JPH08229680A - Output control device of consumable electrode type pulse arc welding machine - Google Patents

Abstract

PURPOSE: To reduce the amount of the generated spatter by suppressing the output to the current of the lower level while the droplet is separated from the wire end during the welding to achieve the droplet transfer in a consumable electrode type pulse arc welding machine. CONSTITUTION: When the droplet separation is generated during the pulse energization, the output voltage rises, then the output voltage exceeds the reference voltage when the droplet is separated. A comparator 14 outputs the separation detection signal. An output correcter 16 receives the separation detection signal to output the signal to an output controller 11. Based on the signal, the output controller 11 outputs the signal to change the output from an output circuit 1234 into the current of the lower level than that of the pulse current in the pulse period after the separation detection signal among the pulse period to be set by a pulse time setting instrument 17. The signal from a pulse waveform generator 20 is corrected low thereby. The arc force on the droplet after the separation is weakened to prevent the spatter from being scattered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an output control device for a consumable electrode type pulse arc welding machine which uses a shield gas containing carbon dioxide as a main component and alternately passes a pulse current (peak current) and a base current. is there.

[0002]

2. Description of the Related Art In the consumable electrode type pulse arc welding method, it has been customary to use a shield gas containing an inert gas, argon, as a main component. As described above, in the method using argon as a main component and the sulshield gas, a pulse current higher than the critical current value capable of spray transfer and a base current lower than the critical current value for maintaining the arc are related to the wire feeding speed. It was being repeated at alternating frequencies. This allows the spray transfer to be performed at a lower average current than the DC welding method, and the droplet transfer to be performed in the least affected by the arc force during the base current period for maintaining the arc. Be seen. In this way, it was possible to significantly reduce spatter. But,
The pulse arc welding method is restricted by the composition of the shield gas, and if the carbon dioxide gas in the shield gas exceeds 30%, the effect of reducing spatter becomes weak. However, if a large amount of expensive argon gas is used as the main component, the cost of the shield gas becomes high. Therefore, improvement of the consumable electrode type pulse arc welding method using a shield gas containing carbon dioxide as a main component has been demanded.

Output control of consumable electrode type pulse arc welding using a shielding gas containing carbon dioxide as a main component is as follows.
The structure shown in Japanese Patent Publication No. Hei 2-31630 has been common. In the technique of this prior art, a pulse current (peak current) and a base current are alternately applied to generate an arc, the droplets are separated by a pinch force at the beginning of the pulse energization time, and then the electrode tip is melted. To form droplets. Then, the formed molten metal was released during the next peak energization time. However, the above-mentioned special fair 2
In the conventional output control method like Japanese Patent No. 31630,
There is a risk that the droplets will break off during energization with a pulse (peak) current, and the separated droplets will be subjected to a strong arc force due to the pulse current and will be spattered and scattered.

When the mixing ratio of carbon dioxide gas is increased, a strong electromagnetic pinch force due to the peak current must constantly work in order to separate the droplets. Therefore, the inert gas Ar
When a shield gas containing as a main component is used, droplet separation / droplet transfer for maintaining the arc is performed during the base period, whereas a shield gas containing carbon dioxide as a main component is used. If there is a drop, both droplet detachment and droplet transfer are performed during the peak period. The droplets released during the peak period are easily affected by the strong arc force and are prone to spatter. Therefore, even if one droplet can be released from the wire end every pulse period, the conventional inert gas Ar is mainly used. The effect of reducing spatter cannot be expected as much as when using a shielding gas as a component.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to prevent spatter scattering in a shielding gas containing carbon dioxide gas as a main component, which is inexpensive. How to detect droplet detachment in order to achieve the above object,
How to prevent spatter is an important issue.

[0006]

In order to solve the above-mentioned problems, in the present invention, the welding output is controlled to be lowered by a detachment detection signal output in synchronization with the droplet detachment, thereby preventing the scattering of spatter. It is a thing. Therefore, for each pulse, the welding voltage is detected by the voltage detector, the detected voltage and the reference voltage from the voltage setting device are compared and calculated, and when the former exceeds the latter, a disconnection detection signal is output, The output compensator is operated by this comparison output to reduce the welding output to a level lower than the pulse current (peak current). Further, when the comparison output is further generated, the current is pulsed for a predetermined current decrease time t _M from the time when the comparison output is generated until at least the droplet is completely absorbed in the base metal molten pool. The current (peak current) I _P is lowered to a lower current I _r which is set to a lower level, thereby weakening the arc force after droplet detachment, preventing spatter scattering, and performing more stable welding. .

[0007]

An output control device for a consumable electrode type pulse arc welding machine according to the first aspect of the present invention comprises a voltage detector for detecting a welding voltage, a detection voltage from the voltage detector and a voltage setting device. A comparator that outputs a detection signal when the detection voltage exceeds the reference voltage by performing a comparison calculation with the reference voltage of
An output compensator for reducing the welding output to a level lower than the pulse current according to the detection signal of the comparator is provided.

In the output control device of the consumable electrode type pulse arc welding machine according to the second aspect of the invention, in the invention according to the first aspect, the comparator stores the voltage value at the beginning of pulse energization by the signal from the voltage detector. The output signal from the initial voltage memory, the detection signal from the voltage detector, and the setting signal from the voltage setting device are input, and the difference between the detection voltage of the voltage detector and the initial voltage from the initial voltage memory is input. Is a comparator that outputs a detection signal when the voltage exceeds the set voltage from the voltage setter.

In the output control device of the consumable electrode type pulse arc welding machine according to the third aspect of the invention, in the first aspect of the invention, the comparator is a differentiator for detecting the rate of change of the detected voltage from the voltage detector. This is a comparator that outputs a detection signal when the differential value exceeds the set value from the differential value setting device.

In the output control device of the consumable electrode type pulse arc welding machine according to the fourth aspect of the invention, in the invention according to the third aspect, the detected voltage from the voltage detector is compared with the set value from the reference value setting device. From the output of the short-circuit detector that determines the short-circuit and the arc from, provided with a time setter that sets the voltage rise time when transitioning from the short-circuit to the arc, within the set time of the time setter from the comparator The detection signal is canceled.

