Additive Manufacturing (AM) is another name for rapid prototyping and 3D printing (3DP), an advanced manufacturing technology that creates 3D objects. AM's ability to produce complex shapes in industrial production is one of its chief advantages. AM is spreading to different areas in healthcare and is being considered a disruptive innovation that is changing orthopedics.  However, integrating AM into daily orthopedic practice remains a challenging task. This thesis aims to explore clinicians' views on the adoption of AM implants, surgical guides and accessories as well as investigating which way do regulations and policies affect the adoption of 3DP in the orthopedic industry in Sweden. Apart from reviewing existing literature contemplated on factors that affect the adoption of AM in an industry, in this study, a qualitative research approach have been used. A semi-structured interview has been applied to all the seven orthopedic surgeons who participated in the research. Using a thematic analysis approach, the data have been analyzed to address the thesis research questions.    According to the thesis findings, AM adoption in the orthopedic sector is influenced by a number of factors. With the technology, organization, and environment (TOE framework) there are classified into three main contexts. The study used the findings along with the TOE model, which embeds the regulation factor within an environmental context. The findings indicate that the medical device regulation (MDR) affects the adoption of medical devices both positively and negatively in the orthopedic industry in Sweden.  Technologically, the dilemma and challenge of adopting AM is influenced by the lack of resources in the healthcare field which also influence the organization context. It is the viewpoint of the buyer that orthopedists and hospitals have when it comes to adoption of AM. This means that the trading factor expressed in the environment context is another driving factor for AM adoption. By using the Kraljic model, AM technology has been classified as a strategic item. The procurement and purchase efforts should focus on establishing a long-term relationship with a single manufacturing company and both aiming to combine effort and resources to reduce total costs. In conclusion, The implementation of AM in orthopedic practice will be possible as long as all factors are taken into account. In orthopedic practice, AM should be used to create surgical guides, 3D models for surgical planning, and custom implants.

Additive manufacturing (AM) also commonly known as 3D-printing is a manufacturing method which creates parts from adding layer into another. In the field of printed electronics Inkjet printing (IJP) and Aerosol Jet printing (AJP) are the most common AM techniques. IJP and AJP are non-contact-based printing techniques where ink is deposited on a surface with droplets. AJP aerosolizes the ink into a mist which is deposited on a surface according to the predetermined pattern. IJP instead produces singular droplets when printing. These printing methods have been used for manufacturing various printed electronics such as strain gauges which has been the focus of this project.  The purpose of this thesis was to investigate the feasibility of printing strain gauges. Through a literature study the overall function and use for strain gauges and various printing methods were investigated, as well as previous studies related to printed strain gauges using AJP and IJP. To further investigate one of these techniques, strain gauges were printed using Inkjet printing. The sensors were printed using two different inks, one containing silver particles and the other containing constantan particles. The strain gauges were also printed on various substrates such as Polyimide (PI) and Polyetheretherketone (PEEK), to determine the best material combination. The silver strain gauges were then sintered in an oven while the constantan sensors were sintered using photonic sintering. To evaluate each ink-substrate combination several tests was performed throughout the printing and sintering process. A tape test was used to determine adhesion, SEM analysis was performed to study the effect of the sintering process and the resistance was measured to calculate the conductivity and study the printability on different substrates. To characterise the printed strain gauges a bending test was performed where the change in resistance was measured with changing strain. The output was also studied over time to determine the stability of the printed sensors.  The silver ink showed overall better properties compared to the constantan ink, which could be due to that the silver ink has been more developed than the constantan ink. The resistivity of the silver ink was calculated to 7.0E-07 Ωm and the constantan ink to 2.23E-05 Ωm. The average gauge factor for the silver ink printed on PI was calculated to GFavg~1.6 at low strain and GFavg~2.1 at high strain, the silver samples printed on PEEK was GFavg~2.4 at low strain and GFavg~2.3 at higher strain, and the constantan samples was determined to GFavg~2.7 during loading at low strain and GFavg~17 at high strain due to deformation. Some of the samples printed with silver ink showed quite linear behaviour while the samples printed with constantan deformed when applying high stress. The silver samples printed on PEEK showed more hysteresis compared to the silver samples printed on PI, but the PEEK samples showed a better stability over time compared to PI.  The thesis shows that it is possible to manufacture strain gauges, but the result depends a lot on the ink and substrate material chosen. Silver inks has been developed over a long period and thus making it easier to handle and the result is better compared to newer inks such as constantan.

