CNC machines consist of programs, input/output devices, CNC units, servo systems, position feedback systems, and machine bodies.
(1) CNC unit
CNC unit is the core of CNC machine tools, CNC unit consists of information input, processing and output of three parts.
CNC unit accepts digital information, after the control software and logic circuit of the CNC device for decoding, interpolation, logic processing, will be a variety of instruction information output to the servo system, the servo system to drive the executive parts for the feed movement.
Others are the main moving parts of the variable speed, reversing and start-stop signal; selection and exchange of tools tool command signal, cooling, lubrication start-stop, workpiece and machine parts loosening, clamping, indexing table rotation and other auxiliary command signal.
(2) Servo system
By the driver, drive motor, and with the machine tool on the implementation of the components and mechanical drive components of the CNC machine tool feed system. Its role is to convert the pulse signal from the CNC device into the movement of the moving parts of the machine tool. For stepper motors, each pulse signal makes the motor turn an angle, which in turn drives the machine tool moving parts to move a small distance. Each feed motion of the executive components have the corresponding servo drive system, the performance of the entire machine depends mainly on the servo system.
(3) Position feedback system
Servo motor feedback of the angular displacement, CNC machine tool actuator (table) displacement feedback. Including grating, rotary encoder, laser rangefinder, magnetic scale, etc.
Feedback device to detect the results into electrical signals back to the CNC device, through comparison, calculate the deviation between the actual position and the command position, and issue deviation instructions to control the feed movement of the executive components.
(4) mechanical components of the machine tool
For the machining center class of CNC machine tools, and storage tool magazine, tool exchange robot and other components, CNC machine tool mechanical components and ordinary machine tools are similar, but the transmission structure requirements are more simple, in terms of accuracy, rigidity, vibration resistance and other requirements, and its transmission and speed change system is more convenient to achieve automation expansion.
