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  • 1.
    Augustsson, Svante
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Gustavsson Christiernin, Linn
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Human and robot interaction based on safety zones in a shared work environment2014In: HRI '14: Proceedings of the 2014 ACM/IEEE international conference on Human-robot interaction, New York: Association for Computing Machinery (ACM), 2014, p. 118-119Conference paper (Refereed)
    Abstract [en]

    In this paper, early work on how to implement flexible safety zones is presented. In the case study an industrial robot cell emulates the environment at a wall construction site, with a robot performing nailing routines. Tests are performed with humans entering the safety zones of a SafetyEye system. The zone violation is detected, and new warning zones initiated. The robot retracts but continues its work tasks with reduced speed and within a safe distance of the human operator. Interaction is achieved through simultaneous work on the same work piece and the warning zones can be initiated and adjusted in a flexible way.

  • 2.
    Augustsson, Svante
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    Olsson, Jonas
    University West, Department of Engineering Science, Division of Manufacturing Processes. University West, Department of Engineering Science, Division of Subtractive and Additive Manufacturing.
    Gustavsson Christiernin, Linn
    University West, Department of Engineering Science, Division of Manufacturing Processes.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    How to Transfer Information Between Collaborating Human Operators and Industrial Robots in an Assembly2014In: Proceedings the NordiCHI 2014: The 8th Nordic Conference on Human-Computer Interaction: Fun, Fast, Foundational, ACM Publications, 2014, p. 286-294Conference paper (Refereed)
    Abstract [en]

    Flexible human-robot industrial coproduction will be important in many small and middle-sized companies in the future. One of the major challenges in a flexible robot cell is how to transfer information between the human and the robot with help of existing and safety approved equipment. In this paper a case study will be presented where the first half focus on data transfer to the robot communicating the human's position and movements forcing the robot to respond to the triggers. The second half focuses on how to visualize information about the settings and assembly order to the human. The outcome was successful and flexible, efficient coproduction could be achieved but also a number of new challenges were found.

  • 3.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Reconfigurable and Flexible Industrial Robot Systems2014In: Advances in Robotics & Automation, E-ISSN 2168-9695, Vol. 3, p. 117-Article, review/survey (Other academic)
    Abstract [en]

    This paper presents a concept for reconfigurable and flexible robot systems. To reach a technology readiness level where solutions and results can be implemented in industry, the focus in this work is on systems with limited number of robots, and work scenarios which are reasonable complex but hard to automate using standard solutions.Four distinct areas have been identified as important within the concept and further studies: (i) human machine interaction, (ii) safety including collaboration, (iii) programming and deployment, and (iv) planning and scheduling. Feasibility studies have been made which addressed issues (ii) and (iii), in scenarios with collaboration between robot and human, or between two robots. For the chosen work scenario, manufacturing of structures in wood for family houses, challenges related to programming and safety was identified and possible solutions outlined.The concept and the studies indicate that feasible solutions can be found and designed given a reasonable consistent work processes and products. In this study, the processes are similar, nailing and screwing but different sizes may apply, the material is similar but variations may apply, and the construction is different of each product, but include the same type of operations at different locations. Our study confirm that human collaboration improves the ability to implement and use robots as it make it possible to move some operations to the human which otherwise would add to the complexity of the system. Furthermore, programming can also I general be simplified although methods for automatic programming has been tried out. But in some cases, the solution space is limited and the ability to move certain operations to a human simplifies the programming task. However, further work needs to be done in this area specifically related to safety issues for safe collaboration.

  • 4.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Supporting Tools for Operator in Robot Collaborative Mode2015In: Procedia Manufacturing, E-ISSN 2351-9789, Vol. 3, p. 409-416Article in journal (Refereed)
    Abstract [en]

