Fabrication and measurement of micro imaging lens

• Main Author: Ong, Jiong Hong.
• Other Authors: Murukeshan Vadakke Matham
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Manufacturing::Product engineering
• Online Access: http://hdl.handle.net/10356/40066
• Institution: Nanyang Technological University

In recent years, micro devices have been prevalent in various industries and received considerable interest. In this study, the fabrication technique involved in producing the high refractive and precise micro lens is being investigated to determine the essential processing requirements. As the functionality of the lens is dependent on its design shape and material therefore these parameters are not considered for investigation. Based on the Taguchi method, a L9 orthogonal array with 9 experimental runs per set is conducted at random order so as to avoid any influence of the experiment setup. Each set of experiments is repeated three times to obtain a total of 27 runs. The S/N ratio of the results determined the optimum process conditions to be A2B1C3. A2 is the mold temperature of 190°C, B1 is the demold temperature of 40°C and C3 is the holding time of 5.5 mins. The table of ANOVA has shown that the three chosen process parameters, namely mold temperature, demold temperature and holding time do not have significant effects on the surface roughness of molded lenses during micro compression molding at a confidence level of 90% based on the indicator – variance ratio, F. Nonetheless, a confirmation experiment is conducted for completeness sake. The confirmation experiment obtained a surface roughness of 3.746μm and has shown that optimization is realized as indicated by one of the lowest surface roughness obtained in comparison to those values in the Taguchi experiments. All of the three factors under investigation have shown insignificant effect on the concerned quality characteristic – surface roughness. However, other process parameters can be explored in future studies such as molding velocity, demolding velocity, heating rate, cooling rate and shapes of the raw plastics. This report also documents the various modifications made to the existing mold press that are believed to have improved the machine reliability and performance.