compliances, such as the torsional compliance of the Y-axis CCCY account for deflection of less than 0.5% of that for the main compliances and has a negative value which is mechanically unexpected. It is explained in detail in the results and discussion section.
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| 3. |
- Bertoni, Alessandro, 1985-, et al.
(författare)
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PSS cost engineering : A model-based approach for concept design
- 2020
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier. - 1755-5817 .- 1878-0016. ; 29:Part: B, s. 176-190
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Tidskriftsartikel (refereegranskat)abstract
- Manufacturing companies are increasingly moving toward delivering combinations of products and services to provide higher value to their customers. The development of such Product Service Systems (PSS) escalates in complexity when several products developed by different suppliers need to be integrated into a unique system. For first tier suppliers, it is a great challenge to model and simulate the impact of changing design variables at the micro-level on both hardware properties and governing behaviours of services over the entire life-cycle of the PSS. The paper describes a model-based approach developed to estimate the life cycle cost of a PSS hardware already at a concept design stage. The proposed approach computes the relative cost efficiency of a set of design variants using as input the data generated by the simulations run in the Computer Aided Engineering (CAE) environment. The approach allows the exploration of the design space of a PSS given by the variation of the geometry of a Computer Aided Design (CAD) model, building on the computation of customised cost modules selected by a generic list of PSS cost dimensions. For each evaluated design case, the model produces as output a unique monetary figure of the cost expected to incur by owning or using the asset throughout the lifetime. The work has been conducted in collaboration with a tier-one aerospace component manufacturer, and the application of the model is exemplified through a case study related to the development of a turbine rear structure (TRS) for commercial jet engines. The approach is most suitable for the development of complex systems in which new products and components are integrated into a shared product platform. The results are discussed in relation to the current literature on PSS cost engineering, highlighting challenges to be addressed to increase cost estimation accuracy and increase uncertainty identification and awareness.
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| 4. |
- Bertoni, Alessandro, et al.
(författare)
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Value-driven product service systems development : Methods and industrial application
- 2016
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier. - 1755-5817 .- 1878-0016. ; 15, s. 42-55
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Tidskriftsartikel (refereegranskat)abstract
- In recent times a service-dominant logic is permeating the design of complex systems. However, in spite of their appeal, initiatives such as Product Service Systems (PSS) have not become mainstream, and methods are lacking to support this transition. This paper argues that methodological guidance, as well as tools for decision support, may be found in the research field of Value Driven Design (VDD), which originates in the realm of Systems Engineering. The paper objective is to elaborate on gaps and opportunities for cross-pollination between VDD and PSS. The results of a systematic review of methods and tools for design decision support highlight the opportunity for introducing optimization models derived from VDD in the PSS design process, while the latter can enrich VDD research with a more qualitative value assessment logic. The paper summarizes this integration in a methodological approach, and exemplifies its application in case studies mainly from the aerospace and road construction equipment sector.
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| 5. |
- Bonilla Hernández, Ana Esther, et al.
(författare)
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Integrated optimization model for cutting data selection based on maximal MRR and tool utilization in continuous machining operations
- 2016
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 13, s. 46-50
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Tidskriftsartikel (refereegranskat)abstract
- The search for increased productivity can be interpreted as the increase of material removal rate (MRR). Namely, increase of feed, depth of cut and/or cutting speed. The increase of any of these three variables, will increase the tool wear rate; therefore decreasing its tool life according to the same tool life criteria. This paper proposes an integrated model for efficient selection of cutting data for maximal MRR and maximal tool utilization. The results show that, it is possible to obtain a limited range of cutting parameters from where the CAM Programmer can select the cutting data assuring both objectives.
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| 6. |
- Dahl, Martin, 1984, et al.
(författare)
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Interactive formal specification for efficient preparation of intelligent automation systems
- 2022
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Ingår i: CIRP Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 38, s. 129-138
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Tidskriftsartikel (refereegranskat)abstract
- The automation system of the future will consist of an increasing amount of complex resources, such as collaborative robots and/or autonomously roaming robots for material handling. To control these devices in an environment shared with human operators require state of the art computer perception and motion planning algorithms to be used as part of the automation system. This new type of intelligent automation system, where intelligent machines and learning algorithms are replacing more traditional automation solutions, requires new methods and workflows to keep up with the increase in complexity. This paper presents an interactive and iterative framework for solving some of these new challenges. The framework supports model-based control system preparation performed simultaneously to preparation of 3D geometries, positioning of robots, and tool design. The workflow enables an interactive preparation process, where new resources and constraints can be added to a live (real or simulated) automation system and control system failures can be analyzed in familiar tools for virtual preparation. Additionally, the paper describes how the integrated preparation process was applied to reconfiguring an industrial use case that includes a collaborative robot working side by side with a human operator, smart tools, and a vision system for localizing both work objects and tools.
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| 7. |
- de Andrade Schwerz, Claudia, 1992, et al.
