Abstract Poly (methyl methacrylate) organic glass is used in aircraft windshield application; these structures should have better fatigue and fracture resistance to yield good service life. The tendency towards achieving these properties is lost during manufacturing process. This study aims to determine the effect of grooving on PMMA Organic glass. The grooves are manufactured using two different processes namely Micro-Milling (MM) and Laser Ablation (LA). The tribological properties of laser ablated PMMA (LA-PMMA) and micro-milled PMMA (MM-PMMA) were studied using Pin-on-disc tribometer. The grooved surface roughness of both MM-PMMA and LA-PMMA samples has decreased with increase in wear time, whereas after reaching minimum roughness the coefficient of friction has increased; due to higher adhesion between polymer and sliding metal. The tensile properties of differently machined samples have not shown significant difference; whereas the fracture toughness values were higher with LA-PMMA samples. This effect indicated LA-PMMA had greater capacity to resist crack propagation compare to MM-PMMA samples. Similarly the fatigue endurance limit was found higher with LA-PMMA compared to MM-PMMA, due to better finish of LA-PMMA. Further, the microscopic analysis of laser grooved sample before and after fracture have also shown smoother surface and less conic shapes (fracture point) compare to MM-PMMA.

中文翻译：

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表面粗糙度对微铣削和激光烧蚀聚甲基丙烯酸甲酯 PMMA 有机玻璃摩擦学和机械性能的影响

摘要 聚甲基丙烯酸甲酯有机玻璃用于飞机挡风玻璃；这些结构应具有更好的抗疲劳性和抗断裂性，以产生良好的使用寿命。在制造过程中失去了实现这些特性的趋势。本研究旨在确定开槽对 PMMA 有机玻璃的影响。凹槽使用两种不同的工艺制造，即微铣削 (MM) 和激光烧蚀 (LA)。使用针盘摩擦计研究了激光烧蚀 PMMA (LA-PMMA) 和微铣削 PMMA (MM-PMMA) 的摩擦学特性。MM-PMMA 和 LA-PMMA 样品的沟槽表面粗糙度随着磨损时间的增加而降低，而在达到最小粗糙度后，摩擦系数增加；由于聚合物和滑动金属之间具有更高的附着力。不同加工样品的拉伸性能未表现出显着差异；而 LA-PMMA 样品的断裂韧性值更高。这种效应表明，与 MM-PMMA 样品相比，LA-PMMA 具有更大的抗裂纹扩展能力。类似地，由于 LA-PMMA 的光洁度更好，因此与 MM-PMMA 相比，LA-PMMA 的疲劳耐久极限更高。此外，与 MM-PMMA 相比，断裂前后激光开槽样品的显微分析也显示出更光滑的表面和更少的圆锥形状（断裂点）。类似地，由于 LA-PMMA 的光洁度更好，因此与 MM-PMMA 相比，LA-PMMA 的疲劳耐久极限更高。此外，与 MM-PMMA 相比，断裂前后激光开槽样品的显微分析也显示出更光滑的表面和更少的圆锥形状（断裂点）。类似地，由于 LA-PMMA 的光洁度更好，因此与 MM-PMMA 相比，LA-PMMA 的疲劳耐久极限更高。此外，与 MM-PMMA 相比，断裂前后激光开槽样品的显微分析也显示出更光滑的表面和更少的圆锥形状（断裂点）。