In the output control device of the consumable electrode type pulse arc welding machine according to the fifth aspect of the invention, in the first aspect of the invention, the comparator detects the welding voltage and the detected voltage value from the voltage detector. The detected resistance value from the current detector to be detected is input and the detected resistance value is calculated by comparing the detected resistance value from the resistance value calculator with the reference resistance value from the resistance value setting device This is a comparator that outputs a detection signal when the reference resistance value is exceeded.

In the output control device of the consumable electrode type pulse arc welding machine according to the sixth aspect of the invention, in the invention according to the first aspect, the comparator detects the welding voltage and the detected voltage value from the voltage detector. Initial resistance that stores the resistance value at the beginning of pulse energization by the output signal from the resistance value calculator that calculates the detection resistance value by inputting the detected current value from the current detector to detect and the signal from the resistance value calculator Input the output signal from the storage device and the setting signal from the resistance value setting device, and the difference between the detection resistance of the resistance value calculator and the initial resistance from the initial resistance storage device is the reference from the resistance value setting device. This is a comparator that outputs a detection signal when the resistance value is exceeded.

In the output control device of the consumable electrode type pulse arc welding machine according to the seventh aspect of the invention, in the invention according to the first aspect, the comparator detects the welding voltage and the detected voltage value from the voltage detector. Input the detected current value from the current detector to detect and calculate the detected resistance value. The differential value from the differentiator that detects the rate of change of the resistance value signal from the resistance calculator is the set value from the reference value setter. This is a comparator that outputs a detection signal when the value exceeds.

The output control device of the consumable electrode type pulse arc welding machine according to the eighth aspect of the present invention discriminates between a short circuit and an arc by comparing the detected voltage from the voltage detector and the set value from the reference value setter. A seventh time setting device is provided which receives the output of the short-circuit detector and sets a voltage rising period when the short-circuit transitions to the arc, and cancels the detection signal from the comparator within the set time of the time setting device. It is the one described in the means.

An output control device for a consumable electrode type pulse arc welding machine according to a ninth aspect of the present invention comprises a voltage detector for detecting a welding voltage, a detection voltage from the voltage detector and a reference voltage from a voltage setting device. A comparator that outputs a detection signal when the detected voltage exceeds the reference voltage, a drop time setter, a drop current setter, the drop time setter, the drop current setter, and a pulse time. Input the setting signals of the setter, base current setter, and pulse current setter and the detection signal from the comparator, and use the detection signal from the comparator as the starting point, and at least the droplets are completely in the base metal molten pool. A pulse waveform generator for decreasing the current to the decrease current I _r set by the decrease current setting device at a level lower than the pulse current I _p during the decrease time t _M set by the decrease time setting device until being absorbed by Was done .

The output control device of the consumable electrode type pulse arc welding machine according to the tenth aspect of the invention is the pulse wave generator according to the ninth aspect of the invention, wherein the pulse waveform generator detects the setting signal from the fall time setting device and the detection from the voltage detector. Input the output signal of the voltage drop time regulator inputting voltage and the voltage drop current setting device, the pulse time setting device, the setting signal of the base current setting device and the pulse current setting device, and the detection signal from the comparator, and Starting from the detection signal from the comparator, at least the drop time until the droplet is completely absorbed by the base metal molten pool is adjusted by the decrease time adjuster t _M + the decrease adjustment time Δt _M , the current is pulsed current I _Lowering current I _r set by the lowering current setting device at a level lower than _p
It is a pulse waveform generator that lowers the voltage.

The output control device of the consumable electrode type pulse arc welding machine according to the eleventh aspect of the present invention is the pulse waveform generator according to the ninth aspect of the invention, wherein the pulse waveform generator comprises a decrease time setting device, a decrease current setting device and an extension time setting device. Input the set signal of the pulse time setter, the base current setter, and the pulse current setter and the detection signal from the comparator, and use the detection signal from the comparator as the starting point, and at least the droplet will enter the base metal molten pool. At the lowering time t _M set by the lowering time setting device until complete absorption, the current is lowered to the lowering current I _r set by the lowering current setting device at a level lower than the pulse current I _p , and the droplet detachment is prevented. The pulse waveform generator extends the pulse period of the detected pulse by the extension time t _E set by the extension time setting device.

The output control device of the consumable electrode type pulse arc welding machine according to the twelfth aspect of the invention is the pulse wave generator according to the ninth aspect of the invention, in which the pulse waveform generator detects the setting signal from the fall time setting device and the voltage detector The output signal of the fall time regulator that receives voltage and the set signal of the fall current setter, the extension time setter, the pulse time setter, the base current setter, and the pulse current setter, and the detection signal from the comparator. Is input, and at least the drop time t _M + the drop adjustment time Δt _M adjusted by the drop time adjuster from the detection signal from the comparator as a starting point until the droplet is completely absorbed by the base metal molten pool The current is reduced to the lower current I _r set by the lower current setting device at a level lower than the pulse current I _p , and the pulse period of the pulse in which droplet detachment is detected is set by the extension time setting device t _E Power to extend It is a loose waveform generator.

The output control device of the consumable electrode type pulse arc welding machine according to the thirteenth aspect of the present invention is the pulse wave generator according to the ninth aspect of the invention, wherein the pulse waveform generator detects the setting signal from the fall time setting device and the detection from the voltage detector. An output signal of a fall time adjuster having a voltage as an input, an output signal of an extension time adjuster having a setting signal from an extension time setting device and a detection voltage from the voltage detector as an input, and a fall current setting device And pulse time setting device, base current setting device and pulse current setting device,
The detection time from the comparator is input, and the decrease time t _M adjusted by the decrease time adjuster from the detection signal from the comparator as a starting point until at least the droplet is completely absorbed by the base metal molten pool + The current is lowered to the lowering current I _r set by the lowering current setting device at a level lower than the pulse current I _p during the lowering adjustment time Δt _M , and the pulse period of the pulse in which droplet detachment is detected is set to the longer time adjusting device. This is a pulse waveform generator that extends the extension time t _E adjusted in step + extension adjustment time Δt _E.

An output control device for a consumable electrode type pulse arc welding machine according to a fourteenth aspect of the present invention is the output control device according to the tenth aspect of the present invention, wherein the fall time adjuster is a set signal for the fall time setter and an output signal for the voltage detector. It is a fuzzy reasoner with and as input signals.

