Precise WEDM of micro-textured mould for micro-injection molding of hydrophobic polymer surface

ABSTRACT

In this paper, the hydrophobic polymer surface with regular and controllable micro-textured structures was effectively and rapidly fabricated by micro-injection molding using a novel micro-textured mold machined by wire electrical discharge machining (WEDM). The phase constitutions of smooth and micro-textured mold surfaces were compared along with machined surface roughness of molds. The surface topographies of micro-textured molds and micro-injection molded polymers were characterized. The machining accuracy of WEDM for micro-textured mold and the replication rate of micro-injection molding for micro-textured polymer were calculated and analyzed. The wetting behaviors of smooth and micro-textured polymer surface were investigated together with the static contact angle and contact angle evolution versus time. The experimental results show that the maximum contact angle on the micro-textured polymer surface can reach to 127.5°, which was improved by about 71.6% compared with smooth polymer surface. It is shown that the highest machining accuracy of mold and the maximum replication rate of micro-injection molding can reach to 0.153% and 99.455%, respectively.

KEYWORDS:

• Hydrophobic
• electro-discharge
• injection
• micromachining
• mold
• polymers
• surface
• texture

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant numbers 51575360 and 51805334]; the Science and Technology Planning Project of Guangdong Province [grant numbers 2016A040403043 and 2017A010102003]; the major project for industrial technology of Guangzhou City [grant number 201902010018]; the Fundamental Research Funds for the Shenzhen University [grant number 2018031]; the Youth Projects for Creative Talents of Educational Commission of Guangdong Province [grant number 2015KQNCX009]; the Opening Project of the National Engineering Search Center of Near-net-shape Forming for Metallic Materials [grant numbers 2015001 and 2017008].