JPH0659548B2 - Wire inching control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to arc welding, in which a consumable electrode wire or a filler wire is fed while being fed to a welded portion, and a manual push button for these wires is used as a preparatory work before starting welding. The present invention relates to a control method for inching and feeding (wire inching) until a proper amount of protrusion is made from a tip of a welding torch by a switch.

2. Description of the Related Art In automatic or semi-automatic arc welding, the wire feed during welding is automatically fed after the speed is determined according to the welding current, welding voltage and the like. However, when a new wire is fed from the coiled wire reel to the tip of the welding torch, or when the tip of the wire has already reached the welding torch, the defective portion of the tip shape is still cut off and the wire feeding state is confirmed. For this reason, there is a case where it is desired to feed only an arbitrary amount of wire separately from welding. In response to such a request, a switch for a normal wire inching command is provided separately, and an operator pushes the switch as appropriate to feed the wire in an inching manner to perform each of the above operations. . Conventionally, at the time of inching feeding, a wire slowdown speed (a welding start command for starting welding, for example, a torch switch is pressed to start the welding of the workpiece to be welded after starting the welding) is provided to improve the arc start during actual welding. The speed is set at the time of sending at low speed before contacting the surface and generating an arc), and the wire is set to the tip side of the welding torch only while pushing the inching command switch at this wire slowdown speed during inching. It was supposed to be sent to the other side. However, the feeding speed during the wire slowdown is set to an extremely slow speed as compared with that during normal welding in order to improve the arc start. Therefore, such a low speed may be used when the wire has already reached the tip of the welding torch, but is extremely inefficient when the wire wound on the wire reel is used up or the wire is replaced. It will be a work.
That is, there is a long path of several meters or a dozen meters between the drive unit for feeding the wire and the welding torch, and in the meantime, many of the structures usually pass through a flexible conduit, which requires human power. For this reason, the wire cannot be inserted into this. For this reason, there is no choice but to send a long feeding path by an inching operation by the electric motor of the wire feeding drive section, and at this time, if the speed is slow as described above, it takes a long time. Of course, there is a variable resistor to set the wire slowdown speed, and it can be changed arbitrarily, but this wire slowdown speed should be set to the value at which the arc start is normally performed well, the wire used and the welding current. Therefore, it is not preferable to change the value for wire inching each time because of not only the usability but also the setting error. Moreover, even when performing the same wire inching operation, as described above, when the tip of the wire has already reached the tip of the welding torch and it is necessary to feed it out only slightly, and when feeding a long feeding path such as when replacing the wire. Therefore, if it is set to a high speed when a small amount should be sent, and if it is continuously fed for the time that the inching command switch is pressed, not only adjustment of the feed amount becomes difficult,
It is also dangerous for workers. Furthermore, when a wire is newly fed from the starting end of the long feeding path, the feeding should be stopped immediately when the wire projects from the tip of the welding torch.
The tip of the welding torch needs to be constantly monitored for long delivery times. For this reason, the operator is restrained at the position where the wire inching command switch can be operated during the long feeding time. Also, it is preferable that the tip of the welding torch can be seen through from the feed start end, but if this is difficult, for example, when another device is installed between the feed start end and the welding torch, the inching command switch should be used. It is necessary to devise a method in which the operator to operate and the person to monitor the protrusion of the wire at the welding torch portion perform a two-person operation, or inching command switches are provided at two locations.

