JP3033368B2 - Consumable electrode type pulse arc welding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a consumable electrode type pulse arc welding method, and more particularly to a method of transferring a consumable electrode to a workpiece as a droplet at each pulse and feeding a consumable electrode as needed. The present invention relates to a consumable electrode type pulse arc welding method for continuously performing beautiful welding.

[0002]

2. Description of the Related Art Conventionally, there has been known a method of performing arc welding by forming an arc current in which a pulse current of a predetermined period and a base current are superimposed between a consumable electrode and a workpiece. According to this method, the tip of the consumable electrode melted by the heat of the arc current is appropriately dropletized by the pinch effect generated when the pulse current is generated.

That is, when a pulse current is generated between the consumable electrode and the workpiece at predetermined intervals, a magnetic field is generated so as to narrow the arc current in accordance with a sudden change in the current value. Then, due to the influence of the magnetic field, the melted portion at the tip of the consumable electrode is squeezed out and transferred to the workpiece as fine particles (hereinafter referred to as spray transfer). Therefore, according to this method, the spray transfer of the droplet occurs at each pulse, and welding with beautiful appearance is realized.

In this welding method, it is necessary that the amount of the consumable electrode to be supplied and the amount of the consumable electrode to be consumed are in an equilibrium state. In other words, the distance between the tip of the consumable electrode and the workpiece is
It is preferable that the average is constant when averaged.

[0005] For example, when the supply amount of the consumable electrode exceeds the consumable amount, the distance between the consumable electrode and the workpiece is gradually narrowed, and eventually a short circuit phenomenon occurs. If the two are short-circuited, the melted portion at the tip of the consumable electrode scatters as spatter due to the impact at the time of the short-circuit, thereby deteriorating welding quality.

[0006] When the supply amount of the consumable electrode is insufficient, a desired arc current cannot be obtained as the interval is widened, and welding may not be sufficiently performed.

[0007] Japanese Patent Publication No. Sho 62-50221 discloses a method of keeping the supply amount of the consumable electrode and the consumable amount at the time of performing such welding in an equilibrium state. According to this method, when performing arc welding using a pulse current, the consumable electrode is fed at a constant speed and the arc voltage is monitored. Since the arc voltage is a value corresponding to the interval between the consumable electrode and the workpiece, the amount of consumption is adjusted by increasing or decreasing the arc current value so that this value is constant.

Therefore, according to the method described in the above publication, the amount of wear of the consumable electrode is consequently constant, and the average value of the distance between the consumable electrode and the workpiece is kept constant.

[0009]

However, the above-mentioned conventional welding method is configured to feed the consumable electrode at a constant speed.
However, as described above, the consumption of the consumable electrode is performed in units of one droplet. Therefore, the distance between the consumable electrode and the workpiece, that is, the arc length changes every time the droplet moves, and becomes the maximum length immediately after the droplet moves.

[0010] Incidentally, it is necessary to ensure a sufficient space between the consumable electrode and the article to be joined so that a short circuit does not occur when the droplet transfers. On the other hand, if an interval enough to prevent a short circuit is secured, the spread of the arc discharge on the workpiece is also increased.

Particularly, in a portion of the workpiece to be welded immediately after the transfer of the droplet, the workpiece melts in a wide range, and the left and right ends of the weld bead become underfilled, that is, a so-called undercut. Occurs.

[0012] Further, in the case where a high voltage is supplied to the consumable electrode as needed as described above, a member called a contact tip is required to supply a voltage to the consumable electrode.
In this case, when a current is supplied from the contact tip to the consumable electrode, Joule heat corresponding to the contact resistance is generated at those contact portions. In particular, when a current corresponding to the pulse current is supplied from the contact tip toward the consumable electrode, an extremely large amount of heat is generated as compared with the case where the base current is supplied.

However, the above-mentioned conventional method does not take this point into consideration at all, and there is no difference in the heat radiation mechanism regardless of whether the current flowing through the consumable electrode is a pulse current or a base current. . For this reason, when a welding device is realized using the above-mentioned conventional method, there is a problem that the wear of the contact tip when supplying a pulse current is remarkably promoted.

