Laser beam welding has been widely applied in different industrial sectors due to its unique advantages. However, there are still challenges, such as beam positioning in T-joint welding, and gap bridging in butt joint welding,especially in the case of varying gap width along a joint. It is expected that enabling more advanced control to a welding system, and obtaining more in-depth process knowledge could help to solve these issues. The aim of this work is to address such welding issues by a laser beam shaping technology using a novel deformable mirror together with computer vision methods and also to increase knowledge about the benefits and limitations with this approach. Beam shaping in this work was realized by a novel deformable mirror system integrated into an industrial processing optics. Together with a wave front sensor, a controlled adaptive beam shaping system was formed with a response time of 10 ms. The processes were monitored by a coaxial camera with selected filters and passive or active illumination. Conduction mode autogenous bead-on-plate welding and butt joint welding experiments have been used to understand the effect of beam shaping on the melt pool geometry. Circular Gaussian, and elliptical Gaussian shapes elongated transverse to and along the welding direction were studied. In-process melt pool images and cross section micrographs of the weld seams/beads were analyzed. The results showed that the melt pool geometry can be significantly modified by beam shaping using the deformable mirror. T-joint welding with different beam offset deviations relative to the center of the joint line was conducted to study the potential of using machine learning to track the process state. The results showed that machine learning can reach sufficient detection and estimation performance, which could also be used for on-line control. In addition, in-process and multidimensional data were accurately acquired using computer vision methods. These data reveal weaknesses of current thermo-fluid simulation model, which in turn can help to better understand and control laser beam welding. The obtained results in this work shows a huge potential in using the proposed methods to solve relevant challenges in laser beam welding. / Lasersvetsning används i stor utsträckning i olika industrisektorer på grund av dess unika fördelar. Det finns emellertid fortfarande utmaningar, såsom rätt positionering av laserstrålen vid genomträngningssvetsning av T-fogar och hantering av varierande spaltbredd längs fogen vid svetsning av stumfogar. Sådana problem förväntas kunna lösas med avancerade metoder för automatisering, metoder som också förväntas ge fördjupade kunskaper om processen. Syftet med detta arbete är att ta itu med dessa problem med hjälp av en teknik för lasereffektens fördelning på arbetsstycket, s.k. beam shaping. Det sker med hjälp av en ny typ av i realtid deformerbar spegel tillsammans med bildbehandling av kamerabilder från processen. För- och nackdelar med detta tillvägagångssätt undersöks.Beam shaping åstadkoms med hjälp av ny typ av deformerbart spegelsystem som integreras i en industriell processoptik. Tillsammans med en vågfrontsensor bildas ett adaptivt system för beam shaping med en svarstid på 10 ms. Processen övervakas av en kamera linjerad koaxialt med laserstrålen. För att kunna ta bilder av svetspunkten belyses den med ljus av lämplig våglängd, och kameran är försedd med ett motsvarande optiskt filter. Försök har utförts med svetsning utan tillsatsmaterial, direkt på plåtar, svetsning utan s.k. nyckelhål, för att förstå effekten av beam shaping på svetssmältans geometri. Gauss fördelade cirkulära och elliptiska former, långsträckta både tvärs och längs svetsriktningen har studerats. Bilder från svetssmältan har analyserats och även mikrostrukturen i tvärsnitt från de svetsade plåtarna. Resultaten visar att svetssmältans geometri kan modifieras signifikant genom beam shaping med hjälp av det deformerbara spegelsystemet. Genomträngningssvetsning av T-fogar med avvikelser relativt foglinjens centrum genomfördes för att studera potentialen i att använda maskininlärning för att fånga processens tillstånd. Resultaten visade att maskininlärning kan nå tillräcklig prestanda för detektering och skattning av denna avvikelse. Något som också kan användas för återkopplad styrning. Flerdimensionell processdata har samlats i realtid och analyserats med hjälp av bildbehandlingsmetoder.  Dessa data avslöjar brister i nuvarande simuleringsmodeller,vilket i sin tur hjälper till med att bättre förstå och styra lasersvetsning.Resultaten från detta arbete uppvisar en god potential i att använda de föreslagna metoderna för att lösa relevanta utmaningar inom lasersvetsning. / <p>Till licentiatuppsats hör 2 inskickade artiklar, som visas inte nu.</p>

