Research On Welding Electrical Signal Monitoring And Analysis System Based On Virtual Instrument

Welding is an important process in modern manufacturing. With wider and wider application, the quality of welding becomes more important. Welding electrical signal contains rich information which is easy to detect. The quality of welding is directly influenced by the stability of arc. The welding electrical signal real-time monitoring and analysis is a way to reflect the stability of welding process and predict the welding quality. In this paper, a set of welding electrical signal monitoring and analysis system has been established basing on virtual instrument LabVIEW. This system can real-time monitoring and analyse the welding current and arc voltage in the process of welding to evaluate welding spatter size, welding stability and melt transfer.The system contains two main parts that are hardware and software. Hardware includes the data acquisition card, shielding box, control module, voltage sensor, current sensor and computer etc. The data acquisition platform made up by these hardwares can realize high-speed, synchronization, stable and undistorted data acquisition of the welding electrical signal. The input of data is in the form of digital signals that can be identified by computer.Software part is written by LabVIEW and the program is mainly divided into data acquisition module and analysis module. Acquisition module can real-time, synchronously and accurately display the welding current and arc voltage waveform on the front panel in the welding process, meanwhile the waveform is stored for the subsequent analysis. Analysis module can be used to analyze saved dates. And it mainly includes statistical analysis module,probability density analysis module, spectrum analysis module, correlation analysis module and U-I analysis module. The welding stability, welding spatter size and arcing conditions of the whole welding process can be accurately evaluated by the integrated application and mutual authentication of the five analysis modules.In order to test the feasibility and accuracy of the established system in this paper,welder A and welder B welded by using manual arc welding and CO2 shielded welding respectively with the same base metal, welding wire (CO2 shielded welding), electrode(manual arc welding), welding equipment and welding procedures. Two groups of welding electrical signal getting from the two welders have been stored and analyzed by using the system.The analysis results of each analysis module have a high consistency. The system can accurately evaluate welding spatter size, welding stability and melt transfer in the welding process. Additionally, the system has the characters of friendly interface, simple operation,stable performance and high-reliability. Therefore, the system established in this paper can satisfy the requirements of monitoring and analysis during the arc welding process.