Examensarbetet har genomförts i samarbete med Lasertech, Epiroc och SSAB. Syftet med arbetet var att SSAB ville pröva sitt pulver och att Epiroc ville undersöka utvecklingsmöjligheter med additiv tillverkning. Lasertech, som handlett arbetet för studenterna, tillhandahöll maskinen som används till 3D-utskriften och är därmed mellanhanden gällande Epiroc och SSAB i arbetet. Rapporten kommer att spegla en omkonstruktion av Epirocs komponent som produceras med konventionella tillverkningsmetoder och ska modelleras om samt optimeras för additiv tillverkning. Problemet idag är omständigheterna med borrandet av hål vid tillverkningen av komponenten. En viktminskning och eventuella andra optimeringar är önskvärda för att förbättra hela systemet och det finns potential att uppnå detta med additiv tillverkning. Resultatet av arbetet visar hur alla komponenter inte är lämpade för att omkonstrueras för additiv tillverkning utan att behöva designas om på ett större sätt, och att begränsning av modellering kan bromsa möjligheten till att uppnå fördelar. Resultaten som framkom visar på ett optimerat flöde samt en säker viktminskning på 34% med möjlighet till en viktminskning på c:a 67,2% vid implementering av gitterstruktur i prototypen. Detta är något som rekommenderas vid fortsatt arbete på resultatet framtaget i detta arbete. / The degree project has been done in collaboration with Lasertech, Epiroc and SSAB. The project started with SSAB wanting to test their powder and Epiroc wanting to investigate development opportunities with additive manufacturing. Lasertech, which supervised the project for the students, provided the machine used for the 3D printing and is thus the intermediary for Epiroc and SSAB in the work. The report will reflect a redesign of Epiroc's component that is produced using conventional manufacturing methods and will be remodeled and optimized for additive manufacturing. The problem today is the circumstances of the drilling of holes in the manufacturing process of the component. A weight loss and other optimizations are desired to improve the whole system and there is potential to achieve this with additive manufacturing. The result of the work shows that not all components are suitable for reconstruction for additive manufacturing without having to be redesigned in a larger scale, limited modeling can slow down the possibility of achieving benefits. The results obtained shows an optimized flow and a proven weight reduction of 34% with the possibility of a weight reduction of approximately 67,2% with implementation of a lattice structure in the prototype. That is something that is recommended for continued work on the results produced

This thesis explores the possibilities with additive manufacturing, applied to the engineering of high performance bike parts. The goal was to study the technique and materials that make up the additive manufacturing in order to apply this to bike stems. Also, the goal was to develop both a physical and a virtual model to further evaluate the possibilities with additive manufacturing. Knowledge of the additive manufacturing processes was gained through an extensive information study. After that, a focus on a particular method, EBM, electron beam melting, was made. The process of development of a bike part, the steering stem, was documented to identify the strength and weaknesses of the technique and to finally evaluate it to a traditionally manufactured reference stem. The design process started with a state-of-the-art study and concept stage to later be followed with an iterative process of modelling and simulating. The concepts were created with accordance of the constraints set upon them from our technical specification and the European standards regarding bike parts which limits the maximum allowed deformation and fatigue. One concept was selected to be modelled as a physical component. Finally, the developed component is discussed and compared to a chosen reference stem. The final concept did not outperform the reference in weight, but valuable insight and knowledge were gained along the way. The main conclusion of the thesis is that additive manufacturing is a suitable tool for manufacturing of high performing bike parts. Suggestions for future work are also given, where a further analysis with other materials using the EBM-technique is suggested. / Detta kandidatsexamensarbete utforskar möjligheterna med additiv tillverkning applicerat på högpresterande cykelkomponenter. Målet med arbetet var att utforska möjligheterna att utnyttja additiv tillverkning för styrstammar, samt ta fram en virtuell och en fysisk modell av en