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  • 1.
    Ali, Sharafat
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Glass surface modification by aerosol technique2016Other (Refereed)
    Abstract [en]

    Glass has been a key material for many important advnces in cilivilization.  Currently there is much scientific and technological interest to obtained flat/float glass surface that has extremely highly resistant to abrasion, anti-fingerprint, surface contamination and optical dimming. The aim of current project is to develop new routes to modify the glass surface in order to increase functionality and enhance performance in various existing and future areas of application. This will be achieved by modifying the glass surface by incorporating nitrogen to the flat/float glass surface by deposition of thin coatings of AlN, Si3N4 and TiN. This will be achieved by gas to particle conversion by physiochemical routs. Thin films of elemental nitrides have not been reported previously by aerosol technique and we anticipate that these can be used to enhance the mechanical, optical and chemical properties of flat/float glass surface. Techniques used for structural and physical characterization include, SEM, TEM, AFM, Raman, thermal analysis, mechanical and optical measurements. Areas of applications of these modified surfaces include automotive, architectural, laser optics, camera lenses, optical filters and display technologies.

  • 2.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Paul, Biplab
    Linköping University, Sweden.
    Magnusson, Roger
    Linköping University, Sweden.
    Erik, Ekström
    Linköping University, Sweden.
    Pallier, Camille
    Linköping University, Sweden.
    Jonson, Bo
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Eklund, Per
    Linköping University, Sweden.
    Birch, Jens
    Linköping University, Sweden.
    Optical and mechanical properties of amorphous Mg-Si-O-N thin films deposited by reactive magnetron sputtering2019In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 372, no 25, p. 9-15Article in journal (Refereed)
    Abstract [en]

    In this work, amorphous thin films in Mg-Si-O-N system typically containing >15 at.% Mg and 35 at.% N were prepared in order to investigate especially the dependence of optical and mechanical properties on Mg composition. Reactive RF magnetron co-sputtering from magnesium and silicon targets were used for the deposition of Mg-Si-O-N thin films. Films were deposited on float glass, silica wafers and sapphire substrates in an Ar, N2 and O2 gas mixture. X-ray photoelectron spectroscopy, atomic force microscopy, scanning electron microscopy, spectroscopic ellipsometry, and nanoindentation were employed to characterize the composition, surface morphology, and properties of the films. The films consist of N and Mg contents up to 40 at.% and 28 at.%, respectively and have good adhesion to substrates and are chemically inert. The thickness and roughness of the films increased with increasing content of Mg. Both hardness (16–21 GPa) and reduced elastic modulus (120–176 GPa) are strongly correlated with the amount of Mg content. The refractive index up to 2.01 and extinction coefficient up to 0.18 were found to increase with Mg content. The optical band gap (3.1–4.3) decreases with increasing the Mg content. Thin film deposited at substrate temperature of 100 °C shows a lower value of hardness (10 GPa), refractive index (1.75), and higher values of reduced elastic modulus (124 GPa) as compared to the thin film deposited at 310 °C and 510 °C respectively, under identical synthesis parameters.

  • 3.
    Burman, Jonas
    et al.
    University of Kalmar, Kalmar Maritime Academy.
    Friberg, Magnus
    University of Kalmar, Kalmar Maritime Academy.
    Projekt Lister: Överhalning av en hjälpmaskin2008Independent thesis Basic level (professional degree), 5 poäng / 7,5 hpStudent thesis
    Abstract [en]

    ABSTRACT

    This is a summary of the formal part of our project. During the autumn of 2007 and spring 2008 we have done an overhaul on one of the auxiliary engines onboard Calmare Nyckel. The assignment was given from Egon Nilson. The engine was in bad shape, lubrication oil and coolingwater was leaking from several cylinders and thereby in big need of a service. There have been some waiting time during the order of new parts because of the rare engine type which are British and therefore all the parts had to be ordered from England. At the end of the project we discovered some difficulties with coolingwater leaking in to the oil sump, this causing further delays finishing the project. The problem were solved and at the test run the engine run satisfactory.

    During the project we have as far as possible followed the manual and other instructions available.

    During a project like this it is important that all documentation of the project is shown.

    The materials that are shown are presented with an introduction followed by the process and the result. To this documentation we have attached a working diary and quotations.

