Within the oil and gas industry on offshore installations in the North Sea, several oil wells are closing in on the brink where they no longer are being profitable to keep producing from. When that day comes the oil wells are closed off and the boreholes are plugged with cement. Before the holes can be cemented shut the companies need to remove all their equipment that has been used for underwater exploitations of the well and if applicable remove the above water installation as well. This includes removing the casing that the holes are lined with which main purpose is to prevent the hole from collapsing on the production line and to prevent oil and gas leaks into the surroundings. This thesis focuses on removal of the borehole casing.  When performing this task problems have been raised regarding corrosion on the casing couplings, making them very hard to separate. When this problem occurs, the need for an alternative method to split them is necessary. As of today this operation is performed by cold cut sawing or with a beveling machine. This is a highly time consuming task and an alternative method to perform a faster cut is wanted. This degree work investigates the possibilities of doing this using the benefits of abrasive water jet (AWJ) cutting. The major concerns on using this technic is whether it is fast enough and if it is possible to perform in accordance with the fire and explosive hazards on a hydrocarbon producing installation. As a reference the maximum cut time is set to one minute. Calculations on theoretical cutting speeds as well as physical testing on the AWJ method has been performed and evaluated. The investigations show that the method does have the possibilities of making the cut within the target time.  The work also contains a simple concept model on how the equipment could be constructed. / Inom olje- och gasindustrin på offshoreanläggningar i Nordsjön, närmar sig flera reservoarer randen där de inte längre är lönsamma att fortsätta producera från. När den dagen kommer pensioneras borrhålen och pluggas med en cementblandning. Innan hålen pluggas måste företagen ta bort all utrustning som har använts vid utvinningen av brunnen, både ovan och under ytan. Detta innefattar avlägsnande av casingen, som hålen är fodrade med, och vars huvudsakliga syfte är att förhindra att hålet kollapsar och skadar produktionsledningen, men även för att förhindra olje- och gasläckor till omgivningen. Denna avhandling fokuserar på borttagandet av casingen. När detta görs upplevs problem med att casingskarvarna är kraftigt korroderade vilket gör dem mycket svåra att separera. Detta är ett problem som efterfrågar en alternativ delningsmetod. I dag utförs den här operationen med antingen kallsågning eller med en avfasningsmaskin. Detta är en mycket tidskrävande uppgift och en metod för att utföra en snabbare delning önskas. Detta examensarbete är tänkt att undersöka möjligheterna att göra detta genom att använda fördelarna med abrasiv vattenskärning för att kapa rören. De största frågorna gällande denna metod är om den är tillräckligt snabb och om det är möjligt att utföra i enlighet med de brand- och explosionsrisker som finns på en kolväteproducerande installation. Som referens är målet för maximal skärtid satt till en minut. Beräkningar på teoretiska skärhastigheter samt fysiska tester på metoden har utförts och utvärderats. Undersökningarna visar på att metoden har möjligheter att göra snittet inom utsatt tid. Arbetet innehåller också en enkel konceptmodell på hur utrustningen skulle kunna konstrueras.

Abrasive Waterjet cutting (AWJ) presents many advantages over competing machining techniques, but several issues are related to the high volume of materials (and in particular of abrasive) used in the process. In this study, the environmental impact of the material flows in the abrasive waterjet industry has been analyzed adopting a life cycle perspective in order to individuate which phases place the largest burden on the environment. Moreover, three alternative abrasives (crushed rock, recycled glass and synthetic abrasive) and three disposal practices (in-site recycling, off-site recycling and recycling as construction material) have been also evaluated to estimate the benefits that can be achieved if these could be used in place of garnet abrasives and landfilling. The transportation of the abrasive resulted to be the phase that has the largest influence in every case and thus should be reduced as much as possible. For what concerns the alternative options, the usage of recycled glass and the in-site recycling of the abrasive were the two alternatives with the best environmental performances. However, crushed rock could be the best option for what concerns the global warming potential if carbon sequestration due to carbonation of silicate rocks is taken into account. Off-site recycling and recycling as construction material are good options only if the transportation to the recycling site can be reduced. Synthetic abrasive are instead found to have a much larger impact compared to every other alternative examined.