Further, when feeding a small amount, it is necessary that the feeding amount can be accurately controlled. For example, in an arc welding robot of the teaching play back type, it is necessary to teach (teach) the welding line to the robot accurately before welding, but at this time the arc generation point is taught, so it protrudes from the welding torch. The position of the wire tip (position with respect to the welding torch) must always be fixed. For this reason, the wire is fed in advance by an inching operation, but if the feeding length is not correct, correct teaching cannot be performed. In the past, it was only decided to feed and stop with a push button switch, so there is no other way than cutting it with pliers etc. at an appropriate position by protruding extra.
For this reason, the accuracy was poor and the work was troublesome. In submerged arc welding, a small lump of steel wool is usually sandwiched between the tip of the wire and the object to be welded to perform arc start. For this purpose, steel wool must be lightly pressed with the wire. If this pressing force is too strong, the thick wire and the work piece will come into strong contact with each other, and when a welding voltage is applied, this part will not be able to immediately blow off the fusion gap and the arc start will fail. Become. On the contrary, if this pressing force is too small, the position of the steel wool will be displaced when the flux is sprayed, or the flux will enter between the steel wool and the wire to insulate the two, and the arc start will also fail. Will be done. Therefore, in any of these cases, in the conventional method in which the tip of the wire to be accurately positioned is adjusted by the time of pushing the inching command switch, the inching speed should be sufficiently slowed and the timing of releasing the switch should be set. It was necessary to know it empirically by adding the amount of coasting of the feeding device, which required skill.

An object of the present invention is to solve the above-mentioned drawbacks of the conventional apparatus and to perform wire feeding in a fixed amount by a relatively small fixed amount to simplify the switch operation at the time of feeding a small amount and to feed a large amount. If a supply amount is required, by pressing and holding the inching command switch for a certain period of time or more, even after stopping the operation of the command switch, the wire is continuously fed until the set amount is reached, and then stopped. Optimal feeding conditions can be set according to the amount of wire inching feeding, and one operator can easily feed the wire to a long feeding path by a single inching command switch. This is an ideal high-efficiency wire inching method that can be achieved.

SUMMARY OF THE INVENTION The present invention feeds a relatively small fixed amount of wire each time the wire inching command switch is closed, and when the closing of the command switch continues for a certain period of time, the constant amount of In addition to the feeding, the wire is continuously fed after this fixed time has elapsed until a large fixed feeding amount is reached. High efficiency is realized by maintaining the feeding state at the time of feeding or increasing the speed and automatically stopping after feeding the required amount.

EXAMPLE FIG. 1 is a connection diagram of an apparatus showing an example for carrying out the method of the present invention. In the figure, reference numeral 1 is a wire inching command switch, which is usually provided on a remote control box, a welding control panel, or a welding torch together with respective setting devices for welding current and welding voltage. Reference numeral 2 denotes an inching speed setting device, which includes a setting device VR1 for short sizing feed and a setting device VR2 for long sizing feed. A timer 3 is a high-level signal (hereinafter referred to as "H") for a time preset by the time setter 3a from the fall of the input signal to the input terminal T.
Output). Reference numerals 4, 5 and 6 are flip-flop circuits, and 4 is triggered by the falling edge of the input signal at the input terminal T, and 5 and 6 are triggered by the rising edge of the input signal to invert the output signal to become the H signal. .
Reference numeral 7 is a timer for determining the wire feed amount after the wire inching feed state is maintained, and outputs an H signal for a preset time by the time setter 7a from the rise of the input signal to the input terminal T. . Reference numerals 8, 9 and 10 are AND gates, 11 and 13 are monomultivibrators, and 11 is triggered by a rising edge of an input signal and 13 is triggered by a falling edge of the input signal, and outputs an H signal for a set time. 12, 15 and 16 are signal inversion inverters,
14 is an OR gate, and 17a and 17b are automatically stopped.
"OFF" switching switches, 18, 19, 28, 29 are analog switches, 20 is an amplifier, and determines the rotation speed of the wire feeding electric motor 21 according to an input signal. 22 is a slope control circuit and a slope " When the "on / off" selection switch 23 is closed, the output of the amplifier 20 changes smoothly even if the input signal of the amplifier 20 changes stepwise. This can be realized by connecting a capacitor to the capacitor and providing a time delay element.
This is a wire feeding roll driven by a wire reel 25, and feeds the wire 25 from the wire reel 26 toward the welding torch 34 and the object to be welded 35 via the feeding path 27. Reference numeral 30 denotes a wire feeding speed setting device at the time of welding, a wire slowdown speed setting device VR3 for setting a low feeding speed until an arc is generated at the start of welding, and a wire feeding at the time of normal welding after the arc is generated. It comprises a speed setting device VR4 and the like. Reference numeral 31 is a welding start command switch, which is a torch switch provided on an operation panel (not shown) or attached to the welding torch 34. A welding control circuit 33 slows down the wire 25 from the time the welding start command switch 31 is pressed until the wire 25 contacts the workpiece 35 and a current flows and the occurrence of a welding arc is detected. The analog switch 28 is made conductive so as to feed at a low speed determined by the speed setter VR3, and the output of the wire feed speed setter VR5 at the time of welding becomes higher after the occurrence of an arc is fed to the amplifier 20. It has a known function of controlling the analog switch 29 to be supplied so as to be supplied and supplying an output command signal determined by an output setting device (not shown) to the welding power source 33.