    Making use of robot automation for customized products put high demand not only on the robot but on the efficiency, simplicity and flexibility to actually deploy and use robots in manufacturing stations and production lines in short batches and low volume production. Hence, market oriented product development and production requires more products to be developed and offered in less time than before, and produced for the market with more customizable options. The role of the operator is in this context an important factor and tools are needed to support the operator for highly efficient and flexible production. In this paper, the development and study of supporting tools for operators is presented. A demonstrator has been built for robotic nailing, screwing and manipulation operation in producing scaled down gable wall elements in wood for a family house. Issues raised to support the operator included automatic programming and generating relevant information for the operator for the deployment procedure to prepare for production. During production, different concepts of safety system to support collaboration mode between the operator and the robot was developed and studied. Wearable devices was used for the operator to access the information generated and different safety configurations were developed and evaluated. The baseline for this work has been to identify industrial use cases which has a clear need for automation as well as collaboration between operator(s) and robot(s). Work scenarios were discussed and analyzed with industrial partners and it was concluded that, in addition to the deployment tools, a smart safety system which is able to detect and react on humans entering the robot system work area is needed. This should support for efficient production and less downtime for both automatic mode and collaboration mode. The benefit of operator – robot collaboration is clearly shown as well as the need for supporting tools.

  • 5.
    Bolmsjö, Gunnar
    et al.
    University West, Department of Engineering Science, Division of Production System.
    Bennulf, Mattias
    University West, Department of Engineering Science, Division of Production System.
    Zhang, Xiaoxiao
    University West, Department of Engineering Science, Division of Production System.
    Safety System for Industrial Robots to Support Collaboration2016In: Advances in Ergonomics of Manufacturing: Managing the Enterprise of the Future. Proceedings of the AHFE 2016 International Conference on Human Aspects of Advanced Manufacturing, July 27-31, 2016, Walt Disney World®, Florida, USA / [ed] Christopher Schlick, Stefan Trzcieliński, Springer International Publishing , 2016, p. 253-265Chapter in book (Refereed)
    Abstract [en]

    The ongoing trend towards manufacturing of customized products generates an increased demand on highly efficient work methods to manage product variants through flexible automation. Adopting robots for automation is not always feasible in low batch production. However, the combination of humans together with robots performing tasks in collaboration provides a complementary mix of skill and creativity of humans, and precision and strength of robots which support flexible production in small series down to one-off production. Through this, collaboration can be used with implications on reconfiguration and production. In this paper, the focus and study is on designing safety for efficient collaboration operator—robot in selected work task scenarios. The recently published ISO/TS 15066:2016 describing collaboration between operator and robot is in this context an important document for development and implementation of robotic systems designed for collaboration between operator and robot.

  • 6.
    Bolmsjö, Gunnar
    et al.
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Danielsson, Fredrik
    University West, Department of Engineering Science, Division of Electrical and Automation Engineering.
    Svensson, Bo
    University West, Department of Engineering Science, Division of Electrical and Automation Engineering.
    Collaborative Robots to Support Flexible Operation in a Manufacturing System2012In: Flexible Automation and Intelligent Manufacturing, FAIM 2012 / [ed] Hasse Nylund, Satu Kantti, Ville Toivonen, Seppo Torvinen, Tampere University, Finland, 2012, p. 531-538Conference paper (Refereed)
    Abstract [en]

    Collaborative robotic systems where human(s) and robot(s) cooperate in performing a common task is an attractive solution to introduce automation combined with high flexibility for tasks that have a high complexity and characterized by low volume or down to one-off. By introducing collaboration in robotics systems, the operator can complement with cognitive capacity and skill in order to gain in flexibility and agility in the task operation. This paper describes on-going work related to work on collaboration between operator and robot. User scenarios are outlined together with methods, software components and hardware to support collaboration, where some of these are under development. As the standards related to collaborative robotic systems are soon to be completed, it is expected that this type of semi-automatic systems will be important for flexible and agile automation of production which otherwise cannot be automated.

  • 7.
    Bolmsjö, Gunnar
    et al.
    Linnaeus University, Växjö, Sweden.
    Ferreira Magalhães, Ana Catarina
    University West, Department of Engineering Science, Division of Production Systems. University West, Department of Engineering Science, Division of Welding Technology.
    Cederqvist, L.
    SKB AB, Oskarshamn, Sweden.
    De Backer, Jeroen
    University West, Department of Engineering Science, Division of Production Systems.
    Robotic Friction Stir Welding of complex geometry and mixed materials2018In: 50th International Symposium on Robotics, ISR 2018, VDE Verlag GmbH , 2018, p. 35-41Conference paper (Refereed)
    Abstract [en]

