1, point control CNC machine tools
Some hole machining CNC machine tools, such as coordinate drilling machines, coordinate grinding machines, CNC punching machines, etc., only require accurate hole coordinate position control, and there is no requirement for moving the track from one hole to another. Point control CNC system. In order to ensure the accuracy of positioning, such a system can adopt multi-stage deceleration processing according to its motion speed and positioning accuracy requirements. The point numerical control system has a simple structure and a low price.
2, linear control CNC system
For some CNC machine tools, such as CNC lathes, CNC boring and milling machines, machining centers, etc., not only requires accurate positioning function, but also digital control technology requires linear movement from one point to another, and can control the displacement speed to adapt to different tools. And processing of materials. In order to no longer reprogram when the tool size changes slightly after changing the tool, this system generally has tool radius compensation, length compensation and spindle speed control. This type of system generally has 2 to 3 axes, but only one control axis.
3. Contour control CNC system
Most modern CNC machine tools have a two-coordinate or two-coordinate linkage function, that is, parts that can be curved or curved. This type of machine has CNC lathes, CNC milling machines, machining centers, etc. that can machine curved surfaces. This type of system not only has radius compensation, tool length compensation, but also screw pitch error compensation, transmission backlash compensation, spindle speed control and positioning control functions, automatic tool change function. Figure 1-3 shows an example of a machined part of a two-coordinate contour control system. The thick solid line in the figure is the contour of the workpiece, and the dotted line is the tool center trajectory. It can be seen from the figure that the tool center trajectory is changed due to different tool radius. With the tool radius compensation function, when the tool wear needs to be changed during the machining process, the control computer will simply enter the actual radius value of the new tool through the control panel. The required tool center path will be recalculated without machining errors due to tool changes or reprogramming. Continuous control over two coordinates can produce a variety of complex 3D surface parts.