JP2004050202A - Consumable electrode type arc spot welding method and consumable electrode type arc welding equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a consumable electrode type arc spot welding method and consumable electrode type arc welding unit with a simple constitution which can easily be applied even to narrow places. <P>SOLUTION: Welding operation is divided into a start control period where an arc is started; a welding output control period where welding is performed successively to the welding in the start control period; and a spherical drop control period where the tip of a consumable electrode is shaped successively to the welding output control period. Then, in each period, a mean arc voltage Vav, a pulse voltage Vp, a base voltage Vb, a pulse width Tp, a wire feed rate WF and a certain time T as the length of the period are decided. At this time, at least the welding output control period is divided into two or more periods. Then, the welding is performed based on designated data for the time T. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a consumable electrode type arc spot welding method and a consumable electrode type arc welding apparatus for welding a relatively thin lap welding joint using a consumable electrode.
[0002]
[Prior art]
Generally, when welding a lap welding joint in an automobile body or the like, resistance spot welding is frequently used. However, in the case of resistance spot welding, it is necessary to sandwich the weld joint from above and below by its principle, and a special welding gun or device is required depending on the work shape. Further, in order to insert the welding gun, it may be necessary to process a working hole. Furthermore, when welding a galvanized steel sheet, there is also a problem that the zinc on the surface, which is the main component of the plating layer, adheres to the copper electrode of the welding gun and shortens the electrode life.
[0003]
Therefore, in Japanese Patent No. 3245412 (hereinafter, referred to as a first conventional technique), a lap welded joint is welded only by working from one side of the welded joint by plasma arc spot welding using a plasma arc.
[0004]
JP-A-63-188473 (hereinafter referred to as a second prior art) discloses a welding current command signal, a welding voltage and a welding voltage as an arc welding apparatus using a consumable electrode used with a welding robot and a welding jig. A technique of an arc welding apparatus including an output control circuit for selecting an optimum value from data stored in a welding condition data bank based on a command signal and a welding speed command signal and performing welding output control is disclosed. I have.
[0005]
Further, Japanese Patent Application Laid-Open No. Hei 10-6005 (hereinafter referred to as a third prior art) discloses, as an arc welding method using a welding robot, the positions of the start point and the end point of the section where the welding conditions are changed, and the start point and the end point. There is disclosed a technique of an arc welding method in which welding conditions are taught and set, and while the welding torch moves from a start point to an end point, the welding conditions at the start point are gradually changed to the welding conditions at the end point.
[0006]
[Problems to be solved by the invention]
However, in the first conventional technique, it is necessary to change not only the plasma arc current during the welding period but also the plasma gas flow rate and the shield gas component. For this reason, the device configuration becomes complicated.
[0007]
Further, plasma arc welding is a non-consumable electrode type welding method, and it is necessary to supply a filler material (wire) to a welded portion in a welded joint having a gap. For this reason, a welding torch becomes large and it is difficult to apply it to a narrow place.
[0008]
The second conventional technique uses a welding speed as one of the parameters, and does not consider arc spot welding where the welding speed is 0.
[0009]
Also, the third prior art does not consider arc spot welding in which the start point and the end point are the same point.
[0010]
SUMMARY OF THE INVENTION An object of the present invention is to provide a consumable electrode type arc spot welding method and a consumable electrode type arc welding apparatus which solve the above-described problems in the prior art, have a simple apparatus configuration, and can be easily applied to narrow places. It is in.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, the first means includes a start control period for starting an arc, a welding output control period for performing welding following the start control period welding, and a tip of the consumable electrode following the welding output control period. In the consumable electrode type arc spot welding method for controlling the welding power and the supply speed of the consumable electrode during each period of the ball drop control period for shaping, the welding output control period is divided into two or more periods and divided. The output level and the supply speed of the consumable electrode are switched every period.
[0012]
In this case, each of the divided periods may be set to less than 1 second. Further, a welding stop period of 1 second or less may be provided between the divided period and the next divided period. Further, a ball may be interposed between the welding stopped period and a welding period immediately before the welding stopped period. Preferably, a drop control period is provided.
