Study On The Inner Surface Finishing Of Slightness Metal Tube By Ceramic Abrasive Flow

With the rapid development of science and advanced manufacturing technology, surface finishing technology is of greater importance in ensuring the miniaturization, lightweight and reliability of the mechanical precision machining. Surface quality directly affects the working life, operational performance and appearance quality of the mechanical parts. As to plane structures, grinding process can be adopted on surface finishing processing. However, the inner surface of slim precision pipe fittings, especially capillary pieces, which are applied in aviation, aerospace, medical treatment, artificial intelligence and other technology fields, is difficult to be finish machined, constrained by pipe diameter, working conditions, geometric shape complexity, etc. According to using intentions, grinding methods applied on the inner surface of tubes generally fall into four types, honing method, electrolytic grinding method,magnetic force grinding method and chemical grinding method. But the working range of honing method, electrolytic grinding method is limited by the length-diameter ratio of the slender tube, Magnetic force grinding method and chemical grinding method causes residual particles easily, so they are not suitable for high precision machining.In this paper, a grinding process where finishing is achieved by high speed ceramic abrasive flow is put forward and verified by experiments, which can go deep into the slender tube or complex cavity. In this process, micro powder grinding fluid is selected as grinding medium. The grinding effect can be achieved when the medium runs through the inner surface of a slender tube at a high speed. The effect on the inner surface of slender tubes was studied by using different grinding process and grinding grains respectively. For grinding process, grinding hours, position and speed of grinding fluid, three factors were investigated.And for grinding grains, the mean grain size, concentration of grinding fluid and the type of abrasive, three factors were also researched. The results showed that, extending grinding hours, faster flow speed, self-sharpening property of abrasive, proper grain size and concentration could cause greater machining effect. There was no obvious difference at different grinding positions. The initial conditions of inner surface and different pipe work hardening ability had certain influence to finishing. Grinding model and Semi-empirical simulation formula were build which could offer grinding mechanism from microsystem level.By stereoscopic microscope observation, the roughness of the inner surface of the slender tube has been improved greatly,and the racked rib and concave defects on the inner side of the drawing tube have been repaired effectively. Effective inner surface finishing of tubes that made from H62 brass alloy, 6061 aluminum alloy and TA16 titanium alloy can be achieved by using self-designed grinding device. After grinding,the wear rate per unit length reached 0.11%, and the wall thinning rate reached 0.05%.