The network management system of NC machine tools

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The construction of NC machine tool network management system in NC training base of Huaqiao University this paper introduces the background and necessity of implementing network management in NC training base of Huaqiao University, discusses the scheme of NC machine tool network management system in NC training base, and introduces the main functions of machine tool network system and the effect after the implementation of the scheme. Through this article, we can see that the CNC link4.1 CNC machine tool joint system developed by Beijing leitist Control Technology Co., Ltd. is suitable for the teaching and training needs of CNC training base in Colleges and universities

with the popularization and application of cad/cam integrated technology and local area technology, at present, most enterprises have significantly improved the efficiency and quality of new product design and development, process planning and NC machine tool programming, and the technology management and production management of enterprises have entered the networking era. The society has a growing demand for senior engineering and technical personnel engaged in 3D product design and NC machining. As an institution of higher learning, it should make its own contribution to economic development and social needs. In terms of the design and manufacture of variable angle shear attachments for theoretical teaching of numerical control technology according to gb/t23561.11 (2) 010, we have corresponding curriculum arrangements, but there is still a certain gap in the practical training of practical ability. For various reasons, it is very difficult for students to participate in numerical control training in the society, and it is difficult to have the opportunity to do it by themselves. In the past, Huaqiao University did not undertake the hardware conditions of numerical control training, and students' numerical control training only had to find an internship place in the society, which brought a series of difficulties and problems to the numerical control training, and the teaching effect was also greatly affected. It is an urgent problem to establish the school's own training base so that students can have better learning and practice opportunities. To this end, Huaqiao University has invested 1.7 million yuan to build a numerical control training base by using the national interest discount loan

I. main problems before the integration of CNC machine tools

our training base selects 3 domestic vertical CNC milling and boring machines and 3 domestic CNC lathes, all of which adopt the latest FANUC 0I system. The 3D design software adopts pro/engineer2001 of American PTC company and CADCEUS V6 software of Unisys company, the mainstream 3d design software company in Japan

the local area has been built in this training base, but previously the local area was not connected with the NC machine tool, and the data transmission of the NC machine tool is still transmitted by a single machine through the S232 interface. Its basic principle is that the serial port (COM) of the computer and the RS232C interface of the NC machine tool follow the same data communication protocol. By using the data transmission between them, the communication between the computer and the NC machine tool can be conveniently realized, so as to complete the DNC control of the machine tool by the computer

for some NC machine tools with relatively few program requirements, the most original manual keyboard input mode has been adopted. The disadvantages of this method are low efficiency, long machine time and error prone. For some CNC machine tools with large program input, a desktop computer is placed beside the machine tool for program transmission. The disadvantage of this method is that the environment is bad and the computer maintenance is difficult (the communication software is DOS version, it is difficult to upgrade, and the management of program files is chaotic)

the computer is used for program transmission. Due to frequent plugging and unplugging of the transmission cable, the serial interface of the computer is very easy to be burned. Most of the students' internship time is spent on manual program input, which can account for two fifths of the machine tool startup time, seriously affecting the use efficiency of the machine tool

the above disadvantages have seriously affected the production efficiency of NC machining, so it is urgent to find an effective method to improve the current situation of NC machine tools for systematic management

II. Construction of network management system for NC machine tools

the cooperation between the NC training base of overseas Chinese University and Beijing leitist control technology company has successfully solved the above problems, realized the network management of NC machine tools in the NC training base, and improved the management and teaching level of the base

at present, the local area in the base has been built, the NC machine tool has a certain scale, and the cad/cam application foundation is also relatively good. Therefore, the best choice to solve the problem is to take the road of network management for the NC machine tool

through multi-party comparison, we selected the CNC link4.1 CNC machine tool system developed by Beijing letiz special control parts Co., Ltd. which can be dried in the air or dried with clean and dry air with soft air pipe. The two sides cooperate to debug and connect all CNC equipment in the base one by one, and finally all of them are connected to the local area for unified management

1. The composition of the system

is shown in Figure 1. The contact system of the machine tool includes 8 parts: network server, local area line, cad/cam system, CNC link4.1 management system, main controller of the system, remote communication interface, communication cable and CNC machine tool. Among them, network server, local area line, cad/cam system and CNC machine tool are the existing resources of the enterprise; CNC link4.1 system management machine is an industrial PC computer with special software installed. It can install the customer management software on any local computer as a management workstation; The joint system management machine is a special computer running UNIX operating system. Its function is to accept the scheduling of each workstation, send instructions to all CNC machine tools on the network, and realize the unified management of machine tool information; The remote communication interface equipment is a multi serial port distributor specially used for the communication between the main control computer and the machine tool. Its characteristic is that it can realize long-distance transmission without signal loss; The communication cable is a super class 5 twisted pair shielded cable, and photoelectric isolators are added at both ends to avoid interference with signals

