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Silva, A., De Backer, J. & Bolmsjö, G. (2017). Temperature measurements during friction stir welding. The International Journal of Advanced Manufacturing Technology, 88(9-12), 2899-2908
Open this publication in new window or tab >>Temperature measurements during friction stir welding
2017 (English)In: 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) Published
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.

Keywords
Friction stir welding, TWT method, temperature, aluminium, thermocouples
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-9531 (URN)10.1007/s00170-016-9007-4 (DOI)000394323600047 ()2-s2.0-84973646335 (Scopus ID)
Funder
Region Västra Götaland, RUN 612-0254-15
Note

Funders: Swedish Agency for Economic and Regional Growth through European Regional Development Fund, 20200328

Available from: 2016-07-08 Created: 2016-07-08 Last updated: 2019-05-23Bibliographically approved
Silva, A., De Backer, J. & Bolmsjö, G. (2017). Welding Temperature during FSW of 5 mm thickness AA6082-T6. In: 5th international conference on scientific and technical advances on friction stir welding & processing, Metz, France, 11-13 October 2017.: . Paper presented at 5th international conference on scientific and technical advances on friction stir welding & processing, Metz, France, 11-13 October 2017..
Open this publication in new window or tab >>Welding Temperature during FSW of 5 mm thickness AA6082-T6
2017 (English)In: 5th international conference on scientific and technical advances on friction stir welding & processing, Metz, France, 11-13 October 2017., 2017Conference paper, Oral presentation only (Other academic)
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-14369 (URN)
Conference
5th international conference on scientific and technical advances on friction stir welding & processing, Metz, France, 11-13 October 2017.
Available from: 2019-09-03 Created: 2019-09-03 Last updated: 2019-09-03Bibliographically approved
Silva, A., De Backer, J. & Bolmsjö, G. (2016). Analysis of Plunge and Dwell Parameters of Robotic FSW Using TWT Temperature Feedback Control. In: Proceedings of 11th International Symposium on Friction Stir Welding: . Paper presented at 11th International Symposium on Friction Stir Welding, Cambridge, UK, 17-19 May, 2016 (pp. 1-11). Cambridge, UK
Open this publication in new window or tab >>Analysis of Plunge and Dwell Parameters of Robotic FSW Using TWT Temperature Feedback Control
2016 (English)In: Proceedings of 11th International Symposium on Friction Stir Welding, Cambridge, UK, 2016, p. 1-11Conference paper, Published 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.

Place, publisher, year, edition, pages
Cambridge, UK: , 2016
Keywords
Plunging, Friction Stir Spot Welding, Temperature, TWT, Robot
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering; Production Technology
Identifiers
urn:nbn:se:hv:diva-9530 (URN)
Conference
11th International Symposium on Friction Stir Welding, Cambridge, UK, 17-19 May, 2016
Available from: 2016-07-08 Created: 2016-07-08 Last updated: 2018-08-12Bibliographically approved
Bolmsjö, G., Bennulf, M. & Zhang, X. (2016). Safety System for Industrial Robots to Support Collaboration. In: Christopher Schlick, Stefan Trzcieliński (Ed.), 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 (pp. 253-265). Springer International Publishing
Open this publication in new window or tab >>Safety System for Industrial Robots to Support Collaboration
2016 (English)In: 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.

Place, publisher, year, edition, pages
Springer International Publishing, 2016
Series
Advances in Intelligent Systems and Computing, ISSN 2194-5357 ; 490
Keywords
Human-robot interaction, Collaboration, Robot safety
National Category
Production Engineering, Human Work Science and Ergonomics Robotics
Research subject
Production Technology; ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-10160 (URN)10.1007/978-3-319-41697-7_23 (DOI)2-s2.0-84986272619 (Scopus ID)978-3-319-41696-0 (ISBN)978-3-319-41697-7 (ISBN)
Available from: 2016-11-21 Created: 2016-11-21 Last updated: 2019-12-04Bibliographically approved
Silva, A., De Backer, J. & Bolmsjö, G. (2015). Cooling rate effect on temperature controlled FSW process. In: : . Paper presented at IIW International Conference High-Strength Materials - Challenges and Applications, 2-3 July 2015, Helsinki, Finland, Helsingfors, 2015 (pp. 1-5). Helsinki, Finland
Open this publication in new window or tab >>Cooling rate effect on temperature controlled FSW process
2015 (English)Conference paper, Oral presentation only (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.

