CFRP复合材料铣削力、温度及表层损伤分析

Measurement and Analysis of Cutting Force, Temperature and Cutting-induced Top-layer Damage in Edge Trimming of CFRPs

碳纤维增强树脂基复合材料(Carbon fiber reinforced polymer,CFRP)以其轻质、高强等优点,在航空航天高端装备上展现出巨大优势。然而,CFRP中各组成相所需的切削能量及热导率具有差异性,在切断高强纤维的同时极易造成低强的纤维/树脂界面发生开裂,而热量积聚所引起的高温又会使树脂软化加剧裂纹扩展,严重影响装备的服役性能和可靠性。阐明切削力和切削热对加工损伤的影响机制是实现CFRP高质高效加工的关键。基于数字图像处理技术,建立CFRP铣削加工表层损伤面积评价方法,该方法可有效避免传统方法因只能考虑损伤的一维长度信息而无法评价加工损伤程度的问题。分析主轴转速和每齿进给对表层损伤面积、切削力以及切削温度的影响规律,并讨论切削力和切削温度对表层损伤面积因子的影响。研究表明:通过减小单次切削厚度和控制切削温度在适合区间可有效降低加工损伤。

Carbon fiber reinforced polymer(CFRP) composites have a great advantage in the fields including aeronautics and astronautics for their light weight and high strength, when compared to the more conventional materials. However, the cutting energy and the heat conductivity are serious difference between fibers and resin phases. Consequently, when cutting off the high-strength fibers, it is prone to provide problems like crack for the low-strength interface. Besides, heat accumulation may cause resin softening, which in turn deteriorates the crack growth. In some cases, the crack has a strong impact on the service performance and reliability of final parts. To solve the problems encountered in realizing the high quality and efficiency when machining of CFRP composites, the mechanism of damage formation under the combined effects of cutting force and cutting heat should be clarified first. In the current paper, a novel method to evaluate the damage extent on the top layer of CFRP composites is developed. This method can replace the conventional assessment approach of damage extent, which can only taking the maximum length of damage into account. Afterwards, the influences of cutting parameters on the damage, cutting force and cutting temperature are analyzed. The effects of cutting force and cutting temperature on the damage formation is also discussed. It suggests that reducing the single cutting thickness and controlling the cutting temperature in the reasonable range are the effective approach to improve machining quality.