<p>Abrasive waterjet (AWJ) machining is a complex, non-conventional machining process involving numerous input parameters including hydraulic, abrasive, mixing and cutting that must be accurately manipulated to guarantee precise cutting and quality. Currently, available models are empirical or require continuous calibration, or extensive experimental work. To reduce the calibration and experimental time required for accurate prediction of AWJ cutting, computational fluid dynamics (CFD) is being utilized to model the nozzle flow interaction; high pressure water is pushed through the orifice into the mixing chamber, pulling the abrasive into the flow and cohering in the focus tube. Initial research worked towards understanding the effect that input parameters - such as pressure, particle size and shape, focus tube length and volume fraction of air in fluid mixture - have on the velocity profile through the nozzle and upon exit to the atmosphere. Once understood, the CFD model can be utilized to vary mass-inlet, mixing head, orifice and focus tube dimensions to optimize velocity profile of abrasive material including magnitude and jet coherency. Primarily focused on pump pressure, which is limited by technology - an optimized AWJ nozzle will increase material removal rate and/or enhance cut quality without making changes to any other AWJM components.</p> <p>Utilizing the velocity output information from the CFD model, a depth of penetration erosion prediction model was generated. Based on methodology from Finnie, and modified by Hashish and ElTobgy, a multi-particle erosion model of an impacted work piece is developed. With an updated formulation for the specific cutting resistance of a work piece, dependent on particle velocity and nozzle traverse speed, the erosion prediction over the sixty-five different setups modelled and tested experimentally, reduced error on average 41.8%. Moreover, the development of this model created multi-layered surface plots, illustrating for quick reference, the erosion of a work piece for a given set of parameters albeit mass flow rate, pump pressure and traverse rate.</p> <p>Further, a database of quick reference guides, including variable input settings, nozzle types, garnet types and work piece materials can easily be developed. Finally, a new methodology for the leading edge of the waterjet is described and can be incorporated into the erosion simulation by making use of the ``top-hat`` profile generated in the CFD model. This would reduce reliance on model constants to account for secondary cutting, or when particles do not contribute to cutting but are simply entrained in the fluid flow.</p> <p>Both models demonstrated good correlation with experiments or literature. The use of these models will increase understanding of the complex abrasive waterjet process and reduce the need for costly experiments moving forward.</p> / Master of Applied Science (MASc)

Abrasive waterjet (AWJ) cutting is one of the most recently developed nontraditional manufacturing technologies. It has been increasingly used in industry owing to its various distinct advantages over the other cutting technologies. However, many aspects of this technology require to be fully understood in order to increase its capability and cutting performance as well as to optimize the cutting process. This thesis contains an extensive literature review on the investigations of the various aspects in AWJ machining. It shows that while considerable work has been carried out, very little reported research has been found on the AWJ contouring process although it is a common AWJ cutting application. Because of the very nature of the AWJ cutting process, the changing nozzle traverse direction involved in AWJ contouring results in kerf geometrical or shape errors. A thorough understanding of the AWJ contouring process is essential for the reduction or elimination of these shape errors. It also shows that a lack of understanding of the AWJ hydrodynamic characteristics has limited the development of cutting performance models that are required for process control and optimization. Accordingly, a detailed experimental investigation is presented in this thesis to study the various cutting performance measures in AWJ contouring of an 87% alumina ceramic over a wide range of process parameters. For a comparison purpose, the study also considers AWJ straight-slit cutting. The effects of process parameters on the major cutting performance measures in AWJ contouring have been comprehensively discussed and plausible trends are amply analysed. It finds that the taper angles on the two kerf walls are in different magnitudes in AWJ contouring. The kerf taper on the outer kerf wall increases with the arc radius (or profile curvature), while that on the inner kerf wall decreases. Moreover, the depth of cut increases with an increase in arc radius and approaches the maximum in straight cutting for a given combination of parameters. The other process variables affect the AWJ contouring process in a way similar to that in straight cutting. The analysis has provided a guideline for the selection of process parameters in the AWJ contouring of alumina ceramics. In order to predict the cutting performance in process planning and ultimately optimize the cutting process, mathematical models for the major cutting performance measures in both straight-slit cutting and contouring are developed using a dimensional analysis technique. The models are then verified by assessing both qualitatively and quantitatively the model predictions with respect to the corresponding experimental data. It shows that the models can adequately predict the cutting performance measures and form the essential basis for developing strategies for selecting the optimum process parameters in AWJ cutting. To achieve an in-depth understanding of the jet dynamic characteristics such as the velocity and pressure distributions inside a jet, a Computational Fluid Dynamics (CFD) simulation is carried out using a Fluent6 flow solver and the simulation results are validated by an experimental investigation. The water and particle velocities in the jet are obtained under different input and boundary conditions to provide an insight into the jet characteristics and a good understanding of the kerf formation process in AWJ cutting. Various plausible trends and characteristics of the water and particle velocities are analysed and discussed, which provides the essential knowledge for optimizing the jet performance through optimizing the jetting and abrasive parameters. Mathematical models for the water and particle velocity distributions in an AWJ are finally developed and verified by comparing the predicted jet characteristics with the corresponding CFD simulation data. It shows that the jet characteristics models can yield good predictions for both water and particle velocity distributions in an AWJ. The successful development of these jet dynamic characteristics models is an essential step towards developing more comprehensive mathematical cutting performance models for AWJ cutting and eventually developing the optimization strategies for the effective and efficient use of this advanced manufacturing technology.

