Basic Knowledge Of CNC Machine Tools

I. CNC Machine Tools and CNC Systems
CNC stands for Computer Numerical Control.

CNC Machine Tools
(1) Metal Cutting Machines:

Hole drilling, tapping, boring, milling, turning, threading, facing, contour machining, surface grinding, cylindrical grinding, internal grinding, etc.

(2) Wire Electrical Discharge Machines (EDM).

(3) Press machines: punching, nibbling, stamping, metal forming, tube bending, etc.

(4) Industrial robots.

(5) Injection molding machines.

(6) Inspection and measuring machines.

(7) Woodworking machinery.

(8) Special material processing machines: e.g., for processing stone, glass, radioactive materials, etc.

(9) Special processing machines: laser processing machines, gas cutting machines, welding machines, plotters, printing machines, etc.

With the development of electronic technology, computer technology, and IT, these machine tools and processing equipment can now be controlled by computers using numerical data, known as CNC control.

 

CNC Systems
The term CNC system refers to Computer Numerical Control systems.

Basic Configuration of a CNC System
CNC control of machine tools is an integrated multidisciplinary control technology.

A CNC system includes:
(1) CNC control unit (numerical controller section).
(2) Servo drive unit and feed servo motor.
(3) Spindle drive unit and spindle motor.
(4) PMC (PLC) controller.
(5) Machine tool power cabinet (including tool magazine) control signal input/output (I/O) unit.
(6) Machine tool position measurement and feedback unit (usually included in the servo drive unit).
(7) External axis (mechanical) control unit: e.g., for tool magazines, pallet changers, loading/unloading robotic arms, etc.
(8) Information input/output devices: e.g., computers, disk drives, memory cards, keyboards, specialized information devices, etc.
(9) Network interfaces: e.g., Ethernet, HSSB (High-Speed Serial Bus), RS-232C ports, and on-site local area networks (LAN).

The hardware of the CNC unit (controller section) is essentially a specialized microcomputer. It serves as the core control component designed and manufactured by CNC equipment producers specifically for machine tool control. The following diagrams illustrate its basic hardware modules, fundamental control functional modules, and the actual hardware of a controller.