With the continuing trend towards miniaturization, micro milling plays an increasingly important role in fabrication of freeform and high-accuracy micro parts or components directly and cost-effectively. The technology is in kinematics scaled down from the conventional milling, however, existing knowledge and experiences are limited and comprehensive studies on the micro tooling performance are essential and much needed particularly for the process planning and optimization. The cutting performance of micro tools is largely dependent on the dynamic performance of machine tools, tooling characteristics, work material properties and process conditions, and the latter three aspects will be focused in the study. The state of the art of micro milling technology with respect to the tooling performance has been critically reviewed, together with modelling work for performance prediction as well as metrology and instrumentation for the performance characterization. A novel 3D finite element method taking into account the geometry of a micro tool, including the tool diameter, rake angle, relief angle, cutting edge radius and helix angle, has been proposed for modelling and simulation of the micro milling process. Validation through well-designed micro milling trials demonstrates that the approach is capable of characterizing the milling process effectively. With the support of FEM simulation developed, the tooling geometrical effects, including those from helix angle, rake angle and cutting edge radius with influences on cutting forces, tool stresses, tool temperatures, milling chip formation and temperatures have been comprehensively studied and compared for potential micro tool design and optimization purposes. In an effort to prolong the tool life and enhance the tooling efficiency, DLC and NCD coatings have been deposited on micro end mills by PE-CVD and HF-CVD processes respectively. Corresponding cutting performance of these coated tools have been assessed and compared with those of WC micro tools in both dry and wet cutting conditions so as for better understanding of the coating influence on micro tools. Furthermore, the cutting characteristics of the DLC coated and uncoated tools have been analysed through verified plane-strain simulations. The effects of coating friction coefficient, coating thickness and UCT have been determined and evaluated by design of simulation method. Mechanical, chemical and physical properties of a work material have a direct influence on its micro-machinability. Five most common engineering materials including Al 6061-T6, C101, AISI 1045, 304 and P20, have been experimentally investigated and their micro milling behaviours in terms of the cutting forces, tool wear, surface roughness, and micro-burr formation have been compared and characterized. Feed rate, cutting speed and axial depth of cut constitute the complete set of process variables and they have significant effects on the tooling performance. Fundamental understanding of their influences is essential for production engineers to determine optimum cutting parameters so as to achieve the maximum extension of the tool life. 3D FE-based simulations have been carried out to predict the process variable effects on the cutting forces, tool stresses, tool temperatures as well as micro milling chip formation and temperatures. Furthermore, experimental approach has been adopted for the surface roughness characterization. Suggestions on selecting practical cutting variables have been provided in light of the results obtained. Conclusions with respect to the holistic investigation on the tooling performance in micro milling have been drawn based on the research objectives achieved. Recommendations for future work have been pointed out particularly for further future research in the research area.

Thesis (MScEng (Industrial Engineering))--University of Stellenbosch, 2005. / The LOMOLD process is a new plastic moulding process being researched at the University of Stellenbosch. The process essentially combines injection moulding and compression moulding. Molten plastic is forced into the mould cavity using a plunger. This plunger then forms part of the cavity wall. The plunger face must therefore follow the geometry of the part. Rapid Tooling evolved from Rapid Prototyping. There are two categories of Rapid Tooling: indirect and direct rapid tools. Indirect rapid tools are manufactured by using a master pattern to form the mould cavity. The accuracy of the mould cavity depends heavily on the accuracy of the master pattern. The master pattern is usually produced using Rapid Prototyping technology. Direct rapid tools use Rapid Prototyping technology to build the mould through and additive, layer by layer process or a subtractive process. This research investigates the use of Rapid Tools for the LOMOLD process. Aluminium Filled Epoxy Tooling (AFET) represents the indirect technology and CNC-machined tooling the direct technology. Both of these technologies are available at the University of Stellenbosch. Parts are manufactured on these tools using an experimental LOMOLD machine. These two technologies are compared in terms of part accuracy, tool lead time, tool cost and part cost. The research concluded that the only advantage the AFET has over the CNC-machined tool is a shorter manufacturing lead-time. In terms of tool cost, tool life, part geometric accuracy, part cost and cycle time the CNC tool is superior. Therefore the application of AFET is limited to small volume, prototype or pre-production runs for tool design confirmation, part functional testing and part appearance testing. It is also demonstrated that a cooling system on the AFET tool has no significant influence on the tool performance and should therefore, especially for production runs less than 150 parts, not be included in the tool to save on tool cost. Another conclusion is that the LOMOLD process is not consistent enough for a production process. This statement could be limited to the machine used for the research but to prove this statement wrong, the machine must be improved and more investigation is required.