The output control device for the consumable electrode type pulse arc welding machine according to the fifteenth aspect of the present invention is the output control device according to the thirteenth aspect, wherein the extension time adjuster is a set signal of the extension time setter and an output signal of the voltage detector. It is a fuzzy reasoner with and as input signals.

In a consumable electrode type pulse arc welding in which a shield gas containing carbon dioxide as a main component is used and a pulse current and a base current lower than the pulse current are alternately repeated during welding, the wire end generally melts and grows. The droplet receives forces such as arc force, surface tension, and gravity. However, as the droplets grow, the balance of these forces is lost and the droplets are separated from the wire end. This process will be described with reference to the schematic diagram of FIG. 2 corresponding to the output voltage.

2 (a), (b), (c), (d),
(E) and (f) show the state of droplets at the tip of the wire, and the temporal correspondence with the welding voltage waveform at the bottom is indicated by arrows. When the base period shifts to the pulse period, the droplet 41
Grows rapidly (FIG. 2 (b)). When the wire grows to a certain extent, a constriction k occurs between the wire solid part 40 ((c) of FIG. 2). Its constriction grows over time. Eventually, the droplet separates from the tip of the wire ((d) of FIG. 2). However, at this time, the arc 42 becomes longer than before due to the pole point moving from the melt drop portion to the tip of the wire. The arc length is further lengthened due to the effect that the portion of the wire having a small heat capacity (g portion) is directly melted by the arc. Since the increase in the arc length appears as an increase in the welding voltage, the welding voltage waveform rapidly increases in the process of changing from the state of FIG. 2C to the state of FIG. 2D.
After that, the wire is melted again to form the droplet 41, but the arc length does not become short due to the relationship between the wire feeding speed and the melting amount ((e) in FIG. 2). In this way, when the pulse current period ends and the next base current period starts, the melting amount decreases with respect to the wire feeding speed due to the low base current, and therefore the arc length decreases again (FIG. 2). (F)). As described above, the voltage becomes higher in the second half of the pulse period than in the first half of the pulse period with the droplet separation as the boundary. This increase in voltage can be captured as an increase in resistance value due to an increase in arc length.

According to the present invention, the increase in voltage or resistance due to the droplet detachment is detected by comparison detection with an absolute reference value, detection of an increment from the initial pulse or detection of an increase rate by differentiation. Therefore, the detachment detection signal can be output in synchronization with the droplet detachment. Upon receipt of this separation detection signal, the welding output is reduced for a fixed reduction time. As a result, it is possible to reduce the arc force applied to the droplets that have been separated from the wire end and are being transferred to the drop, and to suppress spatter scattering. Consumable electrode type pulse arc welding using a shield gas containing carbon dioxide as a main component is usually performed in a drop transfer state, but a short circuit may occur depending on the construction conditions. The voltage rises sharply when the short circuit is opened and the arc is transferred. If the disconnection detection signal is obtained by differentiating the voltage or the arc resistance, it will be an erroneous detection. Therefore, it is necessary to cancel the differential signal when the short circuit is released.

Further, by detecting the detachment of the droplet and changing the lowering time for lowering the welding output according to the welding voltage value, the droplet can be surely kept at a low level even if the welding voltage fluctuates during welding. Can be transferred to the molten pool with a decreasing current I _r of. In this way, the amount of spatter generation can be reduced. Depending on the pulse frequency, droplet detachment does not occur with every pulse. In this case, an imbalance occurs in the pulse output state between the pulse in which the droplets have separated and the pulse in which the droplets have not separated. In that case, this imbalance can be corrected by extending the pulse period in which the droplet separation occurs, the welding voltage can be made uniform, and stable welding can be obtained. To adjust the drop time to detect the droplet detachment and reduce the welding output, a fuzzy reasoner that uses the constant time signal set by the drop time setting device and the voltage signal detected by the voltage detector as input signals. Can be used. In addition, to adjust the extension time of the pulse period when the droplets have separated, use a fuzzy reasoner that uses the constant extension time signal set by the extension time setting device and the voltage signal detected by the voltage detector as input signals. Can be used.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

<< First Embodiment >> FIG. 1 shows a first embodiment of the present invention. As shown in FIG. 1, during the peak pulse time set by the pulse time setter 17, the pulse current I _{p of} the peak value set by the pulse current setter 19 is set.
However, during the base time, a periodic output trace waveform is formed by the pulse waveform generator 20 so that the base current I _b set by the base current setter 18 is obtained. The output controller 11 adjusts the output so that the output current matches the output trace waveform, and inputs the signal to the output control element 1. The output adjusted by the output control element 1 is stepped down by the transformer 2, rectified into a direct current by the rectifier 3, smoothed by the reactor 4, and applied between the electrode 8 and the base material 9. In this way, output control of pulse welding is performed. On the other hand, the welding voltage waveform is input to the comparator 14 as the detection voltage V _o by the voltage detector 13, and the voltage setting device 15
_Is compared with the reference voltage V _ref set by The operation of the circuit will be described below with reference to FIG. 3 showing the relationship among the detection voltage V _o , the welding current and the reference voltage V _ref . In FIG. 3, since the output during the pulse time is dropped to a low level at the same time as the droplet detachment detection, the voltage waveform becomes different from that in FIG. In the upper curve of FIG. 3, the reference voltage V _ref is a set value set by the voltage setter 15.

As described above, since the output voltage rises (at the time point A) when the droplet detachment occurs during pulse energization, the reference voltage _Vref is exceeded at the point A when the droplet detaches. In this way, the comparator 14 outputs the departure detection signal at the time point A.
The output corrector 16 receives the departure detection signal and outputs a signal to the output controller 11. Based on the signal, the output controller 11 outputs the output circuit 1234 in the pulse period after the departure detection signal in the corresponding pulse period set by the pulse time setter 17, as shown in the lower curve of FIG. Outputs a signal that causes the output of the above to be a current I _{r of a} level lower than the pulse current I _p . Thereby, the signal from the pulse waveform generator 20 is corrected low. As a result, the output current waveform of the output circuit 1234 is I _p in the first half of the pulse period as shown in the lower curve of FIG. 3, but becomes a low level I _r after the droplet detachment detection. Then, the arc force applied to the droplet after separation can be weakened to prevent the spatter from scattering.