(författare)
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A neural network for identification and classification of systematic internal flaws in laser powder bed fusion
- 2022
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Ingår i: CIRP Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 37, s. 312-318
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Tidskriftsartikel (refereegranskat)abstract
- Quality control of mechanical components is crucial to ensure their expected performance and prevent their failure. For components manufactured additively, quality control performed in-process is particularly interesting, as the sequential deposition and remelting of layers represent a possibility to mitigate existing flaws. The first step towards closed-loop control is to ensure that the monitoring setup and the data analytics approach can flag and discriminate flaws. This study aims to assess the potential of a layerwise monitoring system associated with a supervised machine learning approach to identify and classify internal flaws in laser powder bed fusion of Hastelloy X. For that, systematically generated internal flaws were mapped ex-situ in 72 distinct process conditions. The outputs of the near-infrared long-exposure acquisition system were labeled according to the ex-situ characterization and used to train a fully convolutional neural network. The network was then used to classify previously unseen monitoring images into three classes, according to the predominant flaw type expected, lack of fusion, keyhole porosity, or residual porosity. Accuracy, precision and recall over 96% are obtained, indicating that the monitoring system combined with this supervised machine learning approach successfully identifies and classifies internal flaws.
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| 8. |
- Erdem, Ilker, 1987, et al.
(författare)
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A novel comparative design procedure for reconfigurable assembly fixtures
- 2017
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Ingår i: CIRP Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 19, s. 93-105
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Tidskriftsartikel (refereegranskat)abstract
- While market requirements demand that manufacturing systems increase their responsiveness, assembly fixtures remain limited in corresponding to the same demand. Fixture designers as practitioners are left without guidance to design reconfigurable fixtures. This study proposes a comparative design procedure for reconfigurable assembly fixtures that can adapt to manufacturing system characteristics by using efficiency metrics. In this study, a theoretical analysis based on manufacturing systems is presented to establish efficiency metrics. Later, these metrics are utilized in a design procedure that offers guidance and determines the efficiency of fixtures in conceptual and detailed design stages. Finally, an experimental verification is presented.
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| 9. |
- Eynian, Mahdi, 1980-
(författare)
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Prediction of vibration frequencies in milling using modified Nyquist method
- 2015
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier. - 1755-5817 .- 1878-0016. ; 11:November, s. 73-81
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Tidskriftsartikel (refereegranskat)abstract
- Study of the vibration frequencies at different cutting conditions is an alternative to the use of impact hammer test for identification of natural frequencies of the machining structure and calculation of stability lobe diagrams. Vibration frequencies not only depend on the natural frequencies of the structure, but also they are dependent on the spindle speed, damping ratio of the structure and the depth of cut. Ignoring these additional parameters would lead to errors in identification of the natural frequencies of the system and considerable deviation of the calculated stability lobe diagrams from actual cutting tests. In this study modified Nyquist method is used to investigate the effects of spindle speed, depth of cut and damping ratio of the structure on vibration frequencies. The quality of frequency prediction is compared to linear and nonlinear time domain simulations and machining experiments.
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| 10. |
- Farooqui, Ashfaq Hussain, 1990, et al.
(författare)
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From factory floor to process models: A data gathering approach to generate, transform, and visualize manufacturing processes
- 2019
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Ingår i: CIRP Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 24, s. 6-16
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Forskningsöversikt (refereegranskat)abstract
- The need for tools to help guide decision making is growing within the manufacturing industry. The analysis performed by these tools will help operators and engineers to understand the behaviour of the manufacturing stations better and thereby take data-driven decisions to improve them. The tools use techniques borrowed from fields such as Data Analytics, BigData, Predictive Modelling, and Machine Learning. However, to be able to use these tools efficiently, data from the factory floor is required as input. This data needs to be extracted from two sources, the PLCs, and the robots. In practice, methods to extract usable data from robots are rather scarce. The present work describes an approach to capture data from robots, which can be applied to both legacy and current state-of-the-art manufacturing systems. The described approach is developed using Sequence Planner - a tool for modelling and analyzing production systems - and is currently implemented at an automotive company as a pilot project to visualize and examine the ongoing process. By exploiting the robot code structure, robot actions are converted to event streams that are abstracted into operations. We then demonstrate the applicability of the resulting operations, by visualizing the ongoing process in real-time as Gantt charts, that support the operators performing maintenance. And, the data is also analyzed off-line using process mining techniques to create a general model that describes the underlying behaviour existing in the manufacturing station. Such models are used to derive insights about relationships between different operations, and also between resources.
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| 11. |
- Hosseini, Seyed, et al.
(författare)
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A descriptive phenomenological model for white layer formation in hard turning of AISI 52100 bearing steel
- 2021
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier Ltd. - 1755-5817 .- 1878-0016. ; 32, s. 299-310
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigates the characteristics and the formation of white layers and dark layers induced by hard turning of through-hardened AISI 52,100 steel. The investigation showed that different types of white layers exist e.g., formed predominantly through excessive thermal or mechanical energy loading. The thermally induced white layer is formed when the cutting temperature is above the critical austenitisation temperature for the material. The nano-sized microstructure is initiated through dynamic recovery, which transitions to dynamic recrystallisation when the temperature rises above the onset temperature for dynamic recrystallisation. The corresponding white layer is characterised by a higher retained austenite content compared to the unaffected material, and the presence of a dark layer beneath the white layer. The white layer and the adjacent dark layer are found to be ∼12% harder and 14% softer, respectively, compared to the unaffected material. On the other hand, the mechanically induced white layer is formed through severe plastic deformation, where the formation is controlled by dynamic recovery and results in an elongated and broken-down substructure. Neither austenite nor an adjacent dark layer could be found for such white layers. The mechanically induced white layer is ∼26% harder than the unaffected material. For both types of white layer, (Fe, Cr)3C carbides are found in the microstructure. The investigation shows that the heating rate, cooling rate, pressure, and duration of contact between the cutting tool and workpiece surface should also be considered to understand the underlying formation mechanisms. The characteristics of the examined white layers and the cutting conditions are summarised in a descriptive phenomenological model in order to create a systematic approach for the definition of the different types of white layers.
