大直径交点孔螺旋铣精加工技术研究

Research on Helical Milling Technology of Large Diameter Intersection Holes

在飞机装配过程中经常需要进行大直径交点孔的精加工。交点孔的直径大、材料工艺性差导致精加工时切削力大、振动大,不同耳片间初孔不同心导致刀具受力不均易引偏,装配制孔作业环境复杂导致大型加工设备使用困难。目前主要加工方法为使用自动进给钻进行多次的扩孔和铰孔,制孔效率低、使用刀具种类多、成本高。螺旋铣孔是航空航天领域出现的制孔新方法,在难加工材料大直径孔加工中,与传统的钻、扩、铰工艺相比具有更好的制孔质量和效率,尤其在扩孔加工时,螺旋铣孔刀具不会被初孔引偏,优势明显。基于便携式螺旋铣孔装备,开展了大直径交点孔扩孔精加工试验,检测了加工孔的尺寸精度和孔壁表面质量,并进一步研究了孔壁表面完整性,结果表明,孔径尺寸精度优于±0.05 mm,孔壁粗糙度优于R_(a)1.6μm,验证了采用螺旋铣孔方法实现飞机装配交点孔精加工的可行性。

In the process of aircraft assembly,it is often necessary to finish the large diameter intersection hole.The large diameter of the intersection hole and the poor manufacturability of the material lead to large cutting force and large vibration during processing,and the initial holes between different lugs is not concentric,which leads to uneven force of the tool and easy deviation,and the complex assembly and hole making operation environment leads to the difficulty of using large processing equipment.At present,the main processing method is to use automatic feed drill for chambering and reaming.The hole making efficiency is low,and there are many kinds of tools used and the cost is high.Helical milling is a new hole making method in the aerospace field.In the processing of large diameter holes in difficult to machine materials,it has better hole making quality and efficiency than the traditional drilling,chambering and reaming processes.Especially in the chambering process,the helical milling tool will not be biased by the initial hole,with obvious advantages.Based on the portable helical milling equipment,the reaming and finishing test of large-diameter intersection holes was carried out,the dimensional accuracy of the machined holes and the surface quality of the hole wall are tested,and the integrity of the hole wall surface is further studied.The results show that the accuracy of hole size is better than±0.05 mm,and the hole wall roughness is better than R_(a)1.6μm,which verify the feasibility of using the helical milling method to achieve the precision machining of intersection holes for aircraft assembly.