Power Supply Device For Arc Welding And Control Method Of Power Supply Device For Arc Welding

[0042] (First embodiment)

[0043] Hereinafter, a first embodiment of a power supply device for arc welding and a control method of the power supply device for arc welding will be described.

[0044] Such as figure 1 As shown, the arc welding machine 10 is provided with: an arc welding power supply device 11 that generates output power suitable for arc welding; and a welding torch 13 for supplying and maintaining power to the welding wire 12 as a discharge electrode that generates arc; A feeding device 14 for feeding the welding wire 12; and a wire holder 15 for winding the welding wire 12.

[0045] The welding torch 13 is connected to the power supply device 11 via a cable 16 and receives power from the power supply device 11. The welding torch 13 includes a power supply terminal 13 a that supplies power to the welding wire 12. The power supply terminal 13 a allows the feeding action of the welding wire 12 and makes electrical contact that should supply the output power generated by the power supply device 11 to the welding wire 12. The welding torch 13 of this type is arranged so that the welding wire 12 (power supply tip 13a) side faces the object (base material) M to be welded, and the welding torch is used.

[0046] The feeding device 14 includes a motor 14 a as a drive source, and by driving the motor 14 a, the welding wire 12 is drawn from the wire holder 15 and the welding wire 12 is sent to the welding torch 13. Since the welding wire 12 as a discharge electrode is consumed with the generation of an arc, the feeding device 14 feeds the welding wire 12 in order to compensate for the consumption of the welding wire 12. In addition, in the feeding of the welding wire 12, it is not a simple one-direction, fixed-speed feeding method, but forward (forward feed) or backward (reverse feed), and also changes every moment. The feed speed Vft is used to feed. This feeding device 14 (motor 14a) is controlled by the control circuit 20 in the power supply device 11, and controls the switching between the forward and reverse feeds in the feeding operation of the welding wire 12 (forward and reverse rotation of the motor 14a) , The feed speed Vft of the welding wire 12 (rotation speed of the motor 14a), etc.

[0047] The power supply device 11 for arc welding includes a control circuit 20 including a CPU. The control circuit 20 includes: an output control unit 20a that generates output power for arc welding; a period detection unit 20b that detects short circuit and arc periods Ts and Ta; a feed control unit 20c that controls the feeding operation of the welding wire 12; and The synchronization deviation determination unit 20d, etc., which determines whether or not the synchronization deviation of the feed speed of the welding wire 12 has occurred, performs control for appropriately performing arc welding through the above-mentioned parts.

[0048] Here, refer to figure 2 as well as image 3 In the consumable electrode arc welding machine 10 like this embodiment, the short-circuit period Ts in which the welding wire 12 contacts the object to be welded M and the arc period in which the welding wire 12 and the object to be welded M are separated to generate an arc are alternately generated Ta. The control circuit 20 adjusts the output power (output voltage Vw, output current Iw) performed by the output control section 20a, and adjusts the feed direction and the feed speed Vft of the welding wire 12 performed by the feed control section 20c so that The ground generates a short-circuit period Ts and an arc period Ta. At this time, the control circuit 20 detects the short-circuit period Ts and the arc period Ta based on the detection of the output voltage Vw of the power supply device 11 detected by the period detection unit 20b.

[0049] However, the relative distance between the power supply tip 13a of the welding torch 13 and the to-be-welded object M, that is, the so-called distance L between the tip base materials, etc., changes depending on the welding environment. At this time, if the feed speed Vft of the welding wire 12 is not changed according to the distance L, it will adversely affect the periodic generation of the short-circuit period Ts and the arc period Ta in the arc welding, and there is a possibility that the arc welding cannot be properly performed. Sex. Here, the control circuit 20 adjusts the feeding direction of the welding wire 12 and the feeding speed Vft together with the adjustment of the output power every time.

[0050] Such as figure 2 as well as image 3 As shown, in the condition before the change in the distance L between the base materials of the ends (before time A1, A2), the short-circuit period Ts and the short-circuit period Ts that can be grasped by the output voltage (arc voltage) Vw or the output current (welding current) Iw The change of Ta during the arc changes the feed speed Vft of the welding wire 12 on the sinusoidal change curve Xa including the positive and negative (forward and reverse feed) shapes. In other words, the feed speed Vft of the welding wire 12 is changed on the sinusoidal change curve Xa, and the short-circuit period Ts and the arc period Ta are periodically generated.

