At present, economical CNC machine tools are still the CNC machine tools with the largest demand and the highest sales volume in the Chinese market. The application of existing idle old machine tools, through numerical control innovation, to make it a new, versatile and economical numerical control machine tool, is an effective method to revitalize the stock capital, and it is also one of the ways to realize the initiative of low cost . The small CNC lathe we developed is just the exploration and practice of this thought.
The small CNC lathe is composed of two parts: the microcomputer numerical control system and the machine tool body. When processing the workpiece, firstly compile the numerical control sequence of the workpiece, and then check the feasible numerical control sequence key to the numerical control installation, and then the numerical control installation calculates the feed pulse sequence according to the order command disk, and then the multi-function NC board is used for pulse adjustment, after the power amplifier Or after the power of the drive power is reduced, it will cause the control signal of the drive installation, so as to grasp the rotation speed of the machine tool spindle, start and stop ball screws, the static direction, speed and displacement of the feed system, as well as the choice of tools, cool and smooth start and stop And other initiatives. Make the tool, workpiece and other auxiliary installations strictly follow the sequence, stroke and parameters of the CNC sequence rules to perform the task, so as to process the parts whose shape, size and accuracy meet the requirements.
The small CNC lathe adopts an open-loop economical control system that masters the X-axis and Z-axis to realize two-axis linkage, and can realize linear interpolation of two coordinates. It is mainly composed of a microcomputer, a stepping motor drive power supply, a stepping motor, a multi-function NC interface board, and a master circuit. The microcomputer can use any microcomputer and compatible computers above IBMPC-286, insert a CNC card in its bus slot, apply the developed CNC software package of the lathe, pass the processing order of the workpiece through the keyboard keys, and store it with the power-off protection function In order to improve the reliability of the system operation and realize the CNC machining of the workpiece.
The driving power of the stepping motor adopts pulse width adjustment circuit and sliding subdivision circuit to improve the torque of the stepping motor at high frequency, improve the rapid performance of the system, and reduce the vibration of the stepping motor at low frequency to make the operation more stable. In addition, it also has over-temperature, over-pressure, over-current and under-voltage protection functions.
In the system, a photoelectric clutch is also adopted for isolation to improve the anti-disturbance of the system.