Exploring Vacuum Casting Techniques for Micron and Submicron Features

A study of resolution limits in standard rapid prototyping vacuum cast molding processes and adaptation of this technique to reach submicron accuracy is proposed. Micro-fabrication technologies are used to fabricate micron and submicron high aspect-ratio patterns on the original parts. The molding of the original parts is optimized to allow replication of submicron features. In carefully exploring materials and surface treatments, cast parts are successfully replicated with submicron and high aspect ratio micron structures. These encouraging results enable the use of such processes for micro- and nano-systems applications and open the door to development and production of low cost, high resolution biochips.Mechanical Engineerin

Microembossing of ultrafine grained Al: microstructural analysis and finite element modelling

Ultra fine grained (UFG) Al-1050 processed by equal channel angular pressing (ECAP) and UFG Al-Mg-Cu-Mn processed by high pressure torsion (HPT) were embossed at both room temperature and 300 °C, with the aim of producing micro-channels. The behaviour of Al alloys during the embossing process was analysed using finite element (FE) modelling. The cold embossing of both Al alloys is characterised by a partial pattern transfer, a large embossing force, channels with oblique sidewalls and a large failure rate of the mould. The hot embossing is characterised by straight channel sidewalls, fully transferred patterns and reduced loads which decrease the failure rate of the mould. Hot embossing of UFG Al-Mg-Cu-Mn produced by HPT shows a potential of fabrication of microelectromechanical system (MEMS) components with micro channels

Polymer based tunneling sensor

A process for fabricating a polymer based circuit by the following steps. A mold of a design is formed through a lithography process. The design is transferred to a polymer substrate through a hot embossing process. A metal layer is then deposited over at least part of said design and at least one electrical lead is connected to said metal layer

Design and Simulation of an Electrostatically-Driven MEMS Micro-Mixer

Bio MEMS ( Biology Micro-electro-mechanical Systems) focus on some micro-fabricated devices including electrical and mechanical parts to study the biological system such as new polymer-based drug delivery systems for anti-cancer agents, specialized tools for minimally invasive surgery, novel cell sorting systems for high-throughput data collection, and precision measurement techniques enabled by micro-fabricated devices. Especially some micro-liquid handling devices like micro-pumps, active and passive micro-mixers that can make two or more micro-fluids mixing completely, with the chaotic advection. This kind of rapid mixing is very important in the biochemistry analysis, drug delivery and sequencing or synthesis of nucleic acids. Besides, some biological processes like cell activation, enzyme reactions and protein folding also require mixing of reactants for initiation, electrophoresis activation. Turbulence and inter-diffusion of them play crucial role in the process of mixing of different fluids. In this report, it will introduce a new kind of electromechanical active micro-mixer, which includes two inlets and one outlet under the electrostatic driven voltage. Two different fluids will enter the micro-mixer and shows different colors separately blue and red. Choosing the ANSYS for the simulation of the fluids running in the micro-mixers, we can see nearly 100% fluids that have been mixed. ANSYS is used to show the effectiveness of the micro-mixer

Development of a rapid prototyping method for hard polymer microfluidic systems tested through iterative design of a PCR chamber chip

Tese de mestrado integrado, Engenharia Biomédica e Biofísica (Engenharia Clínica e Instrumentação Médica), Universidade de Lisboa, Faculdade de Ciências, 2014One of the challenges of working with polymer microfluidics is the lack of an established prototyping method which allows for easy translation to industrial production. By combining Hot Embossing and Computer Numerically Controlled Milling a microfluidic rapid prototyping method was established for Polycarbonate and Cyclic Olefin Polymer. This method was then tested and optimized through an iterative design process of a microfluidic Polymerase-Chain Reaction chamber. The fabrication method proved to be suitable for microfluidic prototyping, allowing for rapid design changes and fabrication of good quality copies in a simple and straightforward fashion.Uma das dificuldades em trabalhar com microfluídica em polímeros é a falta da existência de um método de prototipagem que permita uma passagem simples para um ambiente de produção industrial. Neste trabalho foi desenvolvido um método de prototipagem rápida para microfluídica em Policarbonato e Cyclic Olefin Polymer utilizando uma Fresadora de Controlo Numérico Computorizado e Hot Embossing. Este método foi testado e optimizado através de um processo de design iterativo de uma câmara microfluídica de Reacção em Cadeia da Polimerase em Policarbonato. O método desenvolvido provou ser adequado para prototipagem microfluídica, permitindo alterações rápidas ao desenho e fabricação de várias cópias com boa qualidade de cada desenho

Passive alignment of micro-fluidic chips using the principle of elastic averaging

This thesis presents a novel design for a passive alignment feature for vertically stacking chips in a micro fluidic device. Each chip is the size of a standard microscopic slide (75mm—25mm) and is a highly specialized functional unit designed and fabricated to process fluidic samples. The fluidic samples in the device flows from one chip to another using inter connecting holes 500μm-100μm in diameter. Hence an alignment of better than 100μm between chips is necessary to allow for the interconnecting holes to overlap so as to provide with a path for the fluid to flow. The feature to be used for alignment consists of v-grooves and dowel pins. Five v-grooves are hot embossed to each longer side walls of the chip such that the groove runs along the thickness of the chip. The dowel pins are fixed to a base and equal the number of v-groves. An elastic fit in between the groove and the pin provide the necessary alignment. A mathematical model has been developed and is used to predict the alignment of the method. The results from the model have been further verified experimentally