JP2001225166A - Welding method for consumable electrode type arc welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformize cycles of the generation of an arc and a short circuit, to suitably apply heat energy to a limited weld zone and to control intended cyclic welding by forcedly imparting vibrations of the nearly same cycle as the cycle of the generation of the arc and the short circuit to a molten pool, in consumable electrode type arc wedding in which an electrode wire is fed to work base material and the generation of the arc and the short circuit are cyclically repeated between the tip end of the electrode wire and the work base material to perform welding. SOLUTION: The electrode wire 3 is fed to work base material 5, the cycle of the generation of the arc and the short circuit between the tip end of the electrode wire 3 and work base material 5 is grasped, vibrations of the nearly same cycle as it are forcedly imparted to the vicinity of the molten pool 26. A sound welded part is obtained by imparting controlled vibrations to the molten pool 26 in such a manner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION In consumable electrode type arc welding, welding is performed by periodically repeating arc generation and short circuit between a tip end of an electrode wire and a workpiece base material. The invention belongs to the field of such welding techniques.

[0002]

2. Description of the Related Art There are various types of welding systems in which an electrode wire is fed toward a workpiece base material, and arc generation and short-circuiting are periodically repeated between the tip end of the electrode wire and the workpiece base material. It is introduced in the literature. As one of them,
There is a "Welding and Joining Handbook" published by Maruzen Co., Ltd., published on March 30 by the Japan Welding Society 4 (a) of FIG. 4 ・ 66 and FIG. 4 ・ 67 of the same book, FIG. 4 and FIG.
And FIG. 6 are disclosed, in particular, FIGS.
Describes the periodic phenomenon described above.

FIG. 4 shows an arc welding unit 11 generally employed, in which an electrode tip 2 is arranged in a pipe-shaped gas nozzle 1, an electrode wire 3 penetrates through the electrode tip 2, The wire 3 is fed by a feed roller 4 toward the workpiece base material 5 at a predetermined speed. The shielding gas is a mixed gas of carbon dioxide gas and argon gas, and flows out so as to cover the welding local part as shown by a two-dot chain line. Work base material 5 is a jig (not shown in FIG. 4)
And the gas nozzle 1 moves toward the arrow 6.

When the electrode wire 3 and the work base material 5 are connected to a power source, an arc 7 is generated from the tip of the electrode wire 3 toward the work base material 5, and the heat thereof causes the work base material 5 to move.
Are sequentially melted, and the welding proceeds. During this process, a molten pool 8 is formed, which solidifies into a weld metal 9.

[0005] The welding process will be described with reference to Figs. FIG. 5 is a diagram showing the relationship between the voltage and the current. When a voltage is applied between the electrode wire 3 and the work base material 5, the tip of the electrode wire 3 and the work base material 5 An arc 7 is generated between the two. This is the section indicated by the symbol A, and corresponds to the stages a and b in FIG. That is, in the initial stage of arc generation, the amount of fusion between the surface portion of the workpiece base material 5 and the tip end portion of the electrode wire 3 is small as shown in a. Thereafter, as the melting of both proceeds with the passage of time, the amount of melting increases as shown by b. Since the electrode wire 3 is continuously fed, if the amount of melting in the state b further increases, a short circuit occurs as in the state c. At this time, as shown by the symbol S in FIG. 5, the voltage becomes the minimum value, the current rises, and conversely, at the end of the section S, the short-circuited portion becomes thin as in the d state and becomes a pinch portion. The part is cut off and the cycle C1 ends. The cycle C2 starts from the e state.

[0006]

It is difficult to keep the above-described periodic repetition of arc generation and short-circuit at a constant cycle. The factors include the fact that the values such as the voltage, the flowing state of the shielding gas, the moving speed of the torch, and the distance between the electrode wire and the workpiece base material are not at predetermined values. From another point of view, in a state controlled by the above-mentioned change in each value, the cycle is determined according to the situation at each time. Therefore, the thermal energy input to the workpiece base material
Becomes excessive, the amount of melting of the workpiece base material becomes excessive, and in the case of welding a steel plate, a fatal welding defect that the molten portion penetrates the plate thickness is caused. The problem as described above is shown in FIG.
, Cn are not uniform.

