Answer: C, point-controlled CNC machine tools.
Answer analysis: Generally, CNC drilling and boring machines belong to point-controlled CNC machine tools.
CNC drilling and boring machines are high-precision and high-efficiency machine tools, mainly used for drilling and boring holes, and can also perform various processing operations such as tapping, reaming, milling, cutting, etc. It is widely used in various industries such as aerospace, automobiles, electronics, medical equipment, energy, and mining.
In the classification of CNC machine tools, according to the different control methods and processing capabilities of machine tools, they can be divided into point-controlled CNC machine tools, linear control CNC machine tools, contour control CNC machine tools and other types. Among them, the characteristic of point-controlled CNC machine tools is that the CNC system of the machine tool only controls the accurate positioning of the tool from one point to another, and then performs fixed-point processing, but does not control the path of the tool movement. This control method is suitable for hole processing machine tools, such as CNC drilling machines, CNC boring machines, CNC punching machines, etc.
Therefore, general CNC boring and drilling machines are classified as point-controlled CNC machine tools because they are mainly used for point processing operations such as drilling and boring. This classification is determined based on the actual application and control method of the machine tool, and has nothing to do with factors such as the structure, size, and model of the machine tool.
It should be noted that although CNC boring and drilling machines may move in straight or curved lines during processing, their main purpose is to achieve accurate point processing rather than precise control of the movement path. Therefore, it still belongs to the category of point-controlled CNC machine tools.