JPH0622760B2 - Droplet transfer timing detection method - Google Patents

Description

The present invention relates to a droplet transfer timing detection method capable of detecting welding transfer timing in real time.

[Conventional technology]

FIG. 9 shows a conventional optical method that is a typical method for detecting or observing droplet transfer. In FIG. 9, a positive voltage of the welding power source 1 is applied to the power feeding tip 5 and a negative voltage is applied to the object to be welded 7, and the consumable electrode (hereinafter referred to as wire)
An arc 6 is generated between the welding target 7 and the object 7 to be welded.

The wire 2 is fed by a roller 4, and the roller 4 is mechanically coupled to the electric motor 3 so that the electric motor 3
It is designed to be driven by.

On the other hand, the power supply 10 turns on the xenon lamp 11. The light beam emitted by the xenon lamp 11 is detected by the camera 13 through the arc 6. The light of the xenon lamp 11 is made to travel toward the arc 6 by the reflecting mirror 12. The optical axis of the light is on the line connecting the xenon lamp 11 and the arc 6, and the focal point is the position of the camera 13 near the arc 6. A shield nozzle 8 guides the shield gas 9.

Next, the operation will be described. The droplets (not shown) that separate from the wire 2 toward the workpiece 7 are normally invisible because they are blocked by the intense light of the arc 6.

Then, when the light emitted from the xenon lamp 11 which is stronger than the arc light is applied to the arc 6 from the direction opposite to the camera 13, a droplet not shown is photographed as a shadow picture.

[Problems to be solved by the invention]

In the prior art, it is not possible to observe the droplet transfer in real time, since the droplet transfer is imaged on the film and therefore requires a phenomenon and a fixing process to be observed.

Further, when the droplet transfer is detected and the transfer timing is to be controlled, the droplet transfer timing cannot be detected in real time, and therefore the droplet transfer cannot be controlled by the conventional technique.

Further, in pulse welding, it is impossible to stabilize the welding phenomenon that droplet transfer occurs in synchronism with the pulse cycle. Therefore, the relationship between the pulse waveform and droplet transfer timing is detected and controlled to synchronize them. .

The present invention has been made to eliminate the above-mentioned conventional drawbacks, and a droplet transfer timing detection method that can detect the droplet transfer timing in real time and can be used as a droplet transfer timing control and a droplet transfer monitor. The purpose is to provide.

[Means for solving problems]

The droplet transfer timing detection method of the present invention introduces a step of detecting a welding current and a welding voltage, performing waveform processing, and then inputting them to a logic circuit to detect a timing at which a droplet transfers from a wire. is there.

[Action]

According to the present invention, when the droplet current and the welding voltage are respectively detected by the above steps and predetermined waveform shaping is performed, the droplets are separated from the wire in real time by inputting them to a logic circuit and performing logical operation processing. To detect.

〔Example〕

Hereinafter, an embodiment of the droplet transfer timing detection method of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of a droplet transfer timing detection device applied to the embodiment.

In FIG. 1, the same portions as those in FIG. 9 are denoted by the same reference numerals to avoid redundant description, and the description thereof will be omitted. The portions different from those of FIG. 9 will be mainly described. Describe.

As is apparent from a comparison of FIG. 1 with FIG. 9, the portions indicated by reference numerals 1 to 9 are the same as those in FIG. 9, and in FIG. Is a part newly added according to FIG.

That is, 14 is a shunt for detecting the welding current. The shunt 14 is inserted between the welding power source 1 and the workpiece 7, and the detection output is sent to the partial circuit 18 via the amplifier 16. The partial circuit 18 outputs a welding current of 1
It differentiates (di / dt) with respect to (t), and its output is sent to the waveform shaping circuit 20.

On the other hand, the welding voltage generated by the welding power source 1 is input to the amplifier 15. The amplifier 15 amplifies the welding voltage v to an appropriate magnitude and sends its output to the partial circuit 17.

The partial circuit 17 divides the welding voltage v with respect to time t (dv /
dt), and its differential output is sent to the waveform shaping circuit 19.