[0007] The above-mentioned problem due to the deviation of each value is caused by the arc welding unit 11 in the robot apparatus 10 as shown in FIG.
It becomes more serious when the is attached.
It is very difficult for the robot device to keep the above-mentioned moving speed and interval within a small allowable value due to the bending of the entire robot device and the accumulation of working gaps. Further, in order to minimize the amount of deviation, it is necessary to repeat teaching of the robot device many times to obtain the best robot trajectory, which is a very troublesome operation.

The configuration shown in FIG. 3 will be described. Robot device 10
Is a normal 6-axis type, and the control head 12
And a unit support member 13 is attached to the head. The arc welding unit 11 is firmly fixed to the unit support member 13, and the tip of the electrode wire 3 is close to the workpiece base material 5. The workpiece base material 5 here is obtained by stacking two steel plates 5a and 5b.
A molten pool is formed at a corner 5c formed by the end face of the steel plate 5a and the surface of the steel plate 5b, and the two steel plates 5a and 5b are welded. The corner 5c extends in a direction perpendicular to the paper surface of FIG. 3, and therefore, the moving direction of the electrode wire 3 is also along the corner 5c. Both steel plates 5a, 5
b is placed on the support base 14 and is firmly fixed by the clamp mechanism 15.

Each of the above steel plates has a thickness of 0.9 mm, and the diameter of the electrode wire 3 is 0.9 mm. Also, C
The cycle of 1, C2, C3,... Cn is 100 cycles / second. These values are the same in the embodiment described later.

[0010]

SUMMARY OF THE INVENTION The present invention has been provided to solve the above-mentioned problems.
The basic idea is to apply a forcible vibration to the molten pool to obtain a controlled molten state and perform sound welding.

According to the first aspect of the present invention, the electrode wire is fed toward the workpiece base material, and welding is performed by periodically repeating arc generation and short circuit between the tip of the electrode wire and the workpiece base material. In a consumable electrode type arc welding, a welding method of a consumable electrode type arc welding characterized by forcibly applying a vibration having substantially the same cycle as that of the arc generation and the short circuit to a molten pool.

By doing so, the cycles of arc generation and short circuit described in FIGS. 5 and 6 are made uniform, and the heat energy supplied to the welding local part becomes proper. That is, since the arc generation and the short circuit as shown in FIG. 6 are performed periodically, in order to prevent the periodicity from being deviated, the molten pool is forced to vibrate at a cycle substantially equal to the cycle of the arc generation and the short circuit. Give. Therefore, after the arc is generated for a certain period of time, the tip of the sequentially fed electrode wire is formed at a time when the short circuit phenomenon is determined by approaching the molten pool or coming into contact with the surface of the molten pool. As described above, the heat generated by the arc is made uniform, and the short circuit due to the molten metal is formed at a predetermined time, so that the welding control at the intended cycle is performed.

According to a second aspect of the present invention, in the first aspect, the direction of the forced vibration is set such that the surface of the molten pool approaches or separates from the tip of the electrode wire. This is a consumable electrode type arc welding welding method.
By defining the direction of such vibration,
The transition to the short-circuit phenomenon at a fixed time during the arc is more reliably performed.

According to a third aspect of the present invention, there is provided a welding method for consumable electrode type arc welding according to the first or second aspect, wherein the arc welding unit is attached to a unit support member of a robot device. When the arc welding unit is moved by the robot apparatus to a state where the molten pool is forcibly vibrated, the above-described regular arc generation and short circuit are repeated.