[0051] The feed speed Vft of the welding wire 12 is set so that the frequency component Va of the feed speed is superimposed on the fixed positive feed speed Vf1. In the positive region where the feed rate Vft is greater than zero, it is a forward feed that advances the welding wire 12, and in a negative region where the feed rate Vft is less than zero, it is a reverse feed that causes the welding wire 12 to retreat. The forward feed of the welding wire 12 is performed from the middle of the arc period Ta to the latter of the short-circuit period Ts, and the reverse feed of the welding wire 12 is performed from the late of the short-circuit period Ts to the middle of the arc period Ta.

[0052] When a change in the distance L between the base materials of the tip and the like is not caused and in a normal state, if the other welding environment does not change, the time t1, t2,... of switching to the short-circuit period Ts are approximately the same time interval. In addition, when in a normal state, it is preferable that the feed speed Vft of the welding wire 12 becomes the predetermined speed Vfa (frequency component Va1) obtained from acceleration in the forward feed and some deceleration at times t1, t2... Switch to the short-circuit period Ts.

[0053] In contrast, for example, when the distance L between the base materials of the ends changes, such as figure 2 As shown, at a time t3a later than the original time t3 in which the short-circuit period Ts should be switched, the short-circuit is switched, or as image 3 As shown, at a time t3b earlier than the original time t3, the short circuit is switched.

[0054] For example, such as figure 2 As shown, in the case where the distance L between the base materials of the ends is extended from the distance L0 to the distance Lh, if the feed speed Vft of the welding wire 12 is maintained at the normal setting state, it will become the switch to the short-circuit period At the original time t3 of Ts, the short-circuit condition has not yet occurred. That is, since the actual time t3a for switching to the short-circuit period Ts is later than the original time t3, the feed speed Vft of the welding wire 12 becomes slower every time t3a when the short-circuit period Ts is actually switched to. In this case, the feed speed Vft of the welding wire 12 needs to be accelerated.

[0055] In addition, for example image 3 As shown, when the distance L between the base materials of the ends is shortened from the distance L0 to the distance L1, if the feed speed Vft of the welding wire 12 remains at the normal setting state, it will be switched to the original value of the short-circuit period Ts. A short circuit is generated before time t3. That is, since the actual time t3b to switch to the short-circuit period Ts is earlier than the original time t3, the feed speed Vft of the welding wire 12 becomes faster every time t3b when the short-circuit period Ts is actually to be switched. In this case, the feed speed Vft of the welding wire 12 needs to be decelerated.

[0056] Based on this situation, the control circuit 20 of this embodiment first recognizes the actual time t3a, t3b when switching from the arc period Ta to the short-circuit period Ts, and determines whether the deviation from the original time t3 when the short-circuit period Ts should be switched is within the allowable range . The original time t3 may be determined in advance, or the original time t3 may be set every time according to the switching of the previous short-circuit period Ts or the like.

[0057] Next, the operation (action) of this embodiment will be described.

[0058] "There is no change in the distance L between the end base metals"

[0059] When the deviation of the actual time (t1, t2) to be switched during the short-circuit period Ts is within the allowable range, the synchronization deviation determination unit 20d of the control circuit 20 determines that there is substantially no change in the distance L between the terminal base materials, and The current feed speed Vft of the welding wire 12 is appropriate (synchronized), and the feed control unit 20c maintains the change form of the feed speed Vft of the welding wire 12 (change curve Xa).

