Date of Graduation

8-2025

Document Type

Thesis

Degree Name

Master of Science in Mechanical Engineering (MSME)

Degree Level

Graduate

Department

Mechanical Engineering

Advisor/Mentor

Zou, Min

Committee Member

Millett, Paul

Second Committee Member

Meng, Xiangbo (Henry)

Keywords

Adhesion; Cast Iron; Friction; Photochemical Etching; Tribology

Abstract

The traditional honing process used to texture cylinder liners in internal combustion engines has long been recognized as suboptimal, as evidenced by the need for a break-in period before achieving peak performance. Although laser-based methods can produce micro-scale features with high precision, they are often cost-prohibitive and difficult to scale for large or complex components. This study explores photochemical machining (PCM) as a low-cost, scalable alternative for fabricating high-resolution surface textures—specifically, hexagonal grooves with corner dimples—on gray cast iron. The resulting textures exhibit uniform groove widths (~13 μm) and varied depths, demonstrating PCM’s capability to create high-resolution patterns with sub-micron precision on industrially relevant substrates. To assess the effects of surface texturing, pull-off adhesion and reciprocating friction tests were conducted under three lubrication regimes: 1 μL (starved), 10 μL (semi-starved), and flooded oil. Adhesion forces increased with oil quantity but consistently decreased with texture depth, indicating that the patterns disrupted capillary-bridge formation and reduced oil-mediated adhesion. Friction behavior was strongly dependent on sliding frequency (1–30 Hz), oil quantity, and texture geometry. At low frequencies, deeper textures often increased the coefficient of friction (COF), likely due to delayed film formation or lubricant trapping. At higher frequencies – especially under starved and semi-starved lubrication – deeper textures reduced COF, attributed to improved oil retention, greater hydrodynamic lift, and smoother transitions into hydrodynamic regimes. Under flooded conditions, textures showed limited or negative effect on friction, potentially due to flow disturbances or groove-induced drag. Statistical analysis using least squares regression and two-way ANOVA confirmed texture was the predominant factor affecting friction at low frequencies, whereas oil quantity played a more important role at higher frequencies. These findings underscore the importance of context-specific texture design and highlight PCM as a cost-effective, scalable alternative to laser-based methods for fabricating < 50 μm features on curved or engine-relevant surfaces such as piston rings and cylinder liners.

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