The present invention has been made in view of the above-mentioned point, and it is possible to prevent the occurrence of undercut by narrowing the interval between the consumable electrode and the workpiece immediately after the transfer of the droplet.
It is another object of the present invention to provide a consumable electrode type pulse arc welding method in which the supply speed of a consumable electrode when a pulse current flows is increased to thereby improve the cooling efficiency of a contact tip when a pulse current is supplied.

[0015]

The occurrence of undercut is solved by the consumable electrode type pulse arc welding method shown in the principle diagram of FIG.

In FIG. 1, in a first step M1, a predetermined pulsed arc current is generated between the consumable electrode and the workpiece to melt the tip of the consumable electrode and feed the consumable electrode at a predetermined speed. And replenish the depletion.

In the second step M2, the first step M1
Detects the time when the consumable electrode transfers to the workpiece as a droplet.

In the third step M3, the second step M2
The feeding speed of the consumable electrode is advanced by a predetermined amount from the average feeding speed for a predetermined period immediately after the time detected in (1).

Further, the suppression of wear of the contact tip can be solved by the consumable electrode type pulse arc welding method shown in the principle diagram of FIG.

That is, the first step M11 in FIG.
Then, similarly to the first step M1, a pulse arc current of a predetermined cycle is generated between the consumable electrode and the workpiece,
At each pulse, the consumable electrode is transferred to the workpiece as a droplet as a droplet, and the consumable electrode is fed at a predetermined speed to replenish the consumable portion.

In the second step M12, a pulse generation time of the pulse arc current is detected.

Then, based on the detection timing, in a third step M13, the supply speed of the consumable electrode is made faster than the average supply speed for a predetermined period during the generation of the pulse current.

[0023]

In the consumable electrode type pulse arc welding method shown in FIG. 1, in the first step M1, the tip of the consumable electrode is melted, and a portion of the consumable electrode consumed by the melting is supplied. .

In the second step M2, the time when the tip of the consumable electrode shifts to the workpiece as a droplet is detected. In other words, the time when the distance between the tip of the consumable electrode and the object to be welded becomes longer as the droplet moves to the object to be welded is detected.

In the third step M3, when it is detected in the second step M2 that the interval between the tip of the consumable electrode and the work to be welded becomes long, the wear for a predetermined period immediately after that is detected. Increase the electrode feed rate from the average feed rate. For this reason, the interval between the consumable electrode and the article to be bonded can be shortened immediately after the transfer of the droplets, while the amount of the consumable electrode consumed per pulse current is kept constant. Therefore, the occurrence of undercut that occurs when the interval between the consumable electrode and the workpiece is wide is suppressed.

In the consumable electrode type pulse arc welding method shown in FIG. 2, pulse arc welding is started in the first step M11 in the same manner as in the first step M1. Then, in the second step M12, a pulse generation time, that is, a time when the current flowing through the consumable electrode rapidly increases is detected.

In the third step M13, the feeding speed of the consumable electrode while the pulse current is flowing is increased based on the timing detected in the second step M12. Also,
The consumable electrode acts to remove heat from the contact tip, which is a current supply source, as the power is supplied. Therefore, while the pulse current is flowing through the consumable electrode, a large amount of heat is generated in the contact tip, while the heat dissipation effect of the consumable electrode is increased, and the wear of the contact tip is suppressed.

[0028]

FIG. 3 is a block diagram showing an embodiment of an apparatus for performing a consumable electrode type pulse arc welding method according to the present invention.
In the figure, reference numeral 1 denotes a rectifier circuit of a primary side input. The output terminal of the rectifier circuit 1 is connected to the smoothing circuit 2,
Connected to inverter circuit 3. The inverter circuit 3
Based on an output signal of a power element drive circuit 22 described later,
This is a circuit for generating a desired current.

The output terminal of the inverter circuit 3 is connected to the high frequency transformer 4. The transformer 4 is connected to a rectifier circuit 5, and the positive terminal of the output terminals of the rectifier circuit 5 is connected to a contact chip 10 via a power cable 8 having a reactor 6, and the negative terminal of the rectifier circuit 5 is connected to a power cable 9 having a shunt 7. Is connected to the work 11 which is a workpiece to be welded.