<< Second Embodiment >> FIG. 4 shows a second embodiment of the present invention. In the figure, an initial voltage storage device 22 receives the output of the pulse time setting device 17 and stores the input from the voltage detector 13 at a time point after a fixed time after the start of pulse energization. The fixed time after the start of the pulse energization is determined by the response speed determined by the time constant of the power circuit and the like, but is usually about 1 mS. The comparator 21 calculates the difference ΔV between the stored voltage of the initial voltage memory 22 and the input value of the voltage detector 13. The reference voltage V _ref from the voltage setter 15 is separately input to the comparator 21. ΔV is V
_When it becomes larger than _ref , the comparator 21 outputs a departure detection signal. The subsequent operation is similar to that of the first embodiment. In this embodiment, as in the first embodiment, the effect of weakening the arc force applied to the droplet after separation and preventing the scattering of spatter can be obtained.

<< Third Embodiment >> FIG. 5 shows a third embodiment of the present invention. In the figure, a differentiator 23 differentiates the detected voltage from the voltage detector 13. The differential value dV / dt thus derived is input to the comparator 14 and compared with the reference value V _dr given by the differential value setting unit 27.
When dV / dt becomes larger than V _dr , the comparator 14 outputs a departure detection signal. On the other hand, the short circuit detector 25 detects the detection voltage given from the voltage detector 13 and the reference value setting device 24.
Compare the inputs from. The short-circuit detector 25 outputs an arc state signal when the detected voltage is higher, and outputs a short-circuit state signal when the detected voltage is lower. Time setting device 26
Receives a signal from the short-circuit detector 25 and counts a fixed time from the time point when the short-circuit state is changed to the arc state. This count time is determined by the response speed determined by the time constant of the power circuit and the like, but is usually about 1 mS.

In this manner, the output compensator 28 receives inputs from the comparator 14 and the time setter 26, and cancels the departure detection signal from the comparator 14 during the count time from the time setter 26. To do. Further, the output corrector 28 receives the input from the pulse time setting device 17, and cancels the disconnection detection signal for a certain period of time after switching from base energization to pulse energization. This fixed time is determined by the response speed determined by the time constant of the power circuit and the like, but is usually about 1 mS. The reason for canceling the departure detection signal by these two methods is to prevent erroneous detection. That is, erroneous detection based on an increase in the differential value caused by a voltage increase at the time of shifting from a short circuit to an arc and a voltage increase at the time of shifting from base energization to pulse energization is prevented. As a result, only the signal due to the increase in the differential value caused by the droplet detachment can be selected as the valid signal. In accordance with the departure detection signal thus selected, the output compensator 2
8 outputs a signal to the output controller 11. Based on the signal, the output controller 11 causes the output circuit 1234 to output the low set value I _r during the pulse period after the departure detection signal in the corresponding pulse period set by the pulse time setter 17. The signal I _c is output. The subsequent operation is the same as that of the first embodiment.

<Fourth Embodiment> FIG. 6 shows a fourth embodiment of the present invention. The first to third embodiments (FIG. 1,
4 and 5) is different from the detection of the detachment by the detection voltage detected by the voltage detector 13, the Exam of FIG.
In ple4, a similar effect can be obtained by using a resistance value signal instead of the detection voltage. In FIG. 6, a resistance value calculator 29 calculates a resistance value from output current / voltage values from the current detector 12 and the voltage detector 13, and the result is calculated by the comparator 1
4 is output. The comparator 14 compares the input resistance value from the resistance value calculator 29 with the reference resistance value from the resistance value setter 30. The comparator 14 outputs a droplet detachment detection signal to the output compensator 16 when the input resistance value becomes larger than the reference resistance value. In this way, by detecting the increase in the resistance value due to the detachment of the droplet, the effect of weakening the arc force applied to the droplet after detachment and preventing the scattering of spatters can be obtained as in the first embodiment. To be The operation after the output corrector 16 is the same as that of the first embodiment.

<Fifth Embodiment> FIG. 7 shows a fifth embodiment of the present invention. In FIG. 7, the resistance value calculator 29 calculates the resistance value from the output current / voltage values from the current detector 12 and the voltage detector 13, and outputs the result to the comparator 21 and the initial resistance memory 31. The initial resistance storage unit 31 receives the output of the pulse time setting unit 17 and stores the input from the resistance value computing unit 29 at a time point after a fixed time after the start of pulse energization. The comparator 21 calculates the difference ΔR between the memory resistance value of the initial resistance memory 31 and the input value of the resistance value calculator 29. The reference resistance value R _ref from the resistance value setting unit 30 is separately input to the comparator 21. When ΔR becomes larger than R _ref , the comparator 21 outputs a departure detection signal and supplies it to the output compensator 16. In this way, by detecting the increase in the resistance value due to the detachment of the droplet, the same effect as that of the second embodiment can be obtained. The operation after the output corrector 16 is the same as the second
The same operation as that of the above embodiment is performed.

<< Sixth Embodiment >> FIG. 8 shows a sixth embodiment of the present invention. In FIG. 8, the resistance value calculator 29 calculates the resistance value from the output current / voltage values from the current detector 12 and the voltage detector 13, and outputs the result to the differentiator 23. Therefore, the comparator 14 determines the resistance differential value dR / dt.
And the reference value R _dr of the differential value setting device 27 are compared, and dR / d
A departure detection signal is output when t becomes larger than R _dr . By performing such an operation, the same effect as that of the third embodiment can be obtained. The operation after the output corrector 28 is the same as that of the third embodiment. In each of the above embodiments, the set value I _r sets the output at a low level in order to prevent the scattering of spatter, so the set value I _b of the base current setter 18 can be used for that purpose. .

<< Seventh Embodiment >> FIG. 9 shows a seventh embodiment of the present invention. Note that, with regard to the overall configuration, since the configuration and the function are similar to those of the first to sixth embodiments, the above description and display are applied. Therefore, duplicate description is omitted. Setting signals of the falling time setting device 34, the falling current setting device 35, the pulse time setting device 17, the base current setting device 18, and the pulse current setting device 19, and the output signals of the comparator 14. Are all input to the pulse waveform generator 33.
An output controller 32 receives the detection signal from the current detector 12 and the output signal from the pulse waveform generator 33.