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| 12. |
- Hovgard, Mattias, 1993, et al.
(författare)
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Applied energy optimization of multi-robot systems through motion parameter tuning
- 2021
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Ingår i: CIRP Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 35, s. 422-430
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, an optimization method for energy reduction of robot stations is presented, including an evaluation on an industrial robot station. The problem is formulated as a convex mixed integer nonlinear optimization problem, where the objective is to reduce the energy use by finding the optimal execution time and execution order of the robot motions. A simulation model of the station is used to find simplified energy models of the robot motions, that is used to solve the optimization problem. The optimal execution times of the robot motions are realized by tuning parameters in the robot control system. Different types of parameter settings are tested, such as reduced acceleration and velocity. The optimal parameter settings are then implemented in robot code in a real four robot welding station. The result shows a 12% reduction in energy use, without extending the cycle time of the station. A validation of the energy models used to solve the optimization problem is also made, by comparing them with real energy measurements.
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| 13. |
- Khan, Adnan, 1984, et al.
(författare)
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On testing and automatic mending of safety PLC code
- 2021
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Ingår i: CIRP Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 35, s. 431-440
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an approach to automatically amend an erroneous model of an implementation using a safety specification as the basis to ensure safety. Industrially, safety PLCs are common to ensure safe operations. However, before its commissioning, the implemented safety code must be tested for faults caused by spurious transitions and missing safety transitions. Spurious transitions are implemented events that are not prescribed by the safety specification, while missing safety transitions are unimplemented safety events that are prescribed by the safety specification. The presence of these faults can result in material or human damage. The proposed approach requires the model of an implementation to be trace equivalent with the given safety specification only in terms of traces composed of safety events, which is captured by the notion of safe-IOCOS. If the implementation emits other than the specified safety events then the implementation is not safe-IOCOS and requires amendment. This is achieved by removing the spurious transitions and adding the missing safety events in the implementation using synthesis techniques from the supervisory control theory. The infimal controllable superlanguage is used to compute the infimal safety extension, which adds the missing safety transitions. It is shown how the resulting model of an implementation after amendment is both safe-IOCOS and controllable with respect to the specification.
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| 14. |
- Khan, Adnan, 1984, et al.
(författare)
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Testing and validation of safety logic in the virtual environment
- 2019
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Ingår i: CIRP Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 26, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an approach for testing safety PLC logic in a virtual environment, using the IOCO testing relation as validation criteria. Manufacturing companies more and more rely on virtual commissioning to reduce the physical commissioning time by testing and debugging the PLC logic of the nominal behavior prior to physical commissioning. However, safety PLC logic testing is still carried out on real systems manually. This manual practice of safety logic validation hinders industry to exploit the full potential of virtual commissioning to reduce the physical commissioning time. The proposed approach assists manufacturing companies in the validation of safety PLC logic using a simulation model before the factory acceptance testing phase. Using the proposed approach, a simulation model can be used to test the safety PLC logic and prepare better for the factory acceptance testing phase, hence, further reduction in physical commissioning time can be achieved.
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| 15. |
- Li, Chengxi, et al.
(författare)
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Deep reinforcement learning in smart manufacturing : A review and prospects
- 2023
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 40, s. 75-101
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Forskningsöversikt (refereegranskat)abstract
- To facilitate the personalized smart manufacturing paradigm with cognitive automation capabilities, Deep Reinforcement Learning (DRL) has attracted ever-increasing attention by offering an adaptive and flexible solution. DRL takes the advantages of both Deep Neural Networks (DNN) and Reinforcement Learning (RL), by embracing the power of representation learning, to make precise and fast decisions when facing dynamic and complex situations. Ever since the first paper of DRL was published in 2013, its applications have sprung up across the manufacturing field with exponential publication growth year by year. However, there still lacks any comprehensive review of the DRL in the field of smart manufacturing. To fill this gap, a systematic review process was conducted, with 261 relevant publications selected to date (20-Oct-2022), to gain a holistic understanding of the development, application, and challenges of DRL in smart manufacturing along the whole engineering lifecycle. First, the concept and development of DRL are summarized. Then, the typical DRL applications are analyzed in the four engineering lifecycle stages: design, manufacturing, dis-tribution, and maintenance. Finally, the challenges and future directions are illustrated, especially emerging DRL-related technologies and solutions that can improve the manufacturing system's deployment feasi-bility, cognitive capability, and learning efficiency, respectively. It is expected that this work can provide an insightful guide to the research of DRL in the smart manufacturing field and shed light on its future perspectives.
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| 16. |
- Lindström, John, et al.
(författare)
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Outlining an overall Functional Product lifecycle : combining and coordinating its economic and technical perspectives
- 2017
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier. - 1755-5817 .- 1878-0016. ; 17, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Currently, industry is showing increasing interest in performance-based business models. Functional Products is one such business model, where the provider offers a function to customers at an agreed-upon level of availability, productivity or efficiency, etc. A Functional Product comprises the following four main constituents: hardware, software, service support system and management of operation, which together deliver value to customers on a long-term basis. This paper, based on empirical data, provides an outline and starts the verification of a proposed overall Functional Product lifecycle combining and coordinating its economic- and technical perspectives. The perspectives are combined and the key aspects of the necessary coordination between and within the perspectives, i.e., sustainable win-win situations and coordination of sub-lifecycles for the economic perspective, and the need for coordination between the Functional Products’ technical perspective's four sub-lifecycles (hardware, software, service-support system and management of operation), are elaborated and discussed. Further, addition of new functionality, contract management, and long-term management of operation are discussed in the light of managing fleets/individual customers, assets and availability. The proposed overall Functional Product lifecycle is further analyzed from a number of views and aspects.