  • 4.
    Carlsson, Bo
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Azoulay, Michel
    KTH.
    Nanoteknologi för ökat mervärde till en trähusfasad: Förstudierapport för DISK programmet inom temat Trä får nya egenskaper med nanoteknik2010Report (Other academic)
    Abstract [sv]

    Aktuell rapport redovisar resultatet av en förstudie över hur man med hjälp av nanoteknologi skulle kunna förbättra ytbehandlingen av en trähusfasad så att ett mervärde skapas.

     För ytbehandling finns idag många tillämpningar där nanotekniken utnyttjas för att skapa mervärde hos en yta jämfört med vad dagens mer traditionella produkter kan erbjuda. Nanobaserade ytbehandlingsprodukter marknadsförs idag som uppges göra ytor smuts- och vattenavvisande, förhindrar påväxt av alger, svamp och mossa, med förbättrad UV- och temperaturresistens och kulörbeständighet, förbättrad reptålighet och nötningshärdighet, samt med antigraffiti egenskaper etc.  De flesta produkterna är dock nya och för en del finns därför frågor som gäller t.ex. långtidsprestanda och teknisk livslängd, underhållsbarhet och därmed sammanhängande ekonomi sett ur ett livscykelperspektiv för den produkt eller system där ytbehandlingen utgör bara en del.

     Många nanoteknikbaserade färger som beskrivs i rapporten finns för mineraliska underlag men mycket få kan rekommenderas för ytbehandling av utvändigt trä dock. Mycket utvecklingsarbete pågår emellertid och vår bedömning är att många av de nanoteknikbaserade ytbehandlingsprodukter som idag finns för mineraliska underlag kommer att kunna modifieras för användning också på utvändigt trä inom ett icke alltför avlägsen framtid.

     I förstudien ingick att uppskatta den ekonomiska potentialen för hur ökad funktionalitet hos ett nanoteknologibaserat ytbehandlingssystem skulle kunna ge ett mervärde. Vi fann att mervärdet bäst kan uttryckas i termer av minskade underhållskostnader relativt de som kännetecknar de mer traditionella material och tekniker som idag används för ytbehandling av trähusfasader. Våra slutsatser är att en trähusfasad, som är smutsavvisande och förhindrar påväxt, borde kunna reducera underhållskostnaderna väsentligt genom att minska eller kanske helt eliminera behovet av fasadrengöring mellan två ommålningar. Vilka förbättringar man kan få med dagens nanobaserade ytbehandlingsprodukter i termer av längre underhållsintervaller är svårare att säga men vi bedömer ändock att det borde vara möjligt att åstadkomma kanske så mycket som en 50 % förlängning av intervallet för förnyad ytbehandling.

     För de mest intressanta nanoteknologibaserade ytbehandlingssystemen bedömer vi dock genomförandet av en flerårig fältmässig utvärdering som motiverad. Syften med studien skulle vara att från resultaten uppskatta nödvändigt intervall för fasadtvätt, förnyad ytbehandling och risk för rötangrepp hos de undersökta färgsystemen, utnyttja resultaten också till att uppskatta skillnader i underhållskostnader mellan de nanoteknologibaserade färgsystemen och referenssystem som baserar sig på användning av traditionell ytbehandlingsteknik samt i detta sammanhang även utvärdera färgsystemens underhållsbarhet avseende långtidsegenskaper efter förnyad ytbehandling          

     

  • 5.
    De Backer, Jeroen
    et al.
    Högskolan Väst, Sweden.
    Bolmsjö, Gunnar
    University West, Sweden.
    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.

  • 6.
    De Backer, Jeroen
    et al.
    Högskolan Väst, Sweden.
    Bolmsjö, Gunnar
    University West, Trollhättan, Sweden.
    Christiansson, Anna-Karin
    Högskolan Väst, Sweden.
    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.

  • 7.
    Egüz, Izzettin Osman
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Hydraulic press construction for fitting the bearings to the housing2008Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report was written as a result of a Bachelor Degree Project, together with Swepart Transmission AB. The report contains the construction of a hydraulic press for the assembly operation.

    The project started with a new construction of a hydraulic press for the bearings’ assembly. The goal within the thesis work was to fit the three bearings to the housing by only one press motion. This operation should be very safety because of the sensitive tolerance at the bearings and housing. Construction of the cylinders, rams and bolster were the most important parts at this project because this parts’ functions are very important for this assembly.