Inom området skyddskläder för utövande av vattenblästring ställs mycket höga krav på säkerhet, de textila material och tillverkningstekniker som används idag ger stela produkter med negativ hälso- och miljöpåverkan vid produktion och är en tidskrävande tillverkningsprocess. Ämnesområdet med en vara av nonwoven som skyddande komponent i skyddskläder vilken sammanfogas med hjälp av en smältfiber har undersökts tidigare i en kort förberedande studie vilket lagt grund för detta examensarbete. Uppdraget om en alternativ tillverkningsmetod till skyddande komponent till en skyddsdräkt för vattenblästring kommer från företaget TST Sweden AB i Kinna. En nonwovenprodukt kan ge ett mjukt och mer följsamt resultat på varan och är relativt kostnadseffektiv att tillverka. De fibertyper som är intressanta för denna kombination är UHMWPE-fiber och bikomponentsfiber. UHMWPE-fibern har tidigare visat klara kraven på säkerhet och bikomponentsfibern fungerar som smältfiber för att skapa bindepunkter i nonwovenvaran. Denna studie undersöker och jämför ett material som tas fram i studien med syfte att klara samma skyddande egenskaper som ett referensmaterial av den produkt som används idag. Målet är att ersätta den kemiska doppningen med en termisk sammanfogning. Studien är både teoretisk och praktisk och går igenom hela processen från kardning till termiska bindesätt och slutligen även för materialegenskapstester genom bland annat dragprovning och penetrationstester. Två olika bikomponenter jämfördes i denna studie, på grund av bristande mottagningskontroll på den beställda bikompPE-fibern tillverkades material utifrån fel specifikationer, vid upptäckt av detta adderades anpassade tillverkningsmetoder. Resultatet från denna studie tyder på att en komponent till skyddsdräkt för vattenblästring tillverkad av UHMWPE/bikomp – nonwoven har kommit framåt i utvecklingen men ännu inte är färdigutvecklad. Studien visar att provserien av nonwoven som bestod av 70% UHMWPE och 30% coPES/PES vilken behandlades termiskt i mikrovågsugn visade bäst resultat i energiabsorption, men vilket inte nådde upp till samma nivå som referensmaterialet. Med avseende på materialets styvhet nåddes klara förbättringar då alla provserier uppvisade mjukare resultat än referensmaterialet. Hållbarhetsmässigt ses fördelar med nonwoven-konstruktion av lågsmältande bikomponentsfiber jämfört med kemiskt doppad nonwoven.

When developing a Human-Machine-Interface (HMI) it is important to make sure that it is easy to learn and use, to have high usability. If it does not, the operator of the machine suffers unnecessarily and it also becomes harder to sell for the producer of the machine. The effectiveness and efficiency of the machine drops down when it is hard to operate. To make it easier for future developers to reach a high usability factor when developing a HMI, this thesis aimed to find a carefully prepared process to follow when doing so. The result was a process that was tested out with a HMI prototype for waterjet cutting machines. This prototype was then tested in different use cases by both experienced operators as well as beginners. The testing produced positive feedback on the prototype, proving that the process that had been followed was being successful. / När man utvecklar ett Människa-Maskin-Gränssnitt (HMI) så är det viktigt att se till att det är lätt att lära sig och använda, att det har hög användbarhet. Ifall den inte har det så försämrar det operatörers situation i onödan och gör det svårare för producenter att sälja produkten. Produktionseffektiviteten minskar ifall maskinen är svår att hantera. För att göra det lättare för framtida utvecklare att nå en hög användbarhet när de utvecklar ett HMI så siktade detta examensarbete på att hitta en genomtänkt process att följa vid ett sådant tillfälle. Resultatet blev en process som testades via en HMI prototyp för vattenskärnings maskiner. Denna prototyp blev sedan testad i olika användarfall av både erfarna operatörer och nybörjare. Testerna visade sig ge positiv återkoppling, vilket bevisade att processen som följts upp till den punkten fungerade.

