Heat transfer in injection molding for reproduction of sub-micron-sized features

• DOI: 10.1007/s00170-007-1343-y
• Publication Date: 2008-01-30T09:38:06Z
• Authors: M. Nakao; K. Tsuchiya; T. Sadamitsu; Y. Ichikohara; T. Ohba; T. Ooi
• Keywords: Transfer molding; Molding (decorative)

Heat transfer in injection molding was quantitatively measured with micro heat-flux sensors. The 0.1–10 micron-wide micro-grooves with aspect ratios of 0.5–1.0 were etched by focus ion beam on a Ni-plated mold. During the short time just after injecting, heat-flux in the mold was maximized to 10–50 W/cm2, and heat transfer coefficient between plastic and mold was 0.27 W/(cm2K) with PMMA and 0.085 W/(cm2K) with PS. The maximum mold surface temperature just after injecting should be above the glass transition temperature of plastic, then reproducing sub-micron-wide micro-ridges.