A wire 13 supplied from a wire reel 12 is inserted into the contact chip 10 along its central axis. The wire 13 is electrically connected to the power cable 8 in the welding torch 10 and receives a necessary power supply via the power cable 8.

The wire 13 corresponds to a consumable electrode when performing arc welding in the apparatus of this embodiment, and is fed at a predetermined speed by a wire supply roller 14 composed of a pair of rollers.
Note that an output terminal of the motor control unit 15 is connected to the wire supply roller 14, and the feed speed of the wire 13 is determined by a command value of the motor control unit 15.

The above is the configuration for executing the first steps 1 and 11 by the apparatus of this embodiment, and the operation is the same as that of the conventional pulse welding apparatus. That is,
The three-phase alternating current supplied to the primary side of the device is rectified by the rectifier circuit 1 and then smoothed by the smoothing circuit 2 and then supplied to the inverter circuit 3 as a DC power supply.

The inverter circuit 3 outputs a signal having a desired cycle based on the drive signal supplied from the power element drive circuit 22. Then, the current output from the inverter circuit 3 is transformed by the high-frequency transformer 4 and rectified by the rectifier circuit 5, and then applied to the wire 13 and the work 11 in a state where the DC base current and the desired pulse current are superimposed. Supplied.

Accordingly, in the present embodiment, the wire 1
The arc discharge formed between the workpiece 3 and the workpiece 11 has an arc current in a state in which a DC base current and a desired pulse current are superimposed. At this time, the tip of the wire 13 is melted by the heat of the arc discharge, and moves onto the work 11 as a wire droplet. The motor control circuit 15 rotates the wire supply motor 14 at a predetermined speed and replenishes the consumption of the wire 13 due to the transfer of the droplets.

In this embodiment, the wire 13
The current / voltage value of the arc discharge formed between the workpiece and the workpiece 11 is feedback-controlled, thereby ensuring a stable arc discharge. Hereinafter, the feedback system of the apparatus of this embodiment will be described.

In FIG. 3, reference numeral 16 denotes a voltage detector. The voltage detector 16 detects a potential difference between the power cables 8 and 9 and supplies the detected value to a voltage comparator 17. The voltage comparator 17 is connected to an output terminal of a voltage setting unit 18 for setting a predetermined voltage value to be generated between the power cables 8 and 9 in addition to the voltage detector 16. And
These values are compared, and a voltage command is issued to the current waveform setting unit 19 in order to bring the actually measured value closer to the set value.

The potential difference generated between the power cables 8 and 9 indicates a value corresponding to the distance between the tip of the wire 13 and the specific weldment 11. If this value can be maintained at a constant value, the length of the arc discharge (hereinafter referred to as the length) , Arc length) can be maintained substantially constant.

Therefore, when the current waveform setting section 19 detects, for example, that the voltage is lower than the set voltage, that is, when the distance between the wire 13 and the workpiece 11 is narrow, the consumption of the wire 13 is promoted. Therefore, the arc current value is increased. In the opposite case, the arc current is reduced to suppress the consumption of the wire 13.

A current detector 20 is connected to the shunt 7 of the power cable 9. The current detector 20 detects the value of the current discharged from the wire 13 to the work 11, and outputs the detected value to the comparator 21. The comparator 21 compares the current waveform of the current waveform setting unit 19 with the current value supplied from the current detector 20, and outputs a result of the comparison to the power element driving circuit 22.

The power element driving circuit 22 drives the inverter circuit 3 based on the comparison result of the comparator 21 so that the discharge current from the wire 13 follows the current set by the current waveform setting unit 19, and The current flowing through the cables 8 and 9 is controlled.

Hereinafter, the wire feed control unit 30, which is a main part of the apparatus of this embodiment, will be described. Prior to that, the necessity of the wire feed control unit 30 will be described.

FIG. 4 is a time chart for explaining the state of the distal end of the wire 13 when the wire 13 is fed at a constant speed in the apparatus of the embodiment. FIG. 4 (A)
FIG. 4 shows how the tip of the wire 13 changes over time.
(B) and (C) show variations in arc current and wire speed, respectively.