styrstam anpassad för detta. Genom en omfattande infosökning hämtades kunskap in om de tekniker och material som utgör den additiva tillverkningsgruppen. Därefter gjordes en fördjupning i en specifik teknik, nämligen EBM, electron beam melting. Produktutvecklingsprocessen för cykelkomponenten, en styrstam, dokumenterades för att identifiera styrkorna och svagheterna hos tekniken och för att i slutet utvärderas mot en traditionellt tillverkad referenskomponent. Designprocessen inleddes med infosökning och konceptgenerering för att sedan, med hjälp av digital mjukvara såsom Solid Edge och ANSYS, övergå till en iterativ process av modellering och simulering. Koncepten modellerades efter önskade egenskaper definierat i en kravspecifikation samt rådande EU-standard för styrstammar i tillåten deformation och utmattningsbrott. Ett slutgiltigt koncept valdes och sedan tillverkades en 3D-utskriven fysisk prototyp. I den avslutande delen diskuteras den utvecklade komponenten och jämförs med en vald referenskomponent. Det slutgiltiga konceptet lyckades inte prestera bättre än referenskomponenten i vikt. Men däremot erhölls värdefull insikt och kunskap angående den additiva processen. Slutsatsen som drogs var att additiv tillverkning är en legitim tillverkningsmetod för konstruktion av högpresterande cykelkomponenter. Förslag ges även för framtida arbete där framförallt en vidare analys med andra material som utnyttjar EBM-tekniken föreslås.

Additive manufacturing (AM), also known as 3D-printing is an automated manufacturing process in which the component is built layer upon layer from a predefined 3D computer model. In contrast to conventional manufacturing processes where a vast volume of material is wasted due to machining, AM only uses the material that the component consists of. In addition to material savings, the method has a number of potential benefits. Two of these are (1) a large design freedom which enables the production of complex geometries and (2) a reduced compexity in supply chain as parts can be printed on-demand rather than be kept in stock. This master thesis has been performed at Vattenfall Wind Power and aims to investigate the feasibility to reproduce and/or to refurbish one or two spare parts on a wind turbine by AM and if it can introduce any practical benefits. Components with a high failure rate and/or with an suitible design for AM have been investigated. A rotating union or fluid rotary joint (FRJ) was selected for further analysis. A comprehensive background study has been conducted. A current status of metal AM is described as well as a comparison between conventional and additive processes. Furthermore, current and future applications for AM witihin the wind turbine industry are presented. The mehodology "reverse engineering", main components in a wind power plant including the fluid rotary joint as well as fluid dynamics are also treated in the background study. As a part of the process, a fluid rotary joint with worse historical failure data was disassembled and examined. In order to find other design solutions that contributes to a better and more reliable operation, another better performing fluid roraty joint was investigated. Since detail drawings and material information are missing for the examined units, reverse engineering has been carried out to gather details of the designs. A concept for the first unit has been developed, in which improved design solutions has been introduced and a number of changes have been implemented in order to minimize material consumption and to adapt the design for AM. The concept has been evaluated by the use of numerical methods. Costs and build time have also been estimated for the developed concept. This project has illustated that it is feasable to manufacture spare parts by the use of AM. The developed concept demonstrates several improvements that are not possible to achieve with conventional manufacturing processes. Nevertheless, a number of limitations such as insufficient build volume, costs as well as time cosuming engineering effort and post-proccessing methods are present for AM. These restrictions, in combination with lack of 3D-models, limits the possibility to make use of the technology. However, the future looks bright, if the technology continues to develop and if subcontractors are willing to adapt to AM it will probably have a major breakthrough within the windpower industry. / Additiv tillverkning, "additive manufacturing" (AM) eller 3D-printing är en automatiserad tillverkningsmetod där komponenten byggs lager för lager från en fördefinierad 3D datormodell. Till skillnad från konventionella