Papers by Michele Di Foggia
Quantitative InfraRed Thermography Journal
AIP Conference Proceedings, 1996
ABSTRACT
Advances in Science and Technology, Jan 5, 2011
Procedia CIRP, 2015
The reduction of the scraps is fundamental to achieve goals of competitiveness. Some key paramete... more The reduction of the scraps is fundamental to achieve goals of competitiveness. Some key parameters have a direct influence on any process and they need to be predicted and taken under control. This paper present an approach ) is to develop a robust monitoring solution of the ceramic shell manufacture that will be able to determine a significant reduction of the inclusion scraps (due the ceramic shell) of the superalloy components. The control will be obtained by processing data coming both from sensors and laboratory measured values. The sensor data come from the new equipment of the Europea Microfusioni Aerospaziali SpA (EMA) and have been tested and used to develop the EMA demonstrator within the EC FP7 Project on "Intelligent Fault Correction and self-Optimizing Manufacturing systems -IFaCOM". The sensor data will merge the data measured in the EMA laboratories and both the values will concur to create the sensor fusion pattern vector, which will be used to feed an automatic system for the prediction of the process parameters. The automatic system will be implemented using cognitive paradigms, in particular Artificial Neural Networks, that will combine both data. The first testing phase will predict the number of blades with inclusions. It will provide a first idea of the correlation between the input, as a matrix composed by the sensor fusion pattern vectors per each worked blade, and the outputs, as a vector of rejected blades on the total. Moreover, this work will be the basis to implement a predictive system to estimate which is the reference range of each working parameter.
Procedia CIRP, 2013
The investment casting process and its key parameters are described in order to give a quite deta... more The investment casting process and its key parameters are described in order to give a quite detailed knowledge of the main indicators of this production method, for its nature prone to have high costs of rework or scrap. Initially, a schematic flow of the main processes is provided; afterwards the main processes are discussed in more detailed manner with their manufacturing methods and product specifications. These concepts are indispensable to introduce the discussion on the critical parameters for investment casting process and some proposal to implement a few new methods for quality assurance of the processes and products. Finally a description of the economic impact of the critical manufacturing operations related to some specific case studies and possible goals have been identified.
Ceramics International, 2010
Powders obtained by milling ceramics shells, already used as investment material in casting proce... more Powders obtained by milling ceramics shells, already used as investment material in casting processes, were sintered to investigate their possible re-use in the production of ceramic refractories. The sintering behaviour of these powders, consisting essentially of silica and mullite, were analysed both in a heating run by conventional contact dilatometry and in an isothermal process via optical dilatometry. The mechanical properties of sintered composites formed with a matrix of fine powders and an inert coarse phase of the same material are evaluated and discussed in view of possible use in the production of refractory tiles. #
Applied Physics A, 2008
A serious problem in the production of gas turbine blades is the detection of residual ceramic co... more A serious problem in the production of gas turbine blades is the detection of residual ceramic cores inside the cooling passages; in fact, the presence of even small ceramic pieces affects turbine performance and may cause difficulties in successive manufacturing. Therefore, it is important to have a nondestructive technique that must be capable of detecting tiny ceramic fragments in a fast and easy way. In this perspective, the suitability of infrared thermography was investigated within cooperation between the University of Naples and the Europea Microfusioni Aerospaziali S.p.A. (EMA). Several blades of three different types were inspected revealing that in many cases infrared thermography can discover small ceramic fragments which were missed by X-ray inspection. In addition, infrared thermography allows gaining of information about other types of anomalies (e.g., surface defects) during the same testing step (by eventually changing the test parameters) and then saving time and money. The obtained results look promising in view of introducing infrared thermography among industrial instrumentation as an alternative to, or integrated with, the most currently utilized non-destructive techniques.
Advances in Science and Technology, 2010
ABSTRACT Sintered fused silica is often used for making sacrificial cores in investment castings ... more ABSTRACT Sintered fused silica is often used for making sacrificial cores in investment castings of Ni superalloys. Their usage is fundamental in the manufacture of precise superalloy gas turbine components with complex internal cooling passages. In this study SiO2/ZrSiO4/TiO2 cores were prepared from fused silica powders with different grain size and zircon and TiO2 content by slip casting method. Green samples were sintered at 1230°C at various soaking time: from 0,5 to 10 hours. Thermomechanical and microstructural properties of optimized silica obtained by add of 1,5%wt of TiO2 to SiO2/ZrSiO4 composition have been investigated by three point bending tests, XRD and Hg porosimetric analysis. The influence of cristobalite content on thermal stability at high temperature was studied by an optical dilatometer. At temperature below 1200°C TiO2 appears to act as a phase transformation inhibitor reducing the transformation rate of fused silica to cristobalite at high temperatures. At higher temperature it speeds up the formation of cristobalite. A comparison with commercial silica cores made by injection moulding has been performed. A prototype core was obtained and an investment casting was performed on that.
Advances in Science and Technology, 2010
Journal of Inorganic Biochemistry, 2014
Copper and zinc ions Raman spectroscopy Infrared spectroscopy Dynamic light scattering Molecular ... more Copper and zinc ions Raman spectroscopy Infrared spectroscopy Dynamic light scattering Molecular basis of the role played by Cu 2+ and Zn 2+ ions during the thermal aggregation processes of betalactoglobulin (BLG) was studied by using a joint application of different techniques. In particular, Raman spectroscopy was very useful in identifying the different effects caused by the two metals at molecular level (i.e. changes in His protonation state, disulfides bridge conformation, and micro-environment of aromatic residues), evidencing the primary importance of the protein charge distribution during the aggregation process. Both metal ions are able to act on this factor and favor the protein aggregation, but Zn 2+ is able to alter the natural conformational state of BLG, causing a slight unfolding, whereas Cu 2+ ions play a role only during the thermal treatment. Thus, Zn 2+ ions favor the formation of bigger aggregates and branched fibril-like structures, whereas for Cu 2+ ions a greater number of cross-beta structures during thermal incubation and finally, fibrillar structures. The aggregation process occurs in two phases, as suggested by the measurements on the time evolution of the BLG aggregates: the first one is characterized by a partial unfolding of the protein and aggregate growth, forming oligomers and protofibrils, whereas the second one is characterized by further supramolecular assembly, leading to the formation of fibrils.
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Papers by Michele Di Foggia