JP2014087818A - Arc welding method and arc welding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welding method capable of obtaining a more desirable bead shape in stitch pulse welding using a consumable or nonconsumable electrode.SOLUTION: A welding method includes, in a welding section where stitch pulse welding is carried out, a first step of calculating a distance between the welding sections, a second step of calculating the number of divisions of stitch pulse welding by dividing the distance calculated in the first step with a preset moving pitch of the stitch pulse welding, and a third step of calculating a correction moving pitch by dividing the distance calculated in the first step with the number of divisions calculated in the second step. The stitch pulse welding is carried out by the correction moving pitch calculated in the third step to form a welding bead with an equal distance between a welding start point and a welding end point.

Description

  The present invention relates to an arc welding method and an arc welding apparatus that perform welding by switching two welding conditions at a predetermined cycle using welding electrodes such as non-consumable electrodes and consumable electrodes.

  Arc welding is a technology that uses a non-consumable electrode or a consumable electrode to generate an arc between the electrode and the object to be welded (also referred to as a base material) and melt the base material by arc heat to join the metals. is there. In many production sites, an automatic welding system in which welding work is automated using an industrial machine such as an industrial robot is employed.

  One of the welding methods related to arc welding is a stitch pulse welding method. The stitch pulse welding method is a welding method in which the thermal influence on the base material can be easily suppressed by controlling the operation of an industrial machine that holds the welding torch and the heat input and cooling during welding. The stitch pulse welding method has an effect of reducing the amount of welding distortion and an effect of improving the welding appearance as compared with conventional welding (see, for example, Patent Document 1).

  FIG. 9 is a diagram showing an example of an automatic welding system for performing conventional stitch pulse welding. The welding system shown in FIG. 9 includes an industrial manipulator 901, a welding wire feeding device 902, a welding torch 903, a control device 905 that controls the operation of the industrial manipulator 901, and a welding power source device 906.

  Next, a conventional stitch pulse welding control method will be described with reference to FIG.

  First, when stitch pulse welding is started, welding is performed at a preset welding time in a state where the position of the welding torch 903 is fixed at the welding start point (Ps in FIG. 10). This is STEP1.

  When the welding time has elapsed, the automatic welding system stops welding, and moves the welding torch 903 by a preset movement pitch in a state where welding is stopped. This is STEP2.

  When the pitch movement of the welding torch 903 is completed, the welding of the STEP 1 is performed again in a state where the movement of the welding torch 903 is stopped. Thereafter, the welding start and end indicated as STEP 1 and STEP 2 and the movement of the welding torch 903 are stopped. The pitch movement is repeated until the welding end point of the weld line is reached. By performing such control, heat input to the welding object W can be suppressed, and it is possible to prevent the welding object W from being burned out and to reduce welding distortion.

  However, when this method is used, the welding end point of the weld line does not always coincide with the final point of pitch movement. FIG. 10 shows an example of a specific example. When a 200 mm welding section is moved at a moving pitch of 3 mm, the welding ends 2 mm before the welding end point. Does not match the welding point.

  The following three methods are conceivable as countermeasures in the case of such mismatch. The first method is to end the stitch pulse welding at the final welding point (Pe1 in FIG. 10) that reaches the welding section. The second method is to perform welding again at the welding end point (Pe in FIG. 10). In the third method, welding is performed at the last pitch movement point (Pe2 in FIG. 10) exceeding the welding section, and stitch pulse welding is terminated.

  However, in the first method, there is a possibility that weld cracking may occur with respect to the teaching. Further, in the second method, the pitch movement interval changes, so that the weld bead is disturbed only at the welding end portion, and not only the appearance is impaired, but also the weld quality may be affected. Further, in the third method, since the welding is performed exceeding the original welding section, there is a possibility that this also results in poor welding.

  As one of the methods for solving these problems, after performing welding at the final welding point reaching the welding section as in the first method, crater welding is performed on the spot, so that at the welding end portion. Has been devised (see, for example, Patent Document 2).

  In this welding method, the welding end position is set to Pe1 in FIG. 10, and by performing crater welding at Pe1, a more desired bead appearance can be obtained at the welding end portion.