Place, publisher, year, edition, pages
Helsinki, Finland: , 2015
Keywords
Friction Stir weld, Cooling rate, TWT method, Temperature control, Aluminium alloy
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering; Production Technology
Identifiers
urn:nbn:se:hv:diva-9120 (URN)
Conference
IIW International Conference High-Strength Materials - Challenges and Applications, 2-3 July 2015, Helsinki, Finland, Helsingfors, 2015
Available from: 2016-02-25 Created: 2016-02-25 Last updated: 2018-08-12Bibliographically approved
Bolmsjö, G. (2015). Supporting Tools for Operator in Robot Collaborative Mode. Paper presented at 6th International Conference on Applied Human Factors and Ergonomics (AHFE 2015) and theAffiliated Conferences, AHFE 2015. Procedia Manufacturing, 3, 409-416
Open this publication in new window or tab >>Supporting Tools for Operator in Robot Collaborative Mode
2015 (English)In: Procedia Manufacturing, E-ISSN 2351-9789, Vol. 3, p. 409-416Article in journal (Refereed) Published
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.

Keywords
Collaboration, Operator, Safety, Deployment
National Category
Production Engineering, Human Work Science and Ergonomics
Research subject
ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-8576 (URN)10.1016/j.promfg.2015.07.190 (DOI)2-s2.0-85009951579 (Scopus ID)
Conference
6th International Conference on Applied Human Factors and Ergonomics (AHFE 2015) and theAffiliated Conferences, AHFE 2015
Available from: 2015-10-27 Created: 2015-10-27 Last updated: 2019-05-14Bibliographically approved
Silva, A., De Backer, J. & Bolmsjö, G. (2015). TWT method for temperature measurement during FSW process. In: The 4th international Conference on scientific and technical advances on friction stir welding & processing: . Paper presented at The 4th international Conference on scientific and technical advances on friction stir welding & processing October 1-2, 2015 (pp. 95-98). San Sebastian, Spain
Open this publication in new window or tab >>TWT method for temperature measurement during FSW process
2015 (English)In: The 4th international Conference on scientific and technical advances on friction stir welding & processing, San Sebastian, Spain, 2015, p. 95-98Conference paper, Published 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.

Place, publisher, year, edition, pages
San Sebastian, Spain: , 2015
Keywords
Friction stir welding, TWT method, Temperature measurements, Aluminium alloys
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering; Production Technology
Identifiers
urn:nbn:se:hv:diva-9122 (URN)
Conference
The 4th international Conference on scientific and technical advances on friction stir welding & processing October 1-2, 2015
Available from: 2016-02-25 Created: 2016-02-25 Last updated: 2018-08-12Bibliographically approved
De Backer, J. & Bolmsjö, G. (2014). Deflection model for robotic friction stir welding. Industrial robot, 41(4), 365-372
Open this publication in new window or tab >>Deflection model for robotic friction stir welding
2014 (English)In: Industrial robot, ISSN 0143-991X, E-ISSN 1758-5791, Vol. 41, no 4, p. 365-372Article in journal (Refereed) Published
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.

Keywords
Force control;Force control, Deflection model, Friction stir welding, Path compensation, Robot welding
National Category
Production Engineering, Human Work Science and Ergonomics
Research subject
ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-6735 (URN)10.1108/IR-01-2014-0301 (DOI)000341784300006 ()
Funder
Knowledge Foundation
Available from: 2014-10-02 Created: 2014-10-02 Last updated: 2018-07-25Bibliographically approved
Keyvani, A., Hanson, L., Högberg, D., Örtengren, R., Lämkull, D., Rhen, I. & Bolmsjö, G. (2014). Ergonomic Risk Assessment Using Motion Data Modelling, Exposure Calculation and Comparison with an Epidemiological Reference Database. International Journal of Human Factors Modelling and Simulation
Open this publication in new window or tab >>Ergonomic Risk Assessment Using Motion Data Modelling, Exposure Calculation and Comparison with an Epidemiological Reference Database
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2014 (English)In: International Journal of Human Factors Modelling and Simulation, ISSN 742-5549Article in journal (Refereed) Submitted
Place, publisher, year, edition, pages
InderScience Publishers, 2014
Keywords
Ergonomic risk assessment, digital manikins, modelling, time-sensitive, workload, wrist joint
National Category
Robotics
Research subject
ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-7124 (URN)
Note

Ingår i dissertation

Available from: 2014-12-11 Created: 2014-12-11 Last updated: 2019-05-13Bibliographically approved
Keyvani, A., Lämkull, D., Bolmsjö, G. & Örtengren, R. (2014). Extending Functionalities of DHM Tools Using Motion Databases. International Journal of Industrial Ergonomics
Open this publication in new window or tab >>Extending Functionalities of DHM Tools Using Motion Databases
2014 (English)In: International Journal of Industrial Ergonomics, ISSN 0169-8141, E-ISSN 1872-8219Article in journal (Refereed) Submitted
Keywords
Digital Human Modelling, Motion Databases, Natural looking Motion
National Category
Robotics
Research subject
ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-7132 (URN)
Note

Ingår i dissertation

Available from: 2014-12-11 Created: 2014-12-11 Last updated: 2019-05-10Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-1869-232X

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