Stål är ett material som används i olika byggnadskonstruktioner. I de byggnadskonstruktioner som utsätts för upprepade belastningar kan utmattning ske i materialet. Utmattning leder till permanenta skador i form av sprickbildning och slutligen brott. I svetsade konstruktioner är det ofta svetsar som har den lägsta utmattningsstyrkan. För att förbättra en svets utmattningsstyrka finns efterbehandlingsmetoder som benämns Post Weld Treatment (PWT). Idag används den beräkningsmetod som är föreskriven i Eurokod vid verifiering av svetsar. Beräkningsmetoden är förenklad och kan underskatta objektets livslängd med hänsyn till utmattning. Syftet med arbetet är att studera olika dimensioneringsmetoder som behandlar utmattningsbelastade svetsar samt hur tillämpning av PWT kan förbättra en typsvets livslängd. Målet med arbetet är att studera en typsvets och visa skillnaden i antalet lastcykler mellan beräkningsmetoderna samt hur många lastcykler samma typsvets förväntas öka med PWT. Teorin och resultaten utgår från vetenskapliga artiklar, litteraturstudier och enfallstudie som behandlar både en genomsvetsad stumsvets samt en kälsvets lokaliserade på en I-balk. Resultatet pekar mot att den metod som används idag underskattar livslängden och att PWT kan markant kan förbättra en svetsutmattningsstyrka. / Steel is a material used in various building structures. Fatigue can occur in the material if building structures is exposed for repeated loads. Fatigue leads to permanent damages such as crack initiations and fracture. It is common that welds in welded structures have the lowest fatigue strength. A welds fatigue strength can be improved with treatments termed Post Weld Treatment (PWT). Today a welds fatigue strength is verified with a method described in Eurocode. The calculation method is simplified which can underestimate the objects number of lifecycles regarding fatigue. The purpose with this essay is to study different structural design methods for fatigue exposed welds and how many lifecycles a typeweld will increase when applying PWT. The goal with this essay is to study a typeweld and calculate the number of lifecycles between the calculation methods and to show how many lifecycles the same type weld will increase when applying PWT. The results and theory are based on scientific articles, literature studies and a casestudy which both contains a through welded butt weld and a fillet weld placed on an I-beam. The results points at that the calculation method that is used today underestimates the number of lifecycles and that the number of lifecycles increased significant after PWT.

The objective of this research is to develop a method to evaluate important weld dimensions in thin plates by using laser generated ultrasounds and EMAT receiver. The superimposed laser sources (SLS) technique is developed to generate narrowband Lamb waves with fixed wavelengths in thin plates. The method permits the flexibility of selecting desired wavelength. The signal processing procedure that combines wavenumber-frequency (k-w) domain filtering and synthetic phase tuning (SPT) is used to further reduce the complexity of Lamb waves. The k-w domain filtering technique helps to filter out the unwanted wave components traveling at the direction that is not of interest to us and the SPT technique is applied to amplify and isolate a particular Lamb wave mode. The signal processing procedure facilitates the calculation of reflection coefficients of Lamb waves that result from the presence of weld joints. The SLS and signal processing procedure are then applied to measure reflection coefficients in butt welds and lap welds. Two methods, the direct method and indirect method, are used to develop models that use reflection coefficients as predictors to predict these weld dimensions. The models developed in this research are shown to accurately predict weld dimensions in thin plates.