JP-A-6-55268 JP 2011-161453 A

  However, for example, even if the stitch pulse welding end method described in Patent Document 2 is used, the idea of dividing the welding section by the moving pitch has not changed. For this reason, if the welding end point of the weld line and the final welding point after the pitch movement do not match, there is a possibility that a lack of welding may occur in the originally taught welding section.

  In order to avoid such a phenomenon, a method of teaching the welding section longer than the originally desired welding section can be considered. However, what the final welding point will be depends on the welding section and the movement pitch. Therefore, it is necessary for the operator to be careful about whether or not there is a lack of welding in each welding section, which is a burden on the operator.

  An object of the present invention is to provide an arc welding method and an arc welding apparatus that solve the above problems and obtain a more beautiful scale-like bead appearance.

  In order to solve the above problems, an arc welding method of the present invention is an arc welding method in which an arc is generated between a welding electrode and a welding object, and welding is performed, and a welding torch is moved to a welding position. After welding is performed, arc welding is performed while maintaining the arc or with the arc stopped, and welding is performed again at the next welding position separated by a predetermined moving pitch, and welding is repeated. A method of setting a first movement pitch; calculating a welding section distance which is a distance from a welding start position to a welding end position based on a teaching program; and Dividing the welding start position by adding the welding division distance to the step of obtaining the first divided value by dividing by the moving pitch of the first and dividing the predetermined value by the first divided value and multiplying by the welding section distance. And calculating the next welding position, and by setting the predetermined value to a value obtained by adding 1 from 1 to the first divided value, the predetermined value from the welding start position to the welding end position. Welding is performed while moving at a moving pitch.

  In addition to the above, the arc welding method of the present invention further includes a step of obtaining a second movement pitch by dividing the welding section distance by the first division value, the first movement pitch, and the second movement pitch. Is provided with a step of displaying.

  Further, the arc welding method of the present invention is an arc welding method in which an arc is generated between a welding electrode and a welding object and welding is performed, and after welding is performed by moving a welding torch to a welding position, An arc welding method in which welding is performed again at a next welding position separated by a predetermined movement pitch while maintaining the arc or in a state where the arc is stopped, and welding is performed while repeating these steps. A step of setting a movement pitch of 1, a step of calculating a welding section distance that is a distance from a welding start position to a welding end position based on a teaching program, and dividing the welding section distance by the first movement pitch. Obtaining a first division value; and dividing the welding section distance by the first division value to obtain a second movement pitch; and And they perform welding as a constant of the movement pitch.

  In addition to the above, the arc welding method of the present invention includes a step of displaying the first movement pitch and the second movement pitch.

  In the arc welding method of the present invention, in addition to the above, the first division value is rounded up, rounded down, or rounded to a positive integer greater than zero.

  The arc welding apparatus of the present invention includes a welding power supply device that supplies power between a welding electrode and a welding object, a manipulator including a welding torch that holds the welding electrode, and an operation of the manipulator A control device for controlling the welding, and performing welding by generating an arc between the welding electrode and the welding object, after moving the welding torch to a welding position, An arc welding apparatus that performs welding again at a next welding position separated by a predetermined movement pitch while maintaining the arc or with the arc stopped, and performing welding while repeating these steps. A setting unit for setting one movement pitch, a storage unit for storing a teaching program, and a welding start position to a welding end position based on the teaching program stored in the storage unit. A first division by dividing a welding section distance calculation unit that calculates a welding section distance that is a separation, and the welding section distance calculated by the first calculation unit by the first movement pitch set by the setting unit. A first division value calculation unit for calculating a value, and a value obtained by dividing a predetermined value by the first division value and multiplying the welding section distance by adding the welding start position, whereby the next welding is performed. A welding position calculation unit for calculating a position, and by setting the predetermined value to a value obtained by adding 1 from 1 to the first divided value, the predetermined moving pitch from the welding start position to the welding end position; Welding while moving.

  In addition to the above, the arc welding apparatus of the present invention includes a second movement pitch calculation unit that obtains a second movement pitch by dividing the welding section distance by the first division value, and a display unit that displays information. The first movement pitch and the second movement pitch are displayed on the display unit.