    The next step of this thesis was to calculate the hydraulic press components’ parameters and then choose the suitable components. The focus was to choose more useful and reliable components.

    The hydraulic press was modeled in the CAD program Solid Works and 2D technical drawing was drawn in the Autocad. The frame material was chosen and the frame was analysised in the Solid Works.

  • 8.
    Gren, Pierre
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Uppskärningsmaskin: Underlag till CE-märkning2008Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abstract (in English)

    The work that lead to a CE- marking and the creation of a total drawing foundation on an existing machine carried out on the company Polytec Composites Sweden AB in Ljungby. The company have design an machine that exist in six example that runs in the production. To be able to use the machine the company have to work out a CE-marking. The process that summed up all the document that needs for the machine to make a CE-marking. The documentation includes a total drawing over the machine and a risk analysis performed by a group employers on the company. The computer program that i used to make the drawings is Catia V5. The work that the company and the student performed ended up in a CE-marking of the machine.

  • 9.
    Johansson, Theo
    et al.
    University of Kalmar, Kalmar Maritime Academy.
    Seidow, Gustav
    University of Kalmar, Kalmar Maritime Academy.
    samband mellan olyckor i den svenska handelsflottan2008Independent thesis Basic level (professional degree), 5 poäng / 7,5 hpStudent thesis
    Abstract [en]

    Collisions between vessels and allisions between vessel and obstacles as well as groundings constitute a great problem within the shipping business. Serious damage to vessels, environmental disasters and great costs are invoked for everyone involved. Is it possible that deficient bridge procedures are the reasons behind these types of accidents? The purpose of this thesis is to gather material from accident reports from the years 2000-2007, to investigate whether there are any connections between the accidents on Swedish merchant vessels which have been involved in collisions with each other, allided with an obstacle or that have grounded. The results showed, among other things, that motor tankers are involved in groundings more often than other types of vessels. On the basis of these results, interviews were carried out with motor tanker officers and pilots to investigate what the situation is like onboard during the circumstances where these vessels are most usually grounded. Several of the informants state that paperwork and checklists have become a burden to them during their bridge watches, and one of the implications of our investigation is that inadequate supervision could be the reason behind the accidents.

  • 10.
    Lindström, Per
    DNV GL Materials Laboratory, Norway ; University West.
    DNV Platform of Computational Welding Mechanics2013Report (Other academic)
    Abstract [en]

    This document presents the DNV Platform of Computational Welding Mechanics, CWM, with its associated CWM-methodology. That has been developed, validated and implemented as a part of DNV’s Technology Leadership program in the field of Structural Integrity and Materials Technology.A successful CWM implementation requires that the actual organisation has gained the knowledge and understanding of the following related topics:- Welding Engineering with an emphasis on the welding process and its thermodynamics- Weld process quality control such as calibration, validation as well as DAQ, (Data Acquisition)- Transient thermo-mechanical coupled FE-analyses and constitutive modelling- Computational platforms comprising the selection of hardware, operative system and FEM-code as well as suitable pre- and post-processing toolsFrom that perspective there is a lack of reliable and/or hands-on oriented CWM Engineering Handbooks and best recommended practices available on the market. For that sake is the DNV CWM-methodology and its hands on solutions presented.The CWM-methodology described can not only be used for residual stress assessments, as presented in this report. It can also be used for various applications such as assessment of used and/or proposed WPS, Welding Procedure Specifications as well as optimisation of the manufacturing and production process of integrated metallic structures.From the results of a parametric CWM-study have three (3) factors been identified to drive and/or contribute to the magnitude of the weld residual stresses in ship steel plate materials. The contributing and/or driving factors identified are the:- Thermal- and Mechanical Boundary Conditions during the production welding- Yield stress difference between the base- and the weld filler material- Weld heat input, Q, which affects the weld cooling time

  • 11.
    Lindström, Per
    Chalmers University of Technology.
    Heat Transfer Prediction of In-Service Welding in a Forced Flow of Fluid2009In: Journal of Offshore Mechanics and Arctic Engineering-Transactions of The Asme, ISSN 0892-7219, E-ISSN 1528-896X, Vol. 131, no 3, p. 1-6, article id 031304Article in journal (Refereed)
    Abstract [en]

