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Silicon carbide is a useful monolithic and matrix ceramic due to its excellent mechanical properties and corrosion/oxidation resistance at high temperature. This makes it an attractive material for use in advanced applications, such as aircraft engines and high-speed flight. In this study, additively manufactured monolithic SiC and Cf/SiC CMCs, processed via direct ink writing (DIW) of a 53 vol% colloidal suspension, achieved >96% theoretical density through pressureless sintering. When present, fibers are aligned in the direction of the print path. Five different print paths were studied, including a 0o path, 90o path, 0/90o path, 0/15/30/45/60/75/90o path, and 0/30/60/90/60/30/0o path. Four-point bend testing was performed to determine flexural strength and Weibull analysis was performed. Strengths were highest for the 0o print path. The characteristic strength, σo, of this print path was 375 MPa with a Weibull modulus of 7.4 for monolithic SiC and a σo of 361 MPa with a Weibull modulus of 10.7 for Cf/SiC. Weibull modulus was greater for Cf/SiC samples compared to identically printed monolithic SiC samples. SEM and optical microscopy were used to analyze printed parts which showed a high degree of fiber alignment in the direction of the print. Fiber pullout was observed on the fracture surface, as well as intragranular fracture.

Selective laser melting (SLM) is a new and rapidly developing manufacturing method for producing full-density, geometrically complex metal parts. The SLM process is time and cost effective for small-scale production; however, wide-spread adoption of this technique is severely limited by residual stresses that can cause large deformations and in-process build failures. The issues associated with residual stress accumulation are most apparent in parts with overhanging features. Due to the complexity of the SLM process, the accumulation of residual stresses is difficult to assess a priori. The deformations and in-process failures caused by residual stress accumulation often lead to an expensive and time consuming iterative manufacturing process. To aid in the development of general SLM design guidelines for overhanging features, the effect of varying two support structure design parameters on residual stress accumulation were investigated. A part-scale thermo-mechanical finite element model was implemented using Diablo, a multi-physics finite element code developed by Lawrence Livermore National Laboratory (LLNL), and trends observed in the model were validated experimentally. By comparing the distribution and magnitude of residual stresses, it was determined that reducing cooling rate gradients in overhanging features reduces the resulting residual stresses. Additionally, it was shown that volume effective material properties can be used to reduce computational costs in computational models of the SLM process.

Alla ska ha lika stor möjlighet att utöva idrott på lika villkor. Parasport är idrott till för personer med någon form av funktionsnedsättning såsom synnedsättning, intellektuell funktionsnedsättning eller rörelsenedsättning. Inom parasport finns alpin skidåkning som går ut på att ta sig ned för backen så snabbt som möjligt i en utstakad bana. Utbudet av professionell utrustning för både alpint och andra sporter som är möjlig att individanpassa mot idrottsutövarens behov är mycket begränsad om än inte obefintlig. Projektet initierades av landslagstränaren för alpina parasportförbundet, Henrik Bergqvist. Syftet med detta projekt är att möjliggöra en bättre tackling av en slalomkäpp för paraalpinåkare med förkortad underarm. Målet med projektet är att ta fram ett konceptunderlag för att kunna tillverka ett alpint slalomarmskydd. Konceptunderlaget kommer innefatta tredimensionella ritningar för produkten samt materialval och tillverkare. Denna rapport omfattar en produktutvecklingsprocess innehållande fem faser, förstudie, produktspecificering, konceptgenerering, utvärdering och val av koncept, prototyp och detaljkonstruktion. Resultatet av projektet genererades i ett konceptunderlag för ett slalomarmskydd till paraalpinåkare med förkortad underarm. Detta koncept har funktionen att tackla bort slalomkäppen samtidigt som den ska vara ergonomisk mot underarmen, och ha ett material som tål de påfrestningar som skyddet kommer utsättas för. Projektet och dess resultat överlämnas till uppdragsgivaren med goda förutsättningar att vidare kunna tillverka detta slalomarmskydd. / Everyone should have an equal opportunity to practice sports on equal terms. Parasport is sports for people with some form of disability such as visual impairment, intellectual disabilities or mobility impairment. In parasport, there is alpine skiing that involves getting down the slope as quickly as possible in a marked course. The range of professional equipment for both alpine and other sports that can be individually adapted to the athlete's needs is very limited, although not non-existent.   The project was initiated by the national team coach for the alpine parasport association, Henrik Bergqvist. The purpose of this project is to enable a better tackle of a slalom gate for para-alpine skiers with a shortened forearm. The goal of the project is to produce a concept material to be able to manufacture an alpine slalom arm guard. The concept material will include three-dimensional drawings for the product as well as material selection and manufacturers.   This report covers a product development process that includes five phases, feasibility study, product specification, concept generation, evaluation and selection of concepts, prototype and detailed design.   The result of the project was generated in a concept data for a slalom arm protection for para-alpine skiers with a shortened forearm. This concept has functions to tackle the slalom gate while at the same time being ergonomic against the forearm and having a material that can withstand the stresses to which the protection will be exposed.   The project and its results are handed over to the client with good conditions to be able to further manufacture this slalom arm guard. / <p>Betyg 2021-07-16</p>

