Design of CNC system of the hottest high-speed CNC

In recent years, with the development of modern manufacturing industry, especially the development of computer integrated manufacturing systems (CIMS), the speed of product renewal is increasing, the proportion of small and medium-sized batch production is increasing, and the application field of CNC system is expanding, Make users' requirements for CNC system diversified: in terms of communication group, CNC system is required to realize communication with cad/cam/capp and other systems; In terms of the flexibility and portability of the system, CNC system is required to be modular and reconfigurable. According to different user needs, a user oriented control system can be built quickly, efficiently and at low cost

the traditional CNC system obviously cannot keep up with the development requirements due to its strong specificity, difficult function expansion, poor software portability, poor group communication ability and other shortcomings. In order to meet the requirements of more flexibility, flexibility and versatility of CNC system, there is a research on the structure of open CNC system. At present, many countries in the world have invested a lot of human, material and financial resources in this regard, and have made great achievements, such as OSACA in Europe (open sys can also obtain TEM architecture for control within automation through IOS), OMAC in the United States (OPE) to better meet the needs of Baotou's economic development n modular architecture controller) and ose (open system environment) in Japan

personal computer (PC), due to its hardware standardization, high-speed computing ability, open bus, network function and rich software resources, has shown unparalleled advantages in improving the user interface, graphic display, dynamic simulation, NC programming, fault diagnosis, network communication and other functions of CNC system; The system designer can also connect various functional modules (such as axis motion controller, i/o interface card, etc.) into the system, install cad/cam software into the system for operation, and directly control the machine tool processing program. Therefore, PC based Open CNC system has become the main direction of CNC system openness. The open CNC system based on PC, mainly IPC (industrial PC), has the following forms according to the connection between CNC components and PC:

(1) using single chip microcomputer or DSP as the motion control component of CNC axis, using dual port storage technology or serial/parallel communication to exchange data with host (PC) to realize CNC control

(2) using the high-speed computing ability of PC, the hardware function is softened, and the hardware used for CNC control is only a simple interface

(3) use EPCD, CPLD and other large-scale devices as a special digital pulse servo interface card based on IPC to control the movement of the executive motor

with the development of furniture manufacturing industry, advertising signs industry and mold industry, especially the improvement of the requirements of mold industry for surface processing, as well as the shortcomings of traditional EDM, CNC engraving and milling machines, which integrate the advantages of milling and high-speed engraving, have made great progress in China in the past two years. In order to meet the needs of the market, we designed and developed a PC based CNC system of high-speed engraving and milling machine. The design of the system adopts the modular design idea in the function realization; In terms of structure, it adopts the form of/position control card +pc, that is, the third form of PC based Open CNC system for the use of antibacterial materials, and designs a position control card based on CPLD to realize digital pulse servo interface and other i/o interface functions

1. Composition of CNC system of high-speed CNC engraving and milling machine

system structure and functions of each part

pc104 is an industrial control bus specially defined for embedded control. Its signal definition is basically the same as pc/at, but the electrical and mechanical specifications are completely different. It is an optimized, small, stackable embedded control system, which is different from ordinary PC Compared with ISA bus control system, it has the following characteristics:

(1) small size structure: the mechanical size of standard module is 3.6 × 3.8 inches, i.e. 90 × 96mm。

(2) stack connection: the bus is connected in the form of "pins" and "holes", that is, between PC104 bus modules, the bus is connected through the upper, which will also give the extruder industry endless development power. The pins of the layer and the holes of the lower layer bite and connect with each other. This kind of laminated packaging has excellent seismic resistance

(3) easy bus drive: reduce the number of components and power consumption. 4mA bus drive can make the module work normally, and each module consumes 1~2w of energy

because PC104 is small in size, low in power consumption, and reliable in connection, using PC104 as the host can greatly reduce the volume of the CNC controller, and the system is more compact and reliable. Therefore, PC104 industrial control computer is selected as the upper computer to build an open CNC system of "position control card +pc104". The composition block diagram of the system is shown in Figure 1

Figure 1 block diagram of high-speed CNC engraving and milling unit

Figure 1 block diagram of high-speed CNC engraving and milling unit according to different functions, the system can be divided into the following modules: system management module, motion control module, digital pulse servo interface module, electrical control module, machine tool panel operation module and servo drive module. The following is a brief introduction

(1) the functions of the management module and the motion control module

are mainly realized by the upper computer PC104. The main task is to manage and organize the whole CNC system to work in an orderly manner, mainly including the input, compilation, interrupt management, fault self diagnosis of the processing program, the completion of various control algorithms and interpolation algorithms, the response to the input of the operation panel and keyboard, and the feedback data of the motion controller and the working state of the machine tool, Displayed on CRT

(2) digital pulse servo interface module and electrical