  An arc welding apparatus according to the present invention includes a welding power supply device that supplies electric power between a welding electrode and a welding object, a manipulator including a welding torch that holds the welding electrode, and the operation of the manipulator. A control device for controlling, and welding is performed by generating an arc between the welding electrode and the object to be welded. After the welding torch is moved to a welding position and welding is performed, the arc is An arc welding apparatus in which welding is performed again at a next welding position separated by a predetermined movement pitch in a state where the arc is stopped or in a state where the arc is stopped, and welding is performed while repeating these steps. A setting unit for setting the moving pitch, a storage unit for storing the teaching program, and a distance from the welding start position to the welding end position based on the teaching program stored in the storage unit. And a first division value obtained by dividing the welding section distance calculated by the first calculation section by the first movement pitch set by the setting section. And a second movement pitch obtained by dividing the welding section distance calculated by the first calculation unit by the first division value calculated by the second calculation unit. A third calculation unit is provided, and welding is performed with the second movement pitch as the predetermined movement pitch.

  In addition to the above, the arc welding apparatus of the present invention includes a display unit that displays information, and displays the first movement pitch and the second movement pitch on the display unit.

  Further, in addition to the above, the arc welding apparatus of the present invention is configured such that, in the first division value calculation unit, the first division value is rounded up, rounded down, or rounded to a positive integer greater than zero. is there.

  As described above, according to the present invention, the distance of the welding section is calculated based on the teaching program, the distance of the welding section is divided by a predetermined movement pitch to obtain a division value, and the distance of the welding section is divided by the value. The step of obtaining a corrected movement pitch that can be divided into equal parts by dividing the welding section is performed, and stitch pulse welding is performed with the corrected movement pitch, so that no weld chipping occurs in the taught welding section. A uniform bead can be formed.

The figure which shows schematic structure of the stitch pulse welding system in Embodiment 1 of this invention. The figure which shows the outline | summary of the welding torch in Embodiment 1 of this invention. The figure which shows the flowchart in Embodiment 1 of this invention. The figure which shows the flowchart of the stitch pulse initialization process in Embodiment 1 of this invention. (A) The figure for demonstrating calculation of the welding area distance when a welding area is comprised from the some teaching point in Embodiment 1 of this invention (b) It moves with the circular arc in Embodiment 1 of this invention The figure for explaining calculation of the welding section distance of the welding section The figure which shows an example of the display of the teach pendant in Embodiment 1 of this invention The figure for demonstrating the specific example in Embodiment 1 of this invention The figure which shows the flowchart in Embodiment 2 of this invention. The figure which shows schematic structure of the conventional stitch pulse welding system The figure for demonstrating the subject in the conventional stitch pulse welding system

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

(Embodiment 1)
FIG. 1 is a diagram illustrating an example of a schematic configuration of an arc welding apparatus that is an automatic welding system that automatically performs stitch pulse welding using a consumable electrode using a robot system in the first embodiment.

  The arc welding apparatus shown in FIG. 1 includes a manipulator 101, a control device 111 that controls operations of the manipulator 101, a teach pendant 121 that communicates with the control device 111, a welding wire 104 that is a consumable electrode, and a welding target. A welding power supply device 131 that supplies electric power to the object W and a welding wire feeding device 102 for feeding the welding wire 104 are provided.

  A welding torch 103 for consumable electrodes is attached to the manipulator 101. As shown in FIG. 2, a gas nozzle 201 for supplying a shielding gas such as argon is attached to the welding torch 103. From the gas nozzle 201, a shield gas supplied from a gas cylinder (not shown) is supplied to the welding location in accordance with a command from the welding power source 131. A contact tip 202 is attached to the tip of the welding torch 103, the welding wire 104 is fed by the welding wire feeder 102, and the welding wire 104 is fed and fed through the contact tip 202. .

