Abstract
Injection molding technology can replicate precise μm-wide structures such as a 1μm-pitch grating pattern. It cannnot, however, obtain precise mm-wide forms such as a fine flatness of 0.1μm / 10×10mm or a fine straightness of 1μm / 50mm because the mold cannot control physical phenomena of a plastic material in a cavity during processing cycle. Generally, injection molds do not have enough sensors / actuators to measure / coontrol the solidification process in each zone of the cavity. For example, plastic near an edge of the box replication solidifies quickly, causing a large bent at the center of the box. Moreover, the plastic is not uniform, creating a different characteristic during each cycle. We introduce a "smart palm-size injection mold", which has micro-sensors for pressure / temperature / displacement in the cavity zones and has piezo elements and heaters for controlling these parameters for each cycle. The target replica products are small, for example, an optical f-θ lens, a plastic-bonded hard magnet, a micro multi-pins connector and so on.