    An algorithm for heat transfer prediction of in-service welding operations in a forcedflow of fluid is presented. The algorithm presented is derived from Rosenthal’s 3D heatflow equation and boundary layer approximations. This was possible by the introductionof an apparent thermal conductivity kPL, which is a function of the boundary layer’s heattransfer coefficient f and the base material’s thickness . This implies that a weldcooling time tT1 /T2 in a forced flow of fluid can now be calculated by an ordinaryengineering calculator and thus enabling suitable welding parameters to be determined.The magnitude of kPLf , was established by regression analysis of results from aparametric finite element analysis series of a total number of 112 numerical simulations.Furthermore, the result of the regression analysis was validated and verified by a weldingexperiment series accomplished on an in-house designed and constructed in-servicewelding rig. The principle design of the welding rig as well as its instrumentation, a PCbased Data Acquisition system, is described. In addition, a method to measure the weldmetals cooling time tT1 /T2 by means of thermocouple elements is described. Finally,the algorithm presented in this study proved feasible for industrial in-service weldingoperations of fine-grained Carbon and Carbon–Manganese steels with a maximum CarbonEquivalent (IIW) (CE) of 0.32.

  • 12.
    Lindström, Per
    Högskolan Väst.
    Improved CWM platform for modelling welding procedures and their effects on structural behaviour2015Doctoral thesis, monograph (Other academic)
    Abstract [en]

    A welding procedure specification is the document describing how a weld joint should be constructed. Arc weld processes are characterized by transient thermal behavior, leading to rapid changes in material properties and dynamic interaction between weld and base material. The objective of the project is to explore how the use of an improved CWM-platform affects representative stress and strain fields in order to assess welding procedure qualification records. Forthis project, the accumulated thermal and mechanical influences from the first run to the final run are brought forward, in one and the same meshed geometrical model. Both the thermal and mechanical material model of the platform are designed to be used for modelling of the base- and weld material,promoting the simulation of the intricate combination of the thermal, elastic,and plastic strains on the plastic strain hardening and the formation of residual stress fields. The output of the simulation is mainly weld cooling times, residual stresses, and deformations. This analysis is taken further by examining how residual stresses influence crack driving force under elastic and plastic loading. In addition, the output from the simulations can be used to assess the realism of the proposed welding parameters. The main experimental welding procedure examined comes from the IIW RSDP Round Robin Phase II benchmark project, where the main aim was to benchmark residual stress simulations. This work was found to contain many applicable challenges of a CWM-analysis project.

  • 13. Lindström, Per
    et al.
    Caprace, J.-D
    Mishra, B.
    Pires, F.
    Roland, F.
    Schipperen, I.
    Andric, J.
    Li, L
    Osawa, N
    Doig, R.
    Remes, H.
    Kim, M. H.
    Materials and Fabrication Technology: Committee v.32015In: Proceedings of the 19th International Ship and Offshore Structures Congress, Volume 2: Committee v.3 Materials and Fabrication Technology / [ed] Carlos Guedes Soares & Yordan Garbatov, EH Leiden, Nederlands: CRC Press, 2015, 1, Vol. 2, p. 619-698, article id V.3Chapter in book (Other academic)
    Abstract [en]

    Due to the past crises, the shipbuilding and offshore industry has realised that new innovative designs and design and production methods are necessary to decrease operational costs, production costs and emissions,while meeting the changing rules and regulations. This ISSC-V.3 report is discussing recent developmentin materials and fabrication technology applied to ship and offshore structures.Chapter 2 focuses on worldwide trends in materials and fabrication methods. Developments in metallicand non-metallic structural materials are dealt in Chapter 3. Advances in fabrication and joining technologiessuch as welding are increasing. Some main areas of applications and research in those areas aredescribed in Chapter 4. Innovative development about corrosion protection systems are presented inChapter 5 while Chapter 6 give an overview about the application of production simulation and virtualreality to improve the production management of ship and offshore structures.The ISSC-V.3 technical committee has performed a benchmark to define a Best Practice Guideline touse Computational Welding Mechanics tools (CWM) in shipbuilding and offshore industry. To achievethis objective various experimental welding tests have been performed in order to give a reference point.Both the residual welding distortions and residual stresses have been compared between numerical simulationsand welding experiments for a common “T” welded assembly used in the shipbuilding industry.However, it has been decided to publish the results of this study in a separate document. Nevertheless, Chapter 7 of this report presents the state of the art as well as the experimental test case that has been analysed.