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| 17. |
- Liu, Sichao, et al.
(författare)
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Sensorless haptic control for human-robot collaborative assembly
- 2021
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 32, s. 132-144
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an approach to haptically controlling an industrial robot without using any external sensors for human-robot collaborative assembly. The sensorless haptic control approach is enabled by the dynamic models of the robot where only joint angles and joint torques are measurable. Accurate dynamic models of the robot in the presliding and sliding regimes are developed to estimate the external forces/torques, where the friction model is also explored. The estimated external force applied to the robot by an operator is converted to the reference position and speed of the robot by an admittance controller. In this research, adaptive admittance control is adopted to support human-robot collaborative assembly, naturally and easily, with accurate positioning and control for smooth movement. Moreover, torque-based commands are used to control the robot’s assembly operations. Finally, the proposed approach is validated by a case study on assisting an operator during the collaborative assembly of a car engine.
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| 18. |
- Matschewsky, Johannes, 1987-, et al.
(författare)
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Capturing and enhancing provider value in product-service systems throughout the lifecycle : A systematic approach
- 2020
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier. - 1755-5817 .- 1878-0016. ; 29:1, s. 191-204
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Tidskriftsartikel (refereegranskat)abstract
- Although the transition from product seller to product-service system (PSS) provider implies fundamental changes in both value creation for customers and value capture by the provider, prior research has largely focused on the investigation and enhancement of customer value through PSSs. In contrast, a discussion of the changes in how providers attain value and support to enhance this in industrial practice is lacking at this time. This article presents a systematic, empirically-based approach to analyze and enhance PSS providers’ value capture throughout the lifecycle. This is achieved by two methods provider value analysis (PVA) facilitates a structured assessment of the value capture during the provision of PSSs in the use phase of the lifecycle, while provider value evaluation (ProVa) operationalizes the results of this analysis in the design phase to facilitate an improved value capture in the coming iteration. As the approach was developed in close collaboration with a large-scale PSS provider, the article further reports the results of its application in a case study spanning two years. As a result of using PVA, value dimensions of broad relevance for PSS providers are presented, supported by findings of applying the method at an additional PSS provider. Through the approach presented and case study results attained, the article points out how the design and management of a PSS, focusing on the provider’s value and available benefits throughout the lifecycle, can be enhanced in industry, while extending the academic body of knowledge on the value capture of PSS providers and its implications for PSS design and provision.
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| 19. |
- Nourmohammadi, Amir, et al.
(författare)
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Multi-objective optimization of mixed-model assembly lines incorporating musculoskeletal risks assessment using digital human modeling
- 2023
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier. - 1755-5817 .- 1878-0016. ; 47, s. 71-85
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Tidskriftsartikel (refereegranskat)abstract
- In line with Industry 5.0, ergonomic factors have recently received more attention in balancing assembly lines to enhance the human-centric aspect. Meanwhile, today’s mass-customized trend yields manufacturers to offset the assembly lines for different product variants. Thus, this study addresses the mixed-model assembly line balancing problem (MMALBP) by considering worker posture. Digital human modeling and posture assessment technologies are utilized to assess the risks of work-related musculoskeletal disorders using a method known as rapid entire body analysis (REBA). The resulting MMALBP is formulated as a mixed-integer linear programming (MILP) model while considering three objectives: cycle time, maximum ergonomic risk of workstations, and total ergonomic risks. An enhanced non-dominated sorting genetic algorithm (E-NSGA-II) is developed by incorporating a local search procedure that generates neighborhood solutions and a multi-criteria decision-making mechanism that ensures the selection of promising solutions. The E-NSGA-II is benchmarked against Epsilon-constraint, MOGA, and NSGA-II while solving a case study and also test problems taken from the literature. The computational results show that E-NSGA-II can find promising Pareto front solutions while dominating the considered methods in terms of performance metrics. The robustness of E-NSGA-II results is evaluated through one-way ANOVA statistical tests. The analysis of results shows that a smooth distribution of time and ergonomic loads among the workstations can be achieved when all three objectives are simultaneously considered.
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| 20. |
- Pauzon, Camille Nicole Géraldine, 1994, et al.
(författare)
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Reduction of incandescent spatter with helium addition to the process gas during laser powder bed fusion of Ti-6Al-4V
- 2021
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Ingår i: CIRP Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 35, s. 371-378
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Tidskriftsartikel (refereegranskat)abstract
- The effect of the process gas during laser powder bed fusion (L-PBF) was investigated using high-speed shadowgraphy while melting Ti-6Al-4V powder under high purity argon, helium, and a mixture of both, on a laboratory-scale machine. These recordings reveal that the generation of incandescent spatters can be reduced by at least 60% using pure helium and by ∼30% using addition of helium to argon in comparison to the use of traditional argon. The quantity of colder spatters appeared unaffected by the change of process gas. Different configurations of gas flow versus laser scanning direction were investigated and revealed that fumes and spatters are less accumulated at the laser spot with helium addition. Furthermore, the use of the argon–helium mixture proved to be as efficient as pure argon in the dragging and extraction of the fumes. Shadowgraphs revealed the more rapid expansion of fumes in helium-rich atmospheres, limiting the accumulation of scattering objects close to the laser spot and thus melt pool instability. These results were correlated to process snapshots on an industrial-scale system, confirming the reduction of hot spatter generation. Finally, the findings put in evidence the more rapid cooling of spatters with helium addition to the process gas – a promising aspect to limit powder bed degradation during L-PBF. In addition, the use of mixtures of helium and argon would be economically interesting compared to pure helium, typically more expensive than the traditionally used argon.