As shown in FIG. 4 (B), the arc current in the present embodiment shows a state in which a pulse current of a predetermined cycle is superimposed on the base current. In this case, at time t ₁ immediately before the pulse current rises, as shown in FIG. 4A, the tip of the wire 13 is only slightly melted.

When the pulse current rises, the melting of the tip of the wire 13 rapidly progresses with an increase in the discharge energy thereafter, and the tip of the wire 13 is narrowed by the pinch effect of the magnetic field generated by the discharge current (FIG. 4 (A), times t ₂ and t ₃ ). Then, after the pulse current falls, the droplet of the wire 13
1 (time t ₄ in FIG. 4A).

At this time, if the feeding speed of the wire 13 is too fast, a short circuit with the work 11 occurs when the molten portion at the tip of the wire 13 extends due to the action of the pinch effect. Such a short circuit is known to cause spatter, and causes a significant reduction in welding quality. Therefore, FIG.
The feeding speed of the wire 13 shown in (C) is considered so that the wire 13 and the work 11 are not short-circuited in any case, and the interval between them is set sufficiently wide.

In the state immediately before the transfer of the droplet (time t ₃ in FIG. 4A), the distance from the tip of the droplet to the work 11 is the arc length. In a state immediately after the transfer of the droplet (time t ₄ in FIG. 4A), the distance from the tip of the wire 13 having no droplet to the work 11 is the arc length.

Therefore, the arc length changes significantly before and after the droplet moves to the work 11. In particular, when the arc length is set sufficiently long to prevent short circuit as in the apparatus of the present embodiment, the arc length immediately after the transfer of the droplet is long, and the spread of the arc discharge on the workpiece 11 may be too large. is there. For this reason, a portion other than the region to be welded is melted by the arc discharge, and so-called undercut occurs in which both ends of the welded portion are underfilled.

As described above, when the wire is fed at a constant speed, an undercut is easily generated in a portion to be welded immediately after the transfer of the droplet. Therefore, in the present embodiment, the wire feed control device 30 is provided to prevent undercut.

FIG. 5 is a diagram for explaining the principle of preventing undercut. In addition, FIGS.
Similar to FIG. 4, changes in the tip of the wire 13 with time, changes in the arc current, and changes in the wire speed are shown.

In this case, as shown in FIG. 5C, the feeding of the wire 13 is performed immediately after the droplet of the wire 13 is separated from the wire 13 until a predetermined time elapses (time t _{4 to} t ₅ ). Speed has been increased. Then, by reducing the feeding speed in other areas, the feeding length of one cycle is adjusted to be equal to the case shown in FIG.

Accordingly, in the case of this example, as shown in FIG. 5A, immediately after the droplet has separated from the wire 13, the distance between the wire 13 and the work 11 is sharply reduced. In other words, the period from when the droplet moves to the workpiece 11 and the arc length is increased to when the arc length becomes a distance that does not cause undercut is significantly reduced. Therefore, as shown in this example, the wire 13
In this case, the work 11 is prevented from being melted by the arc discharge that has been unduly spread on the work 11, and the undercut can be prevented.

Hereinafter, the configuration and effects of the wire feed control unit 30 (FIG. 3) to which the above principle is applied will be described with reference to a time chart shown in FIG.

In FIG. 3, reference numeral 31 denotes a pulse rising detector 31. The pulse rise detection unit 31 detects the rise time of the pulse current by monitoring the current setting waveform of the current waveform setting unit 19 described above. When the pulse rise detection signal is supplied from the pulse rise detection unit 31, the first or second timed circuit units 32 and 33 count a predetermined time and then switch the switch circuits 34 and 35 for the predetermined time.

The switch circuits 34 and 35 are respectively connected to the first
Alternatively, the second feed speed setting units 36 and 37 and the feed speed command unit 3
A switch for controlling conduction with the feed speed controller 8 supplies the setting signal of the first or second feed speed setting unit 36, 37 to the feed speed command unit 38 for the above-mentioned predetermined time. Then, the feed speed command unit 38 controls the motor control unit 1 only while the setting signal is being supplied from the first or second feed speed setting unit 36, 37.
5 is supplied with the set value.

