FDM 3D printing is an additive manufacturing technology that is widely used, mainly for rapid prototyping. It is also one of the cheapest and most accessible AM technologies for consumers. FDM printers, and especially cheaper alternatives, can have problems with creating high quality prints. Reasons include poor design, inaccurate construction, cheap components, and improper tuning. Input shaping is a control technique that may help mitigate defects caused by poor mechanical design or construction. The “ringing” defect may be eliminated by applying this solution. To perform an evaluation in sub-optimal mechanical conditions a 3D printer was constructed with a cantilever design mainly using plastic prints for mechanically important parts. Printing tests were done with and without input shaping. The results that were produced showed a direct effect of input shaping in 3d printers. / FDM 3D-printing är en additiv tillverkningsteknik som är mycket använd, främst för snabb prototypering. Det är också en av de billigaste och mest tillgängliga AM-teknikerna för konsumenter. FDM skrivare, och särskilt billigare alternativ, kan ha problem med att skapa högkvalitativa utskrifter. Orsaker inkluderar dålig design, konstruktionfel, billiga komponenter och felaktig justering. Input shaping är en kontrollteknik som kan hjälpa till att mildra defekter som orsakas av dålig mekanisk design eller konstruktion. "Ringning" defekten kan elimineras genom att tillämpa denna lösning. För att utföra en utvärdering i dåliga mekaniska förhållanden konstruerades en 3D-skrivare med en fribärande design som använder plastutskrifter för mekaniskt viktiga delar. Utskriftstester gjordes med och utan input shaping. Resultaten som framställdes visade på en uppenbar förbättring av print kvalité som en direkt effekt av input shaping.

The purpose of this master’s thesis was to investigate if suspension of heavy objectsis possible in the glulam arches at Stockholm Central Station. The main goal was todetermine the arches’ load carrying capacity’s utility ratio, in order to give knowledgeif additional loading can be added.The study included a thorough investigation of available blueprints and calculationreports established during and after the process of design and erection of the arches.In addition, an on-site-inventory was made to confirm and verify the studied material.A method to approximate semi-probabilistic material strength-properties, based onold deterministic material strength properties, was used.When the material had been summarized concluding geometrical attributes, loads, andmaterial properties a calculation model of the arch was developed. The global geometrydescribing the arch’s shape mathematically was established through measures onblueprints and analytical calculations in Mathcad. A finite element method (FEM) wasthen used to calculate reaction- and internal forces and buckling modes taking accountfor 2nd order effects. Once calculation of intrenal forces had been made, the structuralcapacity was checked analytically according to Eurocode’s failure criterion.The results showed that the arches do not fulfill required carrying capacity forEurocode’s symmetric- and non-symmetric distributed snow load. The failurecriterion not fulfilled were simultaneously bending and compression, lateral torsionalbuckling and simultaneously tension perpendicular to grain and shear.It is therefore concluded that suspension of heavy objects is not suitable with thepresent condition of the arch. In order to realize suspension, it is suggested thatreinforcement measures have to be conducted. It is also suggested that shear andiiiflexural carbon fiber reinforced polymer (CFRP) reinforcement would be a suitablemethod of enhancing the strength and stiffness of the arches, without disrupting theiraesthetics and integrity.