    Friction stir welding (FSW) is a solid state process for joining materials which has demonstrated advantages compares with other methods which include joining of mixed materials, hard to weld alloys and consistent and high quality. This paper presents a study of robotic FSW initiated by Volvo Skövde plant to join an insert workpiece of extruded aluminium with a cylinder block of aluminium casting. A three-stage procedure was decided to determine the feasibility to apply robotic FSW. The stages included study of welding the mixed materials, weld along the complex joint line with holes and channels close to the joint, and finally welding the cylinder block. The results based on preliminary analysis indicate that the final tests were successful and the process is feasible for the challenging case study. However, further studies are recommended in order to identify the operating parameters window, tool design, and control of the process in order to optimize productivity and quality. © VDE VERLAG GMBH

  • 8.
    De Backer, Jeroen
    et al.
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Deflection model for robotic friction stir welding2014In: Industrial robot, ISSN 0143-991X, E-ISSN 1758-5791, Vol. 41, no 4, p. 365-372Article in journal (Refereed)
    Abstract [en]

    Purpose - This paper aims to present a deflection model to improve positional accuracy of industrial robots. Earlier studies have demonstrated the lack of accuracy of heavy-duty robots when exposed to high external forces. One application where the robot is pushed to its limits in terms of forces is friction stir welding (FSW). This process requires the robot to deliver forces of several kilonewtons causing deflections in the robot joints. Especially for robots with serial kinematics, these deflections will result in significant tool deviations, leading to inferior weld quality. Design/methodology/approach - This paper presents a kinematic deflection model, assuming a rigid link and flexible joint serial kinematics robot. As robotic FSW is a process which involves high external loads and a constant welding speed of usually below 50 mm/s, many of the dynamic effects are negligible. The model uses force feedback from a force sensor, embedded on the robot, and predicts the tool deviation, based on the measured external forces. The deviation is fed back to the robot controller and used for online path compensation. Findings - The model is verified by subjecting an FSW tool to an external load and moving it along a path, with and without deviation compensation. The measured tool deviation with compensation was within the allowable tolerance for FSW. Practical implications - The model can be applied to other robots with a force sensor. Originality/value - The presented deflection model is based on force feedback and can predict and compensate tool deviations online.

  • 9.
    De Backer, Jeroen
    et al.
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Thermoelectric method for temperature measurement in friction stir welding2013In: Science and technology of welding and joining, ISSN 1362-1718, E-ISSN 1743-2936, Vol. 18, no 7, p. 541-550Article in journal (Refereed)
    Abstract [en]

    Previous research within friction stir welding (FSW) has demonstrated that online control of welding parameters can improve the mechanical properties and is necessary for certain applications to guarantee a consistent weld quality. One approach to control the process is by adapting the heat input to maintain a stable welding temperature, within the specified operating boundaries. This requires accurate in-process temperature measurements. This paper presents a novel method to measure the temperature at the interface of the FSW tool and workpiece. The method is based on the thermoelectric effect between dissimilar materials. The measurements are compared to thermocouple measurements and to a physical model and show good correspondence to each other. Experiments demonstrate that the method can quickly detect temperature variations, due to geometrical variations of the workpiece or due to parameter changes. This allows use of the method for online control of robotic FSW.

  • 10.
    De Backer, Jeroen
    et al.
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Christiansson, Anna-Karin
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Temperature control of robotic friction stir welding using the thermoelectric effect2014In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 70, no 1-4, p. 375-383Article in journal (Refereed)
    Abstract [en]

    Friction stir welding (FSW) of non-linear joints receives an increasing interest from several industrial sectors like automotive, urban transport and aerospace. A force-controlled robot is particularly suitable for welding complex geometries in lightweight alloys. However, complex geometries including three-dimensional joints, non-constant thicknesses and heat sinks such as clamps cause varying heat dissipation in the welded product. This will lead to changes in the process temperature and hence an unstable FSW process with varying mechanical properties. Furthermore, overheating can lead to a meltdown, causing the tool to sink down into the workpiece. This paper describes a temperature controller that modifies the spindle speed to maintain a constant welding temperature. A newly developed temperature measurement method is used which is able to measure the average tool temperature without the need for thermocouples inside the tool. The method is used to control both the plunging and welding operation. The developments presented here are applied to a robotic FSW system and can be directly implemented in a production setting.

