Study Of Ultrasonic Assisted Machining Technology For The GFRP Blades Test Pieces

Nowadays, laminated components composed of composites and metallic material are widely used in the aerospace, Many scholars studied the machining technology of rivet and bolt holes for laminated components. Because of the enormous difference in the performance between the composite and metallic materials, it has been one of recognized problem to high-quality and efficiently machining in manufacturing field. Compared with the assembled machining method abroad, currently machining method still used mainly manual in the domestic, Part of enterprise are using traditional multi-step machining method as "drilling-reaming-reamed hole", the machining quality is difficult to ensure and tool wear is intense. The key technology is high-quality, efficient machining two completely different nature of the material within one process. Due to lack of digital machining equipment and the overall machining technology, Existing technology has seriously hampered the development progress and production ability of our key products.In this paper, for different specifications GFRP blades test pieces made up of composite and metal materials, theory analysis and experimental study of ultrasonic assisted machining are carried out; Based on the foundation of ultrasound-assisted helical milling experiment, variable parameter ultrasonic assisted helical milling study method was proposed; Ultrasound-assisted CNC machining device and supporting special fixture of the GFRP blades test pieces were designed. The main contents and the phased academic achievements in this study are shown in the following:(1) For defects of burrs and tearing easily produced in milling GFRP, the experimental study of ultrasonic assisted milling GFRP composite test pieces was conducted; The results show that cutting forces decreased with the increase of the spindle speed, and increased with the feed speed increasing. Compared with conventional milling, burrs and tearing was reduced, and milling surface quality has been significantly improved.(2) The trajectory of ultrasonic assisted helical milling was analyzed. Machining parameters of ultrasonic assisted helical milling was optimized by orthogonal test. The hole wall quality significantly improved, and its roughness reached Ral.27μm. Experimental research of ultrasonic assisted helical milling was carried out to drilling the short fiber filled composites. The impact of process parameters on cutting force and hole surface quality was analyzed; Machining defects during ultrasonic assisted helical milling was analyzed. (3) For the machining needs of metallic materials/composite, the method of ultrasonic assisted helical milling with variable parameters was proposed to drilling laminated composites. The results showed that, cutting force and cutting temperature were effectively reduced, and the hole wall quality was improved, which achieved a high quality and efficient machining of laminated components.(4) For the GFRP blades test parts milling and drilling, a three-axis CNC ultrasonic assisted machining equipment was designed. Mounted and positioning fixture for different type helicopter blades, device protection, vacuuming system, ultrasonic vibration system and structure integrated of ultrasonic horn-tools have been designed to solve problems of processes cumbersome, low machining inefficient and unstable machining quality. Above studies provide a reliable technical means for the enterprises.