Next, the operation will be described. If there is no droplet separation detection signal from the comparator 14 during welding,
From the pulse waveform generator 33, the pulse time t _p set by the pulse time setter 17, the base time t _b , the base current I _b set by the base current setter 18, and the pulse current I set by the pulse current setter 19. _The pulse waveform composed of _p and _p is output to the output controller 32. On the other hand, a comparator 1 that indicates the timing of droplet separation when droplet separation occurs during the pulse period during welding.
4 output signal, the pulse waveform generator 3
3 outputs a low level current signal to the output controller 32. The low-level current signal has a level drop time t from the time of droplet break-off to at least the complete transfer of the droplet to the molten pool for the pulse in which droplet break-off is detected.
_During the period _M , the signal is a signal which is set by the drop current setting unit 35 and has a level lower than the pulse current I _P and reduced to the drop current I _r . In the output controller 32, the detected current from the current detector 12 and the pulse waveform signal from the pulse waveform generator 33 are input. The output is adjusted so that the detected current matches the pulse waveform signal. The signal is input to the output control element 1. As a result, the output current waveform is I _p in the first half of the pulse period, but the constant time t _M after the droplet detachment detection is at a low level I _r , weakening the arc force applied to the droplet after detachment. It is possible to prevent scattering of spatter. The fall time t _M is set by the fall time setting device 34.
FIG. 10 shows an example of the welding current waveform obtained in this example. In the figure, an example is shown in which the drop current I _r, which is lowered after the droplet separation detection is started with the droplet separation timing as the starting point, is a current between the pulse current I _p and the base current I _b . However, in order to increase the effect of reducing the amount of spatter generation, it is desirable to set the lowering current I _r to the base current I _b .

<< Eighth Embodiment >> FIG. 11 shows an eighth embodiment of the present invention. In addition, regarding the overall configuration, first to sixth
Since the configuration and the function are similar to those of the above embodiment, the above description and display are applied. Therefore, duplicate description is omitted. In the present embodiment, the portion of the reduction time setting device 34 that generates one of the input signals to the pulse waveform generator 33 of the seventh embodiment is replaced by the reduction time adjustment device 36. The same functions as those of the seventh embodiment are designated by the same reference numerals and the description thereof will be omitted. In the present embodiment, the fall time adjuster 36 is a fall time adjuster that uses the setting signal of the fall time setting device 34 and the output signal of the voltage detector 13 as input signals.

Next, the operation will be described. The description of the operation of the parts common to the seventh embodiment will be omitted. The feedback signal of the welding voltage from the voltage detector 13 and the setting signal of the degradation time setting device 34 are input to the degradation time adjusting device 36. At the beginning of welding after the arc start, the reduction time adjuster 36 outputs the reduction time t _M set by the reduction time setting device 34 as it is.
Here, the initial welding time is usually set to 1 s in consideration of the transition period from the arc start to the arc stabilization.
The degree. During welding, the decrease time t _M set by the decrease time adjuster 36 is added to the decrease time t _M set by the decrease time setter 34, and the decrease adjustment time Δt _M that changes according to the welding voltage value fed back from the voltage detector 13 is added. [Drop time t _M
+ Decrease adjustment time Δt _M ] is output.

Therefore, when there is a droplet separation detection signal from the comparator 14, the pulse waveform generator 33 outputs
Reduction time of droplet detachment is the starting point of droplet detachment timing only been detected pulses at least until the droplet moves completely molten pool t _M + lowering adjusted period △ t lowered current setting circuit current during _M The output controller 32 outputs a signal lowered to the lowering current I _{r of a} level lower than the pulse current I _P set in 17.
Output to. As a result, the output current waveform is I _p in the first half of the pulse period, but a fixed time t _M + after the droplet detachment is detected.
Δt _M results in a low level of I _r . In this way, the arc force applied to the droplet after separation can be weakened to prevent spatter scattering. However, the fall time t _M + the fall adjustment time Δt _M is obtained by the fall time adjuster 36. The decrease adjustment time △
t _M varies depending on the region of the initial setting voltage, and the boundary of the range of the initial setting voltage is complicated. Therefore, in the present invention, the fall adjustment time Δt _M can be calculated by fuzzy reasoning.

<< Ninth Embodiment >> FIG. 12 shows a ninth embodiment of the present invention. In addition, regarding the overall configuration, first to sixth
Since the configuration and the function are similar to those of the above embodiment, the above description and display are applied. Therefore, duplicate description is omitted. In this embodiment, the pulse waveform generator 33 of the seventh embodiment is replaced with a pulse waveform generator 37. The same functions as those of the seventh embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, the extension time setting device 38, the fall time setting device 34, the fall current setting device 35, the setting signals of the pulse time setting device 17, the base current setting device 18, and the pulse current setting device 19 and the comparator. A pulse waveform generator 37 having an output signal from 14 as an input signal is provided.

Next, the operation will be described. The description of the operation of the parts common to the seventh embodiment will be omitted. If droplet separation occurs during the pulse period during welding and there is an output signal of the comparator 14 indicating the droplet separation timing,
From the pulse waveform generator 37, the drop time t from the droplet detachment timing as a starting point only to the pulse in which droplet detachment is detected until the droplet completely moves to the molten pool
_While lowering the current to _M to the lowering current I _r set by the lowering current setting device 35 to a level lower than the pulse current I _P ,
A pulse signal obtained by extending the pulse period to the extension time t _E set by the extension time setting unit 38 is output to the output controller 32. As a result, the output current waveform is I in the first half of the pulse period.
_Although it is _p , the fixed time t _M after the droplet detachment is detected becomes a low level I _r , and the arc force applied to the droplet after detachment can be weakened to prevent the scattering of spatter. This fall time t _M is set by the fall time setter 34, but the extension time t _M
E is set by the extension time setting device 38. In order to make the welding voltage uniform, it is necessary to make the energy during the period in which the current after the droplet detachment has been lowered equal to the energy in the period during which the pulse period has been extended, so the extension time t _E and the fall time t _M must be chosen to have the relationship shown in equation (1).