A major focus is on integrated Silicon-based optoelectronics for the creation of low-cost photonics for mass-market applications. Especially, the growing demand for sensitive and portable optical sensors in the environmental control and medicine follows in the development of integrated high resolution sensors [1]. In particular, since 2013 the quick onsite verification of pathogens, like legionella in drinking water pipes, is becoming increasingly important [2, 3]. The essential questions regarding the establishment of portable biochemical sensors are the incorporation of electronic and optical devices as well as the implementations of fundamental cross-innovations between biotechnology and microelectronics. This thesis describes the design, fabrication and analysis of high-refractive-index-contrast photonic structures. Besides silicon nitride (Si3N4) strip waveguides, lateral tapers, bended waveguides, two-dimensional photonic crystals (PhCs) the focus lies on monolithically integrated waveguide butt-coupled Silicon-based light emitting devices (Sibased LEDs) [4, 5] for use as bioanalytical sensor components. Firstly, the design and performance characteristics as single mode regime, confinement factor and propagation losses due to the geometry and operation wavelength (1550 nm, 541 nm) of single mode (SM), multi mode (MM) waveguides and bends are studied and simulated. As a result, SM operation is obtained for 1550 nm by limiting the waveguide cross-section to 0.5 μm x 1 μm resulting in modal confinement factors of 87 %. In contrast, for shorter wavelengths as 541 nm SM propagation is excluded if the core height is not further decreased. Moreover, the obtained theoretical propagation losses for the lowestorder TE/TM mode are in the range of 0.3 - 1.3 dB/cm for an interface roughness of 1 nm. The lower silicon dioxide (SiO2) waveguide cladding should be at least 1 μm to avoid substrate radiations. These results are in a good correlation to the known values for common dielectric structures. In the case of bended waveguides, an idealized device with a radius of 10 μm was developed which shows a reflection minimum (S11 = - 22 dB) at 1550 nm resulting in almost perfect transmission of the signal. Additionally, tapered waveguides were investigated for an optimized light coupling between high-aspect-ratio devices. Here, adiabatic down-tapered waveguides were designed for the elimination of higher-order modes and perfect signal transmission. Secondly, fabrication lines including Electron-beam (E-beam) lithography and reactive ion etching (RIE) with an Aluminum (Al) mask were developed and lead to well fabricated optical devices in the (sub)micrometer range. The usage of focused ion beam (FIB) milling is invented for smoother front faces which were analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). As a result, the anisotropy of the RIE process was increased, but the obtained surface roughness parameters are still too high (10 – 20 nm) demonstrating a more advanced lithography technique is needed for higher quality structures. Moreover, this study presents an alternative fabrication pathway for novel designed waveguides with free-edge overlapping endfaces for improving fiber-chipcoupling. Thirdly, the main focus lies on the development of a monolithic integration circuit consisting of the Si-based LED coupled to an integrated waveguide. The light propagation between high-aspect-ratio devices is enabled through low-loss adiabatic tapers. This study shows, that the usage of CMOS-related fabrication technologies result in a monolithic manufacturing pathway for the successful implementation of fully integrated Si-based photonic circuits. Fourth, transmission loss measurements of the fabricated photonic structures as well as the waveguide butt-coupled Si-based LEDs were performed with a generated setup. As a result, free-edge overlapping MM waveguides show propagation loss coefficients of ~ 65 dB/cm in the range of the telecommunication wavelength. The high surface roughness parameters (~ 150 nm) and the modal dispersion in the core are one of the key driving factors. These facts clearly underline the improvement potential of the used fabrication processes. However, electroluminescence (EL) measurements of waveguide butt-coupled Si-based LEDs due to the implanted rare earth (RE) ion (Tb3+, Er3+) and the host material (SiO2/SiNx) were carried out. The detected transmission spectra of the coupled Tb:SiO2 systems show a weak EL signal at the main transition line of the Tb3+-ion (538 nm). A second emission line was detected in the red region of the spectrum either corresponding to a further optical transition of Tb3+ or a Non Bridging Oxygen Hole Center (NBOHC) in SiO2. Unfortunately, no light emission in the infrared range was established for the Er3+-doped photonic circuits caused by the low external quantum efficiencies (EQE) of the Er3+ implanted Si-based LEDs. Nevertheless, transmission measurements between 450 nm – 800 nm lead again to the result that an emission at 650 nm is either caused by an optical transition of the Er3+-ion or initialized by the NBOHC in the host. Overall, it is difficult to assess whether or not these EL signals are generated from the implanted ions, thus detailed statements about the coupling efficiency between the LED and the integrated waveguide are quite inadequate. Nevertheless, the principle of a fully monolithically integrated photonic circuit consisting of a Si-based LED and a waveguide has been successfully proven in this study.

