Single step laser surface texturing for enhancing contact angle and tribological properties

• Published in: International journal of advanced manufacturing technology 2019-02, Vol.100 (5-8), p.1253-1267
• Main Authors: Singh, Abhilasha, Patel, Divyansh Singh, Ramkumar, J., Balani, Kantesh
• Format: Article
• Language: English
• Subjects: Arrays; Austenitic stainless steels; CAE) and Design; Carbon dioxide; Carbon dioxide lasers; Cellulose acetate; Coefficient of friction; Computer-Aided Engineering (CAD; Contact angle; Density; Dimpling; Electric contacts; Electric discharges; Engineering; Fiber lasers; Hydrophobicity; Industrial and Production Engineering; Kapton (trademark); Laser beam texturing; Lasers; Machining; Magnetic tape; Mechanical Engineering; Media Management; Metal surfaces; Micromachining; Mylar; Original Article; Polyethylene terephthalate; Polyimide resins; Stainless steels; Substrates; Surface energy; Texture; Titanium alloys; Titanium base alloys; Tribology; Wear
• ISSN: 0268-3768; 1433-3015
• DOI: 10.1007/s00170-018-1579-8

Surface texturing is a process of inducing specific patterns on a surface to enhance the performance of the surface in its working environment. The arrays of patterns can be either micro-scale, nano-scale, or its combination. In general, micro-texturing of a surface regulates the surface energy and contact angle (CA), which can lead to hydrophobicity and improved tribological properties to the surface. Laser surface texturing process (direct write method) is one of the best suitable processes for producing micro-patterns because of its better accuracy, repeatability, and machining rate over the advanced machining processes (electric discharge machining, electrochemical micro-machining, etc.). In the present work, an attempt has been made to produce micro-textures on polymeric as well as metallic surfaces using CO 2 laser and solid-state pulsed ytterbium fiber laser respectively. An experimental analysis is executed to understand how CA and coefficient of friction (COF) depend on substrate’s surface topography and areal density of the texture. Various polymeric and metal surfaces such as Kapton, Mylar™ (polyethylene terephthalate or PET), cellulose acetate film, titanium alloy (Ti6Al4V), and stainless steel (SS304) are laser textured by producing various micro-patterns such as array of micro-pillars of the square and triangular cross section, and micro-dimples. A novel study of the influence of areal density of textures on the coefficient of friction and wear is performed to signify the applicability of the textured surfaces. Textures of 32, 140, and 670 pillars/mm 2 areal densities are machined and tested through fretting wear test. In Ti6Al4V, texture with (30 μm pillar width) areal density 640 pillars/mm 2 leads to lowest COF and highest contact angle of 140°.