ALD FOR PREPARING TRIBOLOGICAL COATINGS ON MICRO-INJECTION MOLD INSERTS

摘要

Plastic parts with micrometer and submicrometer features are everyday objects today. Compact discs(CDs) and digital versatile discs(DVDs) are examples of products with features in micrometer scale. One of the growing fields exploiting micro- and nanometer-scale textures in plastics is diffractive optics. Micro-injection molding (u-IM) is the most widely used tool for mass production of plastic parts with micrometer- and submicrometer-scale textures. With u-IM, large quantities of plastic parts can be produced fast and cost-effectively. Challenges in the process nevertheless-remain. As an example, structures with high-aspect ratios are still hard to replicate. In addition, micrometer-scale patterns generate high-surface areas, which increase the adhesion between the mold and plastic cast and hinder the ejection of the plastic part. The sticking gradually contaminates the mold, and the dimensions of the mold deteriorate. This is a major drawback, since in u-IM the tolerances for the dimensions of the molded part are strict. The coefficient of friction is an effective measure of the sticking of plastic to the mold.