JPS61229467A - Power supply device for arc welding - Google Patents

Abstract

PURPOSE:To make uniform the time for arc generation and to obtain a uniform weld bead by providing a short circuit detecting circuit and timer circuit to a power supply device for arc welding and decreasing the welding output when the time count value of the timer circuit exceeds a specified value during the arc generation. CONSTITUTION:The short circuit detecting circuit 11 discriminates whether the short circuit or the arc under generation according to whether the welding voltage value is below or above the specified value, then the circuit outputs a detection signal. The timer circuit 12 is inputted with the output signal from the circuit 11 and outputs the time count value with the point of the time when the short circuit transfers to the arc generation as a start point. An output control circuit 13 is inputted with the output signal from the circuit 11 and the output signal from the timer circuit 12 and outputs a control signal to a welding output control element 4 so as to decrease the welding output when the time count value attains the specified value during the arc generation. The amt. of the spatters to be generated in the arc generation stage after the release of the short circuit is thus suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an arc welding power supply device for automatically feeding a welding wire, which is a consumable electrode, to perform arc welding.

Conventional technology The output control element of an arc welding power source that automatically feeds welding wire to perform welding conventionally controls the welding output according to the amount of wire feed, or controls the welding output according to disturbances such as fluctuations in the input power supply voltage. On the other hand, it has been used to keep the average value of welding voltage constant. In addition, even in the case of a structure in which the rising speed of the welding current is suppressed when the wire □ is short-circuited to the workpiece, the welding output is controlled using the time when the wire is short-circuited as the starting point for time counting.

Problems to be Solved by the Invention According to the above-mentioned prior art, the arc generation time cannot be controlled. That is, the time from when the arc occurs until the next wire short circuit must depend on the self-control action of the arc, and the amount of molten globule that grows at the tip of the wire during this time cannot be controlled either. Therefore, it is not possible to maintain a uniform amount of molten metal in response to instantaneous fluctuations in the amount of wire flare-up or wire feed rate when an arc occurs, and this causes problems such as scattering of large spatter and wire catching. Ta.

The present invention solves the above-mentioned conventional drawbacks, and relates to an arc welding power supply device that can equalize the amount of molten metal transferred to the workpiece at the time of the next wire short circuit after arc generation.

Means for Solving the Problems In order to solve the above-mentioned problems, the arc welding power source Ti Akane of the present invention transmits a signal to determine whether the welding wire is short-circuited by contact with the workpiece or an arc is generated. A wire short circuit detection circuit outputs a wire short circuit detection circuit, a timer circuit receives the output signal of this wire short circuit detection circuit as an input, and outputs a time count value starting from the point in time when the wire short circuit changes to arc generation; and the output signals of these wire short circuit detection circuits and and an output control circuit that receives an output signal of the timer circuit and outputs a control signal to a welding output control element, and reduces the welding output when the time count value of the timer path exceeds a certain value during arc generation. It is structured as follows.

Effects According to the above configuration, time can be counted starting from the time when the wire short circuit is released and an arc is generated, and when the time count value reaches a predetermined constant value while the arc is occurring, the welding output control element will control the welding output. can be controlled to reduce the

EXAMPLE Hereinafter, an example of the present invention will be described based on FIGS. 1 and 2.

FIG. 1 is a configuration diagram of a welding device using an arc welding power supply device according to an embodiment of the present invention, in which 1 is a welding power source input terminal, 2 is a welding main transformer, 3 is a rectifier, and 4 is a welding output control. element, 5 is a welding reactor, 6 is a welding power source output terminal, 7
Reference numeral denotes an energizing contact tip, 8 a welding wire, 9 an object to be welded, 10 a welding arc, 11 a wire short circuit detection circuit, 12 a timer circuit, and 13 an output control circuit. In this embodiment, a microcomputer is used as the timer circuit 12 and the U output control circuit 13, and the second
The figure shows the program 70 chart. In addition, Fig. 2 shows how to determine the ON time of the switching elements constituting the welding output l1liIIIl element 4 based on the time count value, and the count value is cleared from arc generation and the time count value is counted in synchronization with the internal clock signal. 70 of the timer circuit 12
Chat was omitted. The time counting signal of the timer circuit 12 can be set with an arbitrary output control reduction point according to the feed rate, and has a frequency of 4KH2 so as to control the welding phenomenon. This value can also be set arbitrarily to improve resolution.

The effects of the above configuration will be explained below.

The wire short circuit detection circuit 11 identifies whether a wire short circuit or an arc is occurring depending on whether the welding voltage value is less than a certain value or not.
Outputs a detection signal. The timer circuit 12 receives the output signal of the wire short circuit detection circuit 11 as an input, and outputs a time count value starting from the point in time when a transition from wire short circuit to arc occurrence occurs. The output control circuit 13 inputs the output signal of the wire short circuit detection circuit 11 and the output signal of the timer circuit 12, and controls the welding output so as to reduce the welding output when the time count value reaches a certain value during arc generation. A control signal is output to element 4.

That is, when the welding output control element 4 is a switching element such as a transistor, a control signal is outputted so as to know the on time.

In this way, time can be counted starting from the time when the wire short circuit is released and an arc occurs, and when the time count value reaches a predetermined constant value while the arc is occurring, the welding output control element 4
The welding output can be controlled to be reduced.

Effects of the Invention As described above, according to the present invention, since the arc generation time can be made uniform, the amount of metal m transferred from the welding wire to the workpiece in one welding process can be made uniform. Uniform welding speed can be obtained. Furthermore, by making the amount of transferred metal uniform, there is no need to set the welding current value at an unnecessarily high value when the wire is short-circuited, and therefore the amount of spatter generated when an arc is generated after the wire short-circuit is removed can be suppressed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a welding apparatus equipped with an arc welding power supply device according to an embodiment of the present invention, and FIG. 2 is a flowchart showing the operation of an output lb control circuit in the arc welding power supply device.

Claims (1)

[Claims] 1. A wire short circuit detection circuit that outputs a signal to determine whether the welding wire is short-circuited by contact with the workpiece or an arc is generated, and the output signal of this wire short circuit detection circuit is input to detect arc generation from a wire short circuit. It is equipped with a timer circuit that outputs a time count value starting from the time of transition, and an output control circuit that receives the output signal of the wire short circuit detection circuit and the output signal of the timer circuit as input and outputs a control signal to the welding output control element. An arc welding power supply device configured to reduce welding output when a time count value of the timer circuit exceeds a certain value during arc generation.