Necking detection control method in consumable electrode electric arc welding

Abstract

The invention provides a necking detection control method in the consumable electrode electric arc welding. In the consumable electrode electric arc welding, the molten drop necking detection precision can be improved. The necking of the molten drop is carried out through making the change of the resistance between a consumable electrode (1) and a base metal (2) reach to a necking detection reference value, and if the necking phenomenon is detected, the output control is carried out through reducing the welding current Iw and generating the arc in a low current state. In each short circuit, the necking detection time from the necking phenomenon detection time to the arc regeneration time is detected. When the necking detection time is below a lower limit time, 1 is subtracted from a counter, and when the necking detection time is above an upper limit time, 1 is added into a counter. When the value of the counter reaches to a negative reference value, the necking detection reference value Vtn is reduced, and when the value of the counter reaches to a positive reference value, the necking detection reference value Vtn is added. In such a manner, the necking detection reference value Vtn becomes proper, and the necking detection precision is improved.

Description

technical field [0001] The present invention relates to a necking detection and control method of consumable electrode arc welding for detecting the necking phenomenon of droplet during short circuit so as to reduce welding current and improve welding quality. Background technique [0002] Figure 5 It is a diagram showing current-voltage waveforms and droplet transfer in consumable electrode arc welding in which short-circuit period Ts and arc period Ta are repeated. Figure 5 (A) shows the time change of the welding current Iw that energizes the consumable electrode (hereinafter referred to as welding wire 1), Figure 5 (B) shows the time change of the welding voltage Vw applied between the welding wire 1 and the base metal 2, Figure 5 (C) to (E) show the transition state of the droplet 1a. Below, refer to Figure 5 Be explained. [0003] During the short-circuit period Ts from time t1 to t3, the droplet 1a at the tip of the welding wire 1 is short-circuited with the base...

AI Technical Summary

Problems solved by technology

In the invention of Patent Document 3, when the constriction detection time Tn is greater than the upper limit time (when the sensitivity is too high), the sensitivity is reduced by increasing the constriction detection reference value Vtn, thereby achieving optimization.

However, in the invention of Patent Document 3, when the constriction detection time Tn is short (when the sensitivity is too low), the constriction detection reference value Vtn cannot be optimized.

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