  • 11.
    De Backer, Jeroen
    et al.
    University West, Department of Engineering Science, Division of Electrical and Automation Engineering.
    Christiansson, Anna-Karin
    University West, Department of Engineering Science, Division of Process and Product Development.
    Oqueka, Jens
    University West, Department of Engineering Science.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation and Computer Engineering.
    Investigation of path compensation methods for robotic friction stir welding2012In: Industrial robot, ISSN 0143-991X, E-ISSN 1758-5791, Vol. 39, no 6, p. 601-608Article in journal (Refereed)
    Abstract [en]

    Purpose – Friction stir welding (FSW) is a novel method for joining materials without using consumables and without melting the materials. The purpose of this paper is to present the state of the art in robotic FSW and outline important steps for its implementation in industry and specifically the automotive industry.

    Design/methodology/approach – This study focuses on the robot deflections during FSW, by relating process forces to the deviations from the programmed robot path and to the strength of the obtained joint. A robot adapted for the FSW process has been used in the experimental study. Two sensor-based methods are implemented to determine path deviations during test runs and the resulting welds were examined with respect to tensile strength and path deviation.

    Findings – It can be concluded that deflections must be compensated for in high strengths alloys. Several strategies can be applied including online sensing or compensation of the deflection in the robot program. The welding process was proven to be insensitive for small deviations and the presented path compensation methods are sufficient to obtain a strong and defect-free welding joint.

    Originality/value – This paper demonstrates the effect of FSW process forces on the robot, which is not found in literature. This is expected to contribute to the use of robots for FSW. The experiments were performed in a demonstrator facility which clearly showed the possibility of applying robotic FSW as a flexible industrial manufacturing process.

  • 12.
    Ericsson, Mikael
    et al.
    University West, Department of Technology, Mathematics and Computer Science, Division for Mechanical Engineering.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Nylén, Per
    University West, Department of Engineering Science, Research Enviroment Production Technology West.
    Three-dimensional simulation of robot path and heat transfer of a TIG-welded part with complex geometry2002In: 11th International Conferences on Computer Technology in Welding: Colombus, Ohio December 6-7, 2001, 2002, p. 309-316Conference paper (Other academic)
    Abstract [en]

    The application of commercial software (OLP) packages for robot simulation, and programming, use interactive computer graphics, provide powerful tools for creating welding paths off-line. By the use of such software, problems of robot reach, accessibility, collision and timing can be eliminated during the planning stage. This paper describes how such software can be integrated with a numerical model that predicts temperature-time histories in the solid material. The objective of this integration is to develop a tool for the engineer where robot trajectories and process parameters can be optimized on parts with complex geometry. Such a tool would decrease the number of weld trials, increase productivity and reduce costs. Assumptions and principles behind the modeling techniques are presented together with experimental evaluation of the correlation between modeled and measured temperatures.

  • 13.
    Keyvani, Ali
    et al.
    University West, Department of Engineering Science, Divison of Natural Sciences, Surveying and Mechanical Engineering.
    Hanson, L.
    Högberg, D.
    Örtengren, Roland
    Chalmers tekniska högskola.
    Lämkull, D.
    Virtal Methods and IT, Volvo Cars, Gothenburg.
    Rhen, I.M.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Ergonomic Risk Assessment Using Motion Data Modelling, Exposure Calculation and Comparison with an Epidemiological Reference Database2014In: International Journal of Human Factors Modelling and Simulation, ISSN 742-5549Article in journal (Refereed)
  • 14.
    Keyvani, Ali
    et al.
    University West, Department of Engineering Science, Divison of Natural Sciences, Surveying and Mechanical Engineering.
    Lämkull, D.
    Virtal Methods and IT, Volvo Cars, Gothenburg.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Örtengren, Roland
    Chalmers tekniska högskola.
    Extending Functionalities of DHM Tools Using Motion Databases2014In: International Journal of Industrial Ergonomics, ISSN 0169-8141, E-ISSN 1872-8219Article in journal (Refereed)
  • 15.
    Keyvani, Ali
    et al.
    University West, Department of Engineering Science, Divison of Natural Sciences, Surveying and Mechanical Engineering.
    Lämkull, D.
    Virtal Methods and IT, Volvo Cars, Gothenburg.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Örtengren, Roland
    Chalmers tekniska högskola.
    Functionalities of DHM Tools Using Motion Databases2014In: International Journal of Industrial Ergonomics, ISSN 0169-8141, E-ISSN 1872-8219Article in journal (Refereed)
  • 16.
    Keyvani, Ali
    et al.
    University West, Department of Engineering Science, Division of Natural Sciences and Electrical and Surveying Engineering. University West, Department of Engineering Science, Research Enviroment Production Technology West.
    Lämkull, Dan
    Volvo Car Corporation, Gothenburg.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Production Engineering.
    Örtengren, Roland
    Chalmers University.
    Using methods-time measurement to connect digital humans and motion databases2013In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 8026, no Part 2, p. 343-352Article in journal (Refereed)
    Abstract [en]