  • 14.
    Lindström, Per
    et al.
    Chalmers University of Technology.
    Ulfvarson, Anders
    Chalmers University of Technology.
    An Experimental Rig For Verification of The Mechanical Properties of Welds Produced at In-Service Welding2003In: Proceedings of OMAE’03 22nd International Conference on Offshore Mechanics and Arctic Engineering, June 8 – 13, 2003, Cancun, Mexico, ASME Press, 2003, Vol. 3, p. 57-65, article id 37105Conference paper (Refereed)
    Abstract [en]

    The strength of a weld joint is determined by its geometry and its metallurgic structure, which is dependent on the cooling rate, its chemical composition and the original grain size of the base material. During in-service welding of structures affected by a forced flow of fluid on its reversed side the cooling rate depends on the fluid’s boundary layer, the material’s thickness and the heat input of the welding process. Currently, the calculation of the cooling rate during in-service welding is made by means of numerical methods such as the Finite Element Method, FEM. Through the introduction of an apparent thermal conductivity, kPL, it possible to determine the cooling rate for specific welding parameters by means of Rosenthal’s equation. This can be done with a standard pocket calculator.An experimental rig for measurement of the heat transfer during the in-service welding of structures affected by a forced flow of fluid on its reversed side has been designed and built. The physical principles of welding on plates affected by a forced flow of fluid on their reverse side are the same as for welding on the circumference of a pipe containing a forced flow of fluid. In the rig, the required boundary layer is built up in a pipe system by means of a pump. As the flow and the temperature of the fluid can be controlled to simulate the specific heat transfer, it is now possible to verify the values of the apparent thermal conductivity, kPL, that were calculated

    values of the apparent thermal conductivity, kPL, for various configurations.For the purpose of evaluation and qualification of in-service Welding Procedures Specifications, WPS, the sponsors of the research project use the experimental rig.

  • 15.
    Lindström, Per
    et al.
    Chalmers University of Technology.
    Ulfvarson, Anders
    Chalmers University of Technology.
    Weld Repair of Shell Plates During Seagoing Operations2002In: Proceedings of OMAE’02; 21st International Conference on Offshore Mechanics and Artic Engineering: June 23-28, 2002, Oslo, Norway, ASME Press, 2002, Vol. 3, p. 499-506Conference paper (Refereed)
    Abstract [en]

    An algorithm to estimate the cooling rate of welding seamson the shell plating of a ship, below the waterline, while it is onvoyage has been derived. The demand for this technique hasarisen from the wish of ship operators to make it possible forthe safe repair of ship structures without taking them out ofoperation. [1] The strength of the shell plating after welding isdetermined by its metallurgic structure, which is dependent onthe cooling rate, its chemical composition and the original grainsize of the base material. [2] The cooling rate for this type ofwelding seam depends on the velocity of the water flow, thedistance from the bow, the thickness of the plate, and the heatfrom the heat input of the welding. The algorithm makes itpossible to calculate the cooling rate for a base material affectedby a forced flow of fluid by means of Rosenthal’s equation andthus enabling suitable welding parameters to be determined.As the welding parameters can be chosen to fit the specificrepair to be made, it is now possible to determine the suitabilityof a welding procedure in advance. The algorithm is applicablewhen determining welding parameters at Hot-Tappingoperations as well, where the base material is affected by aforced flow of fluid. A number of experiments have beenperformed and the results support the theoretical model. Theresearch project continues with the aim of finding an algorithmto include the enhanced cooling rate due to the layer of boilingfluid on the back of the base material. A method to improve themeasurements of the most important parameter in the algorithmhas been developed and makes it possible to build up aquantitative database of typical values for various configurations.

  • 16.
    Silva, Ana
    et al.
    University West, Sweden.
    De Backer, Jeroen
    University West, Sweden.
    Bolmsjö, Gunnar
    University West, Sweden.
    Analysis of Plunge and Dwell Parameters of Robotic FSW Using TWT Temperature Feedback Control2016In: Proceedings of 11th International Symposium on Friction Stir Welding, Cambridge: TWI Ltd , 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.

  • 17.
    Silva, Ana
    et al.
    Högskolan Väst, Sweden.
    De Backer, Jeroen
    Högskolan Väst, Sweden.
    Bolmsjö, Gunnar
    University West, Sweden.
    TWT method for temperature measurement during FSW process2015In: The 4th international Conference on scientific and technical advances on friction stir welding & processing, 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.

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