1 the composition of CNC machine tools CNC machine tools are generally composed of input and output equipment, numerical control device ( CNC ), a servo unit, drive unit ( or executive ), programmable controller ( PLC ) and electric control unit, auxiliary device, machine body and a measuring device.
( 1) NC machine tool plant input and output device. Is a CNC system and operating personnel for the exchange of information, realize the man-machine dialogue interaction device. The input device is the role of the program carrier NC code into the corresponding electric pulse signals, both CNC device into one. The output device is : the numerical control system through the display for the operator to provide the necessary information. Display information can be in the program being edited, coordinate values and alarm signal.
( 2) numerical control device ( CNC device ). Computer numerical control system is the core, is composed of two parts: hardware and software. It receives the input device in pulse signal, the signal through the device of numerical control system software or logic circuit compilation, operation and logic processing, output various signals and command, control of machine tool parts, so that its provisions, orderly movement.
( 3) a programmable logic controller ( PLC ). CNC machine tool by CNC and PLC together control function, wherein, CNC mainly completed with digital operation and management and other related functions, such as parts of the program editor, interpolation, decoding, movement of the cutting tool position servo control. While the PLC is mainly completed with logic operations related to some action, it receives the control code ( CNC M auxiliary function ), S ( spindle ), T ( choice knife, knife changing ) switch quantity movement information, on-off action information to decode, converted into the corresponding control signals, control auxiliary device of machine tool the switch. It also receives machine control panel instructions, a direct control machine movements ( such as manually operated machine tools ), on the other hand will be part of instruction to control the device, used for grinding process control.
( 4) servo unit. Servo unit receives from a numerical control device of velocity and displacement of instruction.
( 5) driving device. Driving device of the servo unit after amplified instruction signal into mechanical motion, via a mechanical connecting part driving the work table of the machine tool worktable, make accurate positioning or according to the provisions of the trajectory of strict relative motion, processing shape, size and precision to meet the requirements of the parts.
( 6) the machine tool. The CNC machine tools machinery parts, including the main moving parts, the feed movement execution unit ( table, carriage and transmission components ) and the supporting member ( bed, column and so on ), including cooling, lubrication, transposition and clamping functions of the auxiliary device.In addition, in order to ensure the full play of function of numerical control machine tool, there are a number of auxiliary system, cooling system, lubricating system, hydraulic ( or pneumatic ) system, drainage system, protection system.