[0042]

[Equation 1]

When I _{r is set} to I _b , t _E = t _M according to the equation (1). FIG. 13 shows an example of the welding current waveform obtained in this example.

<< Tenth Embodiment >> FIG. 14 shows a first embodiment of the present invention.
0 is an example. Regarding the overall configuration,
-Since the sixth embodiment has a similar configuration and similar function to those of the sixth embodiment, the above description and display are applied. Therefore, duplicate description is omitted. In this embodiment, one of the input signals to the pulse waveform generator 37 of the ninth embodiment, that of the fall time setting device 34, is replaced with the fall time adjusting device 36 shown in the eighth embodiment. . The same functions as those in the ninth or eighth embodiment are designated by the same reference numerals and the description thereof will be omitted.

Next, the operation will be described. The description of the operation of the parts common to the ninth and eighth embodiments will be omitted. The feedback signal of the welding voltage from the voltage detector 13 and the setting signal of the degradation time setting device 34 are input to the degradation time adjusting device 36. At the beginning of welding after the arc start, the decrease time adjuster 36 outputs the decrease time t _M set by the decrease time setter 34 as it is. Here, in consideration of the transition period from the arc start to the arc stabilization, the initial welding time is usually set to 1 s. During welding, the drop time adjuster 3
6 to the decrease time t _M set by the decrease time setter 34.
Said voltage detector 13 decreases adjustment time varying according to the feedback welding voltage value from △ t _M reduced time obtained by adding the t _M + lowering adjusted period △ t _M outputs to.

Therefore, when there is a droplet detachment detection signal from the comparator 14, the pulse waveform generator 37 determines at least the droplet with the droplet detachment timing as the starting point only for the pulse in which droplet detachment is detected. completely during the reduction until the transition to the molten pool time t _M + lowering adjusted period △ t _M is reduced to decrease the current I _r of less than the pulse current I _P set by the lowered current setting device 35 the current level. At the same time, a pulse signal obtained by extending the pulse period of the same pulse by the extension time t _E set by the extension time setting unit 38 is output to the output controller 32. As a result, the output current waveform is I in the first half of the pulse period.
is a _p, can prevent scattering of sputtered weakly fixed time t _M + △ t _M low level of I _r next after droplet separation detection, the arc force on the droplet after detachment. However, the fall time t _M + the fall adjustment time Δt _M is obtained by the fall time adjuster 36, but the extension time t _E set by the extension time setter 38 is the fall time t _M set by the fall time setter 34. Can be calculated from (Equation 1).

<< Eleventh Embodiment >> FIG. 15 shows the first embodiment of the present invention.
It is an example of No. 1. Regarding the overall configuration,
-Since the sixth embodiment has a similar configuration and similar function to those of the sixth embodiment, the above description and display are applied. Therefore, duplicate description is omitted. In the present embodiment, one of the input signals to the pulse waveform generator 37 of the tenth embodiment, that part of the extension time setting device 38, is replaced with an extension time adjusting device 39. In addition,
Those having the same functions as those of the tenth embodiment are designated by the same reference numerals, and the description thereof will be omitted. In the present embodiment, 39 is an extension time adjuster which uses the setting signal of the extension time setting device 38 and the output signal of the voltage detector 13 as input signals.

Next, the operation will be described. The description of the operation of the parts common to the tenth embodiment will be omitted. A feedback signal of the welding voltage from the voltage detector 13 and a setting signal of the extension time setting device 38 are input to the extension time adjusting device 39. At the beginning of welding after the arc start, the extension time adjuster 39 outputs the extension time t _E set by the extension time setting device 38 as it is. Here, in consideration of the transition period from the arc start to the arc stabilization, the initial welding time is usually set to 1 s. During welding, an extension adjustment time Δt _E that changes according to the welding voltage value fed back from the voltage detector 13 is added to the extension time t _E set by the extension time adjuster 39 by the extension time setter 38. Output extension time t _E + extension adjustment time Δt _E. Therefore, when there is a droplet detachment detection signal from the comparator 14, at least the droplet is completely melted starting from the droplet detachment timing only for the pulse in which the droplet detachment is detected from the pulse waveform generator 37. together lowered to decrease the time t _M + lowering adjusted period △ t _M reduction in a level lower than the pulse current I _P set the current at a reduced current setting unit 35 to the current I _r to migrate into the pond,
In the same pulse period, an extension time t _E + extension adjustment time obtained by adding an extension adjustment time Δt _E that changes according to the welding voltage signal fed back from the voltage detector 13 to the extension time t _E preset by the extension time setting device 38. Δt _{E The} extended pulse signal is output to the output controller 32.

As a result, the output current waveform is I _p in the first half of the pulse period, but a fixed time t _M + after the droplet detachment is detected.
Δt _{M It} becomes a low level I _r , and the arc force applied to the droplet after separation can be weakened to prevent spatter scattering. However, the fall time t _M + the fall adjustment time Δt _M is obtained by the fall time adjuster 36. The extension time t _E + extension adjustment time Δt _E is obtained by the extension time adjuster 39. Further, the relationship between the extension adjustment time Δt _E and the decrease adjustment time Δt _M shown in Expression (2) can be obtained from the relationship between the extension time t _E and the decrease time t _M shown in Expression (1). .

[0050]

[Equation 2]

When I _{r is set} to I _b , Δt _E = Δt _{M according} to the equation (2). The extension adjustment time Δt _E differs depending on the region of the initial setting voltage, like the decrease adjustment time Δt _M , and the boundary of the range of the initial setting voltage is complicated. Therefore, in the present invention, it is preferable to calculate the extended adjustment time Δt _E by fuzzy reasoning. FIG.
6 shows an example of the welding current waveform obtained in this example.

[0052]

As described above, according to the first to eighth aspects of the present invention, the output is suppressed to a low level I _r while the droplets are separated from the wire end and drop-transferred during welding. Since it is possible to suppress the arc force applied to the droplet during the drop transfer, it is possible to reduce the spatter generation amount. According to the invention of claim 9, the droplet detachment detection signal is used as a starting point after the droplet detachment timing is detected during the welding pulse period, and at least the droplet is completely absorbed in the base metal molten pool. The amount of spatter generated can be reduced by controlling the current to be reduced to the reduction current I _r only during the reduction time t _M until the temperature rises. According to the tenth aspect of the invention, the welding voltage is fed back during welding, and the period during which the current is reduced to the reduced current I _r after the droplet detachment is detected is changed according to the fed back welding voltage value. Even if there is, the droplet can be completely transferred to the molten pool with a low current,
The amount of spatter generated can be reduced.