[0013]
In addition, the start control period is divided into a first period and a second period following the first period, and the output level and the supply speed of the consumable electrode in the first period can be easily arced. It is preferable that the output level and the supply speed of the consumable electrode in the second period are set as conditions for stably forming a molten pool.
[0014]
The second means includes a welding output control means for controlling a welding output, and a consumable electrode supply control means for controlling a supply amount of a consumable electrode, and supplies a preset welding output to a welding portion. In an electrode-type arc welding apparatus, storage means for storing a set of parameters for defining the welding output, duration of the welding output, and feed rate of a consumable electrode, and specifying means for specifying the set of data The consumable electrode supply control means supplies a wire at a specified speed for a time corresponding to the set specified by the specifying means, and the welding output control means corresponds to the specified set. The welding power to be supplied is supplied to the welding portion.
[0015]
In this case, it is simple to assign a number to the set in advance, and to specify the data set by specifying the number. Further, it is preferable that a timing unit for measuring the duration of the welding output is provided, and the output time is controlled according to the output of the timing unit.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a configuration diagram of a consumable electrode type arc spot welding apparatus according to the present invention.
[0017]
In FIG. 1, a rectifier 1 converts a commercial alternating current into a direct current. An inverter circuit 2 including an insulated gate bipolar transistor (IGBT) converts a DC output from the rectifier 1 into a high-frequency AC and controls a welding output supplied to a welding portion. The transformer 3 reduces the output controlled by the inverter circuit 2 to a voltage required for welding. Rectifier 4 converts the output of transformer 3 to DC. The wire feed roller 6 is driven by the wire feed control circuit 13 and feeds the welding wire 5 toward the base material 7.
[0018]
The PWM (pulse width) control circuit 8 outputs a PWM control signal for controlling output to the inverter circuit 2 based on a command from the pulse output control circuit 9. The pulse output control circuit 9 issues a command signal based on the pulse parameters set by the setting unit 10, that is, the pulse voltage Vp, the base voltage Vb and the pulse width Tp, and the value of the base period Tb set by the setting unit 11. To the PWM control circuit 8. In this embodiment, the average arc voltage Vav is controlled by setting the base period Tb.
[0019]
The CPU 12 includes a storage area capable of storing a data table 12a and the like, a timer 12b, and the like. The CPU 12 measures each period described later, and based on control signals input from the mode setting unit 14 and the start switch 15, The data stored in the table 12a is output to the pulse parameter setting device 10, the average arc voltage setting device 11, and the wire feed control circuit 13.
[0020]
Next, the mode number (No.) and the data number (No.) will be described.
[0021]
The data numbers are given serial numbers for each welding condition when appropriate welding can be performed. As shown in FIG. 4, the wire feed speed WF, the average arc voltage Vav, the pulse voltage Vp, the base voltage Vb, pulse width Tp, and time T for maintaining these values are registered as a set in the data table 12a.
[0022]
The mode number is a serial number of the welding sequence. As shown in FIG. 5, data numbers used when performing a certain welding operation are arranged in chronological order. In this embodiment, one welding operation is performed. Are controlled separately into a start control period (STR) for starting an arc, a welding output control period (WELD) for performing welding, and a ball drop control period (KYU) for shaping the end of the wire. Note that the welding output control period is subdivided into periods 0 to x (steps). In the figure, the column in which the data number is described as F is a skipped period, and the execution of the step is omitted. Therefore, when a certain mode number is designated, the welding conditions used for welding are uniquely determined.
[0023]
FIG. 2 is a flowchart showing the operation of this embodiment.
[0024]
When a control power supply (not shown) is turned on, the CPU 12 checks whether the mode number set by the mode setting unit 14 has been changed (procedure S100 in FIG. 2). Immediately, the process of S140 is performed. When the mode number has been changed, after reading the mode number (S110), each data number of the mode number is stored (S120), and the number of data numbers in the welding output control period, that is, the number of steps m is set (S130), and the process of S140 is performed.