According to a fourth aspect of the present invention, in any one of the first, second, and third aspects, the arc welding unit is attached to a unit supporting member of the robot apparatus, and the means for forcibly generating vibration. Is a consumable electrode type arc welding method characterized by being attached to the support member. Since both the arc welding unit and the vibrating means are attached to the unit support member of the robot device, the relative positional relationship between these two is determined,
Further, by bringing the vibrating means into contact with a predetermined position of the workpiece base material, the relative position between the tip end portion of the electrode wire and the workpiece base material is finally maintained in a good state.

The invention according to claim 5 is based on claim 1, claim 2,
A method for consumable electrode type arc welding according to any one of claims 3 and 4, wherein the vibrating force of forced vibration is applied to a work base material near the molten pool. By applying the vibrating force to such a position, the vibration is reliably transmitted to the molten pool, and at the same time, the vibrating means and the tip of the electrode wire can be arranged close to each other. Can be sought.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in FIGS. Note that the same reference numerals are given in the drawings to those having the same functions as the members described above. Although the support base 14 in FIG. 3 has a large area, the support base 16 according to the embodiment is a support piece 16 corresponding to the clamp mechanism 15 and is fixed on the stationary member 17. Therefore, the workpiece base material 5 is fixed at both ends in the drawing, and the intermediate portion is in a floating state.

As the vibrating means 18, various types such as an electromagnetic solenoid type and a rotary motor type can be adopted. Here, the case where an electric motor is used is shown. The vibrating electric motor 19 is a general motor having an eccentric weight inside, and the vibration caused by the eccentric weight is transmitted from the roller 20 to the steel plate 5a of the workpiece base material. A yoke member 21 is fixed below the vibrating electric motor 19, and a roller 20 is inserted into the yoke member 21 so as to be rotatably supported by a shaft 22. Since the vibrating means 18, that is, the roller 20 in this case, must be pressed against the steel plate 5 a with a constant force, a pressing means is employed.
This means may be a component such as a coil spring, but here, an air cylinder 23 is employed. The air cylinder 23 is fixed to the unit support member 13, and its piston rod 24 is connected to the electric motor 19. Note that, in order to prevent an excessive vibration reaction force from being transmitted to the air cylinder 23, a buffer member 25 is interposed between the vibrating electric motor 19 and the piston rod 24. For the buffer member 25, for example, urethane is suitably used.

The roller 20 rolls along the corner 5c, and the point of contact with the workpiece base material 5 is near the corner 5c. Reference numeral 26 denotes a molten pool formed at the corner 5c. Therefore, the vibrating force is applied to the vicinity of the molten pool 26. Note that a shoe member that slides on the workpiece base material 5 instead of the rolling of the roller 20 may be used. When the molten pool 26 is vibrated by the electric motor 19, the surface of the molten pool 26 approaches or separates from the tip of the electrode wire 3 depending on the direction of the vibration. For this purpose, the electrode wire 3 is brought close to the molten pool 26 from above.

The operation of the above embodiment will be described. The vibration cycle of the vibration motor 19 is set to be substantially the same as the desirable cycle of arc generation and short circuit. The roller 20 is lightly pressed against the steel plate 5a by the output of the air cylinder 23,
When the vibrating electric motor 19 is operated, the workpiece base material 5 vibrates up and down as shown in FIG. Due to such vibration displacement, the periodic repetition of the arc generation and the short circuit described with reference to FIGS. 5 and 6 continues, and the welding proceeds.

FIG. 2A shows the bending vibration of the workpiece base material, while FIG. 2B shows a displacement structure provided on the support piece side.
That is, the coil spring 27 erected on the stationary member 17 is combined with a cup-shaped support piece 28 so as to cover the coil spring 27, and a clamp mechanism 29 is coupled to the support piece 28. With such a structure, the work base material 5 is supported by the coil spring 27, and when vibrated by the rollers 20, the work base material vibrates, and the molten pool 26 vibrates.

As is clear from FIG. 1, the surface of the molten pool 26 is inclined downward to the right. In this case, when there is a concern that the molten metal is shifted to the right, the workpiece base material 5 is inclined counterclockwise so that the surface of the molten pool 26 is horizontal.

