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Many manufacturing processes require complex tooling which contributes significantly to the cost and time required to develop new products. Bead foam molding is often hampered by these limitations. This thesis presents an analysis of Additive Manufacturing (AM) applications in low cost bead foam molding, focusing on molding trials, economic analysis, and future potential. Through molding trials, the thesis evaluates the efficacy of AM tooling in comparison to traditional aluminum tooling, specifically in evaluating tool life and cost. A key finding is a reduction in lead time up to 70% and cost of up to 63% compared to traditional tooling, particularly in low-volume production scenarios. This thesis includes a detailed cost analysis, which breaks down the cost components associated with AM processes such as pre-processing, production, material costs, post-processing, and overheads. This analysis reveals that AM tooling can offer substantial cost savings over conventional methods, making it a viable option for specific manufacturing contexts. Findings suggest that while AM tooling shows significant promise in reducing costs and accelerating production in bead foam molding, further research is required. This research should focus on exploring the scalability of AM for larger tools and investigating the application of new and emerging AM processes and materials. / Master of Science / This thesis explores the use of Additive Manufacturing (AM), often known as 3D printing, in creating molds for bead foam molding—a process used in manufacturing a variety of foam products. Findings reveal that using AM for toolmaking can be faster and more cost-effective than traditional methods, especially for small-scale production. The thesis details experiments comparing AM with conventional tooling and presents a cost analysis showing the potential time and cost savings. While promising, further research is needed to fully harness the benefits of AM in this field. This study opens doors to more efficient and economical manufacturing techniques using emerging AM technology.

published_or_final_version / Electrical Engineering / Master / Master of Philosophy

Designing an injection molded plastic part requires optimizing the part with respect to various stakeholders’ needs throughout its life cycle. The conditions in which a product is operating in service are often inadequately understood or specified, resulting in wrong material selection, which in turn leads to failure when the product is used. Many aspects interrelate with the initial part design and the essential rules of each should be taken into account to ensure a well-functioning plastic product. Regardless, a part design often passes sequentially from concept development to the manufacturing phase with features that unnecessarily complicate production, add costs and weaken the intended embodiment of the product. Therefore, a checklist was developed to ensure that oversights do not happen and verify that a design fulfills the requirements set for it. The commissioning company in the project was the design office Sytyte Oy. The aim of this thesis work was to investigate the effects of design decisions on the product’s feasibility and performance in service. The study focused on the underlying reasons for failures in plastic products, failure phenomena and ways of preventing them. The project started with literature research. To support the theoretical review, a small-scale survey was conducted among operators in plastic industry in Finland to strengthen the outcome of the project. The findings from the research were compiled into a checklist. The approach into the list was adopted from the FMEA method aiming to create a stripped-down version of it. The result offers a tool for anticipating and spotting possible failures by bringing up the influences that most frequently affect the part performance. It contributes to preventing delays in processing and premature failures in service. The checklist was verified by specialist consultation to receive suggestions and requirements for improvements and to ensure its reliability.

Submitted in fulfillment of the requirements for the degree of Doctor of Engineering: Mechanical Engineering, Durban University of Technology, Durban, South Africa, 2015. / Vacuum Infusion (VI) and Resin Transfer Moulding (RTM) are liquid composite moulding processes used in the manufacture of components from composite materials. The composite material in this case consists of a resin matrix combined with fibre reinforcement. In both moulding processes, a dry reinforcement preform is placed in the mould cavity and a liquid resin is introduced, driven by a pressure differential. Two rigid surfaces are used in RTM to create a fixed mould cavity. In contrast VI implements only one rigid surface and a flexible membrane or vacuum bag to form a non rigid cavity. The flexible cavity in VI influences and differentiates resin flow behaviour from that of RTM. Modelling resin flow enables the velocity, pressure and flow direction to be predicted. Resin flow in the RTM process is understood and modelled using Darcy’s law. However, flow in the VI process is not accurately modelled due to the added complexity introduced as a result of the flexible cavity. In the present work a novel approach was developed to investigate fluid flow in both processes. A unique experimental setup and testing procedure allowed for the direct comparison of fluid flow in RTM and VI. Identical flow parameters, conditions and preform construction were used in the assessment. The comparison isolated the effect of preform thickness variation as a differentiating factor influencing flow. From the experimentation, material behaviour was characterised and used to evaluate flow models for RTM and in particular VI. The model solutions were compared back to corresponding experiments. The pressure distribution behind the flow front, fill time and thickness behaviours were assessed. The pressure distribution / profiles behind the flow front of both VI and RTM were noted to be scalable with flow front progression. The profiles were curved in the VI experiments and linear in the RTM case. All VI models evaluated including the non accumulation based model accurately predicted the pressure distribution and consequently thickness variations in the VI tests. Fill times of the VI experiments were longer than that of the equivalent RTM tests. This behaviour is in contrast to previously interpreted fill time behaviour for the VI process based on VI models. It was also noted that the VI fill times were not only proportional to the square of the fill length, as in the RTM case, but also proportional to the square of the mass present. In addition, no significant accumulation was noted in the VI experiments. / D

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1978. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / B.S.

Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Mechanical Engineering. / Microfiche copy available in Archives and Engineering. / Includes bibliographical references. / M.S.