[0025]
In S140, it is checked whether or not the activation switch 15 has been turned on. If it has not been turned on, the process of S100 is performed, and in other cases, the process of S150 is performed.
[0026]
In S150, the control data used for the start control period is read from the data table 12a, and the read data of the average arc voltage (Vav) s, the pulse voltage (Vp) s, the base voltage (Vb) s, and the pulse width (Tp) s are read. Is input to the pulse output control circuit 9 via the setting devices 10 and 11, and data of the wire feed speed (WF) s is input to the wire feed control circuit 13 (S160). Further, the start control time Ts is set in the timer 12b (S170), and the welding is started (S180). The symbol s added to the end of each control data indicates control data used in the start control period. Further, as described later, the symbol n is appended to the end of each control data in the welding output control period, and the symbol e is appended to the end of each control data in the ball droplet control period.
[0027]
When welding is started and the occurrence of an arc is confirmed by an arc occurrence confirming means (for example, an ammeter) not shown, the CPU 12 operates the timer 12b and controls the control data of the start control period until the start control time Ts elapses. (S190).
[0028]
When the start control time Ts has elapsed, the CPU 12 resets a counter n that counts the number of steps in the welding output control period (S200), and calculates the average arc voltage from the data number corresponding to step n (here, n = 0). Each data of (Vav) n, pulse voltage (Vp) n, base voltage (Vb) n, and pulse width (Tp) n is read (S210), and each read control data is output as a pulse via setting devices 10 and 11. While input to the control circuit 9, the wire feed speed (WF) n is input to the wire feed control circuit 13 (S220). Further, after setting the welding output control time Tn in the timer 12b (S230), it is checked whether (Vav) n = 10, and if (Vav) n is 10, the process of S330 is performed. In this case, the process of S300 is performed (S240).
[0029]
In S300, the welding based on the welding output control data n is performed until the time measured by the timer 12b reaches the welding output control time Tn set. When the welding output control time Tn is up, 1 is added to the counter n (S310), and then the counter n is compared with the number of steps m. If n> m, the process of S330 is performed. Performs the processing of S210 (S320).
[0030]
In S330, the control unit reads the ball drop control data, and sets the read data of the average arc voltage (Vav) e, the pulse voltage (Vp) e, the base voltage (Vb) e, and the pulse width (Tp) e to the setting units 10 and 11. In addition to the input to the pulse output control circuit 9, the wire feed speed (WF) e is input to the wire feed control circuit 13 (S340). In addition, the ball drop control time Te is set in the timer 12b (S350). The welding is performed based on the ball drop control data until the time measured by the timer 12b reaches the ball drop control time Te (S360).
[0031]
When the ball drop control time Te is up, the counter n is compared with the number of steps m (S370). If n> m, the processing of S380 is performed. Otherwise, all the processing is completed. An end process is performed (S410).
[0032]
In S380, timing of the welding temporary stop time Tn is started, and after waiting for the welding temporary stop time Tn to elapse (S390), 1 is added to the counter n (S400), and the process of S210 is performed.
[0033]
In the above description, one type of welding condition is used in the start control period. However, the start control period may be divided into two periods.
[0034]
FIG. 3 is a flowchart showing a control procedure according to another embodiment during the start control period. Procedures before S140 and procedures after S210 are the same as the procedures described in FIG. It is.
[0035]
In this embodiment, when the start switch is turned on in S140, after resetting the counter q in the start control period (S500), the average arc voltage (Vav) q and the pulse voltage (Vp) used in the start control period. q, base voltage (Vb) q, and pulse width (Tp) q are read from the data table 12a (S510), and the read control data are input to the pulse output control circuit 9 via the setting units 10 and 11. At the same time, the wire feed speed (WF) q is input to the wire feed control circuit 13 (S520). Then, the start control time Tq is set in the timer 12b (S530), and the welding is started (S540).
[0036]
When the welding is started and the occurrence of the arc is confirmed, the timing is started, and the welding based on the start control data is continued until the start control time Tq elapses (S550).