[0060] "The case where the distance L between the base materials of the ends extends"

[0061] Such as figure 2 As shown, when the deviation between the actual time t3a and the original time t3 for switching to the short-circuit period Ts exceeds the allowable range, and the actual time t3a is later than the original time t3, the synchronization deviation determination unit 20d determines that the end The distance L between the head base materials is extended and the feed speed Vft of the welding wire 12 is slow, and the feed control unit 20c lags the phase of the change curve Xa of the feed speed Vft of the welding wire 12 by α1. At this time, at the original time t3 in the normal state, the feed speed Vft of the welding wire 12 becomes the predetermined speed Vfa in the deceleration zone X2 during the forward feed, so the phase is delayed by α1 until it is at the acceleration during the forward feed. The same speed Vfa in the area X1 is on the change curve Xa. Therefore, if the distance L between the base materials of the ends is extended, the feed speed Vft of the welding wire 12 tends to slow down. However, instead of suppressing the speed drop after time t3, it is better to temporarily increase the speed as in this embodiment. The feeding speed Vfa of the welding wire 12 quickly approaches the desired speed (acceleration control).

[0062] Next, when it becomes the actual time t3a for switching to the short-circuit period Ts, the feed control unit 20c advances the phase by α2 until the normal speed for switching to the short-circuit period Ts, that is, the feed speed Vft of the welding wire 12 becomes positive. On the change curve Xa of the predetermined speed Vfa in the deceleration zone X2 during the feed. In addition, when the change curve Xa of the feed speed Vft of the welding wire 12 is delayed by the phase α1, even if the speed Vfa in the deceleration zone X2 is reached again, the short-circuit period Ts (the actual time t3a is not reached) is still not switched to The control unit 20c again lags the phase of the variation curve Xa by α1 at this point.

[0063] In addition, the feed control unit 20c performs the above-mentioned phase adjustment only at one point immediately after the distance L between the tip base materials changes, and does not perform the phase adjustment if the distance L does not change after that. In addition, when the distance L changes again after the phase is adjusted, the above-mentioned phase adjustment is performed immediately after the change. That is, when the distance L changes with respect to one time, the phase adjustment is performed at one point immediately after the change.

[0064] As described above, under the condition that the distance L between the base materials of the terminals is extended, the above-mentioned phase adjustment of the feed speed Vft of the welding wire 12 results in adjustment so that the protruding length from the power supply terminal 13a of the welding wire 12 becomes The length is an amount corresponding to the extension of the distance L, and the distance between the tip of the welding wire 12 and the to-be-welded object (base material) M is maintained approximately.

[0065] "The case where the distance L between the base materials of the ends is shortened"

[0066] Such as image 3 As shown, when the deviation between the actual time t3b and the original time t3 when switching to the short-circuit period Ts exceeds the allowable range, and the actual time t3b is earlier than the original time t3, the synchronization deviation determination unit 20d determines that the end The distance L between the base materials is shortened, the feed speed Vft of the welding wire 12 is faster, and the feed control unit 20c advances the phase of the change curve Xa of the feed speed Vft of the welding wire 12 by α3. That is, the phase is advanced by α3 until it is positioned on the change curve Xa where the normal speed switched to the short-circuit period Ts, that is, the feed speed Vft of the welding wire 12 becomes the predetermined speed Vfa in the deceleration zone X2 during forward feeding. Therefore, if the distance L between the base materials of the tips is shortened, the feed speed Vft of the welding wire 12 tends to increase, but after time t3b, the speed is further reduced, and the feed speed Vfa of the welding wire 12 rapidly approaches the desired speed (deceleration control ).

[0067] In addition, when the distance L between the feed control unit 20c and the base material of the tip is extended, the phase adjustment is performed only at one point just after the distance L changes. After that, if the distance L does not change, the phase adjustment is not performed. . That is, when the distance L between the tip base materials is shortened, the phase adjustment is performed at one point immediately after the change with respect to each change in the distance L.

[0068] As described above, under the condition that the distance L between the base materials of the tips is shortened, the above-mentioned phase adjustment of the feed speed Vft of the welding wire 12 results in the adjustment of the projection length of the welding wire 12 from the power supply terminal 13a and the distance The amount of the shortening of L substantially maintains the distance between the tip of the welding wire 12 and the object (base material) M to be welded.

[0069] Next, the characteristic effect of this embodiment is described.