Lau Hau Yu. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 79-83). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.iv / Table of Contents --- p.vi / Chapter Chapter 1: --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Objective --- p.4 / Chapter Chapter 2: --- Literature Survey --- p.6 / Chapter 2.1 --- Plastic Injection Molding Process --- p.6 / Chapter 2.2 --- Monitoring and Diagnosis Methods --- p.10 / Chapter 2.3 --- Remote Monitoring --- p.12 / Chapter Chapter 3: --- Monitoring Methods --- p.15 / Chapter 3.1 --- Predict nozzle pressure and part weight using the Radial Basis Function Neural Network --- p.15 / Chapter 3.1.1 --- Motivation --- p.15 / Chapter 3.1.2 --- Background --- p.15 / Chapter 3.1.3 --- Hybrid RBF neural network --- p.17 / Chapter 3.1.4 --- Estimation of nozzle pressure --- p.21 / Chapter 3.1.5 --- Estimation of part weight: The two steps and one step methods --- p.22 / Chapter 3.2 --- Short shot Monitoring using Similarity --- p.25 / Chapter 3.2.1 --- Background --- p.25 / Chapter 3.2.2 --- The Dissimilarity Approach --- p.26 / Chapter 3.3 --- Parameter Resetting using Support Vector Machine (SVM) and Virtual Search Method (VSM) --- p.27 / Chapter 3.3.1 --- Background --- p.27 / Chapter 3.3.2 --- Support Vector Regression --- p.27 / Chapter 3.3.3 --- SVM Parameters Resetting using Virtual Search Method (VSM) --- p.31 / Chapter 3.4 --- Experiments and Results --- p.33 / Chapter 3.4.1 --- Introduction to Design of Experiment (DOE) --- p.33 / Chapter 3.4.2 --- Set-points selection based on Design of Experiment (DOE) --- p.34 / Chapter 3.4.3 --- Nozzle pressure estimation --- p.40 / Chapter 3.4.4 --- Part weight prediction using the One Step Method --- p.47 / Chapter 3.4.5 --- Similarity Monitoring using estimated nozzle pressure --- p.49 / Chapter 3.4.6 --- Similarity Monitoring using ram position --- p.54 / Chapter 3.4.7 --- Parameter Resetting using SVM and VSM --- p.61 / Chapter Chapter 4: --- The Remote Monitoring and Diagnosis System (RMDS) --- p.63 / Chapter 4.1 --- Introduction to the Remote Monitoring and Diagnosis System --- p.63 / Chapter 4.2 --- Starting Use of the Software --- p.65 / Chapter 4.3 --- Properties and Channel Settings --- p.66 / Chapter 4.3.1 --- Statistic Process Control (SPC) --- p.69 / Chapter 4.3.2 --- Settings --- p.71 / Chapter 4.3.3 --- Viewing the signals --- p.72 / Chapter 4.3.4 --- Short shot monitoring --- p.73 / Chapter 4.3.5 --- Data management --- p.73 / Chapter Chapter 5: --- Coeclusions and Future Works --- p.76 / References --- p.79 / Appendix A: Machine settings in the experiment --- p.84 / Appendix B: Measured part weight in the part weight prediction experiment --- p.86 / Appendix C: Measured part weight in the similarity monitoring experiment --- p.87 / Appendix D: Results of Parameters Resetting Experiment --- p.88 / Appendix E: List of figures --- p.89 / Appendix F: List of tables --- p.91

A possibilidade de redução ou até mesmo da eliminação do uso de formas e escoramento, diminuição do tempo e melhoria da qualidade da obra, são alguns aspectos que têm levado à adoção da pré-moldagem em superestruturas de pontes. Recentes estudos relatam que as chamadas pontes integrais - pontes sem juntas - estão tornando-se cada vez mais utilizadas nos Estados Unidos e Canadá, pois minimizam os custos com manutenção e prolongam a vida útil da obra. Procurando associar os benefícios conseguidos com a utilização dos elementos pré-moldados aos da ausência de juntas, apresenta-se neste trabalho um tipo construtivo para pontes de pequenos vãos em pórtico, com utilização de elementos pré-moldados na superestrutura ligados rigidamente à infraestrutura. Um processo aproximado de cálculo é apresentado e, a partir de um exemplo desenvolvido, compara-se esta alternativa com uma construção similar em viga, verificando-se que os custos diretos são basicamente iguais. Através da avaliação dos esforços provenientes do carregamento móvel com a técnica dos elementos finitos, chega-se a momentos fletores até 50% menores que os obtidos pelo método aproximado, resultando assim numa considerável redução dos custos diretos quando se utiliza o sistema estrutural em pórtico. / The possibility of reduction or even the elimination of the use of forms and bearings, reducing the time and improving the qualitity of the work, are some aspects which have led to the use of precasting in bridges superstructure. Recent studies report that the so-called integral bridges, jointless bridges, are becoming more used in the United States of America and in Canada because they reduce the costs of maintenance and prolonge the useful life of the constructions. Trying to associate the benefits which have resulted from the utilization of precast elements to the ones from the absence of joints, it is present in this work a constructive proposal to small span frame bridges using the precast elements in the superstructure strictly connected to the infrastructure. A design process for bending moments is presented. The comparation between the construtive proposal and similar with joint between the superestructure and infrastructure, by using this design process, shows that the direct cost is basically the same. Through the evaluation of the efforts that come from the mobile carrying with the technique of finite elements, it can reach bending moments that are even 50% lower than those gotten from the presented method. In this case, a significative direct cost reduction can gotten with frame structure system.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Includes bibliographical references. / by Francis Abbott Waldman. / M.S.