The Research On Speed Control System Of PTFE Extruder

PTFE(polytetrafluoroethylene) is an excellent resin with capability ofheat-resistant, corrosion-resistant, great insulation and physical strength. The wire orcable made by PTFE has been used widely in the field of metallurgy, chemicalengineering, medical treatment, vehicle, communication etc. especially in the field ofaviation and military equipment.There are big disparities between local and abroad in capacity of PTFEextruding machine, also in machine's control accuracy. The latest PTFE extrudingmachine from America or Europe can make long and accurate PTFE insulation wire,which use hydraulic power and feedback control technique. But it can't be done inChina, we can only produce short and normal precision PTFE insulation wire by ourtradition machine. So we did the works to improve PTFE extruding machine byhydraulic power and feedback control technique. My job was designing the speedcontrol system of capstan and piston that is a very important part in the PTFE pasteextrude machine. In the thesis, I calculate the speed control system's transferfunction and draw its graph by MATLAB. I estimate the system's stability by BodeDiagram, which come from the system's open transfer function;estimate thesystem's transient response character meet the design request by unit-step response,unit-impulse response and unit-ramp response, which come from the system's closedtransfer function. I rectify piston speed control system by PID controller, that makethe speed control system more stable.After the closed speed control system of capstan and piston designed, I make anautomatic speed control system of capstan and piston by industry control computer.The automatic speed control system use A/D circuit to get the feedback simulationsignal and give the data signal to computer. On the other hand, the automatic speedcontrol system use D/A circuit to get the computer's data signal and give thesimulation signal to the comparing control circuit. The program of speed controlsystem and the machine's adjusting would be introduced in the end of thesis.The new PTFE paste extrude machine has produced some long and accuratePTFE insulation wire successful. All these wire meet the produce standard. It meansthe design of speed control system is successful.