Special Milling Machine CNC System For Car Keys

It is well-known that each car has its special key. However, notorious is the problem that car keys are universal, which is often found in newspaper news. Researches have discovered that the main cause of the problem is the low dimensional accuracy of the car keys, especially the lower inclined surface roughness, which reduces the recombination rate of the keys.This paper presents the overall design of the key milling machine CNC system based on the analysis of the causes that affect the machining accuracy according to the processing characteristics and the basic structure of the existing milling machine. (1) The hardware of the system: specialized computer is used with ARM9-based processor host that is multi-CPU controlling the X, Y, Z axis to feed real-time synchronization so as to realize hardware interpolation.(2) The software of the system: Special NC system of user software for milling machine is developed by selecting G code as its background support and applying Embedded Visual C++ to the WINCE5.0 operating system platforms. (3) The establishment of the mathematical model of the key tooth coding and the automatic coding of key tooth with the use of backtracking algorithm and selection function. (4) The preparation of NC program through classifying the different types of keys with the group technology.Experiments have showed that keys processed by the system have significantly-improved surface roughness and dimensional accuracy with stable operation and strong anti-interference.