2 (a) to (i) are diagrams for explaining the operation of the embodiment of FIG. 1 described above with the passage of time,
In the figure, (a) shows the open / closed state of the inching command switch 1, (b) shows the timer 3, (c) shows the flip-flop circuit 4,
(d) shows a flip-flop circuit 5, (e) shows a flip-flop circuit 6, (f) shows a timer 7, (g) shows a mono-multivibrator 10, and (h) shows a state of each output of the mono-multivibrator 13. ) Indicates the output of the amplifier 20. Further, the broken line in the figure shows a state when the slope control circuit 22 is enabled.

Next, the operation of the apparatus shown in FIG. 1 will be described with reference to FIG.

In FIG. 1, before the inching command switch 1 is pressed, the timers 3, 7 flip-flop circuits 4, 5, 6 and mono-multivibrator 11, 13 are all reset, and all outputs are low level (hereinafter referred to as L signal). If it is an output, analog switches 18, 19
Are both open, therefore the input of the amplifier 20 is zero and the motor 21 is stopped. When the inching command switch 1 is pressed at time t ₁ in FIG. 2, the input of the timer 3 is grounded and becomes an L signal, and the falling of this input signal causes the timer 3 to start and the H signal for a fixed time T _1. Is output. During this time, the outputs of the flip-flop circuits 4 and 6 remain the L signal, and therefore the inverters 12, 15, 16
The inputs of the AND gate 10 inverted by
The signal also becomes an H signal, and the mono-multivibrator 11 is triggered by the rising of this H signal and outputs the H signal for a fixed time T ₂ . The H output of the mono multivibrator 11 allows the analog switch 19
Conducts. As a result, the amplifier 20 is supplied with the output of the setting device VR1 when the inching speed setting device 2 is fed at a constant size, and the electric motor 21 is driven at a relatively low speed determined by the output of the setting device VR1. The wire 25 is fed only during the time T ₂ . If the wire inching command switch 1 is opened before the end of the time period T ₁ of the timer 3, the timer 3 is immediately reset and the AND gate 10 is opened to return all the initial states. Therefore, when the closing time of the wire inching command switch 1 is short, a fixed amount of wire determined by the set time T _{2 of the} multivibrator 11 and the set value of the speed setter VR1 is generated regardless of the actual closing time. Will be sent.

