Guido Tosello

Characterisation and analysis of microchannels and submicrometre surface roughness of injection moulded microfluidic systems using optical metrology

Abstract Precision injection moulding of miniaturised products with microfeatures, such as channels for microfluidic applications, poses the greatest challenges in terms of tooling technology and process optimisation. The injection moulding process window of polypropylene was validated using a metrological approach for the production of a microfluidic substrate. The dimensional accuracy of microchannels that are 48 μm wide and 110 μm deep and the quality surface topography replication (surface roughness from 30 to 360 nm) were investigated using non-contact measuring instruments, such as an optical coordinate measuring machine and a white light interferometer respectively. The effect of the dimensional scale range on the micro-/nanofeature replication was evaluated, and it was found to be the dominant parameter if compared with the effect of the other process related parameters investigated (melt and mould temperatures and injection speed).

High Accuracy and Precision Micro Injection Moulding of Thermoplastic Elastomers Micro Ring Production

The mass-replication nature of the process calls for fast monitoring of process parameters and product geometrical characteristics. In this direction, the present study addresses the possibility to develop a micro manufacturing platform for micro assembly injection moulding with real-time process/product monitoring and metrology. The study represent a new concept yet to be developed with great potential for high precision mass-manufacturing of highly functional 3D multi-material (i.e. including metal/soft polymer) micro components. The activities related to HINMICO project objectives proves the importance of using tool geometries as reference calibrated artefacts to establish effective process technology development and control. The results allow identifying the correct process windows for optimal part quality reducing product dimensional variation in the micrometer dimensional range. The proposed metrological approach enabled to quantify product dimensional variations based on process and tooling capabilities.

Chapter 6 – Micro-Injection-Molding

Publisher Summary This chapter recognizes micro-injection molding as a manufacturing process enabling the mass fabrication of polymer micro-components. Injection molding is one of the most versatile and important operations for the mass production of complex plastic parts. Injection-molded parts typically have good dimensional tolerance and require almost no finishing and assembly operations. Fundamental process parameters for the control of both the micro-product and the process are the temperature of the melt, the temperature of the mold, the injection speed, and the cavity injection pressure. Process simulation can be used for polymer micro product and process design, and can provide at the present time mostly qualitative input to the designer and the process engineer. Further, process analysis methods and optimization tools are being used in order to provide reliable validation of both process and simulations. The essential condition for the market success of micro-systems is the cost-effective production of micro-structures on a large scale.

Chapter 11 – Micro-Mechanical-Assembly

Publisher Summary This chapter provides an introduction to micromechanical assembly and proposes a classification and characterization of micro-mechanical assembly methods. Micro-mechanical assembly is defined as assembly methods on a micro-scale, where the relative position of components is retained by exchange of contact forces provided by mechanical constraints. Manual micro-assembly procedures are extremely demanding on the human operators performing them, time-consuming, costly, and frequently they give rise to quality problems in terms of uniformity. Mechanical micro-assembly methods are among the most highly relevant in micro-manufacturing. They allow the assembly of different materials, primarily non-silicon, and potentially they can incorporate possibilities for disassembly. The challenges related to micro-mechanical assembly include the almost total lack of guidelines (i.e. standards, best practice) and the need for tailor-made tools for the processes.