Classification of CNC machine tools by motion trajectory

According to the trajectory of the relative movement between the tool and the workpiece, the CNC machine tool can be divided into point control CNC machine tools, point linear control CNC machine tools, contour control CNC machine tools and so on. It is now described as follows:

(1) Point control CNC machine tools. The numerical control device of this type of machine can only control the moving parts of the machine tool to accurately move from one position (point) to another position (point), that is, only the coordinate value of the end point of the stroke is controlled, and no cutting process is performed during the movement, as for two The speed and route of movement between related points depends on productivity. In order to have the highest possible productivity on the basis of precise positioning, the movement between the two correlation points is first to move quickly to a new position, and then to a speed of 1-3, so that it slowly approaches the positioning point, Guarantee its positioning accuracy.

This type of machine tool is mainly CNC coordinate boring machine, CNC drilling machine, CNC punching machine and CNC measuring machine. Its corresponding numerical control device is called point control device.

(2) Point linear control CNC machine tools. This kind of machine works not only to control the position (ie distance) between the two related points, but also to control the moving speed and route (ie the trajectory) between the two related points. The route is generally composed of straight segments parallel to each axis. The difference between it and the point-controlled CNC machine is that when the moving part of the machine moves, it can be cut in the direction of one coordinate axis (generally, it can also be cut along a 45° oblique line, but cannot be cut along a straight line of any slope). Machining, and its auxiliary functions are more than CNC machines with point control. For example, it is necessary to increase the functions of spindle speed control, cycle feed machining, and tool selection. This type of machine tool mainly includes simple CNC lathes, CNC boring and milling machines and CNC machining centers. The corresponding numerical control device is called a point linear control device.

(3) Contour control CNC machine tool. The control unit of this type of machine can continuously control two or more axes at the same time. The machining not only controls the starting point and the end point, but also controls the speed and position of each point in the entire machining process, so that the machine can machine the parts with complex shapes that meet the requirements of the drawings. Its auxiliary functions are also relatively complete.