INVESTIGADORES
FRONTINI patricia Maria
congresos y reuniones científicas
Título:
Mechanical testing of micro moulded plastic parts by nanoidentation
Autor/es:
TATIANA ZHILTSOVA; VICTOR NETO; OLIVEIRA, M.S.A; BERNARDO DAGA; PATRICIA FRONTINI
Reunión:
Conferencia; International Conference on Polymers and Moulds Innovations PMI2016; 2016
Resumen:
Weld lines are unavoidable where two flow fronts come together. They may result in purely cosmetic imperfections, but also may represent part failure if placed in an area on the plastic highly subjected to stress during service. Qualitative assessment of these structural and cosmetics defects is normally accomplished by conventional mechanical characterization, destructive by nature, such as tensile testing or dynamic mechanical analysis (DMA). These techniques, however, have a limited span of application when considering the test of micro molded parts due to their reduced dimensions, and requirements to meet standard sample size criteria. Nano indentation offers the possibility for quick quasi-non-destructive in-situ testing, allowing to monitor the changes that occur in the surface layer of a plastic micro parts and hence derive relationships between the process variables and product characteristics. In this study, a methodology for the assessment of the superficial properties: hardness ?H? and reduce modulus ?Er? of micro-molded parts was developed. The micro parts, molded from POM with two different sets of processing conditions were tested throughout the entire length and in the vicinity of the welding line. The observed hardness ?H? and reduce modulus ?Er?, in both cases, suggest that there is a steady increase in both values along the weld line from the adjoining flow front point at the inner side of the micro part towards the outer edge. In addition, ?H? and ?Er? were found out to vary consistently with the alterations induced on the processing conditions