Made available in DSpace on 2016-08-02T21:42:41Z (GMT). No. of bitstreams: 1 JOAO CARLOS SANCHES.pdf: 288041 bytes, checksum: 3c59f0a91370310bbcc60d22ea4c47e8 (MD5) Previous issue date: 2007-02-15 / The aim of the current study was to investigate through a comparative study, a competitive positioning of three Multitask and Tooling Machines in Brazilian market..Initial hypothesis were based on: a) the national tooling machine industries are being penalized with the industrial policies practiced by the federal government, and b) the relative importance attributed to multicriteria elements of the specifications of the national machines, when considered on the growing trends, are not always met by the imported competing machines as a result of aggregated technological values meant to reach plain competitiveness. Thus, we inquire: to what extent are the multitask and tooling machines selected for test are alighned with the chosen criteria and their relative importance appreciated by the two users of the machines. As a methodology the study adopted a multi-case study of two medium industries of the same sector. We used the multicriteria decision method through Analytic Hierarchy Process (AHP) so as to obtain the most suitable alternative between the national and imported multitasks similar machineries. Results indicate that for the two cases analyzed, it is advantageous to acquire the imported machines, even though it is notorious to mention the national technological advancement. These machines need innovations as they loose competitiveness, not to mention some important criteria such as versatility and productivity. Based on our findings therefore, we conclude that the national tooling and machines suppliers of the multitasks types analyzed in this study are not competitive as compared to the imported ones. / O principal objetivo desta dissertação foi analisar por meio de estudo comparativo, o posicionamento competitivo de três máquinas ferramentas multitarefas. As hipóteses iniciais partiram das seguintes suposições: a) a indústria nacional de máquinas ferramentas esta sendo penalizada pela política industrial praticada pelo governo federal; e b) a importância relativa atribuída aos elementos multicriteriais das especificações das máquinas nacionais quando demonstram tendências elevadas, nem sempre alcançam as concorrentes importadas devido aos recursos tecnológicos agregados para se atingir a competitividade plena. Assim, indaga-se: até que ponto as máquinas ferramentas multitarefas selecionadas para o estudo, estão alinhadas com os critérios escolhidos e com suas importâncias relativas avaliadas por dois usuários desse equipamento. Como metodologia adotou-se estudo de caso múltiplo de duas empresas de médio porte do mesmo ramo. Utilizou-se o método multicritério de apoio à decisão por meio de Analytic Hierarchy Process (AHP), para a escolha da melhor alternativa entre máquinas ferramentas multitarefas similares, nacionais e importadas. Os resultados identificam que, para essas duas empresas usuárias pesquisadas, existe vantagem na aquisição da máquina importada, embora seja notório o avanço tecnológico da indústria nacional. Estas máquinas ainda carecem de algumas inovações, perdendo em competitividade, bem como em critérios importantes como versatilidade e rendimento. Com base nos trabalhos, conclui-se que, as máquinas ferramentas do tipo multitarefas nacionais das duas empresas fornecedoras analisadas não são competitivas em comparação as importadas.

Användningen och intresset för additiv tillverkning (AM) har ökat markant de senaste åren och det finns en teori kring att tillverkningsmetoden kan vara det nästa steget i den industriella revolutionen. Eftersom AM fortfarande befinner sig i utvecklingsstatidet går det att anta att tekniken ännu inte uppnått sin fulla potential och att det kan komma att finnas möjligheter att implementera tekniken i fler branscher och företag. Detta skulle innebära en bredare marknad för AM. Syftet med examensarbetet var att undersöka vilka möjligheter och hinder som finns för ökad användning av AM i Sverige. Studien genomfördes genom kvalitativa intervjuer med åtta olika verksamheter tillhörande den svenska industrin och en litteraturgenomgång för att presentera nuläget för AM i svensk industriell marknad. Resultatet av datainsamlingen analyserades med modellerna PEST, 4P och slutligen SWOT. De fördelar som har setts med användningen av AM har varit minskade ledtider, minskade kostnader för tillverkning av produkter och verktyg, minskat materialspill och en optimal designprocess med ökad kreativitet. De begränsningar som finns i tekniken i dagsläget är att priset för material och maskiner är dyrt. Vidare anses även kvalitet på slutdetalj, begränsad byggvolym och opålitliga processer vara problematiska. De möjligheter som finns beror huvudsakligen på den forskning som görs. Förutsättningarna för AM i svensk industri kommer att bero på hur tekniken kommer att utvecklas. De hinder som finns är kopplat till kompetensbrist och att det inte finns befintliga standarder för material eller process inom AM. / Within the industrial sector, an increased interest and usage of Additive Manufacturing (AM) throughout the decade has been formed. The layer-upon-layer building technology has been seen and recognized as one of the next industrial revolutionizing methods of production. As the technology is still in the trending and uprising phase it should be considered that its full potential has not yet been achieved, as large opportunities for implementation of AM exist and that new companies and markets have a growing interest in this technology. Through this study a market research was conducted to identify and present what opportunities and obstacles there are for an increased usage of AM in Sweden. A literature study on the Swedish market has been made to present the market as of today. Eight qualitative interviews have also been conducted with companies within the industrial sector to identify the areas of use within AM for production. The concepts and models used to analyze these questions was PEST, Marketing Mix and SWOT. The concluded results for advantages in using AM are shortened lead times, reduced costs of production of components and tools, reduced material waste and optimization of design processes with increased creativity. The concluded challenges are expensive materials and machine, the quality of finished components, limited printing volume due to the 3D-printers and reliability of printing processes. The finalized opportunities that are presented in this work are that AM is dependent on how much research on the subject and factors around it is done. How AM will be applied in the coming future revolves around the advancement in the technology. The obstacles that are found in this study are lack of competence and lack of standard for materials and processes within AM.

