Establishment of network integrated management sys

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The establishment of CNC machine tool network integrated management system

1 introduction

CNC machine tools are becoming more and more important in modern production and processing, and represent a trend of equipment upgrading. However, in practical application, there are many factors that make CNC machine tools unable to play its full efficiency. First, at this stage, the memory capacity of CNC machine tools is generally small, When there are many kinds of processed parts, a large number of part programs cannot be stored and have to be deleted and typed repeatedly. Sometimes it is even impossible to store a complete and complex part processing program. The repeated preparation of the program not only wastes a lot of working time, but also affects the processing stability of product quality. Even if the machine tool has a large hard disk, the program will not be deleted because of the storage space, However, the program used on this machine tool is inconvenient to use on other machine tools of the same model; The second factor is that the level of operators is uneven, and there is a lack of scientific understanding and application of the high-speed cutting characteristics of NC machine tools, the selection of NC tools, and the selection of cutting parameters

generally, the connection between computer and CNC machine tools for program transmission and processing is a connection between a computer and a CNC machine tool. Each CNC machine tool is equipped with a computer. With the continuous increase of CNC machine tools, the number of computers will increase, and the management is scattered

now most enterprises have used cad/cam software to design products and gradually realize CIMS management. As long as the design, management and operation of NC machine tools can be organically linked, the characteristics of high precision and high efficiency of NC machine tools can be brought into play

2 overview of DNC interface

dnc (direct numerical control) refers to computer direct numerical control or distributed numerical control, which means that one or more computers implement integrated digital control over multiple numerical control machine tools. DNC Integrated system belongs to a mode of automatic manufacturing system, which is the link to realize the integration of cad/cam and calculation. It is recommended to select no more than 10% machine aided production management system (CAPMs) for products heated in the experiment. It emphasizes the integration of information and the automation of information flow, and the control and execution of material flow can be largely involved in human-computer interaction. Compared with FMS, DNC has the advantages of small investment, fast effect and good flexibility. It is an integrated control system of multiple NC machining equipment. DNC interface is an integral part of DNC Integrated System. It is an intermediate link connecting numerical control equipment and industrial network. It is mainly responsible for the communication between DNC computer and numerical control equipment and industrial network. (establish an intelligent automatic network management platform)

3 the overall structure of DNC interface

the DNC interface architecture is supported by a high-performance general network server, which is connected to the industrial network upward through the network adapter card or modem and downward through the serial port expansion card (the economic NC machine tool without serial port should also be equipped with an adapter), and is equipped with the corresponding communication and management software to realize multi serial port communication; Establish communication protocol database and heterogeneous communication protocol to realize the communication of heterogeneous CNC system; Using the mature microcomputer network technology, different CNC machine tools are connected with industry through DNC interface. For example, Beijing leitiste company adopts this structure for machine tool coupling. As shown in figure 1dnc interface overall structure

Figure 1 overall structure of DNC interface

4 network management system establishment

4.1 NC machine tool interface detection

to establish a NC machine tool network, you first need to determine whether the i/o interface of the machine tool is intact. You can use a computer to connect directly with the NC machine tool through COM interface. Weld the connecting cable according to the cable wiring diagram in Figure 2

Figure 2 cable wiring diagram

after the connection is completed, connect the CNC machine tool with software on the computer and conduct data transmission test. (if it cannot be connected, contact the manufacturer of CNC machine tool or CNC system to determine the port definition method, and weld the connecting cable according to its definition.)

4.2 connecting CNC machines and tools has multiple range changes. Like the experimental machine, confirm the verification point bed to the computer

port respectively. After the detection is completed, weld the interfaces at both ends with shielded cable (calculated length) according to the method in Figure 1. One end is connected to the CNC machine tool, and the other end is connected to the serial port interface of lt-link4000 serial port expansion card. Since the CNC machine tool is generally placed separately, marks should be made at both ends of the connection to distinguish. Lt-link4000 serial port expansion card has a special computer interface to connect it with the computer. For example, Beijing leitiste company uses this kind of card. (tighten the fastening screws to prevent loosening) as shown in Figure 3

