The development of a manufacturability analysis system for micro-milling

Manufacturability analysis systems (MASs) have been developed to enable the evaluation of manufacturability aspects during the design stage. MASs have been shown to be useful for macro-manufacturing processes but less attention or effort has been put for their development in the scope of micro-manufacturing. This thesis describes the development of a MAS for a micro-machining domain (MicroMAS) with a custom-made 4-axis Miniature Machine Tool (MMT) being the scope of implementation. There are three important components in this study which are; MAS, Uncertainty Evaluation Model (UEM) and micro-milling experiments. The integration between the results from the UEM analysis and micro-machining experiments were being incorporated into the MicroMAS to provide the system with the real condition of the MMT. In MicroMAS, Primitive Feature Analysis (PFA) is introduced as a new technique in gathering information from a CAD model and analysing its manufacturability. The results from the manufacturability assessment in MicroMAS are successfully achieved through the manufacturability index which indicates the relative ease of machining the CAD model and list of related suggestions. UEM is developed to analyse the influence of the errors stemmed from the MMT construction on the geometrical accuracy of the machined micro-parts. The model has allowed a methodology for the errors in a custom-made machine tool to be predicted and to further understand the origin of the errors on the machined micro-part (either from the machine or the process itself). The abilities of the MMT are evaluated through various types of experiments where the surface quality and geometrical accuracy can be concluded to be at an acceptable range. From the experience gained from the research, the development of MicroMAS for micro-milling has been found to be practical in assisting a user to generate micro-parts using the MMT

Manufacturability analysis for non-feature-based objects

This dissertation presents a general methodology for evaluating key manufacturability indicators using an approach that does not require feature recognition, or feature-based design input. The contributions involve methods for computing three manufacturability indicators that can be applied in a hierarchical manner. The analysis begins with the computation of visibility, which determines the potential manufacturability of a part using material removal processes such as CNC machining. This manufacturability indicator is purely based on accessibility, without considering the actual machine setup and tooling. Then, the analysis becomes more specific by analyzing the complexity in setup planning for the part; i.e. how the part geometry can be oriented to a cutting tool in an accessible manner. This indicator establishes if the part geometry is accessible about an axis of rotation, namely, whether it can be manufactured on a 4th-axis indexed machining system. The third indicator is geometric machinability, which is computed for each machining operation to indicate the actual manufacturability when employing a cutting tool with specific shape and size. The three manufacturability indicators presented in this dissertation are usable as steps in a process; however they can be executed alone or hierarchically in order to render manufacturability information. At the end of this dissertation, a Multi-Layered Visibility Map is proposed, which would serve as a re-design mechanism that can guide a part design toward increased manufacturability

The development of a manufacturability analysis system for micro-milling

Manufacturability analysis systems (MASs) have been developed to enable the evaluation of manufacturability aspects during the design stage. MASs have been shown to be useful for macro-manufacturing processes but less attention or effort has been put for their development in the scope of micro-manufacturing. This thesis describes the development of a MAS for a micro-machining domain (MicroMAS) with a custom-made 4-axis Miniature Machine Tool (MMT) being the scope of implementation. There are three important components in this study which are; MAS, Uncertainty Evaluation Model (UEM) and micro-milling experiments. The integration between the results from the UEM analysis and micro-machining experiments were being incorporated into the MicroMAS to provide the system with the real condition of the MMT. In MicroMAS, Primitive Feature Analysis (PFA) is introduced as a new technique in gathering information from a CAD model and analysing its manufacturability. The results from the manufacturability assessment in MicroMAS are successfully achieved through the manufacturability index which indicates the relative ease of machining the CAD model and list of related suggestions. UEM is developed to analyse the influence of the errors stemmed from the MMT construction on the geometrical accuracy of the machined micro-parts. The model has allowed a methodology for the errors in a custom-made machine tool to be predicted and to further understand the origin of the errors on the machined micro-part (either from the machine or the process itself). The abilities of the MMT are evaluated through various types of experiments where the surface quality and geometrical accuracy can be concluded to be at an acceptable range. From the experience gained from the research, the development of MicroMAS for micro-milling has been found to be practical in assisting a user to generate micro-parts using the MMT

