Develop a bladder assisted RTM tool to manufacture seat posts with glass fiber and CNT-epoxy resin

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In this project, a bladder-assisted Resin Transfer Moulding tool to manufacture glass fiber bicycle seat posts with epoxy resin charged with carbon nanotubes (CNTs) is developed through the application of a "Systematic Approach to the design of Technical Systems and Products" guideline to provide an optimum solution for the filtering of CNTs during the injection process. The impregnation process is identified as the key characteristic on the tool development. The bladder assisted-RTM process parameters and manufacturing seat post features are evaluated to define the requirements that fulfill the main task, a homogeneous distribution of CNTs through the fiber glass reinforcement. According to the requirements, the task is divided in function and subfunctions to be fulfilled by the tool development. Interfaces between sub-functions are established in order to re-organize them into realizable modules. This module structure showed a preliminary indication for the breakdown of solution into realizable groups or elements, and together with their interfaces facilitated an efficient distribution of design effort. Tool constituent elements are designated and multiple principle solutions are provided for every element. Once selected the most adequate individual solution, a tool concept design is presented and begins the layouts development for the individual modules (Housing shape, Cooling system, Front cover with compressed air connection, Rear cover with resin injection port, Rear cover with airextraction exhaust, closing device, centering of the tool components, gaskets for the tightness and bladder as core design). Detailed drawings and calculations are performed to confirm that the design solution meets the requirements of the general task. The impregnation concept process using the inflatable bladder designed is explained, showing the collapsible channel operation in order to infuse correctly the braided glass fiber reinforcement using the high viscosity resin due the CNTs addition. At the end of the project, manufacturing tests are done to select the inflatable bladder with three different elastic materials using a reduced tool. After bladder material selection, a real scale tool is designed and constructed to manufacture a simple inflatable bladder, as first approach to the final bladder manufacturing. For the bladder manufacturing, a real scale bladder dipping mandrel is manufactured using water soluble fugitive core material.
Carbon nanotubes (CNTs), Resin transfer molding tool, Composite materials
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