tillverkningsmetoder där en stor mängd material ofta bearbetas bort, använder AM nästintill endast det material som komponenten består utav. Förutom materialbesparingar, har metoden ett flertal andra potentiella fördelar. Två av dessa är (1) en stor designfrihet vilket möjliggör produktion av komplexa geometrier och (2) en möjlighet till en förenklad logistikkedja eftersom komponenter kan tillverkas vid behov istället för att lagerföras. Detta examensarbete har utförts på Vattenfall Vindkraft och har till syfte att undersöka om det är möjligt att tillverka och/eller reparera en eller två reservdelar genom AM och om det i så fall kan införa några praktiska fördelar. En kartläggning av komponenter med hög felfrekvens och/eller som kan vara lämpade för AM har genomförts. Av dessa har en roterande oljekoppling även kallad roterskarv valts ut för vidare analys. En omfattande bakgrundsstudie har utförts. En nulägesorientering inom området AM för metaller redogörs, här redovisas även en generell jämförelse mellan konventionella och additiva tillverkningsmetoder. Vidare behandlas aktuella och framtida användningsområden för AM inom vindkraftsindustrin. I bakgrundsstudien behandlas också arbetssättet "reverse engineering", huvudkomponenter i ett vindkraftsverk inklusive roterskarven samt flödesdynamik. Under arbetets gång har en roterskarv med sämre driftshistorik undersökts. I syfte att finna andra konstruktionslösningar som bidrar till en säkrare drift har en bättre presenterande enhet från en annan tillverkare granskats. Då viss detaljteknisk data och konstruktionsunderlag saknas för de undersökta enheterna har "reverse engineering" tillämpats. Ett koncept har sedan utvecklats för den första enheten där förbättrade konstruktionslösningar har introducerats samtidigt som en rad konstruktionsförändringar har gjorts i syfte att minimera materialåtgången och samtidigt anpassa enheten för AM. Konceptet har sedan evaluerats med hjälp av numeriska beräkningsmetoder. För det givna konceptet har även kostnad och byggtid uppskattats. Arbetet visar på att det är möjligt att ta fram reservdelar till vindkraftverk med hjälp av AM. Det framtagna konceptet visar på ett flertal förbättringar som inte kan uppnås med konventionella tillverkningsmetoder. Emellertid finns det en rad begränsningar såsom otillräcklig byggvolym, kostnader och tidskrävande ingenjörsmässigt arbete och efterbehandlingsmetoder. Dessa förbehåll i kombination med avsaknad av 3D-modeller begränsar möjligheterna att nyttja tekniken i dagsläget. Framtiden ser dock ljus ut, om tekniken fortsätter att utvecklas samtidigt som underleverantörer är villiga att nyttja denna teknik kan AM få ett stort genombrott i vindkraftsindustrin.

Additive manufacturing of titanium and other metals is a rapidly growing field that could potentially improve component manufacturing through optimization of geometries, less material waste and fewer process steps. Although powder-based additive manufacturing processes have so far been predominant, methods using a wire as feedstock has gained popularity due to faster deposition rates and lower porosity in deposited material. The titanium alloy Ti-6Al-4V accounts for the majority of aerospace titanium alloy consumption and as titanium is a precious and expensive resource, reducing material waste is an important factor.  Laser metal deposition with wire (LMD-w) is currently used in production at GKN Aerospace in Trolhättan. One important process parameter is the oxygen level in the chamber during deposition as titanium is highly reactive with oxygen at process temperatures. Oxygen enrichment of titanium can cause embrittlement and reduced fatigue life due to formation of alpha-case, an oxygen enriched region directly beneath the surface. The oxygen level in the chamber is controlled through extensive use of protective inert gas which is a costly and time-consuming practice. The objective of this thesis was to study how elevated oxygen levels in the chamber would affect surface oxidation, chemical composition, tensile properties and microstructure.  Two different sample geometries were built with Ti-6Al-4V wire at an oxygen level of 100, 500 and 850 ppm. The subsequent analysis was based around microstructural features, alpha-case formation, chemical composition in surface layers, and tensile tests. Results showed that elevated oxygen levels in the build chamber did not degrade the chemical composition or tensile properties with regard to aerospace specifications. However, significant layers of alpha-case were found in all samples indicating that subsequent processing such as machining or etching is needed.