[0070] (1) As the feeding control of the welding wire 12, the feeding speed Vft of the welding wire 12 is periodically changed so that the feeding speed Vft is in the deceleration zone X2 of the change curve Xa during the forward feeding of the welding wire 12 Next, it is switched to the short-circuit period Ts, and the feed speed Vft of the welding wire 12 is adjusted in the deceleration zone X2. Furthermore, if it is determined that the feed speed Vft of the welding wire 12 is slow in the feed speed synchronization deviation, the acceleration control including temporary acceleration ( figure 2 ), if it is determined that the feed speed Vft of the welding wire 12 is relatively fast, and the feed speed synchronization deviation is determined, the deceleration control ( image 3 ). That is, the welding environment changes such as the distance between the power supply tip 13a of the welding torch 13 and the to-be-welded object M (the distance between the tip base materials L), etc., and the feed speed Vft of the welding wire 12 is slow. As acceleration control, the feeding speed Vft of the welding wire 12 is temporarily changed from deceleration to acceleration. When the feeding speed Vft of the welding wire 12 is in a relatively fast condition, as the deceleration control, the feeding speed Vft of the welding wire 12 is changed to the deceleration zone X2 is on the further deceleration side, so it can quickly approach the desired speed in various situations, and arc welding can be performed well.

[0071] In addition, the description is centered on the adjustment of the feed speed Vft of the welding wire 12 corresponding to the change in the distance L between the tip base materials, but the welding wire 12 corresponding to the change in the welding environment other than the distance L between the tip base materials is also performed. Adjustment of the feed rate Vft.

[0072] (2) The determination of whether the synchronization deviation of the feed speed Vft of the welding wire 12 has occurred is performed based on the deviation between the original time t3 when the short-circuit period Ts should be switched to and the actual time t3a, t3b. That is, it is possible to easily determine the synchronization deviation of the feed speed Vft of the welding wire 12 by time counting.

[0073] (3) Perform feed control that changes the feed speed Vft of the welding wire 12 along the periodic change curve Xa. When performing acceleration control when the feed speed Vft of the welding wire 12 is slow, adjust the phase of the change curve Xa until It becomes the same speed Vfa of the acceleration area X1 on the change curve Xa, and thus the change curve Xa of the acceleration area X1 is used. In addition, when the deceleration control is performed when the feed speed Vft of the welding wire 12 is fast, the phase of the variation curve Xa is adjusted so as to become the further deceleration side of the deceleration area X2 on the variation curve Xa, thereby using the further deceleration side The change curve Xa. That is, since the control is performed according to the phase adjustment of the periodic variation curve Xa for setting the feed speed Vft of the welding wire 12 each time, it contributes to simplifying the feed control of the welding wire 12.

[0074] (Second embodiment)

[0075] Hereinafter, a second embodiment of a power supply device for arc welding and a control method of the power supply device for arc welding will be described.

[0076] In the present embodiment, the control method of the feed control unit 20c of the control circuit 20 is different from the previous first embodiment. In the first embodiment, the phase adjustment (fixed amplitude) of the feed speed Vft of the welding wire 12 on the variation curve Xa is performed, while the present embodiment is the following control method: the feed speed Vft of the welding wire 12 is adjusted on the variation curve Xa Amplitude adjustment (fixed phase).

[0077] "The case where the distance L between the base materials of the ends extends"

[0078] Such as Figure 4 As shown, when the deviation between the actual time t3a of the switching to the short-circuit period Ts and the original time t3 exceeds the allowable range, and the actual time t3a is slower than the original time t3, the synchronization deviation determination unit 20d determines that it is the end The distance L between the base materials of the head is extended, and the feed speed Vft of the welding wire 12 is slow. The feed control unit 20c makes the feed speed Vft of the welding wire 12 increase by the amplitude of the change curve Xa of the feed speed Vft of the welding wire 12 A change occurs on the change curve Xb. At this time, at the original time t3 in the normal state, the feed speed Vft of the welding wire 12 becomes the predetermined speed Vfa in the deceleration zone X2 in the forward feed, and therefore becomes the same speed in the acceleration zone X1 in the forward feed. On the change curve Xb of Vfa, change again. Therefore, if the distance L between the base materials of the tips is extended, the feed speed Vft of the welding wire 12 tends to slow down. Instead of suppressing the speed drop after time t3, it is better to temporarily increase the speed as in the present embodiment. The feed speed Vfa of 12 quickly approaches the desired speed (acceleration control).