[0023]

According to the present invention, the electrode wire is fed toward the workpiece base material, and arc generation and short-circuiting are repeatedly repeated between the tip of the electrode wire and the workpiece base material to perform welding. In the consumable electrode type arc welding described above, vibration of a cycle substantially equal to the cycle of the arc generation and the short circuit is forcibly applied to the molten pool. By doing so, the cycle of arc generation and short circuit described in FIGS.
The heat energy supplied to the welding local part becomes appropriate. That is, since the arc generation and the short circuit as shown in FIG. 6 are performed periodically, in order to prevent the periodicity from being deviated, the molten pool is forced to vibrate at a cycle substantially equal to the cycle of the arc generation and the short circuit. Give. The value is set so that this forced vibration does not cause excessive melting. Therefore, after the arc is generated for a certain period of time, the tip of the sequentially fed electrode wire is formed at a time when the short circuit phenomenon is determined by approaching the molten pool or coming into contact with the surface of the molten pool. As described above, the heat generated by the arc is made uniform, and the short circuit due to the molten metal is formed at a predetermined time. Therefore, the welding control at the intended cycle is performed without the occurrence of the molten penetration portion in the steel plate or the like.

Since the direction of the forced vibration is set so that the surface of the molten pool approaches or separates from the tip of the electrode wire, the transition to the short-circuit phenomenon occurs at a fixed time during the arc generation. Is performed more reliably.

Since the arc welding unit is attached to the unit support member of the robot apparatus, the arc welding unit is moved by the robot apparatus to a state where the molten pool is forcibly vibrated.
The periodic arc generation and short circuit described above are repeated.

The arc welding unit is mounted on a unit supporting member of the robot apparatus, and a forcible vibration generating means is also mounted on the supporting member. Both the arc welding unit and the vibrating means are attached to the unit support member of the robot apparatus. Therefore, the relative positional relationship between the two is determined, and the vibrating means is determined by the work base material. By contacting the position, finally, the relative position between the tip end of the electrode wire and the workpiece base material is also maintained in a good state.

The vibrating force of the forced vibration is applied to the work base material near the molten pool. By applying the vibrating force to such a position, the vibration is reliably transmitted to the molten pool, and at the same time, the vibrating means and the tip of the electrode wire can be arranged close to each other. Can be sought.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIGS. 2A and 2B show a vibration form of a workpiece base material, wherein FIG. 2A is a bending method and FIG.

FIG. 3 is a simplified front view when a robot device is used.

FIG. 4 is a longitudinal sectional side view showing a state of general arc welding.

FIG. 5 is a diagram showing a relationship between voltage and current.

FIG. 6 is a process diagram sequentially showing a repetition phenomenon of arc generation and short circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 Electrode wire 5 Work base material 7 Arc 18 Vibration means 26 Melt pool 11 Arc welding unit 10 Robot apparatus 13 Unit support member

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] February 16, 2000 (2000.2.1
6)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG. 2

FIG.

FIG. 3

FIG. 4

FIG. 5

FIG. 6

Claims (5)

[Claims] Consumable electrode type arc welding in which an electrode wire is fed toward a work base material and welding is performed by periodically repeating arc generation and short circuit between the tip of the electrode wire and the work base material. , Wherein a vibration having substantially the same cycle as the arc generation and short circuit is forcibly applied to the molten pool. 2. The consumable electrode type arc according to claim 1, wherein the direction of the forced vibration is set such that the surface of the molten pool approaches or separates from the tip of the electrode wire. Welding method of welding. 3. The welding method according to claim 1, wherein the arc welding unit is attached to a unit support member of the robot apparatus. 4. The arc welding unit according to claim 1, wherein the arc welding unit is mounted on a unit support member of the robot apparatus, and a means for forcibly generating vibration is provided on the support member. A welding method for consumable electrode type arc welding characterized by being attached. 5. The method according to claim 1, wherein the vibrating force of the forced vibration is applied to a work base material near the molten pool. Consumable electrode arc welding welding method.