The set value of the base speed setting unit 39 is constantly supplied to the feed speed command unit 38, and the set value is supplied from the first or second feed speed setting unit 36, 37. If not, the set value of the base speed setting unit 39 is supplied to the motor control unit 15.

In the apparatus of this embodiment, as shown in FIG. 6A, a setting is made such that a welding wire of 1.2 mmφ is used as the wire 13 and the 0.43 mm wire 13 is formed into droplets every pulse. The current waveform setting unit 19 sets the current waveform shown in FIG. 6B to realize this.

Also, the first timed circuit section 32 has a duration of 1.5 ms.
(After counting the time T ₁ in FIG. 6C), 1.5
The switch 34 is switched for ms (period in FIG. 6C). That is, in the present embodiment, the wire 13
Is assumed to shift 1.5 ms after the rise of the pulse current, and the feeding speed is increased from 30 mm / s to 390 mm / s by 1.5 ms after the elapse of this time.

Therefore, according to the apparatus of this embodiment, FIG.
As in the case described above, the arc length is shortened immediately after the transfer of the droplet, and the occurrence of undercut can be prevented.

The apparatus according to the present embodiment includes a second timed circuit 33.
1.2 ms after the pulse current rises due to
(C, period), that is, during the period in which the pulse current is flowing, the setting value of the second feed speed setting unit 37 is supplied to the feed speed command unit 38, and the feed speed during this period is − It is 150 mm / s.

As described above, when the current value of the arc discharge is a large current, the molten portion at the tip of the wire 13 is narrowed by the pinch effect. This narrowing acts to temporarily reduce the distance between the tip of the wire 13 and the work 11,
Therefore, it was necessary to widen the interval.

However, when the arc length is long, the arc discharge fluctuates back and forth and left and right due to the influence of the magnetic field generated by itself, so that a so-called magnetic blowing phenomenon may occur. Therefore, it is known that the shorter the arc length is, the more advantageous when performing high-precision welding.

Therefore, in the present embodiment, when the tip of the wire 13 is extended by the pinch effect, the wire 13 is pulled back to prevent a short circuit due to the extension of the wire 13. Therefore, according to the apparatus of the present embodiment, the basic arc length can be set shorter than that of the conventional apparatus, and the welding accuracy can be improved.

As described above, according to the present embodiment,
The arc length can be shortened immediately after detachment of the droplet, and the basic arc length can be set shorter than in the conventional apparatus. For this reason, undercut can be reliably prevented, and welding can be performed with higher precision than a conventional device.

FIG. 7 is an enlarged sectional view of the contact chip 10 of the device of this embodiment. In FIG. 7, reference numeral 10a indicates a contact point between the contact chip 10 and the wire 13. The contact 10a is a point for electrically connecting the contact chip 10 to the wire 13 and a portion for regulating the position of the wire 13.

The current discharged from the wire 13 toward the work 11 is supplied from the contact chip 10 to the wire 13 through the contact 10a as shown by a broken line in FIG. When a current flows through this route, Joule heat corresponding to the contact resistance is generated at the contact 10a.

In the apparatus of this embodiment, when performing arc welding, the wire 13 is fed at any time in accordance with its consumption. For this reason, while the apparatus of the present embodiment is operating, the contact 10a always experiences friction due to the feeding of the wire 13. When such friction occurs in a high-temperature environment due to the above-described Joule heat, as shown in FIG. 7B, abrasion occurs near the contact 10a of the contact chip 10.

In particular, when a pulse current is supplied to the wire 13, Joule heat corresponding to the pulse current is generated at the contact 10a, and wear is remarkably promoted as compared with when the base current is supplied. Then, as the wear progresses, the position of the wire 13 deviates from the original position (the figure shown by the broken line in FIG. 7B), and a deviation occurs in the welded portion.

FIG. 8 shows that the contact tip 1 is controlled by controlling the wire feeding speed in the above embodiment.
FIG. 3 is a view for explaining the principle of suppressing wear of No. 0.

As described above, Joule heat generated at the contact 10a is generated in a large amount especially when a pulse current is supplied. Therefore, in order to effectively suppress the wear of the contact tip 10, the contact
It is necessary to enhance the heat dissipation of the Oa.