Both of the waveform shaping circuits 19 and 20 are for shaping the outputs of the differentiating circuits 17 and 18, and of the outputs of the differentiating circuits 17 and 18, +
Only the (plus) signal is taken out and an appropriate pulse width is obtained.

The two input signals from the waveform shaping circuits 19 and 20 are input to the NOR circuit 21, and the NOR circuit 21 performs an exclusive OR (NOR) of these two input signals. This NOR
The output terminal of the circuit 21 is connected to the output terminal 22.

Next, the droplet transfer timing detection method of the present invention will be described with reference to FIG. If the welding power source 1 is a power source capable of passing a pulse current and its characteristic is a constant current, the welding current i detected by the shunt 14 is as shown in FIG.

Further, when the droplets separate from the tip of the wire 2 into the arc 6, the welding voltage v changes (indicated by 23) as shown in FIG.

When the welding current i is amplified by the amplifier 16 and then differentiated by the differentiating circuit 18, a positive pulse is generated when the current rises and a negative pulse is generated when the current falls, as shown in FIG.

Similarly, when the welding voltage v is amplified by the amplifier 15 and then differentiated by the differentiating circuit 17, positive and negative pulses are generated at the rising and falling edges of the voltage and the droplet transfer timing 23 is reached as shown in FIG. Positive and negative pulses occur at corresponding positions.

When the differential waveforms of the welding current i and the welding voltage v shown in FIGS. 4 and 5 are shaped by the waveform shaping circuits 20 and 19 so that only the positive pulse is squared, FIG. And FIG. 5 becomes like FIG. 7.

Therefore, when the pulse signals shown in FIGS. 6 and 7 are applied to the NOR circuit 21, as shown in FIG.
A pulse signal corresponding to 3 appears at the output terminal 22. That is, the droplet transfer timing can be detected.

〔The invention's effect〕

As described above, according to the droplet transfer timing detection method of the present invention, since the welding current and voltage are detected and differentiated, waveform processing is performed to perform logical operation processing. The time can be detected. Therefore, it can be used as a droplet transfer timing control and a droplet transfer monitor.

[Brief description of drawings]

FIG. 1 is a block diagram of a droplet transfer timing detection device applied to an embodiment of the droplet transfer timing detection method of the present invention, and FIG. 2 is a welding current waveform in the droplet transfer timing detection device of FIG. Fig. 3 is a diagram showing a welding voltage waveform in the droplet transfer timing detection device of Fig. 1, Fig. 4 is a differential waveform diagram of the welding current of Fig. 2, and Fig. 5 is a welding voltage of Fig. 3. 6 is an output waveform diagram of the waveform shaping circuit 20 in the droplet transfer timing detection device of FIG. 1, and FIG. 7 is an output waveform of the waveform shaping circuit in the droplet transfer timing detection device of FIG. FIG. 8 is an output waveform diagram of the NOR circuit in the droplet transfer timing detection device of FIG. 1, and FIG. 9 is a diagram for explaining a conventional droplet transfer timing detection method. 1 ... Welding power source, 2 ... Myer, 3 ... Electric motor, 4 ...
Roller, 5 ... Feeding tip, 6 ... Arc, 7 ... Welding object, 14 ... Shunt, 17, 18 ... Differentiation circuit, 1
9, 20 ... Waveform shaping circuit, 21 ... NOR circuit.

Claims (1)

[Claims] 1. A differentiating circuit differentiates a welding voltage that causes an arc discharge between a consumable electrode and an object to be welded with respect to time, and then extracts only one of the polarities of the output of the differentiating circuit to form a predetermined pulse waveform. After shaping and extracting the signal based on the welding voltage, the welding current flowing through the consumable electrode and the workpiece is differentiated with respect to time by a differentiating circuit, and then only one of the polarities of the output of this differentiating circuit is taken out to a predetermined pulse. A droplet transfer timing detection method comprising waveform shaping to extract a signal based on a welding current, and performing an exclusive OR processing of the signal based on the welding voltage and the signal based on the welding current.