Closed-die compression molding for optical lenses

The quality of a plastic optical lens can be evaluated by its performance, except the surface roughness can affect the transparency of the lens, other internal defects, residual stress and reproducibility, can be determined by the hot embossing pressure, time and temperature. Compare to the plastic planking and pellets materials, the cost of plastic powder materials is cheaper and more beneficial for mass production, but its hot embossing variables are more complex than the other materials. The plastic optical concave lens cannot be injection molding because of its geometry structure, the weld line on the product will lead the lens fail to use; hence, hot embossing manufacturing technology is an appropriate method for the plastic optical double concave lens manufacture. To improve the quality of manufacture of the plastics optical concave lens and reduced the cost, this research will use PMMA powders, laboratory computer sever control electro-thermal hot embossing machine, laboratory designed mold and parameters, to manufacture plastics optical lens by hot embossing. Then analyze the surface outline and overall reproducibility of plastics optical concave lens by Taguchi quality experimentation; finally, generalize the appropriate hot embossing parameters for the PMMA powders.