The contact 1 of the wire 13 shown in FIG.
The tip side from 0a has a high temperature due to Joule heat generated when the current supplied from the contact 10a flows through the wire 13, but the top side from the contact 10a has a low temperature because there is no heat source.

Therefore, as shown in FIGS. 8B and 8C, if the feeding speed of the wire 13 is increased in synchronization with the timing at which the pulse current is supplied to the wire 13, the pulse current supply At this time, the amount of heat generated at the contact 10a is robbed by the wire 13 that is sequentially fed, so that heat radiation can be improved.

FIG. 9 shows the apparatus of the embodiment shown in FIG.
4 shows a time chart of the arc current and the wire feeding speed when the wear of the contact tip 10 is suppressed by applying the principle shown in FIG. In this embodiment, as in the case of the embodiment shown in FIG.
Using a welding wire of mmφ, it is set to consume 0.43 mm for each pulse.

As shown in FIG. 9A, in the present embodiment, the base current is 75 A, the pulse current is 460 A, and the energization time is 2.5 ms and 1.2 ms, respectively. The first timed circuit 32 shown in FIG. 3 is set so that the switch circuit 34 is turned on for 1.2 ms after the rise of the pulse current.

Therefore, the feed speed commanding unit 38 determines that the wire 1
3, the wire feed speed set in the first feed speed setting unit 36 is controlled by the motor control unit 1.
5 will be supplied. Here, in the present embodiment, the feeding speed of the first feeding speed setting unit 36 is 300 mm / s.
It is set to ec, and the feeding speed of the base speed setting unit 39 is set to 30 mm / sec.

For this reason, the amount of heat that can be absorbed by the wire 13 at the time of supplying the pulse current increases while keeping the length of the wire 13 supplied for each pulse at 0.43 mm.
0a is improved.

Therefore, according to the present embodiment, the wear of the contact tip 10 is suppressed, the positional accuracy of welding is improved as compared with the conventional apparatus, and the frequency of replacement of the contact tip is reduced. Improvement and ease of maintenance can be achieved.

In the example shown in FIG. 9, the second timed circuit section 33 in FIG. 3 is not required, but the first and second timed circuit sections 32, 33 are used together to perform the above-described undercut. It is good also as a structure which makes a prevention function and the wear suppression function of a contact tip coexist.

FIG. 10 shows a time chart of the arc current (FIG. 10A) and the wire feeding speed (FIG. 10B) when both of the above functions coexist. In this embodiment, the amount of consumption of the wire 13 is the same as in the above embodiments.

In the present embodiment, one of the first and second timed circuit sections 32 and 33 is set so as to turn on the corresponding switch circuits 34 and 35 for 1.2 ms after the rise of the pulse current. . Then, the other timing circuit operates as follows when 0.5 ms elapses after the pulse current falls.
The switch circuits 34 and 35 corresponding to 5 ms are set to be turned on.

The first and second feed speed setting units 36,
The wire feeding speed at 37 is set to 150 mm / s, and the wire feeding speed at the base speed setting unit 39 is set to 30 mm / s.

Accordingly, the command value of the wire feed speed output from the feed speed command unit 38 to the motor control unit 15 shows a variation as shown in FIG. That is,
While the pulse current is flowing through the wire 13 and the wire 1
3, the feeding speed of the wire 13 is reduced from 30 mm / s to 1
Speed up to 50mm / s.

For this reason, according to the apparatus of this embodiment, it is possible to ensure good heat radiation of the contact 10a at the time of supplying the pulse current, and it is possible to effectively suppress the wear of the contact tip 10 and to form the droplet. Since the arc length is quickly reduced to a desired length after the transition, the occurrence of undercut can be prevented.

In the above embodiment, it is assumed that the droplet moves from the wire 13 to the work 11 when a predetermined time has elapsed from the rise of the pulse current, and the transition timing is determined based on the current waveform of the current waveform setting unit 19. Although it is detected, it is not limited to this configuration. For example, focusing on a change in the arc voltage that occurs at the time of droplet transfer, the voltage detector 16
, The transition time may be detected.