Conventionally manufactured stents are available in uniform sizes and straight forms. These standard products are not suitable for all patients and research indicates that this is the reason for migration of stents in the vessel, and tubular structure in general, after deployment. The occurrence of migration makes readmission into hospital and the removal of the deployed stent necessary. This thesis develops a method which results in patient-customized stents which can be manufactured through additive manufacturing. These individualized stents intent to offer the same advantages of conventional stents while mitigating the disadvantages. The work’s core part is thedesign of a stent based on the geometric information through a medical scan. It converts the relevant areas from the medical scan data which is in the DICOM format to the STL file format. After cleaning and further processing, the shape will be the base for the design process of a stent using CAD software. Additionally, it also gives insight into the subjacent technologies such as medical scanning, additive manufacturing, choice of material and necessary further processing steps. A process chain from scanning, data transformation, 3D printing and post processing is described.The developed method delivers a reliable model and results in a fully individualized stent. In the current stage, it involves manual work since the representation of data in the steps is different. Further suggestions for steps to automate the process and an estimation of economic efficiency is given. / Det finns konventionellt tillverkade stenter i likformiga storlekar och raka former. Dem här standardprodukter är inte lämpliga för alla patienter och forskning tyder på att detta är orsaken till migrationen av stenter i blodkärl efter placering. Förekomsten av migration skapa återtagande på sjukhus och avlägsnande av den placerade stenten är nödvändig. Den här avhandlingen utvecklar en metod som resulterar i patient anpassade stenter som kan varatillverkad genom additiv tillverkning. Dessa individualiserade stenter avser att erbjuda samma fördelar som konventionella stenter och mildra nackdelarna. Arbetets kärna är designen av en stent baserad på den geometriska informationen baserande på en medicinsk bildteknik. Det omvandlar relevanta kroppsdelar från det medicinska bildteknik som finns i DICOM-formatet till STLfilformatet. Efter rengöring och vidare bearbetning kommer formen att vara basen för stentens designprocess med CAD-mjukvara. Dessutom ger den också inblick i de underliggande teknikerna som medicinsk bildteknik, tillsatsframställning, materialval och nödvändig vidarebehandling steg. En processkedja från skanning, datatransformation, 3D-utskrift och efterbehandling är beskrivits.Den utvecklade metoden ger en tillförlitlig modell och resulterar i en helt individualiserad stent. I det aktuellt stadium, innebär det manuellt arbete eftersom representationen av data i stegen är annorlunda. Ytterligare förslag till åtgärder för att automatisera processen och en uppskattning av ekonomisk effektivitet är given.

Additive Manufacturing (AM) as a method is on the rise and allow for a high freedom to create unique shapes without being limited by conventional machining methods. The Electron Beam Melting method, developed by Arcam AB in Mölndal, Sweden, use Powder Bed Fusion together with an electron beam and at an elevated temperature (+1000ºC) to lower stress due to thermal gradients. The purpose of this paper is to study the influence of Scan Length during Electron Beam Melting of Alloy 718 in regards to the appearance of shrinkage, porosity, primary carbide precipitation (mainly NbC), primary dendrite width and hardness. Samples built had the dimensions of 10x15xVar mm3 (Height x Depth x Width) with widths ranging from 10 mm in steps of 5 mm up to a maximum of 90 mm. The parameters were set as a single entry within the build project and as such each layer was melted as a single unit. A Light-Optical Microscope (LOM) and a Scanning Electron Microscope (SEM) was used to obtain images for manual counting to calculate the fraction of porosity and NbC-precipitates as well as the columnar grain width. The space between lines of interdendritical precipitation of NbC was used to determine the dendrite arm widths and a series of Hardness Vickers (500g for 15s) indents was performed. An Energy-Dispersive X-Ray Spectroscope (EDS) was used to help identify precipitates and phases. Columnar grain width and the spacing between vertical bands of interdendritical NbC was measured according to ASTM112-13 while porosity and hardness was measured according to ASTM562-11. Both of these only looked at the XZ-plane instead of all three planes. The columnar grain width was measured in the 10 mm, 40 mm and 90 mm samples at a distance of 4 mm from the top and with a slight spread over the sample width according to ASTM112-13 but using only one plane for counting. No significant change to columnar width was found. Primary dendrite arm width was measured on the 10 mm, 40 mm and 90 mm samples at about 5 mm from the top. An average for all samples was found to be 7.82 μm ± 2.89. No significant trend could be found with increased sample width. A total average porosity of 0.33% ± 0.16 was found. Variations between samples were less than the standard deviation. Even though the variations were not high enough to be significant, no obvious trend could be seen in regards to sample width, position on the base plate or heat transfer through the build. The presence of NbC was investigated in all samples with a total average of 0.36% ± 0.23 with variations between sample lengths being within the standard deviation. An insignificant trend could be seen between the smaller samples together with the wider samples having a higher degree of NbC compared to the middle samples. No significant trend could be seen in NbC based on row. Across all samples, the mean hardness was found to be 406.75 HV0.5 ± 16.53. No significant trend could be seen with increased sample width. Based on sample rows no significant trend could be seen.

