Abstracts:An integrated wearable 3-D printable microfluidic pump was developed, which uses a novel actuation process. Fused deposition manufacture 3-D printing was used as a means to accurately produce this device. This resulted in the fabrication of high precision integrated parts made from poly-lactic-acid bioplastic. By integrating an electro-magnetically actuated closed diffuser nozzle pump configuration a micro-fabricated microfluidic pump has been produced. Biofluids have been driven through the device by actuating a composite polydimethylsiloxane diaphragm actuated polymeric microstructure diaphragm membrane using electromagnetic force. This composite diaphragm was made by suspending 10μm iron particles in the polydimethylsiloxane at concentrations of 30%, 40% and 50%. It is shown that this device acts as an effective electromagnetic force actuated a pump. It is successfully demonstrated that a square wave electromagnetic signal is effective for generating a 2.2μL/min flow rate of biofluid. The integration of 3D printed devices to form a micropump is proven through practical testing which demonstrate a controllable flow rate was generated.

Abstracts:Additive Manufacturing (AM) is widely gaining popularity as an alternative manufacturing technique for complex and customised parts. AM materials are used for various medical applications in both metal and polymer options. Adenosine Triphosphate (ATP) bioluminescence technology is a rapid, user-friendly method of quantifying surface cleanliness and was used in this study to gather quantitative data on levels of contamination on AM materials at three different stage processes: post build, post cleaning and post sterilization. The surface cleanliness of eleven AM materials, three metals and eight polymers, was tested. ATP bioluminescence provided the sensitivity to evaluate different material surface characteristics, and specifically the impact of surface finishing techniques on overall cleanliness.

Abstracts:Electron beam additive manufacturing (EBAM) is a relatively new technology to produce metallic parts in a layer by layer fashion by melting and fusing the metallic powders. Ti–6Al–4V is one of the most used industrial alloys used for aerospace and biomedical application. EBAM is a rapid solidification process and the properties of the build material depend on the solidification behavior as well as the microstructure of the build material. Thus, the prediction of part microstructures during the process may be an important factor for process optimization. In this study, a phase field model is developed for microstructure evolution of Ti–6Al–4V powder in EBAM process. FORTRAN code is used to solve the phase field equations, which incorporates the temperature gradient and solidification velocity as the simulation parameters. The effect of temperature gradient and the beam scan speed on microstructure is investigated through simulation. The simulation results are compared with the analytical model and experimental findings by measuring the spacing evolution under the solidification condition

Abstracts:Polymers and reinforced plastics are employed in various load-bearing applications, from household objects to aerospace products. These materials are light, strong, and relatively cheap but can be difficult to form into complex geometries. However, the development of additive manufacturing processes has made it easier to manufacture reinforced plastics in complex shapes. The aim of this work was to study the internal features and mechanical properties of carbon fibre-reinforced polyamide (CF/PA12) fabricated with the additive manufacturing technique of selective laser sintering. The test specimens were studied using computed tomography to analyse the internal geometry, and the material proved to be highly porous. Moreover, the test specimens revealed an internal layered structure, which was found to have a great effect on the tensile properties of the material. The results highlight that there is room for further optimisation of the manufacturing parameters for CF/PA12, because the layered structure makes it challenging to design end user parts with acceptable mechanical properties.

Abstracts:In selective laser melting (SLM) products are built by melting layers of metal powder successively. Optimal process parameters are usually obtained by scanning single vectors and subsequently determining which settings lead to a good compromise between product density and build speed. This paper proposes a model that describes the effects occurring when scanning single vectors. Energy absorption and heat conduction are modeled to determine the temperature distribution and melt pool characteristics for different laser powers, scan speeds and layer thicknesses. The model shows good agreement with experimentally obtained scan vectors and can therefore be used to predict SLM process parameters.