Research On The Influence Of Temperature And Friction On The Positioning Accuracy Of Grating Ruling Machine

As the core component of the spectrum instrument, the diffraction grating is more and more widely applied in various fields. Mechanical scribing is an important method to manufacture diffraction grating which is mainly accomplished by the grating ruling machine. As one of the most precision instrument in the field of mechanical, the grating ruling machine not only has extremely complex structure, but also has many influence factors on its accuracy. Positioning accuracy of the machine positioning system is a major factor which can affect the grating performance. This thesis mainly discussed the influence of ambient temperature and friction on the positioning accuracy and the specific jobs are as follows:(1) In order to study the influence of changes in environmental temperature on the positioning accuracy, this thesis established a model of positioning system and analyzed its thermal deformation by using the finite element method. The result shows that the positioning system deformation is proportional to the temperature variation. In order to ensure the accuracy of positioning system, the temperature should be controlled in±0.01℃during the ruling process.(2) In the process of coarse positioning, the heat of outside workbench with guide rail, ball screw pair and bearings, as well as the natural convection heat transfer coefficient of the positioning system is calculated. We studied the effects of thermal load to the positioning accuracy with the thermal-structure coupling analysis method. The result reflects that the greatest influence on the positioning accuracy is the heat produced by ball screw pair.(3) We obtained the values of the ball ring number, nominal diameter and lead in the ball screw pair by orthogonal test, and recalculate and remodel the scheme to get the optimized results. The simulation results show that the maximum deformation of inside workbench and screw has significantly reduction after optimization.The work and results of this thesis have some references and guidances on improving the positioning accuracy of grating ruling machine.