The Research And Development Of CK61125Series CNC Machine Tools

With its high efficiency and precision, CNC machine tool has nowbecome foundation equipment in modern manufacturing. A large demand ofmarine crankshaft, rod nuclear island, and drive rod of wind power is keepingincreasing due to the development of national energy and shipbuilding inrecent years. Thus, improve the development of huge lathe, especially thosedesigned for machining products with a length over10m.The aim of this thesis is to develop a new series of CNC lathe product bystudying and analyzing the mechanical structure, electrical system and CNCservo system. The control parameters are also analyzed and selectedaccording to the features of CNC system and servo control system.The major tasks of this thesis are:(1) Based on customer-oriented technical requirements, the keycomponents of their demanding are thoroughly analyzed through research.These technical points are accordingly applied to mechanical systems,electrical systems and control systems. A comparison has been made betweendifferent combinations, in order to find out the best-fit product.(2) The mechanical design starts from the analysis of features in differentmodels of motion axis. Since the working length is required for over20m,screw ball is used for X axis, and double rack pinion is used for Z axis, whichmight not only serve the long distance transmission but also avoid the rigidityproblem in the structure. Moreover, a designed calculation of mechanicalcontrol parameters, especially the system inertia, has been done during thedetailed design for motion axis.(3) During the design process for electrical system, firstly, all the developed CNC systems have been review by their features. After the review,Siemens840D CNC system is found to be the best match for customer’srequirement. The design of the overall structure of the electrical system iscombined with the mechanical information and this chosen system. And aservo motor matching is also updated according to the new design.(4) After the structure design for both mechanical system and electricalsystem, another review and study about the principles and theories of servosystem has been conducted. PID control method has been selected and used toestablish electricity loop, velocity loop and position loop in the loop cascadecontrol of the servo axis. And the parameters simulated from Matlab aresuggested to use in the real control adjustment. Improved and optimizedparameters showed satisfactory outcomes.The product is working stable after it has been delivered to the client.This machine can achieve the precision requirements of the client. A largeamount of working time has been saved when the machine is operating hugematerials. Mean while, a big trunk of useful data has been collected for thefuture manufacture of this series.