According to the eleventh aspect of the invention, the drop current I is detected after the droplet detachment timing is detected.
_{By extending the pulse period of the pulse reduced to r by extending the extension time t E} , it is possible to reduce the amount of spatter generation and make the welding voltage uniform, so that stable welding can be obtained. According to the twelfth aspect, the pulse period of the pulse for detecting the droplet detachment timing is extended by the extension time t _E , the welding voltage is fed back during welding, and the current is reduced to the reduced current I _r after the droplet detachment is detected. Even if there is a change in the welding voltage by changing the lowering period according to the value of the welding voltage fed back, the droplets can be completely transferred to the molten pool with a low current, reducing the amount of spatter generation and the welding voltage. Can be stabilized,
Stable welding can be obtained.

According to the thirteenth aspect of the invention, the time for reducing the current to the decreasing current I _r after the droplet detachment from the wire end is detected and the time for extending the pulse period of the pulse for which the droplet detachment is detected are set. Is the sum of the drop adjustment time Δt _M and the extension adjustment time Δt _E , which vary according to the welding voltage value fed back during welding, to the drop time t _M and the extension time t _E , respectively, t _M + Δt _By setting _M and t _E + Δt _E , droplets can be completely transferred to the molten pool with a low current even when there is a change in the welding voltage, reducing the amount of spatter and stabilizing the welding voltage. Can be
Stable welding can be obtained. According to the fourteenth invention, in any one of the tenth invention, the twelfth invention and the thirteenth invention, the output signal of the voltage detector and the setting signal of the fall time setting device are input signals instead of the fall time adjusting device. Even if a fuzzy reasoner that uses
The same effect as any of the inventions can be obtained. Also, the 15th
According to the invention, in the thirteenth invention, even if a fuzzy reasoning device having an output signal of the voltage detector and a setting signal of the extension time setting device as input signals is used instead of the extension time adjusting device, Similar effects are obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an output control device of a consumable electrode type pulse arc welding machine according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a relationship between a droplet state and an output voltage.

FIG. 3 is a waveform diagram showing the relationship between output voltage / current and disconnection detection in the first embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of an output control device of a consumable electrode type pulse arc welding machine according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of an output control device of a consumable electrode type pulse arc welding machine according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing the configuration of an output control device of a consumable electrode type pulse arc welding machine according to a fourth embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of an output control device of a consumable electrode type pulse arc welding machine according to a fifth embodiment of the present invention.

FIG. 8 is a block diagram showing the configuration of an output control device of a consumable electrode type pulse arc welding machine according to a sixth embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration of an output control device of a consumable electrode type pulse arc welding machine according to a seventh embodiment of the present invention.

FIG. 10 is a schematic diagram showing an example of a welding current waveform according to the seventh embodiment of the present invention.

FIG. 11 is a block diagram showing a configuration of an output control device of a consumable electrode type pulse arc welding machine according to an eighth embodiment of the present invention.

FIG. 12 is a block diagram showing a configuration of an output control device of a consumable electrode type pulse arc welding machine according to a ninth embodiment of the present invention.

FIG. 13 is a schematic diagram showing an example of a welding current waveform according to the ninth embodiment of the present invention.

FIG. 14 is a block diagram showing a configuration of an output control device of a consumable electrode type pulse arc welding machine according to a tenth embodiment of the present invention.

FIG. 15 is a block diagram showing a configuration of an output control device of a consumable electrode type pulse arc welding machine according to an eleventh embodiment of the present invention.

FIG. 16 is a schematic diagram showing an example of a welding current waveform according to the eleventh embodiment of the present invention.

[Explanation of symbols]

12 current detector 13 voltage detector 14 comparator 15 voltage setting device 16 output compensator 17 pulse time setting device 18 base current setting device 19 pulse current setting device 20 pulse waveform generator 21 comparator 22 initial voltage storage device 23 differentiator 24 Reference Value Setting Device 25 Short Circuit Detector 26 Time Setting Device 27 Differential Value Setting Device 28 Output Corrector 29 Resistance Value Calculator 30 Resistance Value Setting Device 31 Initial Resistance Memory 32 Output Controller 33 Pulse Waveform Generator 34 Drop Time Setting vessel 35 decreases the current setting device 36 decreases the time adjuster 37 pulse waveform generator 38 extension time setter 39 extended time regulator 40 the wire solid portion 41 droplet 42 arc t _p pulse time t _b the base time I _p pulse current I _b based Current t _M decrease time I _r decrease current t _E extension time Δt _M decrease adjustment time Δt _E extension adjustment time

Claims (15)

