Digitized Spot Welding Process Information Monitoring System Based On LabVIEW

Resistance spot welding quality is instable and difficult to control, which have influenced the wide application of resistance spot welding technology seriously. So it is necessary to develop a kind of online judging system with nondestructive , low cost and high diagnostic reliability. Lots of dynamic information, which can directly and indirectly reflect the quality of weld spot, is included within the dynamic signals of resistance spot welding process. Signal characteristic analysis, parallel treatment and information integration technology are the key to set up quality evaluation model and realize quality inspecting of weld spot online.In this paper, to settle the problem of lack of information, poor real-time and low transmission of the traditional spot welding monitoring system, taking C8051F020 and use CMOS chips that is high speed and abound resources as core, a data sampling circuit that has simple structure, high reliability and maintainability is designed, which can collect welding current, voltage, angle of current flow and fire angle of the SCR with high speed and high precision under the control program. And calculates the root-mean-square value of welding current, the root-mean-square value of voltage. All this provide stability judgment for high precision control and spot welding quality. For these information is formed of module, which can be easily added or deleted and not influence the system.By means of multifunctional LabVIEW, based on the Ethernet, to attain collection system corresponds with PC. Via collecting, transferring and managing the data, to monitoring spot welding quality; to be the reason to changing the spot welding device which can't use easily. The system has been working well in the library, the result shows that: the dynamic data acquisition system developed in this project has high practical value.