An intelligent knowledge based cost modelling system for innovative product development

This research work aims to develop an intelligent knowledge-based system for product cost modelling and design for automation at an early design stage of the product development cycle, that would enable designers/manufacturing planners to make more accurate estimates of the product cost. Consequently, a quicker response to customers’ expectations. The main objectives of the research are to: (1) develop a prototype system that assists an inexperienced designer to estimate the manufacturing cost of the product, (2) advise designers on how to eliminate design and manufacturing related conflicts that may arise during the product development process, (3) recommend the most economic assembly technique for the product in order to consider this technique during the design process and provide design improvement suggestions to simplify the assembly operations (i.e. to provide an opportunity for designers to design for assembly (DFA)), (4) apply a fuzzy logic approach to certain cases, and (5) evaluate the developed prototype system through five case studies. The developed system for cost modelling comprises of a CAD solid modelling system, a material selection module, knowledge-based system (KBS), process optimisation module, design for assembly module, cost estimation technique module, and a user interface. In addition, the system encompasses two types of databases, permanent (static) and temporary (dynamic). These databases are categorised into five separate groups of database, Feature database, Material database, Machinability database, Machine database, and Mould database. The system development process has passed through four major steps: firstly, constructing the knowledge-based and process optimisation system, secondly developing a design for assembly module. Thirdly, integrating the KBS with both material selection database and a CAD system. Finally, developing and implementing a ii fuzzy logic approach to generate reliable estimation of cost and to handle the uncertainty in cost estimation model that cannot be addressed by traditional analytical methods. The developed system has, besides estimating the total cost of a product, the capability to: (1) select a material as well as the machining processes, their sequence and machining parameters based on a set of design and production parameters that the user provides to the system, and (2) recommend the most economic assembly technique for a product and provide design improvement suggestion, in the early stages of the design process, based on a design feasibility technique. It provides recommendations when a design cannot be manufactured with the available manufacturing resources and capabilities. In addition, a feature-by-feature cost estimation report was generated using the system to highlight the features of high manufacturing cost. The system can be applied without the need for detailed design information, so that it can be implemented at an early design stage and consequently cost redesign, and longer lead-time can be avoided. One of the tangible advantages of this system is that it warns users of features that are costly and difficult to manufacture. In addition, the system is developed in such a way that, users can modify the product design at any stage of the design processes. This research dealt with cost modelling of both machined components and injection moulded components. The developed cost effective design environment was evaluated on real products, including a scientific calculator, a telephone handset, and two machined components. Conclusions drawn from the system indicated that the developed prototype system could help companies reducing product cost and lead time by estimating the total product cost throughout the entire product development cycle including assembly cost. Case studies demonstrated that designing a product using the developed system is more cost effective than using traditional systems. The cost estimated for a number of products used in the case studies was almost 10 to 15% less than cost estimated by the traditional system since the latter does not take into consideration process optimisation, design alternatives, nor design for assembly issue

Redesign optimization for manufacturing using additive layer techniques

Improvements in additive manufacturing technologies have the potential to greatly provide value to designers that could also contribute towards improving the sustainability levels of products as well as the production of lightweight products. With these improvements, it is possible to eliminate the design restrictions previously faced by manufacturers. This study examines the principles of additive manufacturing, design guidelines, capabilities of the manufacturing processes and structural optimisation using topology optimisation. Furthermore, a redesign methodology is proposed and illustrated through a redesign case study of an existing bracket. The optimal design is selected using multi-criteria decision analysis method. The challenges for using additive manufacturing technologies are discussed

Tooling and Infusion Design Strategies to Reduce Trade-Offs in Forming and Infusion Quality of Multi-Textile CFRPs