[0037]
When the start control time Tq has elapsed, 1 is added to the counter q (S560). If the value of the counter q is q <2, the process of S510 is performed, and otherwise, the process of S210 is performed (S570). The difference between the welding conditions in the first period (q = 1) and the second period (q = 2) in the start control will be described later.
[0038]
FIG. 6 shows an example of the arc spot welding conditions in the present embodiment.
In this embodiment, the start control period is divided into two periods in each case.
[0039]
Mode No. Reference numeral 1 denotes a welding condition for a lap welded joint having a plate thickness of 0.7 mmt and no gap, and includes two-stage start control, two-stage welding output control, and one-stage ball droplet control.
[0040]
In the first-stage control of the start control, a condition for smoothly starting the arc is selected, and for the second-stage control, a condition for the initial stabilization of the molten pool is selected. Specifically, the second-stage wire feeding speed (WF) q is set to be faster than the first-stage wire feeding speed (WF) q.
[0041]
Usually, as a result of the arc being generated and the wire tip melting rapidly, the distance between the wire tip and the base metal increases, and the arc becomes unstable. However, by making the second-stage wire feeding speed (WF) q faster than the first-stage wire feeding speed (WF) q, it is possible to prevent the distance between the tip of the wire and the base material from becoming large. At the same time, the molten pool can be formed stably.
[0042]
The first stage of the welding output control is mainly a condition that penetrates the upper plate and forms a back seam on the lower surface of the lower plate. Conditions for the purpose of correction are set respectively.
[0043]
Mode No. Reference numeral 2 denotes welding conditions for a lap welded joint having a thickness of 0.7 mmt and a gap of 1 mm, and includes two stages of start control, a total of three stages of welding output control including a temporary suspension period of welding, and one stage of ball droplet control. Have been.
[0044]
In the case of lap welded joints with gaps, the molten metal tends to spread to the periphery of the molten pool, and even if the welding time is extended, the bead diameter only increases and the upper and lower plates cannot be connected, so welding defects (Bridge failure). However, if the welding output control is temporarily stopped to promote the cooling of the molten pool and then the welding is started again to form an extra bead, the upper plate and the lower plate can be reliably connected.
[0045]
Mode No. Reference numeral 3 denotes welding conditions for a lap welded joint having a plate thickness of 1.0 mmt, which is composed of two stages of start control, a total of three stages of welding output control including a temporary suspension period of welding, and one stage of ball droplet control. . The mode No. The condition of No. 3 can be commonly applied to a gap of 0 to 1.0 mm.
[0046]
Mode No. Reference numeral 4 denotes a condition for welding a lap welded joint having a plate thickness of 1.6 mmt, and includes two-stage start control, two-stage welding output control, and one-stage ball droplet control. This condition can be commonly applied to a gap of 0 to 1.0 mm.
[0047]
Mode No. Reference numeral 5 denotes a welding condition for a lap welded joint having a thickness of 2.3 mmt and no gap, and is constituted by two-stage start control, three-stage welding output control, and one-stage ball droplet control. Normally, in such a joint of a relatively thick plate, it is necessary to perform welding with a large output in order to penetrate the upper plate. However, if welding with a large output is continued for a long time, dripping of molten pool metal occurs. Therefore, it is necessary to reduce the output after a certain amount of time has elapsed. In this case, if the output is reduced stepwise in a plurality of steps, it is easy to control the joint area and the shape of the back bead.
[0048]
Mode No. Reference numeral 6 denotes welding conditions for a lap welded joint having a plate thickness of 2.3 mmt and a gap of 1 mm, which is composed of two-stage start control, four-stage welding output control, and one-stage ball droplet control, and has a gap. However, it is possible to secure an appropriate extra bank shape.
[0049]
In addition, since the welding torch used for pulse mag welding or CO ₂ welding is small, welding at narrow locations is easy.
