In micro-injection molding, polymer/mold interface adhesion may cause severe deformation or damage of micro features on the molded products. To reduce the interface adhesion and improve the molding quality of polymer microfluidic chip, Ni-P-PTFE (polytetrafluoroethylene) ternary composite was adopted to electroform mold insert with self-lubricating properties. The influence of phosphorous acid concentration on the composition and performance of Ni-P-PTFE composites was systematically investigated. Our results demonstrated that the content of P and PTFE particles in the composites raised with an increase in phosphorous acid concentration. Elevated phosphorous acid concentration adversely affected the current efficiency and slowed down the deposition rate, allowing sufficient contact time for PTFE to transfer and adsorb onto the electrode surface. The hardness of the deposited nickel increased from 310 HV to 510 HV in the Ni-P-PTFE composites. Furthermore, the Ni-P-PTFE composites demonstrated excellent self-lubricating properties, showcasing friction coefficients of 0.15 and 0.25 during the initial and steady stages, respectively, representing a notable reduction of 66.7 % and 64.3 % compared to pure nickel. This study provides a novel approach to fabricate molds with self-lubricating properties, which contributes to the high-precision injection molding of polymer-based micro devices.
Lu Zhang,Di Yang,Zhigao Ma,Zijian Deng,Zhou Li,Dietmar Drummer,Bingyan Jiang
Polymeric micro features tend to deform and break under the demolding force during injection molding process, which becomes a bottleneck problem limiting its precision manufacturing. To reduce the polymer-mold interfacial adhesion, nickel-polytetrafluoroethylene (Ni-PTFE) nanocomposite molds with low surface adhesion and high wear resistance were manufactured via pulse current electroforming. The electrodeposited Ni-PTFE nanocomposite showed a good hydrophobic property and low friction coefficient (between 0.1 and 0.3) than pure nickel (0.78). Compared with direct current, pulse current electrodeposition was beneficial to reduce the crystallite size and internal stress, thus improving the wear resistance and reducing the cracking defects. The hardness of pulse current electrodeposited Ni-PTFE reached 442.3 HV, which was 51.7 % higher than that of pure nickel. Compared to nickel mold, Ni-PTFE nanocomposite mold significantly improved the dimensional accuracy of molded microfluidic chips. This study systematically investigates the Ni-PTFE nanocomposite electroforming process under both direct and pulse currents, which provides a new approach for the manufacturing of high-performance precision injection mold insert.
危险品化学品经营许可证（带存储）