Seleção de parâmetros de soldagem a ponto por resistência, baseado na medição da resistência elétrica entre chapas

Abstract

Resistance Spot Welding applied in production lines may demand previous programming for welding parameter settings as a function of demanded sequential changes, due to as much as material type as thickness. In the case of a manual operation, the operator is the one in charge of changing the program when different welding conditions is identified in a same sequence of spots. Considering being an online operation, this is a potential source of error. Thus, the main motivation for this work was to verify the possibility of parameter regulation in a spot welding production line, based on measurement of the electrical resistance between the sheets. A series of experiments was carried out to verify the minimum number of cycles and the ideal electrical power needed to measure the electrical resistances between carbon steel and galvanized steel and between a different thickness sheets. The results showed that the electrical resistance can be determined from only six cycles and that it is possible to differentiate sheet combinations. They also reveal that the resistances variation amongst sheet combinations were repetitive and distinguished enough to claim the use of this principle to classify the material combinations by regions of electrical resistance, both by the difference in thickness and type of superficial coating. In this work, it was also defined the technique known as the Burn Zinc and presented an experimental procedure to achieve optimal parameters to use this technique.