[0050]
FIG. 7 is a diagram showing the cross-sectional shape of the arc spot welded portion performed under the above welding conditions, and it can be seen that a sufficient joint diameter is obtained in each case. In the drawing, the cross section of the spot weld is shown by a broken line.
[0051]
In addition, although the case where pulse mag welding is performed has been described above, the welding method is not limited to pulse mag welding, and the same effect can be obtained even by using mag welding without pulse or CO ₂ welding. it can. When performing CO ₂ welding, the operation of the average arc voltage Vav setting device 11 in FIG. 1 is slightly different, but the pulse generation circuit 9 and the pulse parameter setting device 10 can be omitted.
[0052]
In addition, it goes without saying that the present invention can be applied not only to galvanized steel sheets but also to ordinary steel sheets that are not galvanized.
[0053]
【The invention's effect】
As described above, according to the present invention, the lap joint can be welded only by working from one side of the weld joint using the small and lightweight welding torch, so that the workability is greatly improved. Further, the welding device is simplified, and the price of the welding device can be greatly reduced. In addition, semi-automatic welding makes it easier to perform work that had to be done by robots or mechanized welding in the past. Further, since welding conditions can be set using data previously input to the database, the only operations performed by the operator are the setting of the mode number and the ON / OFF operation of the start switch. Therefore, even low-skilled workers can obtain welding results with excellent quality.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a consumable electrode type arc spot welding apparatus according to the present invention.
FIG. 2 is a flowchart showing the operation of the present invention.
FIG. 3 is another flowchart showing the operation of the present invention.
FIG. 4 is an explanatory diagram of a data number according to the present invention.
FIG. 5 is an explanatory diagram of a mode number according to the present invention.
FIG. 6 is an explanatory diagram of specific contents of a mode number according to the present invention.
FIG. 7 is an example of a cross-sectional shape of an arc spot weld according to the present invention.
[Explanation of symbols]
Vav Average arc voltage Vp Pulse voltage Vb Base voltage Tp Pulse width WF Wire feed speed T Length of period

Claims (8)

During each of a start control period for starting an arc, a welding output control period for performing welding following this start control period, and a ball drop control period for shaping the tip of a consumable electrode following this welding output control period, welding power and consumption are determined. In the consumable electrode type arc spot welding method for controlling the supply speed of the electrode,
A consumable electrode-type arc spot welding method, wherein the welding output control period is divided into two or more periods, and at least one of an output level and a supply speed of the consumable electrode is switched for each of the divided periods. The consumable electrode type arc spot welding method according to claim 1, wherein each of the divided periods is less than one second. The consumable electrode type arc spot welding method according to claim 1 or 2, wherein a welding stop period of 1 second or less is provided between the divided period and the next divided period. The consumable electrode type arc spot welding method according to claim 3, wherein a ball drop control period is provided between the welding stop period and a welding period immediately before the welding stop period. The start control period is divided into a first period and a second period following the first period, and an output level and a supply speed of the consumable electrode in the first period are set as conditions under which arc generation is easy, The consumable electrode type arc spot welding according to any one of claims 1 to 4, wherein the output level and the supply speed of the consumable electrode in the second period are set to conditions for stably forming a molten pool. Method. A consumable electrode type arc welding apparatus comprising: a welding output control means for controlling a welding output; and a consumable electrode supply control means for controlling a supply amount of a consumable electrode, and supplying a preset welding output to a welding portion. ,
Storage means for storing a set of parameters for defining the welding output, duration of the welding output, and data of the feeding speed of the consumable electrode,
Designating means for designating the data set;
With
The consumable electrode supply control means supplies a wire at a specified speed for a time corresponding to the set specified by the specifying means, and the welding output control means outputs a welding output corresponding to the specified set. A consumable electrode type arc welding apparatus characterized in that it is supplied to a welding portion. The consumable electrode type arc welding apparatus according to claim 6, wherein a number is assigned to the set in advance, and the specifying means specifies the data set by specifying the number. The consumable electrode type arc welding apparatus according to claim 6, further comprising a time measuring means for measuring a duration of the welding output.

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