  The welding power source device 131 includes an output unit (not shown) for applying a welding voltage to flow a welding current, a voltage detection unit (not shown) for detecting an actual voltage with respect to the output, and a welding wire. It is an apparatus provided with a control part (not shown) etc. The output unit is connected to the welding torch 103 and the welding object W, and a welding voltage is applied between the welding wire 104 that is a consumable electrode and the welding object W through the welding torch 103 according to a command from the control device 111. The

  The welding wire feeding device 102 is usually attached to the upper part of the manipulator 101, and includes an angle detection unit for detecting the angle of the feeding motor with a feeding motor with a guide roller and an angle sensor such as an encoder (not shown). It is a device equipped. And it is an apparatus for operating the welding power supply device 131 and feeding the welding wire 104 as a consumable electrode.

  When welding is started in accordance with a command from the control device 111, the welding power supply device 131 performs drive control of the welding wire feeding device 102 at a feeding speed determined according to the application of the welding voltage and the command current. An arc is generated between the fed welding wire 104 and the welding object W, and the welding wire 104 transfers droplets to the welding object W.

  The control device 111 is taught to perform a playback operation during automatic operation, and a communication unit 112 for performing communication with the teach pendant 121, a calculation unit 113 including a CPU and a memory for performing various internal calculations, and the like. A storage unit 114 for storing data and the like, a manipulator control unit 115 for controlling the operation of the manipulator 101 based on the result calculated by the calculation unit 113, and welding conditions such as welding current to the welding power source 131. Is provided with a welding condition commanding unit 116 for commanding. The welding power supply device 131 may be provided in the control device 111.

  The teach pendant 121 includes a communication unit 122 for communicating with the control device 111, a display unit 123 for displaying various information, and a data setting unit 124 for setting welding conditions and the like. Thus, the operation of the manipulator 101, the setting of calculation parameters for the arc welding method performed in the first embodiment, and the like can be performed.

  The teacher uses the teach pendant 121 to perform teaching work such as operation of the manipulator 101 and welding conditions. The taught data is stored in the storage unit 114 of the control device 111 via the communication unit 122 of the teach pendant 121.

  During the playback operation, the control device 111 calls the data from the storage unit 114, performs various calculations in the calculation unit 113, and issues an operation command of the manipulator 101 and an output command to the welding power source device 131. In addition, the manipulator 101 and the welding power source 131 can be controlled.

  Next, an operation procedure when using stitch pulse welding will be described. When the stitch pulse welding method is used, the teacher uses the data setting unit 124 of the teach pendant 121 to set the movement pitch P, the welding time T, the welding speed S, and the welding parameters, which are operation parameters necessary for stitch pulse welding. A certain current value I, voltage value V, etc. are set. The set data is stored in the storage unit 114 of the control device 111 via the communication unit 122 as teaching data including teaching point information related to the operation of the other manipulator 101.

  Next, details of the operation control of the manipulator 101 using the setting parameters of the stitch welding method according to the first embodiment and the welding control of the welding power supply device 131 will be described with reference to the drawings.

  3 and 4 show a flowchart of processing when the welding method of the first embodiment is used.

  In the playback operation, when the control device 111 reads the teaching program for performing the stitch pulse welding method of the first embodiment from the storage unit 114, the stitch pulse welding initialization process is performed at the teaching point where the stitch pulse welding is started. Performed (STEP 1 in FIG. 3).

  In the stitch pulse welding initialization process, the process is performed in the order of the flowchart shown in FIG. In the initialization process, first, the teaching point distance L is calculated (STEP 1-1 in FIG. 4). Here, the distance L between teaching points is calculated as the distance of the weld line from the teaching point at which the stitch pulse welding method is started to the teaching point at which the stitch pulse welding method is ended based on the teaching program. FIG. 5 shows a calculation example. As shown in FIG. 5A, when the stitch pulse welding section is composed of a plurality of teaching points having a welding intermediate point Pmi in addition to the welding start point Ps and the welding end point Pe, Calculate the total distance between them. Further, as shown in FIG. 5B, in the case of a teaching point that operates in an arc, a distance between teaching points in consideration of the arc is calculated.

  Once the distance L between teaching points in STEP1-1 is calculated, the movement number value CNT is then calculated (STEP1-2 in FIG. 4). The number-of-movements value CNT indicates how many pitch movements are required when the distance L between teaching points calculated in STEP 1-1 is pitch-moved at a preset movement pitch P using the teach pendant 121. It is a calculated value. This movement number value CNT can be obtained by dividing the distance L between teaching points by the movement pitch P. The movement count value CNT is calculated by the calculation unit 113.