[0084]

As described above, according to the first aspect of the present invention, when the droplet is detached from the consumable electrode, the feeding speed of the consumable electrode is immediately increased, and the arc length that is increased due to the detachment of the droplet is reduced. Immediately shortened. For this reason, the arc current discharged from the consumable electrode toward the workpiece does not melt an unreasonably wide range on the workpiece. Therefore, it has the feature that the occurrence of undercut caused by an unreasonably wide arc discharge can be prevented.

According to the second aspect of the present invention, during the period when the pulse current is supplied from the contact tip to the consumable electrode, the supply speed of the consumable electrode is increased, and the contact between the contact tip and the consumable electrode is formed. The generated Joule heat is effectively absorbed by the consumable electrode. For this reason, the temperature rise of the contact portion between the contact tip and the consumable electrode is suppressed, and the wear of the contact tip is suppressed.

[Brief description of the drawings]

FIG. 1 is a principle diagram of a consumable electrode type pulse arc welding method according to the first embodiment.

FIG. 2 is a principle diagram of a consumable electrode type pulse arc welding method according to the second aspect of the present invention.

FIG. 3 is a block diagram showing a configuration of an embodiment of an apparatus for performing a consumable electrode type pulse arc welding method according to the first and second aspects of the present invention.

FIG. 4 is a diagram for explaining an adverse effect when a wire feeding speed is fixed.

FIG. 5 is a diagram for explaining the principle of preventing the occurrence of undercut in the apparatus according to the present embodiment.

FIG. 6 is a diagram illustrating an example of a wire feeding speed for preventing occurrence of an undercut in the apparatus according to the present embodiment.

FIG. 7 is a view for explaining a mechanism by which a contact tip of the apparatus of the present embodiment is worn.

FIG. 8 is a view for explaining the principle of suppressing the wear of the contact tip in the device of the present embodiment.

FIG. 9 is a diagram illustrating an example of a wire feeding speed for suppressing abrasion of a contact tip in the apparatus according to the present embodiment.

FIG. 10 is a diagram illustrating an example of a wire feeding speed for performing both prevention of undercut and suppression of wear of a contact tip in the apparatus according to the present embodiment.

[Explanation of symbols]

 M1, M11 First process M2, M12 Second process M3, M13 Third process 10 Contact chip 11 Work 13 Wire 15 Motor control unit 30 Wire feed control unit 31 Pulse rise detection unit 32 First timed circuit unit 33 Second time limit circuit unit 34, 35 switch circuit 36 First feed speed setting unit 37 Second feed speed setting unit 38 Feed speed command unit 39 Base speed setting unit

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-53-103957 (JP, A) JP-A-60-196269 (JP, A) JP-A-60-180669 (JP, A) JP-A 55-103 156670 (JP, A) JP-A-56-119669 (JP, A) JP-A-60-180675 (JP, A) JP-A-3-193269 (JP, A) JP-B-53-4507 (JP, B2) JP-B-48-11463 (JP, B1) (58) Field surveyed (Int. Cl. ⁷ , DB name) B23K 9/12 B23K 9/09

Claims (2)

(57) [Claims] 1. A caused the arc current caused by the pulses of a predetermined period between the consumable electrode and the object to be welded, a droplet of the consumable electrodes for each pulse of the arc current with shifting to the welding subject, the In the consumable electrode type pulse arc welding method of continuously feeding the consumable electrode and supplying the consumable by the transfer of the droplet by supplying the consumable by the transfer of the droplet, the transfer timing of the droplet of the consumable electrode is detected. The consumption speed is increased by a predetermined amount from the average supply speed of the consumable electrode so that the arc length is reduced for a predetermined period after the droplet has transferred to the workpiece. Electrode pulse arc welding method. 2. A current is supplied from a contact tip to a consumable electrode.
The supply causes an arc current with a pulse of a predetermined period between the consumable electrode and the workpiece, and transfers the droplets of the consumable electrode to the workpiece with each pulse of the arc current. from time to time deliver electrodes, the consumable electrode type pulse arc welding method of performing continuous arc welding by replenishing the depleted fraction by transfer of the droplet, and detects the pulse generation timing of the arc current, the arc A pulsed electrode welding method of a consumable electrode type, wherein a feeding speed of the consumable electrode is increased by a predetermined amount from an average feeding speed in order to shorten an arc length while a current pulse is being generated .