Types and selection of CNC machine tools
The process of CNC machine tools is complex, and a series of factors need to be considered when analysing the process of the workpiece, such as the arrangement of the process route of parts, the selection of machine tools, the selection of cutting tools, the clamping of parts, etc. Among them, the selection of machine tools is particularly critical, because different types of CNC machine tools have differences in process and workpieces. If enterprises want to improve efficiency and reduce investment, it is essential to choose machine tools reasonably.
Common types of CNC machine tools mainly include the following:
I. Types according to CNC machine tool process
1. Metal cutting CNC machine tools: This kind of machine tools correspond to traditional turning, milling, drilling, grinding and gear cutting process machine tools, including CNC lathes, CNC milling machines, CNC drilling machines, CNC grinding machines, CNC gear machine tools, etc. Although these CNC machine tools have great differences in process methods, the movements and movements of machine tools are digitally controlled, with high efficiency and degree of automation.
2. Special process CNC machine tools: In addition to cutting process CNC machine tools, CNC machine tools are also widely used in CNC wire cutting machine tools, CNC spark moulding machine tools, CNC plasma arc cutting machine tools, CNC flame cutting machine tools and CNC laser machine tools, etc.
3. Plate stamping CNC machine tools: This kind of machine tools are mainly used for metal plate stamping, including CNC presses, CNC shearing machines and CNC bending machines.
II. Divide the types according to the controlled movement trajectory
1. Point control CNC machine tool: The CNC system of the machine tool only controls the coordinate value of the end of the journey, and does not control the movement trajectory between the point and the point. This kind of CNC machine tool mainly includes CNC coordinate boring machine, CNC drilling machine, CNC punching machine, CNC spot welding machine, etc.
2. Linear control CNC machine tool: Linear control CNC machine tool can control the tool or operating table to move and cut in a straight line in the direction parallel to the coordinate axis at the appropriate feed speed. The feed speed can change within a certain range according to the cutting conditions. The simple CNC lathe with linear control has only two coordinate axes, which can be used for step axes. The linearly controlled CNC milling machine has three coordinate axes, which can be used for plane milling.
3. Contour control CNC machine tool: Contour control CNC machine tool can continuously control the displacement and speed of two or more movements, so that the motion trajectory of the synthesised plane or space can meet the requirements of the part contour. The commonly used CNC lathes, CNC milling machines and CNC grinders are typical contour control CNC machine tools.
III. Divide the types according to the characteristics of the drive device
1. Open-loop control CNC machine tool: This kind of controlled CNC machine tool has no position detection element in its control system, and the driving component is usually a stepping motor. The information is one-way, so it is called an open-loop control CNC machine tool. It is only suitable for small and medium-sized CNC machine tools with low accuracy requirements, especially simple CNC machine tools.
2. Closed-loop control CNC machine tool: detect the actual displacement of the operating table, feedback the measured actual displacement value to the numerical control device, compare it with the input instruction displacement value, control the machine tool with the difference, and finally realise the accurate movement of the moving parts. This kind of controlled CNC machine tool is called a closed-loop control CNC machine tool because the machine tool operating table is included in the control link.
The reasonable selection of CNC machine tools is of great significance for improving the production efficiency and reducing costs of enterprises. When selecting, it is necessary to comprehensively consider the process requirements of parts, the type characteristics of machine tools and the production needs of enterprises. At the same time, with the continuous progress of technology, CNC machine tools are also developing. Enterprises need to pay attention to the latest technological trends in time, so as to better choose CNC machine tools suitable for their own needs.