Research On Dynamic Characteristic Analysis And The Control System Of Three-Coordinate Automatic Scribing Machine

A scriber is needed to mark lines on the parts that will be processed,and the processing location and outline are usually determined according to the lines that are marked.Vernier caliper,compasses,fitter disc,steel ruler,and other frequently tools are normally used when marking lines.The process of marking is complicated and accuracy is not usually achieved the requirement,but the accuracy will directly determine the quality of processing,especially when the parts are large in size,and have complicated shape,multi-surfaces because it usually results in low precision and efficiency and higher labor intensity in this situation.At the same time,with the development of manufacturing,the production efficiency of artificial scribing can not meet the increase needs of processing,and this will lead to the higher requirement in the quality and efficiency of the scribing technique.With the development of computer and numerical control technology,CNC(computer numeric control)control system has become increasingly popular in the early 20th century.The 3-Coordinate Automatic Scribing Machine was designed to replace the manual one,and this will help to improve the production efficiency and quality.At the same time it will reduce the scribing number to once or twice for one part processing.A 3-Coordinate Automatic Scribing Machine was studied and designed in this thesis,including the mechanical design and control system.The main contents are as follows:(1)The three dimensional mechanical structure design were made using three-dimensional design software Pro/Engineer according to the design principle of the main structure and precision machinery,including the design of general device selection,scribing head structure,motion mechanism design,the choice of the rotary table,Z feed mechanism and base stations.(2)The model and mode analysis of the beam of the scribing machine were made using finite element analysis software ABAQUS,the natural frequency and the analysis order number of experiment were attained and the first 8 orders and vibration of the beam were got also.According to the ABAQUS analysis,the specific mode experiment of the scribing beam was carried out under different working conditions.On the one hand,the analysis of experimental result shows the reasonability of ABAQUS analysis,and on the other hand,it was provided data basis for the setting of scribing head speed and also the influence on natural frequency of scribing head in different work conditions.The design of mechanical structure can be optimized using the dynamic characteristic,and the accuracy of the scribing will be improved also.(3)The designing scheme of the control system of the scribing machine was made according the study above,including to the hardware and software design.The PLC selection,address assignment,wiring,communications and other control system hardware design were accomplished with programmable logic controller(PLC)as the center control.The programming of control of the three coordinate scribing(reset,the knife and point,coordinates,feedback,etc.)and the touch screen interface design and PLC and touch screen serial communication signal connection were accomplished at the same time.(4)Programmable logic controller(PLC)is used for the topic main control system,with encoder,drives,stepper motor,etc.The output logic control of the three axis of the machine was improved and the control function was achieved.In order to improve the control precision,high precision rolling guide screw was adopted and the encoder,PLC and driver were used to form a double closed PID control loop,the three coordinates of the stability of the output feed was achieved in the end and the work reliability of the 3-Coordinate Automatic Scribing Machine was improved.The thesis was offered the date basis for the improving of the accuracy of 3-Coordinate Automatic Scribing Machine according to the dynamic characteristic analysis and the mechanism design.The hardware and software design of the nuclear S7-200PLC of the control system in scribing machine were introduced also in this thesis.The research of the scribing machine was very important to improve the production efficiency of the manufacturing industry in the future.