The target of this work is the development of a monitoring system for 3D printing by the Fused Deposition Modeling method, which will be able to identify printing error conditions. During the solving process the needed error conditions were identified. Then, an algorithm was programmed to identify the error condition using the criterion. The resulting Monitoring Hardware was implemented in the printer and experimentally verified. A system has been developed that can identify error conditions with an accuracy of 94.7%. The main benefit of this work is the automatic identification of error conditions that stop printing if necessary. This leads to a reduction in scrap and cost savings. In the future, the software could automatically adjust the print parameters when identifying an error condition. This would prevent or completely eliminate the error condition without user intervention.

The goal of the thesis was to design a piston manufactured by conventional method and subsequently adjusted one for additive manufacturing. Beside the designs, thermo-structural model was created for both pistons, considering maximal loading of the engine. Analysis evaluation showed the possibility of further application of the new technology in comparison to current one, within automotive industry.

Master’s thesis deals with an issue of 3D printing and of using a topological optimization for editing a shape of a 3D printed product. First part of this thesis provides a general description of a subtractive manufacturing technology, specifically its use in CNC milling machines, and of an additive manufacturing technology which is used in 3D printing. Second part of this thesis describes the topological optimization per se and specific methods which are used in the topological optimization. In the third and the fourth part of this thesis, topological optimization modules of software Ansys and SolidWorks are described. In the fifth part of this thesis, the topological optimization capabilities for 3D printed product on a specific embodiments of a design lightning and a cross-beam are demonstrated.

The diploma thesis is related to the preparation of hydroxyapatite complex structures by additive manufacturing known as Lithography based ceramics manufacturing – LCM. A photosensitive suspension containing hydroxyapatite particles was used for 3D printing of ceramic complex structures. The influence of printing parameters on the resulting macrostructure, microstructure, density, and dimensional accuracy was evaluated. The aim was to obtain ceramic components without delamination of the layers and optimise following post-processing steps (cleaning and thermal treatment). It was found that the exposure time has a significant effect on the dimensional accuracy of printed parts. During observation microstructure of printed parts, a microporosity at the interface of printed layers, which can cause delamination of several layers was identified. High-temperature dilatometry showed different temperature of beginning densification process in the longitudinal and perpendicular directions to the layers. That could be an initiation mechanism for delamination of the layers. X-ray diffraction analysis determined a single-phase composition of powder in photosensitive suspension and sintered parts. A commercial product LithaSol 20 was suggested as a suitable cleaning agent and efficiency of the ultrasound field for cleaning was demonstrated. Based on the thermogravimetric analysis an optimized cycle of heat treatment was designed. The optimisation led to time saving (49 hours), while maintaining density, dimensional accuracy and macrostructure of the 3D printed structures.

The diploma thesis presents an overview of additive production technologies and a summary of technologies used for 3D metal printing using a robot. All of them are generally described and at the same time assigned to their specific commercial use, or the academic research that deals with them. The work examines the suitability of the material EN ISO 14341-A: G 3Si1 for 3D printing, for which a modification of the Col Metal Transfer technology, Cycle Step is used. The experimental printout of the sample is evaluated on the basis of surface and mechanical tests. Capillary test, examination of microstructure a macrostructure, tensile test and microhardness test. All of them were satisfactory and the suitability of the welding wire for 3D printing was confirmed by the given technology.

The design of air conditioning unit is based on combination of the product itself and related architecture. The large-scale 3D printing is becoming more and more popular, that is why this thesis chose additive manufacturing robotic technology for designing the air conditioner. According to analysis the air distribution through perforations is the most convenient one for an indoor unit. An outdoor unit tends to be hidden because of inhomogeneity with the building. To obtain more variant studies for the design a generative process was applied. This method was applied also later on, because additive manufacturing is able to easily change dimension parameters and thus fulfil individual customer requests. Other advantages of robotic printing are the lattice structures that enable perforation manufacturing without waste and the possibility of using generative design methods.