The Construction Of On-Line Monitoring System And Database For Aluninum Alloy Spot Welding

Aluminum alloy spot welding has been widely used in aerial production. But an effective way hasn't been found for on-line inspection of the nugget's quality。Until now, and most of the inspecting works are done by X-ray, ultra-sonic or mechanical ways. Though many researchers have made lots of efforts to solve this problem, but most of their works are still under test in laboratory. That's the background of why we do this work to meet the urgent need of the industry.This work is for one factory of CASC, the major faults in aluminum spot welding are expulsion and unqualified size of nugget, so the aim of our work is to monitor the welding process and find these possible faults. The aluminum spot welding on-line monitoring system was constructed. Welding current and voltage, tip displacement and tip pressure are selected as the characteristic signals to measure and estimate the quality of the nuggets. In order to memorize and query the spot welding process information, a database was constructed and connected with the on-line monitoring system through LabVIEW SQL Toolkit. The Statistical Process Control (SPC) is used to estimate and optimize the critical value and process parameters.After doing a lot of experiments with testing pieces and also factual products, the system has been used in different types of aerial products'spot welding and achieved on-line inspection with high precision. It has been constantly optimized with the database becoming more abundance, and the predominance and the estimating precision of the nuggets'quality will be more accuracy.