  Here, the movement number value CNT is often a decimal number. In the first embodiment, a positive integer greater than zero is obtained by rounding off the first decimal place of the movement number value CNT. The integerization is performed by the calculation unit 113. In the first embodiment, rounding is used as an integerization method. However, as an integer conversion method, rounding up or down, or rounding up or down by an arbitrary value may be performed. Further, the calculated movement number value CNT is stored as an internal variable Count in the storage unit 114 of the control device 111 in order to be used in calculation of the stitch pulse welding method.

  Next, the correction movement pitch PP is calculated (STEP1-3 in FIG. 4). When the distance L between teaching points is moved using the movement pitch P set in advance in the storage unit 114, there is a possibility that the remaining distance may remain halfway at the end of stitch pulse welding. . Therefore, in this STEP, the movement pitch is corrected based on the movement number value CNT calculated from the original movement pitch P. This corrected movement pitch is set as a corrected movement pitch PP. The corrected movement pitch PP can be obtained by dividing the distance L between teaching points by the movement number value CNT converted into an integer. The pitch movement based on the corrected movement pitch PP can be made to coincide with the distance L between the teaching points by performing the movement number value CNT times. That is, the welding end point of the weld line can be matched with the final point of welding by pitch movement. The corrected movement pitch PP is calculated by the calculation unit 113.

  In the first embodiment, the correction movement pitch PP is not used for calculation of stitch pulse operation control. However, the obtained corrected movement pitch PP is stored as a calculation result in the storage unit 114 as data of the teaching program. The movement pitch P and the corrected movement pitch PP stored in the teaching program are displayed on the display unit 123 of the teach pendant 121 via the communication unit 112 of the control device 111 and the communication unit 122 of the teach pendant 121. Is displayed as shown in FIG.

  The above STEP is the initialization process (STEP 1 in FIG. 3) necessary for performing the stitch pulse welding of the first embodiment. Hereinafter, specific control of the stitch pulse welding method using internal variables set in the initialization process will be described.

  In the stitch pulse welding method, a welding start process is performed at the start of welding (STEP 2 in FIG. 3). In the welding start process, a welding voltage is applied between the welding wire 104 and the welding object W through the contact tip 202, and feeding of the welding wire 104 is started. An arc is generated between the welding wire 104 to which the welding voltage is applied and the welding object W.

  After the arc is generated, it waits for the welding time T to elapse with the position of the welding torch 103 fixed without operating the manipulator 101 (STEP 3 in FIG. 3). After the welding time T has elapsed, an arc-off process is performed and the welding is terminated (STEP 4 in FIG. 3). By welding in a fixed state without moving the welding torch 103, a scale-like weld bead is formed on the welding object W. After the end of arc-off, the value of the movement count value CNT stored as an internal variable is confirmed, and the end of stitch pulse welding is determined (step 5 in FIG. 3). In the stitch pulse welding initialization process in STEP 1, the movement number value CNT is a positive integer larger than zero. Therefore, the first time is always judged as NG, and the process proceeds to STEP6. In STEP 6, the movement count value Count, which is an internal variable, is updated to a value obtained by subtracting 1 from the current value, and pitch movement is started (STEP 7 in FIG. 3 to STEP 8 in FIG. 3). The pitch movement controls the operation of the manipulator 101 so as to move at the welding speed S from the current position of the welding torch 103 to the target position Pref obtained by the following (formula 1). The target position Pref is calculated by the calculation unit 113.

Pref = Ps + L × (CNT−Count) / CNT (Formula 1)
When the pitch movement is completed (YES in STEP 8 in FIG. 3), the process returns to STEP 2 again, and the processes from STEP 2 to STEP 8 are repeated until the determination in STEP 5 becomes YES. That is, the processing from the start of the stitch pulse arc to STEP 8 is repeated until the determination value of the movement number value in STEP 5 is YES.

