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Research and Development Unit for Mechanical and Industrial Engineering


Projects > Defects Detection in Microfabrication with Bacterial Cells (MicroBac)
Defects Detection in Microfabrication with Bacterial Cells (MicroBac)

This project aims to develop and apply a new Non-Destructive Testing (NDT) method for microfabrication components based on bacterial film cells. It is envisaged to use the dimension, mobility, fluorescence and adherence of bacterial cells to identify defects in micro manufactured components. In fact bacterial cells adhere to surfaces irregularities as roughness, cracks, voids, cleavages and low pressure points. For this four strategies will be considered involving: 1 - Color, fluorescent and exothermal bacteria 2 - Bacteria with electrical properties 3 - Bacteria with magnetic properties 4 - Antibacterial agent as developer Each of these strategies comprises a set of stages such as: 1) identification and localization of inspection zone; 2) surface cleaning; 3) application of bacterial cells suspension; 4) penetration and cell adherence; 5) excess removal; 6) developing; 7) inspection; 8) final cleaning and sterilization. In stage 4 a set of different procedures is considered depending on the selected bacterial cells properties.




Funding organization: Science and Technology Foundation (PT)


Main achievements: A new NDT technique based on bacterial cell films for micro surface defects identification was developed. A suspension of bacterial cells proved to be adequate to reveal very small size surface defects in different materials. An experimental validation of the basic assumptions of the methodology was performed. It was seen that bacteria cells penetrate and adhere preferentially to defects, remaining inside the defect after mechanically removing the excess of bacteria. A detection limit was estimated for each material in 1-2 micron range. The depth to width ration was seen to be of major importance thus dye penetrant cannot compete with bacteria films but are complementary.

Start date:02 Jan 2012
End date:02 Jan 2015
Main researcher:Telmo dos Santos, Assistant Professor
Research group:Manufacturing Technologies and Automation
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Projeto Estratégico PEst-OE/EME/UI0667/2014