Achieving right-first-time-manufacture (RFTM) of co-infused textile assemblies is challenging, without improving the accessibility to design knowledge of trade-offs between different tooling and infusion strategies. As demonstrated in previous work, the choice between a flexible or rigid mould material can result in trade-offs between dimensional accuracy and geometrical precision. Similarly, the choice of an infusion strategy can result in trade-offs in infusion quality and time. Building on past work, an investigation into forming variability across the length of six co-infused multi-textile components, with three different tooling inserts and two infusions set-ups, was conducted. To quantitatively assess variation, a method adapting principles of statistical process control was employed to analyse the yarn crimp measured from high-resolution cross-sectional scans of the components. The results were compared to a geometrical and dimensional analysis of the manufactured parts presented in a previous work. The analysis represents a method for capturing forming differences in textile preforms, which can be used to inform designs for the manufacture of textile CFRPs. The results were used to improve a hybrid rigid-flexible tooling design for an infused multi-textile component

Continuous improvement of a machining process by designing a new jig

This thesis report gives an insight on how an often overlooked, jig and fixture used as a manufacturing aid to produce a product and essential for delivering products reliably and repeatedly with high quality. This continuous improvement project of an exciting machining process of winding cones used overhead garage doors. The improvement was a necessity with a forecast for 2019 estimating the need for 43% faster production cycle (takt time) compared to the previous year. Hence, the main objective was to reduce the machining time required per part by designing a modular jig system, ideally with 12 parts per cycle. To make the work in an organized structure the project was dived into four phases namely: research, design, machining and implementation. The research phase included in the study of the old jig in use, analysing the process and sketching the basic requirements. The design phase was based on the methodology of Design for Six Sigma methodology for the fixture. Different kind of jig components was designed and assembled using SOLIDWORKS CAD model. The critical review of design iteration was analysed using SWO analysis (short version of the standard SWOT analysis) for design. The machining of most components of the jig was done in-house with tacit knowledge of the machinist instead of using CAM software’s making it first of its kind project in developing knowledge management in the company for future jig requirements. The critical outcomes of the project were harvested from the implementation phase. The newly machined modular jig system proved to have increased the number of parts machined per day by 32% with expected savings of more than €6000 per annum. The added benefit of a modular jig system was that one base (skeleton of the jig) could be used in machining different products. Also, future projects now have the intellectual and physical resources of making jigs and fixtures in-house. This drastically reduces the lead times for new parts, which is crucial for a small-medium enterprise stay competitive.Este relatório dá uma visão sobre como um acessório usado pode auxiliar na produção de forma a produzir um produto e os elementos essenciais para a sua entrega de forma confiável e repetida com alta qualidade. Este é um projeto de melhoria contínua de um processo de maquinagem de cones de enrolamento, usados em portas de garagem suspensas. A melhoria surjiu de uma necessidade com a previsão para 2019, estimando a necessidade de um ciclo de produção 43% mais rápido (takt time) em comparação com o ano anterior. Assim, o objetivo principal passava por reduzir o tempo de maquinagem necessário por peça, projetando um sistema de gabarit modular, idealmente com 12 partes por ciclo. Para realizar o trabalho numa estrutura organizada, o projeto foi dividido em quatro fases: pesquisa, projeto, maquinagem e implementação. As fases de pesquisa foram incluídas no estudo do antigo gabarit em uso, analisando o processo e esboçando os requisitos básicos. A fase de projeto foi baseada na metodologia de Design for Six Sigma para um dispositivo. Foram projetados e montados diferentes tipos de componentes de gabarit usando o modelo SOLIDWORKS CAD. A revisão crítica da iteração do projeto foi analisada usando a análise SWO (versão reduzida da análise SWOT convencional) para projeto. A maquinagem da maioria dos componentes do gabarit foi feita internamente com conhecimento tácito do responsável técnico, recorrendo ao software CAM, tornando-o o primeiro de seu tipo no desenvolvimento da gestão do conhecimento na empresa para futuros requisitos de gabarit. Os principais resultados e conclusões dos projetos foram descritos na fase de implementação. O sistema de gabarit modular recém-maquinado provou ter aumentado o número de peças maquinadas por hora em 32%, com economias comprovadas de mais de € 6.000 por ano. O benefício adicional de um sistema de gabarit modular consiste de criar uma base (esqueleto do gabarit) usada na maquinagem de diferentes produtos, e projetos futuros, permitindo à empresa deter os recursos intelectuais e físicos de criar gabarits e acessórios internos. Assim, foi reduzido drasticamente o tempo de espera para novas peças, o que é crucial para uma pequena média empresa permanecer competitiva