Under år 2008 uppskattades den totala produktionen av kugghjul inom bilindustrin till 2000 – 2500 miljoner detaljer, varav 1000 - 1400 miljoner av dessa är av hög kvalité [1]. För precisionskugghjul med modul under 1 mm kan tidsbegränsning och kostnader kopplade till design av skärverktyget elimineras genom att tillämpa en flexibel tillverkningsmetod som tillexempel abrasiv vattenskärning (AWJM). Denna studie undersöker designen av ett hybridtillverkningssystem konfigurerat kring AWJM samt föreslår finbearbetningsprocess via konventionella bearbetningsmetoder. Den tekniska möjligheten att producera kuggring av hög precision testas med en 5-axlig vattenjetmaskin och utvärderas enligt kvalitets nivåer för DIN-standard. För detta ändamål studerades ett kugghjul med modul 0,55 mm, 199 tänder, 110 mm i ytterdiameter och 72 mm i innerdiameter samt en tjocklek på 6 mm gjord av Armox T500, höghållfast stål. Resultaten visar på hög potential att uppnå ISO standardkvalité för kugghjul. Vissa kvalitetsegenskaper, definierade i DIN- och ISO-standarder, till exempel ytfinhet med låga värden; Ra 0,8 μm, uppnås vid användning av AWJM. Andra kvalitetskännetecken som profilavvikelse är relaterade till parametrar som skäreffekt, matningshastighet, mängd abrasivmedel, etc. Framtagna värden sträcker sig från Q10 och Q11 enligt DIN3967 vilket möjliggör slutoperationer som till exempel slipning. Geometrisk avvikelse, på ovansidan, gav en maximalt värde på 7 μm med en standardavvikelse på 4 μm. Jetstrålens eftersläpning observerades och kan kompenseras för medan resultatet av rundade hörn existerar i alla skärning med AWJ. Radiell förskjutning, tandtjocklek och index avvikelser visar värden som kan förbättras tillsammans med processoptimering, maskinkalibrering och eliminering av inneboende positionsavvikelser i maskinen. Varje enskild geometri kräver specifika processparametrar och CAM-programmens algoritmer behöver vidare optimeras för arbeten med tämligen små geometrier. / Production of gears for the automotive industry during 2008 is estimated to have been between 2000 – 2500 million pieces, from which 1000 to 1400 million pieces were high quality gears [1]. For precision gears with module below 1 mm, the time limitations and costs associated with the design of the cutting tool can be eliminated by using a flexible manufacturing technology such as Abrasive WaterJet Machining (AWJM). This project investigates the design of a hybrid manufacturing system configured by use of AWJM and proposed finishing processes using conventional machining methods. The technical feasibility is analysed to produce high precision ring gears using a 5-axes AWJM system to achieve DIN standards quality levels. For this purpose, a gear with a module of 0.55 mm, 199 teeth and 110 mm in the outer diameter and 130 teeth and 72 mm in the inner diameter with a thickness of 6 mm is studied; the selected material is Armox T500, a high strength steel. The results indicate high potential of producing ISO quality standard gears. Certain quality characteristics defined in DIN and ISO standards, for instance surface roughness – values as low as Ra 0.8 μm, are possible to achieve accurately by using AWJM. Others quality features as profile deviation, are related to parameters as cutting power, feed rate, abrasive feed rate, etc. The displayed values ranged Q10 and Q11 according to DIN3967 which allows for use of further finishing operations such as grinding. The top geometry deviations of a 0.3 mm cut, display a maximum value of 7 μm with an average value of 4 μm. Observed jet lag effects can be improved. Rounded corner effect exists in all AWJ cuts. Runout, tooth thickness and index deviations show values that can be improved together with process optimization, machine calibration and elimination of machine inherent positioning deviations. Each particular geometry needs specific process parameters and CAM software algorithms need further optimization for working with rather small design geometries.