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| 21. |
- Pejryd, Lars, 1955-, et al.
(författare)
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Process monitoring of wire drawing using vibration sensoring
- 2017
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 18, s. 65-74
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Tidskriftsartikel (refereegranskat)abstract
- Automating the detection of processing conditions that may lead to defects in the wire during the wire drawing process is of high interest to the industry. Current practise is based primarily on operator experience. Increasing demands on product quality and process robustness emphasises the need for development of robust in-process detection methods. This work is focusing on investigating the potential of using vibration monitoring to detect process deficiencies or variations that may lead to defects in the product. Wire drawing of a carbon steel in different lubricating situations was used to investigate vibration signal response together with force measurements and surface investigation of the wire product. The results show that vibration measurement is capable of detecting loss of lubrication that leads to poor surface quality of the wire.
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| 22. |
- Repo, Jari, et al.
(författare)
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Measurement method for the identification of individual teeth in milling operations
- 2012
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 5:1, s. 26-32
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Tidskriftsartikel (refereegranskat)abstract
- Internal sensors already available in the machine tools may prove to be an interesting approach to monitor the machining process. Accurate determination of the position of the individual tooth on a milling cutter is important to be able to correlate the measured responses from the machine tool position encoders to the tooth or teeth that may be the cause of the response.The aim of the work presented in this paper is to develop a measurement method to identify the individual tooth on a milling cutter by their angular position relative to a specified 0-degree direction. If the lower and upper bounds of the cutting zone are known, together with the actual spindle position and the starting time of the cut, it will be possible to track and identify which teeth are within the cutting zone at a given time in the following off-line analysis of the responses. This may simplify the task of finding potential correlations between the state of individual teeth on the milling cutter with measured responses from various sensors during the milling process. The proposed method is based on a reflectance detector and uses accurate position information provided by the position encoders.A validation of the measurement method is also presented which shows that the error of the estimated angular position is approximately +/- 0.15 degrees for the validation setup used in this case.
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| 23. |
- Rondini, Alice, et al.
(författare)
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At the origins of Product Service Systems : Supporting the concept assessment with the Engineering Value Assessment method
- 2020
-
Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier. - 1755-5817 .- 1878-0016. ; 29:Part:B, s. 176-190
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, the economic circumstances spur many companies in changing their traditional product-oriented value proposition toward a more customised and sustainable offer referred as Product-Service Systems (PSS). The main advantages of the new solutions are related to their customisation which can grant an improved customer experience. However, while pursuing greater differentiation from competitors and ‘locking-in’ customers and ‘locking-out’ competitors, many of the above-cited companies either miss interesting business opportunities or bet on the wrong solution concept. Early stage engineering phase plays a crucial role concerning the subsequent lifecycle phases, guiding the identification and the selection of valuable solutions while preventing commitment of resources on poor design alternatives. In the light of the criticality of this phase, this paper builds on empirical studies in the manufacturing industry and highlights the need for systematic procedures, methods and metrics able to encompass customer satisfaction together with the producer's value perspective during the early design assessment. The outcome of the paper is the Engineering Value Assessment (EVA) method. It is a 2 step procedure composed of multi-criteria decision-making methods with specific criteria for a comprehensive value assessment of PSS from both the customers’ and the provider's perspectives. The EVA also guides the identification of trade-off between the two through the Importance-Performance Analysis. Verification activities in the power and automation industry highlight the main benefits and the implications of the EVA method in guiding the decision making in the early stages of design and in balancing the trade-off between customer and provider value during the PSS assessment phase. Further developments and improvements are also discussed. © 2018 CIRP
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| 24. |
- Scotti, Fernando Matos, et al.
(författare)
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Effect of O2 content in argon-based shielding gas on arc wandering in WAAM of aluminum thin walls
- 2021
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier Ltd. - 1755-5817 .- 1878-0016. ; 32, s. 338-345
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Tidskriftsartikel (refereegranskat)abstract
- The present work aimed at evaluating the effect of O2 content in argon-based shielding gases over the arc cathodic emission behavior (which can lead to arc wandering) in wire + arc additive manufacturing (WAAM) of thin aluminum walls and its consequences over layer formation. The effect of O2 content on arc wandering was assessed by analyzing cathodic spot behavior through high-speed videography during Gas metal arc (GMA-AM) depositions. Superficial and geometric aspects were analyzed, as well as the sputtering zone width on the wall sides. Through a proposed model, a parallel effect of wire-introduced oxides was weighted to explain arc wandering, searching for oxides in the wall sides (deviating from its action only on the pool). The main finding was that no influence of O2 from the shielding gas was observed on arc wandering, consequently on layer formation, when its content was up to 200 ppm. When an O2 content of 20,000 ppm was employed, oxide searching by the arc in the wall sides was no longer perceived due to enough oxide availability from the shielding gas. However, this favorable condition to layer formation entailed excessive layer oxidation. From the cathodic emission point of view, it can be said that high-purity shielding gases or special mixtures with small additions of O2 (up to 200 ppm) provide no significant advantages for WAAM of aluminum thin walls, at least for the hereby tested alloy and parameters.
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| 25. |
- Sundin, Erik, 1974-, et al.