A necessidade deste trabalho se fez no setor de Planejamento de Fluxo de Materiais e Embalagens (PFME), que pertence ao departamento de engenharia de manufatura de uma filial de montadora instalada no Brasil. Neste setor existe a necessidade de se obter peças protótipo em um menor espaço de tempo possível para realização dos ensaios estáticos dos protótipos das embalagens especiais, uma vez que as embalagens precisam acondicionar as peças produzidas a partir da fase de preparação da produção em série do automóvel (pré-série ou PVS). Neste trabalho, a partir do estudo das tecnologias de Rapid Prototyping (RP) - Prototipagem Rápida (RP) e Rapid Tooling (RT) Ferramental Rápido (RT) é selecionada a técnica mais adequada para se atender às necessidades deste setor. Para isto, algumas condições de contorno foram consideradas: a aplicação das técnicas de RP e RT foram restringidas às peças externas do carro como portas, tampas dianteiras, traseiras e pára-lama e as fontes fornecedoras consultadas encontram-se no mercado doméstico. Com base em um estudo de caso pode-se validar esta proposta. Os resultados obtidos com a aplicação da técnica de ferramental rápido Vacuum Bagging foram uma redução média de 4,5 meses na obtenção das peças protótipo e uma redução global dos custos de aquisição de aproximadamente R$ 100.000,00. / The need of this work was made in the material flow planning and packing (PFME) section, that belongs to the manufacture engineering department of an assembler company installed in Brazil. In this sector, there is a growing need to obtain prototype parts in the shortest time possible in order to carry out static prototype tests of the special packing, since these racks need to be ready to assist the preparation phase of the series production of the vehicle (pre series or PVS). In this work, beginning from the study of Rapid Prototyping (RP) and Rapid Tooling (RT) technologies is selected the technique more adequate to assist to the needs of this section. For that purpose, some limiting conditions were considered: the application of the RP and RT techniques is limited to the external parts of the vehicle, such as doors, front and back hoods and fenders, and the consulted suppliers should be available in the domestic market. Based in a case study this proposal could be validated. The obtained results with the applied Rapid Tooling Vacuum Bagging technique were a medium reduction of 4,5 months in the prototype parts acquisition and a global reduction in the acquisition costs of approximately R$ 100.000,00.

Este trabalho avaliou a aplicação das tecnologias de prototipagem rápida por Impressão 3D e FDM (Fused Deposition Modeling) na produção de moldes rápidos. Esta avaliação foi feita com base nas qualidades das peças obtidas por vazamento nos moldes produzidos, bem como nas limitações encontradas em suas utilizações. Foram estabelecidas as principais diferenças do ponto de vista de qualidade, custos, tempos gastos e praticidade. Foram construídos moldes para peças que contemplando vários graus de dificuldades. Para cada ferramental foram obtidos lotes de peças, através dos quais foram analisadas e comparadas as qualidades dos protótipos. / This work evaluated the application of the Rapid Prototyping technologies 3D printer and FDM (Fused Deposition Modeling) in the rapid manufacturing of molds. This evaluation is based on the quality of the parts molded, as well as in the limitations found in the molds applications. As result the main differences related to quality, and usability was established. The molds produced parts with different degrees of geometric difficulties. For each mold, a few prototypes were produced and their qualities compared.

No description available.

The diploma thesis deals with the design of a direct drive tool turret, which serves as a tool magazine for a CNC lathe. In the introductory part of the work, a research was performed in the field of automatic tool change with a focus on tool turrets and their main structural units. The introductory research is followed by the main part of the work, which begins with the selection of appropriate design solutions, followed by a presentation of the tool turret design created in CAD software Autodesk Inventor 2021 and in the final part of thesis the key elements of the proposed design are verified by calculations.

No description available.

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.