Sensor technology has played an essential role in improving the observability in manufacturing processes and providing input to enabling more effective and efficient product and process design. To analyze an injection molding process, pressure and temperature variations have shown to be the most critical factors that affect quality in the molded parts. The state of sensing in the industry utilizes separate and wired sensors placed away from the mold cavity to measure these parameters, and holes have to be drilled through the mold steel to accommodate the wires. To minimize mold structural modification, which is time consuming and expensive, it is desired to design a miniaturized sensor module that can be structurally embedded into the molding cavity and simultaneously measures the two parameters (i.e. a dual-parameter sensor) in real time, during the molding process. This thesis presents the structural optimization of the sensor and development of a new Fluid-Structure algorithm to analyze the performance of the sensor as in an actual injection molding cycle. Thus, research involves three key tasks. Given a required mold steel thickness, an optimization problem was solved analytically with outer diameter, thickness and number of rings as variables under the maximum allowable pressure and minimum required energy constraints to achieve a minimum volume of the piezo stack. As it is infeasible to test the sensor with different dimensions under the flow to understand its behavior under high pressure and temperature polymer melt, the development of a numerical model is required. A mold-melt interaction algorithm is developed to have a mold-melt interface using finite element analysis, analogous to an injection molding process. The model showed the change in state of polymer melt and its effect on cavity due to change in viscosity with the change in temperature. The model validated the energy output of the optimized sensor when the temperature and pressure of polymer changes and the effect of these parameters on mold and sensor. The voltage output and temperature results were compared with analytical solution. The numerical results of voltage output matched within 0.1% and temperature results matched within 3% of the analytical solutions. Finally a test bed was fabricated to simulate and reconstruct the pressure profile obtained from the numerical model to study the actual output from a fabricated sensor. The aim of the test bed was to reconstruct pressure profiles obtained from numerical simulations to investigate the sensor output from the fabricated injection molding sensor. The test bed evaluated the output from sensor as can be observed in actual injection molding machine. Comparison of the injection molding sensor with a piezo-resistive sensor showed good agreement.

Electric propulsion in the heavy truck industry require knowledge in certain new areas involved in electric machine manufacturing. One of these new manufacturing steps is copper bending for production of stator windings. This thesis aimed to look at whether finite element simulations can be used in gathering experience to improve an existing stator design. Existing winding scheme is modeled, and simplified cases of different bending steps are simulated using finite element method. The result shows the critical areas where the largest stress and strain occurs in the existing design, giving input of how the bending affects the copper wire as well as the isolation layer of the wire, to improve future bending scheme designs. / Transportindustrin för tunga fordon står inför ett teknikskifte, klassisk förbränningsteknik ersätts av elektrisk drift. Denna tekniska utveckling innebär nya produkter i tillverkningen, vilket kräver kunskap kring processer för statorlindning med koppartråd. Detta arbete har ämnat titta på huruvida simulering med finita element metod kan användas för att erhålla kunskap kring böjningens påverkan på koppartråd och dess isoleringsskikt. Det har ingått geometrisk modellering av ett befintligt böjningsmönster, finita element simulering av förenklade geometrier för att utvärdera kopparens samt isoleringsskiktets spänningar och töjning vid böjning, resultatet visar vart de största deformationerna är samt vilka böjningar som kan vara kritiska, vilket ger information för möjliga designförbättringar till kommande lindningsscheman.

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Induktiefgekoppelde-plasmareaktore (IGP’s) het toepassings in verskeie industrieë, insluitend die voorbereiding van metaalpoeiers vir laagvervaardiging. Die skermgas (ook skutgas gnoem) speel ’n belangrike rol in die termiese afskerming van die reaktorwand in ’n IGP. Die energie wat verloor word deur die wand van die reaktor kan verminder word deur die hittesone weg van die wand af te beweeg. Hierdie verplasing van die hittesone word bereik deur ’n skermgas te gebruik wat moeiliker ioniseer as die plasmagas. Die ioniseringsgraad van waterstof is laer as dié van argon weens die hoër elektriese geleidingsvermoë van argon by soortgelyke temperature. Waterstof word dus in klein hoeveelhede in die skutgas gebruik met argon as die hoof bestandeel en hoofplasmagas. Die waterstof voorkom dus plasmavorming naby die wand. Die skutgas het ook ’n heelwat hoër vloeisnelheid en verminder sodoende die beskikbare tyd vir hitte-oordrag na die wand. Die besondere hoë temperature wat in ’n IGP bereik word, belemmer egter die meting van eenvoudige lesings soos vloeisnelheid en temperatuur. Rekenaarmodelle voorsien ons van die geleentheid om die fisiese en chemiese eienskappe van ’n plasma te ondersoek asook die nodige gereedskap om die gedrag van die plasma te analiseer sonder eksperimentele lesings. Daar is verskeie numeriese modelle van IGP-sisteme in die literatuur alhoewel nie een van dié modelle die effek van die skutgassamestelling in ag neem nie. Die hoeveelheid waterstof in die skutgas kan groot newe-effekte hê op die plasmagas a.g.v. die hoër ionisasiepotensiaal van waterstof. ’n Oormaat waterstof in die skutgas is ook ’n verkwisting van voermateriaal. Albei die faktore het ’n invloed op die ekonomiese uitvoerbaarheid van die plasmaproses. Hierdie navorsing het beoog om die optimale skutgassamestelling te vind vir die reaktor wat by Necsa gebruik word vir sferoïedisering. Die werk is uitgevoer met die kommersiële eindige-elementsagtewarepakket COMSOL Multiphysics R. Hierdie rekenaarmodel dui daarop dat die wand beskerm kan word van plasmavorming met ’n waterstof/argon skutgas wat sodoende ook die energieverliese deur die wand verminder. Waterstof verbeter die skutgas se hitte-oordragvermoë, maar verskuif die hittesone weg van die wand af. As gevolg van hierdie twee kompeterende meganismes bestaan daar ’n optimale bedrywingspunt by 3 vol% H2 in die skutgas. Die model is bevestig deur die energiebalans van die model te vergelyk met eksperimentele resultate. / Dissertation (MEng)--University of Pretoria, 2020. / Advanced Metals Initiative Suid Afrikaanse Akademie vir Wetenskap en Kuns / Chemical Engineering / MEng / Unrestricted