Figure 1 integration of machine tool linkage system

2 The main functions of the machine tool linkage system

(1) completely get rid of the situation of manual input program and single machine input program, and realize long-distance automatic program transmission

(2) the PC used for management can be placed at any position in the local area, which is not affected by the distance. The maximum distance between the main control computer and the NC machine tool is allowed to reach 1500m

(3) the program can be transmitted in parallel, that is, one main control computer can communicate with 16 NC machine tools at the same time

(4) the operation is simple. Without the help of other equipment or programmers, the operator can upload or download the part processing program by inputting corresponding instructions on the operation panel of the machine tool

(5) the main control computer works 24 hours, manages and communicates data to the CNC machine tool on the network at any time, and will not affect the three shifts of the machine tool or the overtime operation on holidays

(6) the transmission reliability is high. The special software has data verification function, so there will be no error in the transmission process. In special cases, if there is an error, the computer will alarm immediately. The software has the check function of uploading and downloading files at the same time. After each file is uploaded, one check file can be returned to ensure the safety of data

(7) the program can realize long file name management on the windows platform, thus realizing the unified management mode of file name and part number, and completely changing the restriction of program number on NC program management

(8) with the transmission log function of the software, you can view the date, time, file name, upload or download of data transmission to record the operator's operation process and error information

(9) each NC machine tool can access or download the NC program under the machine tool directory and the public directory

(10) for the CNC system with DNC function, it can realize simultaneous DNC processing of multiple machine tools on the network

(11) the number of NC machine tools is unlimited. It can be seen from the system diagram that the main controller of the linked system is installed on the local area of the enterprise. In principle, any number of main controllers can be installed in the local area, and each main controller can be connected to 32 CNC machine tools

III. Effect after the implementation of the scheme

after the realization of NC machine tool integration, the NC teaching efficiency of the base has been greatly improved, the program management and program transmission have been significantly improved, and the phenomenon of students queuing up to input programs no longer exists. The utility model thoroughly solves the drawback that the serial interface of the computer is easy to be burned due to frequent plugging and unplugging of the transmission cable

before the connection, the NC program is basically in the primary management state. After the connection of the NC machine tool, it depends on the function of the special network management software. All the prepared programs are placed in the directory corresponding to each machine tool. The name of each program is prepared according to the part drawing number, and there will be no duplicate name. The operator knows the programs on the network through instructions at any time and downloads them for use

compared with before and after the connection, there are the following obvious changes:

(1) why does it shorten the time of transmission program, that is, save expensive CNC machine tools? The origin also lies in the idea cost

(2) high accuracy. When the part program is reused, it can be absolutely correct even if it is retransmitted

(3) the labor intensity of the operator is reduced, and the program transmission can be completed only by inputting a simple command on the machine tool panel

(4) easy to modify. If the program used for the first time is modified on site, it can be used for the next time after uploading

(5) the program management is unified

(6) it is clear that once a problem occurs, it is easy to analyze whether it is the programming reason or the operation reason

IV. conclusion

at present, the CNC link4.1 CNC machine tool connection system installed and operated in the CNC training base of Huaqiao University is a network system based on RS232 serial port communication technology. Although this system is developed for enterprises, it can meet the needs of NC training centers in Colleges and universities, especially those with a certain scale. Because the operating environment of NC training centers in Colleges and universities is better than that of enterprises, the use of this system will have better reliability, and the system has good scalability, which can meet the needs of increasing NC machine tools. With the development of numerical control technology, the numerical control system running on Ethernet has gradually been widely used. Therefore, in the future, the contact system of numerical control machine tools and the local area within the school will become a unified system, and its maintenance and management will become faster and more convenient


1 He Li, application of CNC machine tool technology [j], cad/cam and manufacturing informatization, 2003108 (12):

2 Yao Chuanli, Tang Hua, DNC based on bs232 communication interface. The remarkable advantages of this material are extremely low warpage and flexibility and high flame retardant performance [j], cad/cam and manufacturing informatization, 2003108 (12)

about the author:

wangjianjun, male, born in 1963, master of engineering, associate professor, doctor of School of mechanical and electrical engineering, overseas Chinese University. Research fields: CAPP, cad/cam

Tel 0595 e-mail lxwjj1@

address: P.O. Box 43, School of mechanical and electrical engineering, Quanzhou Overseas Chinese University, Fujian post code: 362021 (end)

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