# Effects of light absorber on micro stereolithography parts

Zabti, Mohamed Mohamed (2012). Effects of light absorber on micro stereolithography parts. University of Birmingham. Ph.D.

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## Abstract

This thesis reports the results of an investigation of the effects of adding Tinuvin$$\char{msam10}{0x72}$$327 to PIC-100 acrylate resin on such important parameters as cure depth, critical energy, part density, dimension accuracy and surface quality. Initially, an experimental investigation was carried out to characterise the cure depth of resin after the addition of Tinuvin$$\char{msam10}{0x72}$$327 in five different concentrations using a white light microscope. The investigation has shown that increasing Tinuvin$$\char{msam10}{0x72}$$327 concentration reduces cure depth thickness and increases critical energy; it also found that increasing Tinuvin$$\char{msam10}{0x72}$$327 concentration increased the density of the fabricated parts but significantly reduced the tensile strength. The influence of different concentrations of Tinuvin$$\char{msam10}{0x72}$$327 in PIC-100 acrylate resin on the accuracy of the fabricated parts was investigated, and it was shown that increasing the proportion of Tinuvin$$\char{msam10}{0x72}$$327 from 0.1% to 1% (w/w) caused a significant increase in dimensional . The accuracy of Jacobs’ cure depth model in predicting cure depth after the addition of Tinuvin$$\char{msam10}{0x72}$$327 was investigated by comparing measured cure depth and predicted results using Jacobs’ model. The results show that Jacobs’ model does not keep pace with the changes that occur in the PIC-100 photo polymerisation process with changes in material characteristics due to the addition of Tinuvin$$\char{msam10}{0x72}$$327. Jacobs’ cure model was adapted using two empirically derived constants to accurately predict the cure depth. Finally, a parametric optimisation process was performed using the PARETO multi objective optimisation function of Matlab 2010. For 1% Tinuvin$$\char{msam10}{0x72}$$327 concentration and an irradiation level of 750mW/dm$$^2$$, the optimum exposure time was found to be 10 seconds.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
Supervisor(s):
Supervisor(s)EmailORCID
Pham, Duc TruongUNSPECIFIEDUNSPECIFIED
Licence:
College/Faculty: Colleges (2008 onwards) > College of Engineering & Physical Sciences
School or Department: School of Engineering, Department of Mechanical Engineering
Funders: Other
Other Funders: Ministry of Higher Education and Scientific Research, Libya
Subjects: T Technology > TJ Mechanical engineering and machinery
T Technology > TS Manufactures
URI: http://etheses.bham.ac.uk/id/eprint/3646

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