(författare)
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From Component to System Solution Supplier : Strategic Warranty Management as a Key to Efficient Integrated Product/Service Engineering
- 2010
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier. - 1755-5817 .- 1878-0016. ; 2:3, s. 183-191
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Tidskriftsartikel (refereegranskat)abstract
- As hardening competition in industry pushes manufacturing companies to deliver increased customervalue, communication with the customer during the use phase becomes paramount. This paperinvestigates whether warranty management could be a strategic tool for improved integrated product/service engineering (IPSE) as a firm moves from component to system solution supplier. The researchmethodology appliedwas amultiple case study, with four suppliers as focal firms, where buyer–supplierrelationships were investigated from a supplier perspective. Results show that advanced warrantymanagement, implemented as a strategic tool, can be a key to efficient IPSE.
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| 26. |
- Tamil Alagan, Nageswaran, 1990-, et al.
(författare)
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High-pressure flank cooling and chip morphology in turning Alloy 718
- 2021
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier Ltd. - 1755-5817 .- 1878-0016. ; 35, s. 659-674
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Tidskriftsartikel (refereegranskat)abstract
- The use of cutting fluids is commonly considered a necessity while machining Heat Resistant Super Alloys (HRSA). Specifically, cutting fluids applied under high-pressure, which for many decades have been the solution for the most demanding applications. The results might be diverse and vary between applications, but typically leads to improved tool life, enhanced chip breakability, lower temperature in the cutting zone and better surface quality of the finished product. The available high-pressure cutting fluid delivery systems are usually designed with the intention to improve the cutting fluid penetration at the vicinity of the cutting edge on the rake face side of the insert. However, there has been limited interest in investigating high-pressure cutting fluid applied to its flank face. Both specifically and in combination with cutting fluid directed to the rake face. In this study, the focus has been to investigate the chip formation process during the turning of Alloy 718 (Inconel 718). Particularly, for a defined turning operation where high-pressure cutting fluid is applied to the flank side as well as the rake side of an uncoated carbide insert. Several combinations of pressure levels and jet directions were investigated. The corresponding effects on the tool-chip contact zone and chip characteristics were studied for two cutting speeds. The results of the investigation showed a substantial improvement in lowering the tool-chip contact area at a rake pressure of 16 MPa. At which pressure, additional cutting fluid applied to the flank at a moderate pressure of 8 MPa had no dominant effect on chip formation (chip break). However, flank cooling of the cutting zone supports chip segmentation and thus indirectly chip breakability. For cutting fluid applied to the rake side at a more moderate pressure of 8 MPa, more prominent effects on the insert became apparent when additional cutting fluid was applied to the flank side. This was particularly noticeable when cutting fluid was directed towards the flank side of the insert at the same pressure level as the cutting fluid applied towards its rake face. The additional thermal transfer was seen to have a significant effect on the material deformation phenomena in the primary shear zone (lowering shear angle) as well as the sliding and sticking conditions of the tool-chip interface. Based on the evidence from this study, it can be concluded that cutting fluid applied towards the flank side of the insert has a significant impact on the cutting process. In particular, if applied in combination with a rake pressure at a similar level, in this case, 8 MPa. © 2021 The Authors
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| 27. |
- Tamil Alagan, Nageswaran, 1990-, et al.
(författare)
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Investigation of the quality of Al-CFRP stacks when drilled using innovative approaches
- 2023
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - 1755-5817 .- 1878-0016. ; 43, s. 260-272
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Tidskriftsartikel (refereegranskat)abstract
- The usage of metal/composite stacks such as those made of aluminum alloy (Al) and carbon fiber-reinforced polymer (CRFP) has recently increased in the aerospace industry thanks to their high strength-to-weight ratio. As drilling high-quality holes in metal/composite stacks is still a challenge, innovative machining processes, such as ultrasonic vibration-assisted drilling and cryogenic drilling, have gained increasing attention for the part quality they promise. The feasibility of using the synergistic ultrasonic cryogenic drilling approach on Al/CFRP stacks is investigated for the first time, and the influence of the aforementioned innovative drilling approaches at varying feed in relation to the hole quality declined in terms of geometrical accuracy, surface roughness, delamination, and surface defects evaluated. The cutting forces are acquired as well. The obtained results show that, at increasing feed, the hole quality drastically worsens, nevertheless, it improves when applying innovative drilling technologies with respect to the standard one. Overall, ultrasonic cryogenic drilling carried out at the lowest investigated feeds represents the best drilling scenario thanks to the simultaneous application of ultrasonic vibrations, which enhances the surface finish as a consequence of the decreased contact between the workpiece and tool, and cryogenic cooling, which makes the surfaces harder.
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| 28. |
- Thiede, Sebastian, et al.
(författare)
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Environmental aspects in manufacturing system modelling and simulation – State of the art and research perspectives
- 2013
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Ingår i: CIRP Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 6:1, s. 78-87
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Tidskriftsartikel (refereegranskat)abstract
- The efficient and effective usage of energy and resources is of rising importance in manufacturing companies. This paper argues that manufacturing system simulation is a promising way to realistically cope with those issues and simultaneously consider them with traditional target dimensions. Against this background, the paper analyses whether commercial simulation tools are already capable to address those aspects. It turns out that environmentally related aspects are currently not sufficiently considered as standard functions. Therefore, based on the analysis of on-going research work, different directions for further development are presented and discussed.
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| 29. |
- Treber, Stefan, et al.