[Claims] 1. A voltage detector for detecting a welding voltage, a detected voltage from the voltage detector and a reference voltage from a voltage setting device are compared and calculated, and a detection signal is output when the detected voltage exceeds the reference voltage. An output control device for a consumable electrode type pulse arc welding machine, comprising: a comparator for outputting; and an output compensator for reducing a welding output to a level lower than a pulse current by a detection signal of the comparator. 2. A comparator outputs an output signal from an initial voltage memory that stores a voltage value at the beginning of pulse energization by a signal from the voltage detector, a detection signal from the voltage detector, and a setting signal from the voltage setter. 2. A comparator for outputting a detection signal when the difference between the detection voltage of the voltage detector and the initial voltage from the initial voltage memory exceeds the set voltage from the voltage setter. An output control device for the consumable electrode type pulse arc welding machine described. 3. The comparator is a comparator which outputs a detection signal when the differential value from the differentiator for detecting the change rate of the detected voltage from the voltage detector exceeds the set value from the differential value setting device. Item 1. An output control device for a consumable electrode type pulse arc welding machine according to Item 1. 4. A voltage at the time of shifting from a short circuit to an arc in response to an output of a short circuit detector for discriminating between a short circuit and an arc by comparing a detected voltage from a voltage detector and a set value from a reference value setting device. The output control device for a consumable electrode type pulse arc welding machine according to claim 3, wherein a time setter for setting the rising time is provided, and the detection signal from the comparator is canceled within the set time of the time setter. 5. A comparator for inputting a detected voltage value from a voltage detector for detecting a welding voltage and a detected current value from a current detector for detecting a welding current to calculate a detected resistance value. 2. The consumable electrode type pulse according to claim 1, wherein the comparator is a comparator which outputs a detection signal when the detected resistance value and the reference resistance value from the resistance value setting device are compared and calculated and the detected resistance value exceeds the reference resistance value. Output controller for arc welder. 6. The comparator is a resistance value calculator that inputs a detected voltage value from a voltage detector that detects a welding voltage and a detected current value from a current detector that detects a welding current and calculates a detected resistance value. The output signal from the resistance value calculator and the signal from the resistance value calculator store the resistance value at the beginning of pulse energization. The output signal from the initial resistance memory device and the setting signal from the resistance value calculator are input to the resistance value calculator. 2. The consumable electrode type pulse arc according to claim 1, wherein the comparator is a comparator which outputs a detection signal when the difference between the detection resistance of the first resistance memory and the initial resistance from the initial resistance memory exceeds a reference resistance value from the resistance value setting device. Welder output control device. 7. The comparator is a resistance value calculator that inputs a detection voltage value from a voltage detector that detects a welding voltage and a detection current value from a current detector that detects a welding current, and calculates a detection resistance value. 2. The consumable electrode type pulse arc welding according to claim 1, wherein the comparator is a comparator which outputs a detection signal when the differential value from the differentiator for detecting the change rate of the resistance value signal exceeds the set value from the differential value setter. Machine output control device. 8. A voltage at the time of shifting from a short circuit to an arc in response to an output of a short circuit detector for discriminating between a short circuit and an arc by comparing a detected voltage from a voltage detector and a set value from a reference value setting device. The output control device for a consumable electrode type pulse arc welding machine according to claim 7, wherein a time setter for setting the rising period is provided, and the detection signal from the comparator is canceled within the set time of the time setter. 9. A voltage detector for detecting a welding voltage, a detection voltage from the voltage detector and a reference voltage from a voltage setting device are compared and calculated, and a detection signal is output when the detection voltage exceeds the reference voltage. Output comparator, fall time setting device, fall current setting device, setting signal of the fall time setting device, the fall current setting device, pulse time setting device, base current setting device, and pulse current setting device, and the above The detection signal from the comparator is input, and the decrease time t _M set by the decrease time setting device from the detection signal from the comparator as a starting point until the droplet is completely absorbed by the base metal molten pool And a pulse waveform generator for lowering the current to a lower current I _r set by the lower current setting device at a level lower than the pulse current I _p , and an output control device for a consumable electrode type pulse arc welding machine. 10. The pulse waveform generator has an output signal of a fall time adjuster which receives a setting signal from a fall time setter and a detection voltage from a voltage detector, a fall current setter, a pulse time setter and a base. Input the setting signals of the current setting device and pulse current setting device and the detection signal from the comparator, and use the detection signal from the comparator as a starting point until at least the droplet is completely absorbed by the base metal molten pool. Of the pulse waveform generator that lowers the current to the lowering current I _r set by the lowering current setting device at a level lower than the pulse current I _p at the lowering time t _M adjusted by the lowering time regulator + the lowering adjustment time Δt _M An output control device of the consumable electrode type pulse arc welding machine according to claim 9. 11. The pulse waveform generator is a setting signal for a fall time setting device, a fall current setting device, an extension time setting device, a pulse time setting device, a base current setting device, and a pulse current setting device, and a detection signal from a comparator. By inputting the detection signal from the comparator as a starting point and applying a current to the pulse current I at least for the decrease time t _M set by the decrease time setting device until the droplet is completely absorbed in the base metal molten pool. Generation of a pulse waveform that lowers to a lowering current I _r set by the lowering current setting unit at a level lower than _p and extends the pulse period of a pulse in which droplet detachment is detected by the extension time t _E set by the extension time setting unit. 10. The output control device of the consumable electrode type pulse arc welding machine according to claim 9, which is a vessel. 12. The pulse waveform generator has an output signal of a fall time adjuster which receives a setting signal from a fall time setter and a detection voltage from a voltage detector, a drop current setter, an extension time setter, and a pulse. Input the setting signals of the time setter, base current setter, and pulse current setter and the detection signal from the comparator, and use the detection signal from the comparator as the starting point, and at least the droplets will be completely in the base metal molten pool. Decrease time adjusted by the decrease time adjuster until being absorbed by t _M + decrease adjustment time Δ
At t _M , the current is lowered to the lower current I _r set by the lower current setting device at a level lower than the pulse current I _p , and the pulse period of the pulse in which droplet detachment is detected is set by the extension time setting device. The output control device of the consumable electrode type pulse arc welding machine according to claim 9, wherein the pulse waveform generator extends the time t _E. 13. The pulse waveform generator includes an output signal of a fall time adjuster which receives a setting signal from the fall time setting device and a detection voltage from a voltage detector, a setting signal from the extension time setting device, and The output signal of the extension time regulator that receives the detection voltage from the voltage detector, the setting signals of the drop current setter, pulse time setter, base current setter, and pulse current setter, and the comparator output. And a detection signal from the comparator as a starting point, and at least a drop time until the droplet is completely absorbed in the base metal molten pool adjusted by the decrease time controller t _M + a decrease adjustment time The current is reduced to Δt _M to a lower current I _r set by the lower current setting device at a level lower than the pulse current I _p , and the pulse duration of the pulse in which droplet detachment is detected is adjusted by the extension time adjuster. time t _E + extension tone Consumable electrode type pulsed arc welder of the output control device according to claim 9 in which the time Delta] t _E extended pulse waveform generator. 14. The output control of a consumable electrode type pulse arc welding machine according to claim 10, wherein the fall time adjuster is a fuzzy reasoner which receives the setting signal of the fall time setting device and the output signal of the voltage detector as input signals. apparatus. 15. The output control of the consumable electrode type pulse arc welding machine according to claim 13, wherein the extension time adjuster is a fuzzy reasoner which receives the setting signal of the extension time setting device and the output signal of the voltage detector as input signals. apparatus.