In this paper,the sensors array technique is applied to the quality detection of aluminum alloy spot welding.The sensors array has three forms,i.e.,linear magnetic sensors array,annular magnetic sensors array and cross magnetic sensors array.An algorithm based on principal component analysis is proposed to extract the signal eigenvalues.The three types of magnetic sensors array are used in the experiment of monitoring the signal.After the eigenvalues are extracted,they are used to build a relationship with the nugget information.The result shows that when the distance between the core of the array and the pole is 60 mm,the arrays work best.In this case,when the eigenvalues' range of the linear array is 0.006 5-0.015 1,the quality of the spots is eligible.To the annular and cross array,when the ranges are 0.082 9-0.131 6 and 0.085 1-0.098 2 respectively,the nugget quality is eligible.