(författare)
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Robust optimization of information flows in global production networks using multi-method simulation and surrogate modelling
- 2021
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : ELSEVIER. - 1755-5817 .- 1878-0016. ; 32, s. 491-506
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Tidskriftsartikel (refereegranskat)abstract
- Low information exchange in global production networks results in long response time to disruption and negative performance impact. Digitalization enables a more intensive information exchange. This paper analyses the performance of order management, quality problem resolution and engineering change management in production networks with respect to different disruptions and information flows. Cause-effect relationships are revealed based on a multi-method simulation model and statistical experiments. Using surrogate modelling and robust optimization, a target picture for information exchange is determined. The benefits of the approach are demonstrated using a case study for the production of metal-plastic parts for the automotive supplier industry.
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| 30. |
- Wang, Lihui
(författare)
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Machine availability monitoring and machining process planning towards Cloud manufacturing
- 2013
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 6:4, s. 263-273
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Tidskriftsartikel (refereegranskat)abstract
- Cloud manufacturing as a trend of future manufacturing would provide cost-effective, flexible and scalable solutions to companies by sharing manufacturing resources as services with lower support and maintenance costs. Targeting the Cloud manufacturing, the objective of this research is to develop an Internet- and Web-based service-oriented system for machine availability monitoring and process planning. Particularly, this paper proposes a tiered system architecture and introduces IEC 61499 function blocks for prototype implementation. By connecting to a Wise-ShopFloor framework, it enables real-time machine availability and execution status monitoring during metal-cutting operations, both locally or remotely. The closed-loop information flow makes process planning and monitoring feasible services for the Cloud manufacturing.
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| 31. |
- Wärmefjord, Kristina, 1976, et al.
(författare)
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An investigation of the effect of sample size on geometrical inspection point reduction using cluster analysis
- 2010
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Ingår i: CIRP Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817 .- 1878-0016. ; 3:3, s. 227-235
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Tidskriftsartikel (refereegranskat)abstract
- Since the model program in automotive industry gets more and more extensive, the costs related to inspection increase. Therefore, there are needs for more effective inspection preparation. In this paper a method for reducing the number of inspection points using cluster analysis is tested on production data. This leads to reductions evaluated up to 90 percent in the case studies considered. Furthermore, the relation between movements in locators and the resulting movements in inspection points is used to find inspection points particularly suited to monitor the fixtures and its locating points. Those same points are used as input to the cluster analysis and chosen as representatives for the clusters. Using cluster analysis, the sample size is an important matter. The sample size, of course, affects the statistical confidence, but it is also important to choose a sample large enough to contain as many effects as possible related to the different process phenomena that exist over time. Those issues are investigated and a sample size lower than 50 items cannot be recommended.
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| 32. |
- Zhu, Zhaolong, et al.
(författare)
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Cutting performance in the helical milling of stone-plastic composite with diamond tools
- 2020
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier. - 1755-5817 .- 1878-0016. ; 31, s. 119-129
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Tidskriftsartikel (refereegranskat)abstract
- With the aim of providing scientific guidance for the application of diamond cutting tools to the machining of stone-plastic composite, this work presents results on the influence of tool geometry and cutting parameters on cutting forces and temperature during helical milling of stone–plastic composite with diamond cutters. Four factors—helical angle, spindle speed, feed rate, and cutting depth—were assessed using a response surface method. Mathematical models were developed and identified by verification testing to accurately predict changes in cutting forces and temperature during composite helical milling. Then, the significant contributions of each factor and of two-factor interactions were determined by analysis of variance, and the trends of cutting forces and temperature were studied using response surface methodology. The optimal conditions in terms of low cutting forces and temperature were determined to be a helical angle of 70°, cutting speed of 51.3 m/s, feed per tooth of 0.24 mm, and cutting depth of 0.5 mm. These parameters are proposed for use in the industrial production of stone–plastic composite material to improve machining efficiency.
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| 33. |
- Ståhl, Jan-Eric, et al.
(författare)
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Dynamic manufacturing costs — Describing the dynamic behavior of downtimes from a cost perspective
- 2012
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Ingår i: CIRP Journal of Manufacturing Science and Technology. - 1755-5817. ; 5:4, s. 284-295
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Tidskriftsartikel (refereegranskat)abstract
- Downtimes in a manufacturing cell, a production line or an individual machine are characterized by a complex statistical behavior that their frequency and duration display. The work reported here concerns likenesses and differences between various statistical distributions that apply to functional times (TBF) and downtimes (DT) in connection with different discrete manufacturing processes. The TBF and DT are viewed as varying over the whole production time for the batch. A method is presented for analyzing the dynamic behavior involved in terms of costs. An important element in this method is the statistical analysis of downtimes, making use of both empirical and theoretical distribution functions that apply to functioning times and downtimes of specific types. For demonstrating how the method is employed, use is made of real data obtained from the Swedish company Alfa Laval.
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| 34. |
- Grüne-Yanoff, Till
(författare)
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Action explanations are not inherently normative
- 2008
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Ingår i: Theoria. - : Wiley. - 0040-5817 .- 1558-5816 .- 0040-5825 .- 1755-2567. ; 74:1, s. 60-78
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Tidskriftsartikel (refereegranskat)abstract
- Inherent normativity is the claim that intentional action explanations necessarily have to comply with normatively understood rationality constraints on the ascribed propositional attitudes. This paper argues against inherent normativity in three steps. First, it presents three examples of actions successfully explained with propositional attitudes, where the ascribed attitudes violate relevant rationality constraints. Second, it argues that the inference rules that systematise propositional attitudes are qualitatively different from rationality constraints both in their justification and their recipients. Third, it rejects additional conditions on propositional attitudes, which purport to necessitate a normative commitment. Thus, inherent normativity is rejected; and with it the claim that intentional action explanations differ substantially from other explanations because they are inherently normative.