  The stitch pulse welding method ends when YES is determined in STEP 5. The final pitch movement when YES in STEP 5 is performed with Count = 1 from FIG. Therefore, in the above (Formula 1), in the final pitch movement, the target position Pref becomes the welding end point Pe as shown in the following (Formula 2).

Pref = Ps + L = Pe (Formula 2)
Regarding (Equation 1), the movement count value Count is represented by “current value−1” as indicated by STEP 6 in FIG. 3, and the initial value of the movement count value Count is the movement count value CNT. “(CNT−Count) / CNT” is 1 / CNT in the first calculation, 2 / CNT in the second calculation, and CNT / CNT in the CNT calculation. That is, “(CNT−Count) / CNT” is a value obtained by dividing each value obtained by adding 1 from 1 to CNT by CNT. Accordingly, the target position Pref is a value obtained by multiplying the value obtained by dividing the predetermined value by the number-of-movements value CNT by the distance L between teaching points and adding the welding start point Ps to this value. The predetermined value is a value that increases by 1 from 1 to CNT. The distance L between teaching points is also a direction vector from the welding start point Ps to the welding end point Pe, so that the target position Pref can be specified by (Equation 1).

  Next, the operation of the first embodiment will be described.

  In the first embodiment, in the stitch pulse welding initialization process in STEP 1, the number of movements is calculated from the distance L between teaching points and the movement pitch P, and the corrected movement pitch PP is calculated by correcting the movement pitch again from the number of movements. doing. As for the movement pitch of stitch pulse welding, the distance L between teaching points can be reliably moved by the calculated number of movements. By doing in this way, it becomes possible to weld reliably to the welding start point Ps and the welding end point Pe, and it is possible to prevent the welding failure or the welding beyond the welding point from the original teaching.

  In the first embodiment, the calculated corrected movement pitch PP is stored in the storage unit 114 as teaching program data. Then, the movement pitch P stored in the teaching program and the corrected movement pitch PP are displayed on the display unit 123 of the teach pendant 121. By doing in this way, the operator can confirm how much correction | amendment was carried out at the time of automatic driving | operation with respect to the originally set movement pitch P during teaching operation | work during automatic driving | operation or after automatic driving | operation. That is, as shown in FIG. 6, by displaying the values of the moving pitch P and the corrected moving pitch PP, the operator can set the moving pitch P set by himself and the corrected moving pitch PP used for actual welding. Can be recognized.

  A specific example of this action will be described with reference to FIG. FIG. 7 shows an example in which the welding method of the first embodiment is used. In FIG. 7, it is assumed that stitch pulse welding is performed in a 200 mm welding section at a pitch interval of 3 mm. Based on the first embodiment, the teaching point distance L is calculated as 200 mm. Next, the number-of-movements value CNT is calculated as CNT = 200 ÷ 3 = 666.6666... Next, the corrected movement pitch PP is calculated as PP = 200 ÷ 67≈2.985 mm. When the method according to the first embodiment is used, it moves 200 mm with 67 pitch movements. Therefore, as shown in FIG. 7, weld beads are reliably formed at the welding start point and the welding end point, and stitch pulse welding is performed between them at an equally spaced moving pitch.

  As described above, by using the arc welding method and the arc welding apparatus of the first embodiment, it is possible to realize welding desired by the teacher with few welding defects.

  In the first embodiment, the movement pitch is corrected. Therefore, the pitch is moved by a distance different from the original movement pitch. However, the difference in this example is negligible with little influence on the welding operation. Further, since the error L becomes smaller when the distance L between teaching points, which is the length of the weld line, becomes longer or when the moving pitch P becomes smaller, the influence on welding is reduced.

  In the first embodiment, stitch pulse welding in which arc generation and arc stop using a consumable electrode are repeated is shown. However, the present invention can also be applied to stitch pulse welding using non-consumable electrodes and stitch pulse welding in which the current and welding pulse type are changed while an arc is generated.

  In the first embodiment, stitch pulse welding in which an arc is generated with the welding torch 103 stopped is shown. However, it is also possible to apply the process of stopping the welding torch 103 to stitch pulse welding in which the welding torch 103 is moved in another direction different from the welding line (for example, the vertical direction of the base material).

