Research On Positional Accuracy Method Of Shaft Parts Based On Secondary Clamping

In order to accomplish the turning,many kinds of shaft parts need secondary clamping in the production and manufacturing process.That means the parts need to be machined by clamping twice.The typical problem of secondary clamping is how to control the coaxial error at both ends of the workpiece.In the process of operation,it is how to control the parts when they are located about fine machining benchmark in the secondary clamping.There are many mature methods of controlling position,such as direct alignment,scribing alignment,fixture alignment.But there are some shortcomings in above methods.Direct alignment and scribing alignment are time-consuming and laborious.Their precision is not easy to control.Fixture alignment has high precision but it costs a lot.To sum up,this paper studies the method of controlling the positional precision in shaft parts secondary clamping by using the open sleeve.It is easy to operate,highly controllable and low cost.This paper analyzes the reason why the coaxial error is produced in shaft parts secondary clamping.It is clear that the error is caused by clamping.That is to say,the two shafts are not made in the same process but divided into two clamping,which leads to different benchmark and error.The paper analyzes how to control the positional precision of shaft parts by open sleeve.It is through the experiments to verify the influence on the positional precision of the parts.According to the experimental data,the material,the wall thickness and the structure are summarized.This paper analyzes the important links including fine machining inner hole and requirements in secondary clamping.The optimal method of controlling positional precision is summarized by using open sleeve.Verification by case study,the case is a sample of the “turning” competition in Chengdu secondary vocational school students’ skill competition.The specific content is to complete a set of parts(5)machining.According to the different structures and materials,students choose the open sleeves of different sizes and structures to analyze and control the coaxiality of these five parts.Through practical application and data detection,the effectiveness of controlling coaxiality method is verified by the open sleeve.