Danilo Quagliotti from DTU Mechanical Engineering defends his PhD,
"Multi Scale Micro and Nano Metrology for Advanced Precision Moulding Technologies", Tuesday 21st March at 10.00. The defence takes place in meeting room S12, Building 101, DTU Lyngby.
Supervisors are: Associate Professor Guido Tosello and Professor Hans Nørgaard Hansen, DTU Mechanical Engineering. Examiners are:
Professor Leonardo De Chiffre, DTU Mechanical Engineering, Professor Dr. Harald Bosse, Physikalisch-Technische Bundesanstalt, Germany and Dr. Alessandro Balsamo, Istituto Nazionale di Ricerca Metrologica, Italy.
A complete metrological structure was developed and implemented for micro components with micro/nano structured surfaces and micro/nano geometries, produced by advanced precision moulding technologies and spanning across several length scales.
The aim was to cope with the incessant scaling down of the critical dimensions of the micro and nano production. Uncertainty evaluation and traceability, formulation of specification intervals, assessment of the replication of moulded parts and a deep investigation on the optical instruments currently available for micro/nano dimensional and geometrical measurements were all subjects of the research conducted during the three years of the PhD project and that were collected in this final work.
The technological revolution that has deeply influenced the manufacturing industry over the past two decades opened up new possibilities for the realisation of advanced micro and nano systems but, at the same time, traditional techniques for quality assurance became not adequate any longer, as the technology progressed.
The gap between the needs of the manufacturing industry and the well-organized structure of the dimensional and geometrical metrology appeared, above all, related to the methodologies and, also, to the instrumentation used to deal with the incessant scaling down of the critical dimensions of the novel micro and nano production.
Nowadays, design methodologies and concurrent tolerance guidelines are not yet available for advanced micro manufacture. Moreover, there are no shared methodologies that deals with the uncertainty evaluation of feature of size in the sub-millimetre scale. Conversely, a large choice of measurement equipment is now available but limitations in their use and of the instruments themselves are, in many cases, not completely understood, yet.
In this context, traceability and uncertainty evaluation were dealt with the development of a comprehensive statistical methodology based on the well-known frequentist approach. A novel method was developed on purpose for the formulation of specification intervals. It allows to discriminate between the shrinkage of 1D and 2D features and cope with the influence of length scale. The surface texture replication was investigated about the amplitude and the slope and assessed by the replication fidelity, including the repeatability and reproducibility of the production process. The investigation of optical instruments encompassed an international comparison of surface texture measurements, in the sub-micrometre scale. In addition, limitations of the performance were inspected regarding the measurement noise.
The investigations and the achievements of the present work provided new knowledge and substantial progressions, which opened a variety of new research prospects, not least opportunities for a direct calibration of optical instruments.