Mini-/microchannel components have received attention over the past few decades owing to their compactness and superior thermal performance. Microchannel heat sinks are typically manufactured through traditional manufacturing practices (milling and sawing, electrodischarge machining, and water jet cutting) by changing their components to work in microscale environments or microfabrication techniques (etching and lost wax molding), which have emerged from the semiconductor industry. An extrusion process is used to produce multiport minichannel-based heat exchangers (HXs). However, geometric manufacturing limitations can be considered as drawbacks for all of these techniques. For example, a complex out-of-plane geometry is extremely difficult to fabricate, if not impossible. Such imposed design constraints can be eliminated using additive manufacturing (AM), generally known as three-dimensional (3D) printing. AM is a new and growing technique that has received attention in recent years. The inherent design freedom that it provides to the designer can result in sophisticated geometries that are impossible to produce by traditional technologies and all for the redesign and optimization of existing models. The work presented in this thesis aims to investigate the thermal performance of enhanced minichannel HXs manufactured via metal 3D printing both numerically and experimentally. Rectangular winglet vortex generators (VGs) have been chosen as the thermal enhancement method embedded inside the flat tube. COMSOL Multiphysics, a commercial software package using a finite element method (FEM), has been used as a numerical tool. The influence of the geometric VG parameters on the heat transfer and flow friction characteristics was studied by solving a 3D conjugate heat transfer and laminar flow. The ranges of studied parameters utilized in simulation section were obtained from our previous interaction with various AM technologies including direct metal laser sintering (DMLS) and electron-beam melting (EBM). For the simulation setup, distilled water was chosen as the working fluid with temperaturedependent thermal properties. The minichannel HX was assumed to be made of AlSi10Mg with a hydraulic diameter of 2.86 mm. The minichannel was heated by a constant heat flux of 5 Wcm−2 , and the Reynolds number was varied from 230 to 950. A sensitivity analysis showed that the angle of attack, VG height, VG length, and longitudinal pitch have notable effects on the heat transfer and flow friction characteristics. In contrast, the VG thickness and the distance from the sidewalls do not have a significant influence on the HX performance over the studied range. On the basis of the simulation results, four different prototypes including a smooth channel as a reference were manufactured with AlSi10Mg via DMLS technology owing to the better surface roughness and greater design uniformity. A test rig was developed to test the prototypes. Owing to the experimental facility and working fluid (distilled water), the experiment was categorized as either a simultaneously developing flow or a hydrodynamically developed but thermally developing flow. The Reynolds number ranged from 175 to 1370, and the HX was tested with two different heat fluxes of 1.5 kWm−2 and 3 kWm−2 . The experimental results for the smooth channel were compared to widely accepted correlations in the literature. It was found that 79% of the experimental data were within a range of ±10% of the values from existing correlations developed for the thermal entry length. However, a formula developed for the simultaneously developing flow overpredicted the Nusselt number. Furthermore, the results for the enhanced channels showed that embedding VGs can considerably boost the thermal performance up to three times within the parameters of the printed parts. Finally, the thermal performance of the 3D-printed channel showed that AM is a promising solution for the development of minichannel HXs. The generation of 3D vortices caused by the presence of VGs ii can notably boost the thermal performance, thereby reducing the HX size for a given heat duty.

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