Next, consider the case where the wire inching command switch 1 continues to be closed even at the end of the time period T ₁ of the timer 3.
If the inching command switch 1 is closed from time t ₂ to time t ₄ (however, t ₄ −t ₂ > T ₁ ), the flip-flop circuit 4 is closed due to the end of the timer 3 at time t ₃ .
Is triggered and its output becomes an H signal. As a result, the output of the inverter 12 becomes the L signal, and the AND gate 10 is closed. On the other hand, the H signal of the flip-flop circuit 4 causes the timer 7 to output the H signal for the time T ₃ set by the setter 7a, whereby the analog switch 18 is turned on and the amplifier 20 is connected to the wire. Inching speed setting device 2
The output of the setting device VR2 is supplied. This results in wire 2
5 is fed at the speed set by the setting device VR2. When the inching command switch 1 is opened after this state, all the inputs of the AND gate 8 become the H signal, and as a result, the output of the flip-flop circuit 5 also becomes the H signal. During the time limit of timer 7, analog switch 18
Remains in conduction, and the electric motor 20 continues to rotate at a speed according to the output of the setting device VR2. When the time limit of the timer 7 expires at time t ₅ , its output becomes the L signal, which causes the analog switch 18 to open. As a result, the electric motor 2
1 stops, and the mono-multivibrator 13 outputs the H signal for a fixed time due to the fall of the output signal of the timer 7, and the H signal causes the flip-flop circuit 4, the flip-flop circuit 5 and the timer 7 to be reset and reset again. Return to the initial state. In order to stop the wire inching feeding within the time limit of the timer 7, the wire inching command switch 1 may be pressed again during the time T ₂ . At time t _6, the wire pressing the wire inching command switch 1 between the previous as well as the timer 3 timed at a speed analog switch 19 according to the set value of the speed setter VR1 conducting 2
5 is fed and the mono-multivibrator 11 stops after the time limit. When the output of the flip-flop circuit 4 is inverted and becomes the H signal after the time limit of the timer 3, the timer 7 starts the time limit, the analog switch 19 is opened, the analog switch 18 is turned on, and the speed set by the setter VR2 is set. Then, the wire 25 is fed again. In this state, when the wire inching command switch 1 is once opened at time t ₇ , the output of the flip-flop circuit 5 becomes an H signal, and it is stored that the inching command switch is once released. When the inching command switch 1 is closed again at the time t ₈ within the time limit of the timer 7, both inputs of the AND gate 9 become H signals due to this second closing, and the output of the flip-flop circuit 6 is also inverted to the H signal. Becomes By the H signal output of the flip-flop circuit 6, the flip-flop circuits 4 and 5 and the timer 7 are respectively reset so that their outputs become L signals, the analog switch 18 is opened, and the inverter circuits 16 invert the L signals.
The analog switch 19 also remains open because it is input to the gate 10. Therefore, the input of the amplifier 20 becomes zero, the electric motor 21 stops, and the wire inching ends. The flip-flop circuit 6 is reset by opening the wire inching command switch 1 and returns to the initial state again. If the set time T ₁ of the monomultivibrator 11 is set to the time required for the wire 25 to be sent by several tens of millimeters, the wire inching command switch is turned on and off within this time when a small amount of wire is sent. Can be sent. Therefore, it is advisable to set the setting device VR1 so that the feeding speed at this time is relatively low. Further, when the inching command switch 1 is kept pressed until after this set time elapses, it is a case where a considerably long distance is fed by inching. Therefore, for example, the time limit of the timer 7 is set to the wire feeding path 2
By setting the time for feeding by the length of 7, it is possible to automatically stop when the tip of the wire 25 reaches the torch 34. Further, if the speed setter VR2 at this time is set to be relatively high speed, the work efficiency can be improved. On the other hand, when the slope "ON"-"OFF" selection switch 23 is set to the "ON" side, the slope control circuit 22 becomes effective and the feed speed can be smoothly changed. In this case, if the slope "ON"-"OFF" selection switch 23 is closed ("ON") by the output of the flip-flop circuit 4 as shown by the broken line in FIG. As indicated by a broken line in), the speed change can be smoothly changed only when the speed changes from low speed to high speed.

During welding, the inching command switch 1 is opened, and the welding start command switch 31 is closed instead,
A series of operations including wire feeding at a normal wire slowdown speed, arc generation, and normal welding are performed. However, since these operations are not particularly different from the known method, detailed description thereof will be omitted.

The present invention is not limited to the embodiment of FIG.
Due to the short circuit of the wire inching command switch,
The wire feed is performed with a relatively small fixed size, and if the wire inching command switch 1 is not closed within a preset time from when the switch is closed, the feed state is maintained and this feed amount is preset. Anything can be used as long as it automatically stops when it reaches a predetermined relatively large value, for example, a method of gradually increasing the speed after starting feeding at the initial speed, or a wire inching speed in advance. It may be changed according to the set speed changing program.