The factor of precision has always been the mastermind of the shooting sport. With new shooters coming into the field every day and with more aspiring shooters bringing laurels, a help of technology for training can make a difference. When advanced systems like the SCATT, Electronic Target Systems, etc. are marked for the people of the higher background, an easy handle autonomous system for self-monitoring training of precision improvement has always been a question of far reach. This project is about developing an external removable device, which will monitor and evaluate the shooter efficiency of gripping weapon, measure by pressure given at the contact points of the weapon. In the contact points, such as the trigger, the hand grip, cheek rest, butt plate and the hand rest; we use force sensitive resistors, which are connected to an automatic monitoring system built over an Arduino platform. The system analyses the shots based on the variation in the pressure at each point of contact for every shot. By further analysis and consolidation, the average pressure over a range of shots, an optimal pressure point can be fixed individually for the respective shooter. This pressure points are used as references, by rating them in comparison with the corresponding shot acquired in the target. The system includes a pre-designed training program, which autonomously monitors and trains the shooter to achieve the optimum grip in every shot, thereby increasing the accuracy and precision in a sequence of shots. With time, it helps the body to develop a muscle memory based on controlled training and learn the rhythm of applying optimum pressure to achieve better results. / <p>Noted the puBlication content is patented.</p>

A major focus is on integrated Silicon-based optoelectronics for the creation of low-cost photonics for mass-market applications. Especially, the growing demand for sensitive and portable optical sensors in the environmental control and medicine follows in the development of integrated high resolution sensors [1]. In particular, since 2013 the quick onsite verification of pathogens, like legionella in drinking water pipes, is becoming increasingly important [2, 3]. The essential questions regarding the establishment of portable biochemical sensors are the incorporation of electronic and optical devices as well as the implementations of fundamental cross-innovations between biotechnology and microelectronics. This thesis describes the design, fabrication and analysis of high-refractive-index-contrast photonic structures. Besides silicon nitride (Si3N4) strip waveguides, lateral tapers, bended waveguides, two-dimensional photonic crystals (PhCs) the focus lies on monolithically integrated waveguide butt-coupled Silicon-based light emitting devices (Sibased LEDs) [4, 5] for use as bioanalytical sensor components. Firstly, the design and performance characteristics as single mode regime, confinement factor and propagation losses due to the geometry and operation wavelength (1550 nm, 541 nm) of single mode (SM), multi mode (MM) waveguides and bends are studied and simulated. As a result, SM operation is obtained for 1550 nm by limiting the waveguide cross-section to 0.5 μm x 1 μm resulting in modal confinement factors of 87 %. In contrast, for shorter wavelengths as 541 nm SM propagation is excluded if the core height is not further decreased. Moreover, the obtained theoretical propagation losses for the lowestorder TE/TM mode are in the range of 0.3 - 1.3 dB/cm for an interface roughness of 1 nm. The lower silicon dioxide (SiO2) waveguide cladding should be at least 1 μm to avoid substrate radiations. These results are in a good correlation to the known values for common dielectric structures. In the case of bended waveguides, an idealized device with a radius of 10 μm was developed which shows a reflection minimum (S11 = - 22 dB) at 1550 nm resulting in almost perfect transmission of the signal. Additionally, tapered waveguides were investigated for an optimized light coupling between high-aspect-ratio devices. Here, adiabatic down-tapered waveguides were designed for the elimination of higher-order modes and perfect signal transmission. Secondly, fabrication lines including Electron-beam (E-beam) lithography and reactive ion etching (RIE) with an Aluminum (Al) mask were developed and lead to well fabricated optical devices in the (sub)micrometer range. The usage of focused ion beam (FIB) milling is invented for smoother front faces which were analyzed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). As a result, the anisotropy of the RIE process was increased, but the obtained surface roughness parameters are still too high (10 – 20 nm) demonstrating a more advanced lithography technique is needed for higher quality structures. Moreover, this study presents an alternative fabrication pathway for novel designed waveguides with free-edge overlapping endfaces for improving fiber-chipcoupling. Thirdly, the main focus lies on the development of a monolithic integration circuit consisting of the Si-based LED coupled to an integrated waveguide. The light propagation between high-aspect-ratio devices is enabled through low-loss adiabatic tapers. This study shows, that the usage of CMOS-related fabrication technologies result in a monolithic manufacturing pathway for the successful implementation of fully integrated Si-based photonic circuits. Fourth, transmission loss measurements of the fabricated photonic structures as well as the waveguide butt-coupled Si-based LEDs were performed with a generated setup. As a result, free-edge overlapping MM waveguides show propagation loss coefficients of ~ 65 dB/cm in the range of the telecommunication wavelength. The high surface roughness parameters (~ 150 nm) and the modal dispersion in the core are one of the key driving factors. These facts clearly underline the improvement potential of the used fabrication processes. However, electroluminescence (EL) measurements of waveguide butt-coupled Si-based LEDs due to the implanted rare earth (RE) ion (Tb3+, Er3+) and the host material (SiO2/SiNx) were carried out. The detected transmission spectra of the coupled Tb:SiO2 systems show a weak EL signal at the main transition line of the Tb3+-ion (538 nm). A second emission line was detected in the red region of the spectrum either corresponding to a further optical transition of Tb3+ or a Non Bridging Oxygen Hole Center (NBOHC) in SiO2. Unfortunately, no light emission in the infrared range was established for the Er3+-doped photonic circuits caused by the low external quantum efficiencies (EQE) of the Er3+ implanted Si-based LEDs. Nevertheless, transmission measurements between 450 nm – 800 nm lead again to the result that an emission at 650 nm is either caused by an optical transition of the Er3+-ion or initialized by the NBOHC in the host. Overall, it is difficult to assess whether or not these EL signals are generated from the implanted ions, thus detailed statements about the coupling efficiency between the LED and the integrated waveguide are quite inadequate. Nevertheless, the principle of a fully monolithically integrated photonic circuit consisting of a Si-based LED and a waveguide has been successfully proven in this study.

Das Infrarotschweißen ist ein industriell etabliertes Verfahren zur Herstellung von Bauteilen in unterschiedlichsten Anwendungsbereichen. Die Prozesseinrichtung ist jedoch mit einem hohen Kosten- und Zeitaufwand verbunden, da komplexe Strahler-Werkstoff-Wechselwirkungen das Aufschmelzverhalten des Kunststoffbauteils bestimmen. In vielen industriellen Infrarotschweißprozessen ist daher ein Rauchen der infraroterwärmten Bauteilbereiche zu beobachten. Eine Erforschung des Zusammenhangs zwischen Rauchbildung, Kunststofftemperatur, thermisch-oxidativer Belastung des Kunststoffs und den resultierenden mechanischen Schweißnahteigenschaften steht bislang aus. Weiterhin sind in Infrarotschweißprozessen in der industriellen Fertigung oftmals hohe Umstellzeiten und schwankende Fügeteiltemperaturen festzustellen. In der vorliegenden Arbeit werden erstmals die mechanischen Eigenschaften von Infrarotschweißverbindungen mit der Rauchbildung und thermisch-oxidativen Kunststoffbelastung korreliert und zwei Ansätze zur schonenden Erwärmung untersucht. Die Ergebnisse weisen nach, dass eine thermisch-oxidative Kunststoffschädigung zu einer Verschlechterung der mechanischen Schweißnahteigenschaften führt und bei der Auslegung industrieller Prozesse in Betracht gezogen werden muss. Das Schweißen in Argonatmosphäre und mit aktiver Strahlerleistungsregelung verhindern die Kunststoffzersetzung und führen in der Regel zu besseren mechanischen Schweißnahteigenschaften. Weiterhin wird deutlich, dass die Fügeteiltemperatur einen vernachlässigbaren Einfluss auf die Schweißnahteigenschaften hat, wohingegen Umstellzeiten ≥ 5 s eine erhebliche Reduzierung ebendieser zur Folge haben. Eine weitere Herausforderung ist das Infrarotschweißen (endlos-)faserverstärkter Kunststoffe. Die derzeit übliche Stumpfanordnung der Fügeteile führt zu einer Faserumlenkung in der Fügenaht und hat zur Folge, dass die Faserverstärkung nicht über die Fügeebene hinweg genutzt werden kann. Im Rahmen der Arbeit wird aufgrund dessen das überlappende Infrarotschweißen von Organoblechen untersucht. Um Bauteile aus Organoblechen mit erhöhter Komplexität, Größe und