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| 35. |
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| 36. |
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| 37. |
- Hara, Tatsunori, et al.
(författare)
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Service CAD System to Integrate Product Behavior and Service Activity for Total Value
- 2009
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Ingår i: CIRP Journal of Manufacturing Science & Technology. - : Elsevier BV. - 1755-5817. ; 1:4, s. 262-271
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Tidskriftsartikel (refereegranskat)abstract
- Good combination of product and service is a key issue to balance economic growth with environmental concerns. This paper aims at demonstrating a design method to integrate products and service activities for total value. Our design method differs from Traditional Engineering and Concurrent Engineering in that products and service activities are designed in parallel according to customer value. To establish such design method, the service blueprinting method from marketing field, which describes service delivery processes, is extended to include product and its behavior. Function structure of service for the receiver state works as a bridge between product behavior and service activity. Both the above method and the CAD tool are demonstrated through an example presented herein.
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| 38. |
- Hukkerikar, Abhishek V., et al.
(författare)
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A tribological characterisation of Ti-48Al-2Cr-2Nb and Ti-6Al-4V alloys with dry, flood, and MQL lubricants
- 2023
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Ingår i: CIRP Journal of Manufacturing Science and Technology. - : Elsevier BV. - 1755-5817. ; 41, s. 501-523
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Tidskriftsartikel (refereegranskat)abstract
- The development of cutting tools requires the knowledge of tribological phenomena at the tool – workpiece contact area. This knowledge is in dearth particularly for difficult-to-cut alloys like gamma titanium aluminide (gamma – TiAl alloys). Therefore, this article is an attempt to plug the gap and aid the development of cutting tools for gamma – TiAl alloys. To this end, friction, adhesion, and coating wear between AlTiSiN coated cemented carbide tool and Ti-48Al-2Cr-2Nb (Near lamellar), Ti-48Al-2Cr-2Nb (Duplex), and the most used titanium alloy of Ti-6Al-4V (alpha – beta) were experimentally derived. A Pin-on-Cylinder (PoC) tribometer with contact conditions corresponding to commercial machining conditions was used with dry, flood(EML), and two MQL lubricants. Additionally, the heat generated and partitioned between the pin and workpiece was quantified to assess the thermal exposure to the coatings. The results showed that Ti-6Al-4V had approximately 50% higher apparent friction coefficient than the Ti-48Al-2Cr-2Nb alloys. Interestingly, the friction coefficients of Ti-48Al-2Cr-2Nb alloys were nearly consistent across the entire test matrix. Notably, the change in the microstructure from near lamellar to duplex did not elicit any qualitative or quantitative change in the friction profile of Ti-48Al-2Cr-2Nb alloys. The contact pressure proved to be the statistically significant property influencing friction evolution inversely for Ti-6Al-4V alloy and directly for Ti-48Al-2Cr-2Nb alloys. The results showed higher probability of coating wear in dry conditions as opposed to the flood and MQL lubricants.
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| 39. |
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| 40. |
- Kanger, Stig
(författare)
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Law and logic
- 1972
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Ingår i: Theoria. - : Wiley. - 0040-5817 .- 1558-5816 .- 0040-5825 .- 1755-2567. ; 38:3, s. 105-132
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Tidskriftsartikel (refereegranskat)
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| 41. |
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| 42. |
- Kowalkowski, Christian, 1978-
(författare)
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What does a service-dominant logic really mean for manufacturing firms?
- 2010
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Ingår i: CIRP Journal of Manufacturing Science and Technology. - : Elsevier. - 1755-5817. ; 3:4, s. 285-292
-
Tidskriftsartikel (refereegranskat)abstract
- In parallel with the product-to-service transition in the manufacturing industries, service-dominant logic has emerged as arguably the most challenging recent scholarly marketing debate. The objectives of this work are: (1) to delineate the distinct differences between a product-to-service transition and a transition from a goods-dominant to a service-dominant logic, (2) to discuss what these transitions mean for industry and academia, and (3) to suggest a revised definition of industrial product/service systems (IPS2) more in line with service-dominant logic. A transition to service-dominant logic implies much more than an increased emphasis on services; it implies a reframing of the purpose of the firm and its role in value co-creation.
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| 43. |
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| 44. |
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| 45. |
- Segerberg, Krister
(författare)
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Decidability of four modal logics
- 1968
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Ingår i: Theoria. - : Wiley. - 0040-5817 .- 1558-5816 .- 0040-5825 .- 1755-2567. ; 34, s. 21-25
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Tidskriftsartikel (refereegranskat)
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| 46. |
- Segerberg, Krister
(författare)
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Decidability of S4.1
- 1968
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Ingår i: Theoria. - : Wiley. - 0040-5817 .- 1558-5816 .- 0040-5825 .- 1755-2567. ; 34, s. 7-20
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Tidskriftsartikel (refereegranskat)
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| 47. |
- Segerberg, Krister
(författare)
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On the Logic of "To-morrow"
- 1967
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Ingår i: Theoria. - : Wiley. - 0040-5817 .- 1558-5816 .- 0040-5825 .- 1755-2567. ; 33, s. 45-52
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Tidskriftsartikel (refereegranskat)
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| 48. |
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| 49. |
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| 50. |
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