    To simulate human motions in DHM tools, using techniques which are based on real human data is one promising solution. We have presented a solution in this study to connect motion databases with DHM tools. We have showed that using a motion database with MTM-based annotations is a promising way in order to synthesize natural looking motions. A platform consists of a Motion Database, a Motion Generator, and a DHM tool was introduced and tested. The results showed successful application of the presented platform in the designed test case. © 2013 Springer-Verlag.

  • 17.
    Keyvani, Ali
    et al.
    University West, Department of Engineering Science, Divison of Natural Sciences, Surveying and Mechanical Engineering. Chalmers University of Technology.
    Paul, G.
    School of Public Health and Social Work, Queensland University of Technology, Brisbane.
    Lämkull, D.
    Virtal Methods and IT, Volvo Cars, Gothenburg.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Örtengren, Roland
    Chalmers tekniska högskola.
    Standardization of Motion Databases for DHM Applications: Challenges, Issues and considerations2014In: Article in journal (Refereed)
  • 18.
    Silva, Ana
    et al.
    University West, Department of Engineering Science, Division of Production System.
    De Backer, Jeroen
    University West, Department of Engineering Science, Division of Production System.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Production System.
    Analysis of Plunge and Dwell Parameters of Robotic FSW Using TWT Temperature Feedback Control2016In: Proceedings of 11th International Symposium on Friction Stir Welding, Cambridge, UK, 2016, p. 1-11Conference paper (Other academic)
    Abstract [en]

    Friction stir welding (FSW) and variants of the process have generated high interest in many industries due to its several advantages such as low distortion, superior mechanical properties over arc welding and the possibility of joining dissimilar materials. Increased complexity of industrial applications require a better control of the welding process in order to guarantee a consistent weld quality. This can be achieved by implementing feedback control based on sensor measurements. Previous studies have demonstrated a direct effect of weld temperature on the mechanical properties of FSW joints, [1], and therefore, temperature is chosen as primary process variable in this study.A new method for temperature measurement in FSW referred to as the Tool-WorkpieceThermocouple (TWT) method has recently been developed by De Backer. The TWT method is based on thermoelectric effect and allows accurate, fast and industrially suitable temperature monitoring during welding, without the need for thermocouples inside the tool [2].This paper presents an application of the TWT method for optimisation of the initial weld phases, plunge and dwell, operation in conventional FSW, which can also be applied to friction stir spot welding (FSSW). An analysis of the operation parameters by using feedback temperature control is presented aiming to better control of the initial weld phases through temperature feedback.

    The introduction of the TWT temperature sensor provides additional process information during welding. Fast data acquisition gives opportunity to differentiate different process phases: contact of probe tip with workpiece surface; plunge phase; dwell phase. This would be followed by tool retraction for FSSW or tool traverse phase for FSW.The effect of the plunge parameters on weld temperature and duration of each phase were studied for the purpose of optimising the process with respect to process (i) robustness, (ii)time, (iii) robot deflection and (iv) quality. By using temperature feedback, it is possible to control the plunge phase to reach a predefined weld temperature, avoiding overheating of the material, which is known to have a detrimental influence on mechanical properties. The work presented in this paper is an important step in the optimization of robotic FSSW and FSW.