Furthermore, a wire inching speed setting device that outputs a single set value may be used to set the same speed for both constant size feeding and continuous feeding, and in each of these cases, each signal is digitized. Of course to get.

Further, in order to invalidate these continuous feeding functions when they are not necessary, for example, as shown by the broken line in FIG. 1, a self-holding “ON / OFF” switching switch 36 is provided to bypass the flip-flop circuit 6. do it. In this case, the continuous feeding after the first constant feed is naturally stopped when the inching command switch 1 is opened. Further, if the wire inching command switch 1 is continuously pressed, it automatically stops after the time set by the timer 7.

Further, as shown in FIG. 1, the setting of the wire feeding amount until the automatic stop after the continuous feeding is determined by the feeding time, or by setting the actual feeding length. Of course, in this case, instead of the timer 7, a feed length setter and a feed length detector, for example, a multiplier of the feed speed and the feed time, or the electric motor 21 or the feed roll 24 A comparison circuit for comparing the two signals with those for counting the number of rotations to find a match may be provided.

Further, instead of providing these timers and feed length detectors, a wire detector is provided near the end of the feed path 27, that is, near the welding torch 34, and when the tip of the wire reaches this position, the wire detector continues. The feeding may be automatically stopped, and the safety can be further improved by combining the above means to stop the feeding when any of the set values is reached.

As described above, according to the present invention, when the wire inching command switch is closed for a short time, the wire is fed by a fixed amount regardless of the closing time, and when the command switch is closed continuously for a fixed time or longer, In addition to a fixed amount of feeding, the feeding is continuously performed, and when the feeding amount reaches a preset amount, it automatically stops, so press the wire inching command switch even when feeding a small amount. It is possible to position the wire tip accurately without changing the time subtly, and it is not necessary to keep pressing the command switch when feeding a large number of wires, so highly efficient control with excellent workability can be realized. .

[Brief description of drawings]

FIG. 1 is a connection diagram showing an embodiment of an apparatus for carrying out the method of the present invention, and FIGS. 2 (a) to (i) are diagrams for explaining the operation of the apparatus of FIG. . 1 ... inching command switch, 2 ... inching speed setting device, 3, 7 ... timer, 4, 5, 6 ... flip-flop circuit, 11, 13 ... mono multivibrator,
21 ... electric motor, 25 ... wire, 34 ... torch, 3
5: Object to be welded.

Claims (9)

[Claims] 1. A wire inching control method for an arc welding machine, in which a consumable electrode wire or a filler wire is fed to a welded portion at a predetermined speed to perform predetermined welding, and the wire inching command switch is preset for each closed circuit. The wire is fed by a relatively small constant feed amount, and when the closing of the command switch continues for a certain time or longer, the wire is preset by a relatively large constant feed amount after the elapse of the certain time. A wire inching control method in which the wire is continuously fed until it reaches the limit, and then stopped. 2. The speed of continuous wire feeding after the elapse of the fixed time is higher than the speed at which the wire is fed by the relatively small fixed length. The wire inching control method described. 3. When the command switch is once closed and then closed again during the continuous feed period after the elapse of the certain time, regardless of the set feed amount. The wire inching control method according to claim 1, which is stopped. 4. The wire inching control method according to claim 1, wherein, after the elapse of the predetermined time, the feeding speed is increased at a predetermined gradient in accordance with the feeding amount of the wire. 5. The wire inching control method according to claim 1, wherein after the elapse of the predetermined time, the feeding speed is changed according to a predetermined program in correspondence with the feeding amount of the wire. 6. The wire inching control method according to claim 1, wherein the preset relatively large constant feed amount is set corresponding to the length of the wire feed path. 7. The wire inching control method according to claim 1, wherein each feed amount is determined by a feed time. 8. The wire inching control method according to claim 1, wherein each of the feeding amounts is determined by the length of the wire actually fed. 9. The wire according to claim 1, wherein the fact that the preset relatively large constant feed amount has been reached is known by a wire detection means provided near the end of the feed path. Inching control method.