Shrinkage Characteristics and Positioning Accuracy of PMMA Microlens Arrays in Injection Molding
|Keywords:||收縮特性;陣列透鏡;光散射;高分子;射出成形;Shrinkage;PMMA;light scattering;Microlens Arrays;Injection Molding|
Plastic lens has light in weight, and can be formed into a spherical lens by injection molding. These advantages make plastic lenses suitable for mass production, and reduce the production cost. However, the shrinkage of plastic material during cooling process of injection molding is difficult to avoid. Non-uniform shrinkage can cause bad accuracy of the product, and reduce the quality of imaging. To enhance the imaging quality of plastic optical components, the study aims to reduce non-uniform shrinkage, and improve product accuracy. This research investigate the internal structure and shrinkage behavior of amorphous plastic product with different cooling rates by using light scattering and shrinkage measurement. The result would be used to improve the accuracy of injection molding products. The results show that shrinkage and light scattering signal of product with high mold temperature cooling is higher than product with low mold temperature cooling. The phenomenon is because many short distance structures are non-uniform generated in the products with low cooling rate, and cause the shrinkage of product increase. For the product with high mold temperature cooling after annealing, the light scattering signal become lower. The decrement suggests that after annealing, the distribution of short distance structures become more uniform. But the annealing also cause the secondary shrinking and increase the shrinkage of the products. This study offers effective insights on observing shrinkage characteristics and internal structure distribution.
|Appears in Collections:||Thesis|