  • 19.
    Silva, Ana
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    De Backer, Jeroen
    University West, Department of Engineering Science, Division of Automation Systems.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Cooling rate effect on temperature controlled FSW process2015Conference paper (Refereed)
    Abstract [en]

    A continuous trend towards more demanding jointgeometries is imposed across various manufacturingindustries. During Friction Stir Welding (FSW) of suchcomplex geometries, the surrounding environment playsan important role on the final weld quality, especially inthermal aspects. In order to guarantee a consistent weldquality for different conditions, in-process weldingparameter adaptation is needed.This paper studies the effect of the cooling rate onmechanical properties for temperature controlled FSW byusing different backing bar materials. A new temperaturesensor solution, the Tool-Workpiece Thermocouple(TWT) method [1], was applied to measure thetemperature during welding. A FSW-robot equipped withtemperature and force feedback control was used, whererotation speed was varied to maintain a constant weldingtemperature. AA7075-T6 lap joints were performed withand without temperature control. The cooling rate duringwelding was acquired and macrographs and mechanicalproperties were evaluated for each weld. The rotationspeed offered a fast response promoting the heat inputnecessary to weld at the set temperature. Temperaturecontrolled welds presented a better behaviour undertensile loads. The results prove that temperature controlusing the TWT method is suitable to achieve higher jointquality and provides a fast setup of optimal parameters fordifferent environments.The work presented is an important step in the processoptimization through feedback control which willconsider not only the operational parameters of theprocess as such but also the resulting quality of the joint.

  • 20.
    Silva, Ana
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    De Backer, Jeroen
    University West, Department of Engineering Science, Division of Production Systems.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Production Systems.
    Temperature measurements during friction stir welding2017In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 88, no 9-12, p. 2899-2908Article in journal (Refereed)
    Abstract [en]

    The increasing industrial demand for lighter, more complex and multi-material components supports the development of novel joining processes with increased automation and process control. Friction stir welding (FSW) is such a process and has seen a fast development in several industries.This welding technique gives the opportunity of automation and online feedback control, allowing automatic adaptation to environmental and geometrical variations of the component.Weld temperature is related to the weld quality and therefore proposed to be used for feedback control. For this purpose, accurate temperature measurements are required. This paper presents an overview of temperature measurement methods applied to the FSW process. Three methods were evaluated in this work: thermocouples embedded in the tool, thermocouples embedded in the workpiece and the tool-workpiece thermocouple(TWT) method. The results show that TWT is an accurate and fast method suitable for feedback control of FSW.

  • 21.
    Silva, Ana
    et al.
    University West, Department of Engineering Science, Division of Automation Systems.
    De Backer, Jeroen
    University West, Department of Engineering Science, Division of Automation Systems.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    TWT method for temperature measurement during FSW process2015In: The 4th international Conference on scientific and technical advances on friction stir welding & processing, San Sebastian, Spain, 2015, p. 95-98Conference paper (Refereed)
    Abstract [en]

    Friction stir weld (FSW) has generated a high interest in many industry segments in the past 20 years. Along with new industrial challenges, more complex geometries and high quality demands, a better control of the welding process is required. New approaches using temperature controlled welding have been proposed and revealed good results. However, few temperature measurement methods exist which are accurate, fast and industrially suitable. A new and simple sensor solution, the Tool-Workpiece Thermocouple (TWT) method, based on the thermoelectric effect was recently developed.This paper presents a calibration solution for the TWT method where the TWT temperature is compared to calibrated thermocouples inside the tool. The correspondence between both methods is shown. Furthermore, a calibration strategy in different aluminium alloys is proposed, which is based on plunge iterations. This allows accurate temperature monitoring during welding, without the need for thermocouples inside the tool.

  • 22.
    Silva, Ana
    et al.
    University West, Department of Engineering Science, Division of Production Systems.
    De Backer, Jeroen
    University West, Department of Engineering Science, Division of Production Systems.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Production Systems.
    Welding Temperature during FSW of 5 mm thickness AA6082-T62017In: 5th international conference on scientific and technical advances on friction stir welding & processing, Metz, France, 11-13 October 2017., 2017Conference paper (Other academic)
  • 23.
    Åstrand, Erik
    et al.
    University West, Department of Engineering Science, Research Enviroment Production Technology West.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Automation Systems.
    Sikström, Fredrik
    University West, Department of Engineering Science, Division of Automation Systems.
    Lindgren, Eric
    Improved fatigue properties of welded box beams by tailored welding procedures for high penetration fillet weldsIn: Journal of materials engineering and performance (Print), ISSN 1059-9495, E-ISSN 1544-1024Article in journal (Other academic)
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