Marine waterjet propulsion is a technology that has been developed and refined since the early 1950’ and is proven highly useful for high speed applications with vessels in varying sizes. The intake grill is a component that is mounted in line with the hull to prevent debris from traveling through the waterjet. The intake grill is affected by viscous forces, contact forces and harmonic excitation forces all while affecting the efficiency of the waterjet. In this report a selection of methods is evaluated and verified with the goal of simplifying the design process of the intake grill. A selection of cross-sections is generated and evaluated to draw general conclusions about the efficiency and stability of the intake grill. A selection of computational fluid dynamics and modal analysis methods are utilized. It is concluded that the intake grill is affected by many parameters and can be evaluated by modal FEM analysis and 2D CFD analysis. / Marina vattenjetmotorer har utvecklats och förfinats sedan tidigt 50-tal och har bevisats mycket användbara för applikationer i hög hastighet med båtar i varierande storlekar. Intagsgaller är en komponent som monteras i linje med skrovet på båtar för att förhindra oönskade föremål att färdas genom intaget på vattenjetmotorn. Intagsgallret är påverkat av viskösa krafter, direkta krafter och harmonisk excitation samtidigt som komponenten påverkar vattenjetmotorns effektivitet. I denna rapport så evalueras ett urval av metoder med målet att simplifiera utvecklingsprocessen av intagsgaller. Ett urval av tvärsnittsgeometrier är genererade och evaluerade för att dra generella slutsatser om effektiviteten och stabiliteten av intagsgallret. Ett par olika sorters flödessimuleringar och finita element metoder används. Slutsatsen är att intagsgallret påverkas av ett flertal parametrar och kan utvärderas med modal finita element metoder samt tvådimensionella flödessimuleringar.

During the past several decades, the water jet cutting concept has developed from a novel concept into a well-accepted machine cutting tool. With the addition of abrasive particles and the improvement of high pressure pumps, the water jet stream is currently capable of cutting through metal, concrete, and composite materials. Water jet systems have been utilized at a wide range of different pressures. Research performed at Brigham Young University has revealed that low pressure water jets have the ability to cut human teeth. Experiments have shown that when abrasive particles are added to the water jet stream, an greater amount of tooth material can be removed at lower input pressures. Many different methods have been proposed to entrain and suspend particles in a high pressure water jet system. The abrasive particles can be entrained before the water is pressurized, while the water is being pressurized, or after the water jets stream exits the pressurized system. Each method has its advantages and disadvantages. Unfortunately, keeping abrasive particles homogeneously entrained and suspended in a water jet stream has proven to be difficult. Research at Brigham Young University has encountered similar problems. Researchers are attemping to place abrasive particles in a low pressure water jet stream, but have not been able to maintain a suspended homogeneous slurry. It is the objective of this research to investigate and suggest several possible methods to entrain and suspend abrasive particles into a low pressure water jet system intended for a dental cutting application. A broad review of methods to entrain abrasives in high pressure water jet systems was performed. A list of methods and concepts as possible solutions to entrain abrasives in a low pressure system has been generated. Product design principles were applied to screen, score, and rank these generated concepts to narrow down the list to the most viable concepts for BYU's low pressure dental water jet. Several tests and experiments were also performed to validate the suggested concepts and to provide useful information for future research. It is anticpated that one or more of these methods will be applicable for the proposed dental application as well as other similar applications.

This thesis is an investigation of the fabrication and assembly methodologies employed in the development of a proof-of-principle prototype electric guitar composed of laminated copolyester. The objective of the project was to develop the processes and procedures to create an optimized physical and visual bond between layers to minimize vibratory dissipation, thus maximizing sustain. A high speed CNC router, abrasive waterjet, laser engraver-cutter, as well as various manual fabrication and assembly methods were investigated in the construction of the guitar prototypes. The lamination processes explored include low-temperature, heat-assisted pressure bonding, solvent and chemical welding, and contact adhesives. The project concluded with the completion of a working guitar comprised of a laminated copolyester body and a traditional bolton wooden neck.