(Embodiment 2)
In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The main difference from the first embodiment is the method for calculating the target position Pref. FIG. 8 shows a flowchart in the second embodiment.

  In the second embodiment, when stitch pulse welding is started, as in the first embodiment, in the stitch pulse welding initialization process (STEP 1), the distance L between teaching points, the movement count value CNT, and the corrected movement pitch PP is calculated. Similar to the first embodiment, the obtained corrected movement pitch PP is stored as a calculation result in the teaching program, and is displayed on the display unit 123 of the teach pendant 121 together with the movement pitch P as shown in FIG. Note that the welding control from STEP 2 to STEP 4 after the end of the stitch pulse initialization process is the same as in the first embodiment.

  After the end of the arc-off process in STEP 4, the current value Pn of the welding torch 103 and Pe that is the welding end point are determined. Since the first welding is performed at the welding start point Ps, the determination here is No. When it becomes No determination in STEP5, pitch operation is started. The pitch operation at this time is the operation of the manipulator 101 so as to move at the welding speed S with the value obtained by adding the correction movement pitch PP in the direction of the welding end point Pe from the current value Pn of the welding torch 103 as the target position Pref. Control. When the pitch movement is completed (Yes in STEP 7), the process returns to STEP 2 again, and welding is started with the welding torch 103 fixed. Thereafter, the processing described in STEP 2 to STEP 7 is repeated until YES is determined in STEP 5. The stitch pulse welding method ends when YES is determined in STEP 5.

  Next, the operation of the second embodiment will be described.

  Also in the second embodiment, as in the first embodiment, in the stitch pulse welding initialization process in STEP 1, the number of movements is calculated from the distance L between the teaching points and the movement pitch P, and the movement pitch is again calculated from the number of movements. The corrected movement pitch PP is corrected. Moreover, in this Embodiment 2, the movement pitch is performed using the calculated corrected movement pitch PP, and stitch pulse welding is performed. By doing in this way, it becomes possible to weld reliably to the welding start point Ps and the welding end point Pe, and it is possible to prevent the welding failure or the welding beyond the welding point from the original teaching.

  In the second embodiment, similarly to the first embodiment, the calculated corrected movement pitch PP is stored in the storage unit 114 as teaching program data, and is stored in the teaching program in the display unit 123 of the teach pendant 121. The moving pitch P and the corrected moving pitch PP are displayed. By performing the display in this way, the operator can confirm how much correction has been made during the automatic operation with respect to the originally set movement pitch during the teaching operation after the automatic operation or after the automatic operation.

  As described above, by using the arc welding method and the arc welding apparatus of the second embodiment, it is possible to realize welding desired by the teacher with few welding defects.

  In the second embodiment, the next target position Pref is obtained by adding the correction movement pitch PP to the current value of the welding torch 103, and this is repeated. Ideally, when the pitch movement at the correction movement pitch PP is repeated, it is always possible to coincide with Pe. However, depending on the rounding error of the number of significant digits of the calculation unit 113, it is conceivable that the final target position Pref and the welding end point Pe do not necessarily coincide when the pitch movement by adding the correction movement pitch PP is repeated. In that case, the end determination may be performed by (Equation 3) with a certain tolerance λ allowed in the end determination of STEP5.

Pn ≧ Pe−λ and Pn ≦ Pe + λ (Formula 3)
In the second embodiment, stitch pulse welding in which arc generation and arc stop using a consumable electrode are repeated is shown. However, the present invention can also be applied to stitch pulse welding using non-consumable electrodes and stitch pulse welding in which the current and welding pulse type are changed while an arc is generated.

  In the second embodiment, stitch pulse welding in which an arc is generated with the welding torch 103 stopped is shown. However, it is also possible to apply the process of stopping the welding torch 103 to stitch pulse welding in which the welding torch 103 is moved in another direction different from the welding line (for example, the vertical direction of the base material).

