Rajhi A., Almalki A., Coulter J.P.
Lehigh University, US
Keywords: microinjection molding, micropillars stretching, MoldFlow, processing parameters, replication quotient
This paper investigates the influence of selected processing parameters of microinjection molding on the replication fidelity of micro molded features. Parameters were altered in order to find to what extent the microfeatures can be stretched while maintaining the required geometry with high fidelity. A silicon-based mold insert (Si) with circular cavities of 5 μm diameter and 3 μm edge-to-edge spacing over dense areas was replicated with an aspect ratio (AR) of 4. It was fabricated using photolithography followed by deep reactive ion etching (DRIE) to create the required depth. Prior to molding trails, numerical simulations were performed using Moldflow Insight to obtain optimal processing parameters which then used as a baseline to mold micro featured samples. Packing pressure, cooling time, and injection velocity were varied during molding and replication quotient was used for comparison. It was found that excellent replication quotient occurred at high packing pressure with lower tip stretching. Also, at lower cooling time bulged features occurred while higher cooling time enhanced replication quotient. Sever tip stretching occurred at cooling time of 100 seconds. Lastly, higher velocities resulted in high replication quotient.
Journal: TechConnect Briefs
Volume: TechConnect Briefs 2021
Published: October 18, 2021
Pages: 8 - 12
Industry sector: Advanced Materials & Manufacturing
Topics: 3D Printing, Advanced Manufacturing
ISBN: 978-0-578-99550-2