Hardware composition of CNC machining center CNC system
With the development of large-scale integrated circuit technology and surface mounting technology, the CNC system hardware modules and installation methods have been continuously improved. Then we now have a CNC training on its structure. From the overall installation structure of the CNC system, there are two types of integral structure and split structure.
The so-called monolithic structure is to install a circuit board composed of a CRT and an MDI panel, an operation panel, and a function module board in the same chassis. The advantage of this approach is that it is compact and easy to install, but sometimes it can cause some signal connections to be too long. The split structure usually has a CRT and MDI panel, an operation panel, and the like as one component, and the circuit board composed of the functional modules is installed in a chassis, and the two are connected by wires or fibers. Many CNC machine tools also use the operation panel as a separate component. This is due to the different requirements of the machine tool being controlled. The operation panel is changed accordingly, and the component type is advantageous for replacement and installation.
The CNC operation panel is mounted on the machine tool in the form of hanging type, bed type, control cabinet type, console type and so on.
From the structural characteristics of the circuit board that constitutes the CNC system, there are two common structures, namely a large plate structure and a modular structure. The characteristic of the large-plate structure is that a system generally has a large board called a main board. The main CPU and the position control circuit of each axis are mounted on the main board. Other related daughter boards (boards that perform certain functions), such as the ROM board, the part program memory board, and the PLC board, are directly inserted on the main board to form the core part of the CNC system. It can be seen that the large plate type is compact in structure, small in size, high in reliability, low in price, high in performance/price ratio, and convenient for integrated design of the machine tool. Although the large plate structure has the above advantages, its hardware function is not easy. Changes are not conducive to organizational production.
Another structure with higher flexibility is the modular open system structure of the bus. Its characteristic is that the CPU, memory, input and output control are respectively made into plug-in boards (called hardware modules), and even the CPU, memory, input and output control are composed. The independent microcomputer-level hardware module, the corresponding software is also a module structure, and is solidified in the hardware module. The hardware and software modules form a specific functional unit called a functional module. Functional modules have well-defined interfaces, interfaces are fixed, become factory standards or industry standards, and can exchange information with each other. Therefore, the CNC system can be formed by building blocks, which makes the design simple, has good adaptability and expandability, has a short trial cycle, convenient adjustment and maintenance, and high efficiency.
From the CPU and structure used by the CNC system, the hardware structure of the CNC system is generally divided into two categories: single CPU and multi-CPU architecture. The initial CNC system and some of today's economical CNC systems use a single CPU structure, while the multi-CPU architecture can meet the requirements of high feed rate, high machining accuracy and many complex functions of CNC machine tools, and is also suitable for FMS and CIMS operation. Needs, and thus has been rapidly developed, it reflects the new level of today's CNC systems.
