Approximate entropy based meso-spray transfer analysis of Al-alloy pulsed metal inert-gas welding under self-adapting control

The meso-spray transfer of Al-alloys metal inert-gas (MIG) welding has the advantages of well-adjusting of the length of arc and beautiful appearance of weld due to the characters of droplet transfer. In this study, the self-adapting control which is brought to meet the arc of meso-spray transfer is accessed by analyzing the approximate entropy (ApEn) of the arc voltage on the aspect of non-linear dynamics. Under self-adapting control, the change of ApEn value with the varing metal transfer mode is discussed, which is due to the change of the parameter of process. Under spray transfer, two kinds of ApEn values of the self-adapting control and common pulsed control are compared, and we find that the self-adapting control is fit for meso-spray transfer. The results show that the smaller the value of approximate entropy is, the better the effect of the self-adapting control is.