Research On Numerical Control Tranformation Of Pen Tip Lathe

The question of pen ball-point issued by Premier Li Keqiang had promoted the development of pen-making industry in China.In order to adapt to the development of the pen-making industry and improve the core competitiveness,a large number of small and medium-sized pen-making enterprises,numerical-control transformation on lathe has become a trend.In this paper,based on the actual production needs,the goal of numerical-control transformation had been achieved with the increasing of stability of accuracy through the transforming of mechanical and the design of electrical,electronic cam curve,software for control system,.First,in the mechanical part,by analyzing the transmission system and the machining process of the pen lathe machining machine,it was found that the main reason of the decline of stability of accuracy was inconstant instantaneous transmission ratio of chain transmission mechanism and the defect of the feed cam in the actual production.On this basis,the feed processing movement program which was implemented with "ball screw + servo motor" driven by large carriage was put forward.In addition,the selection of a reasonable ball screw and servo motor which was based on accurate calculation improved transmission stiffness,positioning accuracy and response sensitivity of the feed system.Secondly,in the part of electrical transformation,after selecting the motion controller according to the requirements,the overall structure of the electrical control circuit was designed.In order to solve the problem of tools colliding in the debugging process,the original control circuit of the lathe was improved,which made only principal axis starts,the large carriage's feed motion would begin.Then,the external components electrical schematic of terminal block and electrical control cabinet was designed.Then,in the programming and designing of electronic cam curve,the dimensionless cubic polynomial,quintic polynomial and seven-degree polynomial was respectively designed.After analyzing their dimensionless latent,quinic polynomial was selected.According to the definition of nondimensionalization,the formula of the dimensionless in follow situation was deduced.Take the subsection condition of feed cam into consideration,the dimensionless quintic polynomial electronic cam curve was segment designed of electronic cam lathe.After that,the electronic cam curves of the cam's every segment are combined into an electronic cam curve of a real cycle and then were simulated by Matlab.According to the displacement curve of the electronic cam curve,the data point table was derived,which made preparation for the design of control program.Finally,in the part of the software design of the control system,the visual software development platform was firstly introduced-Based on it,the system was configured to realize the communication between software and hardware.After that,the general frame structure of the control system software was designed,including condition monitoring and motion control module.When the software run,both of them were loop executing with a 10ms cycle.Motion control module was divided into 6 sub modules:Back-to-Zero,manual,production,information recording,output/output and parameter settings.Among them,production sub module was based on follow motion model.As the core control system software,it was the basis of pen tip lathe working according to the predetermined trajectory.After the design of the control system software,the numerical control improvement of the lathe has realized.The pen tip lathe had been put into trial production for 6 months after the improvement above.The test of its products showed that the rims was smooth,the rims'thickness and depth was uniform,the overall length of points and diameter of pen' holes were in high stability,which showed that the lathe's stability of accuracy was effectively improved.