Figure 3 lt-link4000 serial port expansion card connection diagram

4.3 connection implementation process

the computer can automatically detect each serial port of lt-link4000 serial port expansion card and define names for each serial port respectively. Generally, the computer itself has two serial ports, so the serial port names on the serial port card are generally COM3, COM4... Confirm the NC machine tool connected to each serial port by marking, and then conduct transmission tests respectively. Because the NC system, processing characteristics and machine parameters of each machine tool are not necessarily the same, it is necessary to control them separately to prevent the inconvenience caused by program differences in processing. Use software to adjust the location and mode of program storage and access of each airport, store the machine parameters of the NC machine tool, monitor the working state of the NC machine tool, and establish the machine processing archives of the NC machine tool. Use cad/cam software to design and make drawing process and program

4.4 enterprise local area control

use the network adapter to set the IP address of the computer through tcp/ip protocol to adapt to the local area and set up shared resources. After the setting is completed, it can be properly improved in the local area of the enterprise according to the actual situation. Any computer can control and check the situation of the NC machine tool, and write the NC machine tool program to solve the current problems of the NC machine tool

4.5 remote control

use a modem to connect with the Internet network. With the permission of the administrator, you can access the stand-alone management workstation as long as you know the IP address number of the workstation around the world, so as to realize remote maintenance

5 structural characteristics

5.1 the vast majority of domestic CNC machine tools with ordinary RS-232 or RS-422 serial ports and economic CNC machine tools transformed with computers are used. Therefore, the above scheme is a DNC interface solution that meets the national conditions and can practically meet the high requirements of the data for the detection of elongation

5.2 using lt-link4000 serial port expansion card to expand the serial port has stable performance and reliable technology. On this basis, it can easily and reliably realize multi-channel communication at the same time, and solve the problem of DNC computer integrated control of multiple machine tools and machine tools

5.3 the RS-232 serial interface is simple in structure and reliable in transmission. The transmission distance can reach 1km ~ 2km and the communication rate can reach 19.2kbit/s by using the current loop mode; With RS-422A serial interface, the transmission distance can reach 1200m and the transmission rate can reach 10mbit/s. Many CNC machine tools at home and abroad use these two interfaces, and lt-link4000 can provide these two interfaces, which can meet the needs of communication between most production sites and CNC machine tools

5.4 connect with other equipment (such as tool and workpiece tester) through serial port to realize information integration

6 need to buy a hardware

computer (it is recommended to pre install windows system and equip with special software [select program management and processing management software as needed])

lt - link4000 serial port expansion card (buy according to the number of CNC machine tools, a serial port expansion card includes 8 serial ports, and the serial port expansion card can be connected in series by itself)

long line driver (1 pair for each CNC machine tool)

shielded cable (for connecting CNC machine tools and computers)

ordinary serial port connection (for detection port)

interface and other parts

network adapter (card) a

modem (modem) a


the CNC machine tool management network established through the above process can realize the following basic functions in use:

7.1 "data storage exchanger" (control host) in the CNC equipment and management system network Realize long-distance interactive data and information transmission

7.2 the control host is connected with the upper PC server or directly inserted into the CAD/CAM system of the production management workstation and technical management workstation in the enterprise local area for communication

7.3 the remote monitoring function of the system enables the management departments connected to the local area of the enterprise to monitor and manage various production feedback log information in the control host (opening and closing time of each equipment; name of processing parts; quantity of finished products and waste products, etc.)

7.4 control the unattended automatic operation of the host

7.5nc machining program can realize long file name management on Windows platform, and can realize the unification of part number and NC machining program name.

7.6 NC equipment network integrated management system covers all NC equipment with RS-232 data transmission interface. For facilities with incomplete letters on the operation panel, the coding method can also be used for data transmission

7.7 the data sharing function enables workers to call, modify and copy all NC processing programs stored in the control host with the permission of the administrator, which facilitates the transfer processing of production parts.

7.8 the control host provides a great program storage space for all NC machine tools in the network, and allows multiple DNC data to be transmitted at the same time, meeting the processing of multiple machine tools with a large number of programs

7.9 the maintenance and debugging of ultra remote data transmission can be carried out in time to ensure the stability of system operation


[1] Xu Xuedong. Some thoughts on the application of numerical control machine tools. CAD/CAM computer aided design and manufacturing. 2002

[2] Xie Xiren, Chen Ming, Zhang Xingyuan. Computer network. Electronic Industry Press. 1997 (end)

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