[0079] Next, when the actual time t3a is switched to the short-circuit period Ts, the feed control unit 20c changes the feed speed Vft of the welding wire 12, for example, on the change curve Xb with a large amplitude until it reaches the feed speed Vf1. The feed speed Vft of the welding wire 12 is changed on the normal change curve Xa. That is, in this amplitude adjustment, the amplitude adjustment is also performed at one point immediately after the change with respect to one change in the distance L.

[0080] As described above, under the condition that the distance L between the base materials of the terminals is extended, the feed speed Vft of the welding wire 12 is adjusted by the above-mentioned amplitude adjustment, and as a result, it is adjusted that the protruding length of the welding wire 12 from the power supply terminal 13a increases and The amount corresponding to the elongation of the distance L substantially maintains the distance between the tip of the welding wire 12 and the object (base material) M to be welded.

[0081] "The case where the distance L between the base materials of the ends is shortened"

[0082] Such as Figure 5 As shown, when the deviation between the actual time t3b and the original time t3 when switching to the short-circuit period Ts exceeds the allowable range, and the actual time t3b is earlier than the original time t3, the synchronization deviation determination unit 20d determines that the end The distance L between the head base materials is shortened, the feed speed Vft of the welding wire 12 is faster, and the feed control unit 20c reduces the feed speed Vft of the welding wire 12 to the change curve of the change curve Xa of the feed speed Vft of the welding wire 12 There is a change on Xc. Therefore, if the distance L between the tip base materials is shortened, the feed speed Vft of the welding wire 12 tends to accelerate, and the speed decreases further after time t3b, and the feed speed Vfa of the welding wire 12 rapidly approaches the desired speed (deceleration control).

[0083] Then, the feed control unit 20c changes the feed speed Vft of the welding wire 12 on the change curve Xc with a small amplitude until the feed speed Vf1 is reached, and then changes the feed speed Vft on the normal change curve Xa. That is, in the amplitude adjustment when the distance L is shortened, the amplitude adjustment is also performed at a point immediately after the change with respect to one change in the distance L.

[0084] As described above, under the condition that the distance L between the base materials of the tips is shortened, through the above-mentioned amplitude adjustment of the feed speed Vft of the welding wire 12, the result is adjusted so that the protruding length of the welding wire 12 from the power supply terminal 13a is shortened and the distance The amount corresponding to the shortening of L substantially maintains the distance between the tip of the welding wire 12 and the object (base material) M to be welded.

[0085] Next, the characteristic effect of this embodiment is described.

[0086] (1) (2) The same effects as the effects (1) and (2) of the first embodiment can also be obtained in this second embodiment.

[0087] (3) When the acceleration control is performed under the condition that the feed speed Vft of the welding wire 12 is slow, the amplitude of the change curve Xa becomes larger after the temporary acceleration, and the change curve Xb with the larger amplitude is used. In addition, when the deceleration control is performed in a situation where the feed speed Vft of the welding wire 12 is fast, the amplitude of the variation curve Xa becomes smaller, and thus the variation curve Xc with a small amplitude is used. That is, the control is performed based on the amplitude adjustment of the periodic variation curve Xa for setting the feed speed Vft of the welding wire 12 every time, and this contributes to simplifying the feed control of the welding wire.

[0088] In addition, the above-mentioned embodiment may be changed as follows.

[0089] ·By comparing the original time that should be switched to the short-circuit period Ts and the actual time, the synchronization deviation of the feed speed Vft of the welding wire 12 caused by the change in the welding environment such as the change in the distance L between the base metal of the tip is determined. The feed speed synchronization deviation can be determined by using one or more other parameters such as the change of the output voltage Vw or the output current Iw, and the direct measurement of the distance L between the base materials of the ends by the distance measuring device.

[0090] When the acceleration control is performed in a situation where the feed speed Vft of the welding wire 12 is slow, a part of the acceleration area X1 on the variation curve Xa is used, but other variation curves or variation straight lines may be separately prepared.

[0091] In addition, the configuration of the arc welding machine 10, the arc welding power supply device 11, and the control circuit 20 may be changed as appropriate.

[0092] In addition, various controls related to arc welding, such as the control of the feed speed Vft of the welding wire 12, may be appropriately changed.