Steifigkeit herstellen zu können, werden zudem zwei industriell nutzbare Verfahrensvarianten auf Basis des Infrarotschweißens entwickelt. Unter Nutzung dieser, können Organoblechhohlkörper mit Überlappverbindungen gefertigt werden. Die Ergebnisse zeigen, dass sowohl in Plattenprobekörpern als auch in Hohlkörpern eine Nutzung der Faserverstärkung über die Fügeebene hinweg möglich ist.:1 Einleitung und Zielsetzung 2 Grundlagen und Stand der Technik 3 Experimentelles 4 Analyseverfahren 5 Ergebnisse zum Stumpfschweißen 6 Ergebnisse zum Überlappschweißen 7 Bewertung der Ergebnisse 8 Zusammenfassung und Ausblick / The infrared welding is a well-established process in the industrial production of parts in various applications. However, the complex emitter-material interaction, which influences the meltdown behaviour of the plastic parts, results in a high effort for the process setup. A smoking of the plastic parts is to observe in numerous industrial infrared welding processes. The correlations between the smoking of the plastic, its temperature and thermal-oxidative degradation as well as the mechanical properties of the resulting welds are unidentified yet. Furthermore, in industrial infrared welding processes often high changeover times and varying joining part temperatures are existent. Therefore, within the present work the connections between the mechanical joint properties of infrared welds and the thermal-oxidative degradation of plastics are elaborated for the first time and two approaches for the gentle infrared heating are investigated. The findings prove that the thermal-oxidative degradation of the plastic substantially decreases the mechanical weld properties and needs to be taken into account when setting up the industrial infrared welding process. The welding in argon atmosphere and the use of an active infrared emitter power control, which ensures the heating of the plastic below the degradation temperature, lead to better mechanical weld properties. In addition, the outcome of this work shows that the influence of the temperature of the joining part is negligible regarding the mechanical joint properties, whereas changeover times greater than or equal to 5 s lead to a dramatical decrease in the mechanical properties. Another challenge is the infrared welding of fibre reinforced plastics. The butt welding of fibre reinforced thermoplastics is common practice and prevents the use of fibres in the joint plane due to the fibre deflection in this area. As a result, the overlapping welding of organo sheets is investigated as well. In order to produce large and complex parts with high stiffness made of organo sheets, two process variants on the basis of the infrared welding technology are developed, which can be used at the industrial scale to manufacture hollow bodies. The overlapping welds of specimens and in hollow bodes made of organo sheets, enable the fibre utilisation across the joint plane.:1 Einleitung und Zielsetzung 2 Grundlagen und Stand der Technik 3 Experimentelles 4 Analyseverfahren 5 Ergebnisse zum Stumpfschweißen 6 Ergebnisse zum Überlappschweißen 7 Bewertung der Ergebnisse 8 Zusammenfassung und Ausblick

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / Eutectic (63% tin-37% lead) or near-eutectic (40% tin-60% lead) tin-lead solder is widely used for creating electrical interconnections between the printed wiring board (PWB) and the components mounted on the board surface. For components mounted directly on the PWB mounting pads, that is, surface mounted components, the tin-lead solder also constitutes the mechanical interconnection. Eutectic solder has a melting point of 183°C (361°F). It is important to realize that its homologous temperature, defined as the temperature in degrees Kelvin over its melting point temperature (T(m)), also in degrees Kelvin, is defined as T/T(m). At room temperature (25°C = 298K), eutectic solder's homologous temperature is 0.65. It is widely acknowledged that materials having a homologous temperature ≥ 0.5 are readily subject to creep, and the solder joints of printed wiring assemblies are routinely exposed to temperatures above room temperature. Hence, solder joints tend to be subject to both thermal fatigue and creep. This can lead to premature failures during service conditions. The geometry, that is, the lead configuration, of the joints can also affect failure. Various geometries are better suited to withstand failure than others. The purpose of this paper is to explore solder joint failures of dual in-line (DIP) integrated circuit components, leadless ceramic chip carriers (LCCCs), and gull wing and J-lead surface mount components mounted on PWBs.

No description available.