ABSTRACT To minimize the surface roughness and delamination problems during the end milling of natural fiber reinforced composites (NFRCs), it is essential to understand the effects of the machining parameters (spindle speed and feed rate) and the kinematics of material removal. In this study, the effects of machining parameters on the machined surface quality – surface roughness (Ra) and delamination factor (Fd), during end milling of kenaf, jute and rice husk (RH) reinforced polypropylene (PP) composites has been analyzed using a two-factor, three-level experimental plan. It has been noticed that there are significant differences in the silicon contents (kenaf: 0.57%, jute: 4.16% and RH: 22.2%) and hardness values (kenaf: 0.15, jute: 0.20 and RH:0.59 GPa) of the three natural fibers, which has influenced the resulted surface quality of the machined NFRCs. Kenaf/PP composites showed the lowest delamination damages and the best surface finish most likely due to the fiber composition and morphology of kenaf, while predictably, RH/PP composites were the most demanding to machine. With a statistical analysis on the results, it is concluded that the machined surface quality is more influenced by spindle speed with percentage contribution showing at least three times more than feed rate for machining NFRCs.

中文翻译：

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加工参数对天然纤维增强复合材料表面质量的影响

摘要 为了最大限度地减少天然纤维增强复合材料 (NFRC) 端铣过程中的表面粗糙度和分层问题，必须了解加工参数（主轴速度和进给率）和材料去除运动学的影响。在这项研究中，在红麻、黄麻和稻壳 (RH) 增强聚丙烯 (PP) 复合材料的端铣过程中，加工参数对加工表面质量的影响——表面粗糙度 (Ra) 和分层因子 (Fd) 已使用一个双因素、三个水平的实验计划。已经注意到，三种天然木材的硅含量（洋麻：0.57%，黄麻：4.16% 和 RH：22.2%）和硬度值（洋麻：0.15，黄麻：0.20 和 RH：0.59 GPa）存在显着差异。纤维，这影响了加工后的 NFRC 的表面质量。由于洋麻的纤维成分和形态，洋麻/PP 复合材料显示出最低的分层损伤和最佳表面光洁度，而可以预见的是，RH/PP 复合材料对加工的要求最高。通过对结果的统计分析，得出的结论是，加工表面质量受主轴转速的影响更大，其百分比贡献至少是加工 NFRC 的进给率的三倍。