  As described above, in the second embodiment, the next target position Pref is obtained by adding the corrected movement pitch PP to the current value, and the welding is performed to the welding end point Pe by repeating this. However, in the second embodiment in which the next target position Pref is obtained by adding the corrected movement pitch PP, there may be a case where the welding end point Pe and the obtained final target position Pref do not match as described above. . Therefore, in order to ensure that the final target position Pref and the welding end point Pe coincide with each other, it is preferable to calculate the target position Pref according to (Equation 1) of the first embodiment.

  According to the present invention, a desired bead shape can be obtained, which is industrially useful as an arc welding method and an arc welding apparatus used, for example, for forming a scaly bead.

DESCRIPTION OF SYMBOLS 101 Manipulator 102 Welding wire feeder 103 Welding torch 104 Welding wire 111 Controller 112 Communication unit 113 Calculation unit 114 Storage unit 115 Manipulator control unit 116 Welding condition command unit 121 Teach pendant 122 Communication unit 123 Display unit 124 Data setting unit 131 Welding Power supply device 201 Gas nozzle 202 Contact tip P Movement pitch T Welding time S Welding speed I Current value V Voltage value L Distance between teaching points CNT Movement number value Count Movement number value PP Correction movement pitch Ps Welding start point Pe Welding end point Pn Current value λ tolerance

Claims (10)

An arc welding method in which an arc is generated between a welding electrode and an object to be welded and welding is performed by moving a welding torch to a welding position, and then maintaining the arc, or An arc welding method in which welding is performed again at the next welding position separated by a predetermined moving pitch in a state where the arc is stopped, and welding is performed while repeating these steps.
Setting a first movement pitch;
Calculating a welding section distance that is a distance from a welding start position to a welding end position based on a teaching program;
Dividing the welding section distance by the first movement pitch to obtain a first division value;
A step of calculating the next welding position by adding the welding start position to a value obtained by dividing a predetermined value by the first division value and multiplying the welding section distance;
An arc welding method in which welding is performed while moving from the welding start position to the welding end position at the predetermined movement pitch by setting the predetermined value to a value obtained by adding 1 to 1 from the first divided value. Dividing the welding section distance by the first division value to obtain a second movement pitch;
The arc welding method according to claim 1, further comprising a step of displaying a first movement pitch and the second movement pitch. An arc welding method in which an arc is generated between a welding electrode and an object to be welded and welding is performed by moving a welding torch to a welding position, and then maintaining the arc, or An arc welding method in which welding is performed again at the next welding position separated by a predetermined moving pitch in a state where the arc is stopped, and welding is performed while repeating these steps.
Setting a first movement pitch;
Calculating a welding section distance that is a distance from a welding start position to a welding end position based on a teaching program;
Dividing the welding section distance by the first movement pitch to obtain a first division value;
Dividing the welding section distance by the first division value to obtain a second movement pitch, and
An arc welding method of performing welding with the second movement pitch as the predetermined movement pitch. The arc welding method according to claim 3, further comprising a step of displaying the first movement pitch and the second movement pitch. 5. The arc welding method according to claim 1, wherein the first division value is a positive integer greater than zero by rounding up, down, or rounding. 6. A welding power supply for supplying electric power between the welding electrode and the welding object; a manipulator having a welding torch for holding the welding electrode; and a control device for controlling the operation of the manipulator, the welding Welding is performed by generating an arc between the electrode for welding and the object to be welded, and after the welding torch is moved to the welding position and welding is performed, while maintaining the arc, or The arc welding apparatus which performs welding again at the next welding position separated by a predetermined movement pitch in a state where the arc is stopped, and performs welding while repeating these,
A setting unit for setting the first movement pitch;
A storage unit for storing the teaching program;
A welding section distance calculation unit that calculates a welding section distance that is a distance from a welding start position to a welding end position based on the teaching program stored in the storage unit;
A first division value calculation unit that calculates a first division value by dividing the welding section distance calculated by the first calculation unit by the first movement pitch set by the setting unit;
A welding position calculation unit that calculates the next welding position by adding the welding start position to a value obtained by dividing a predetermined value by the first division value and multiplying the welding section distance;
An arc welding apparatus that performs welding while moving at a predetermined movement pitch from the welding start position to the welding end position by setting the predetermined value to a value obtained by adding 1 from 1 to the first divided value. A second movement pitch calculation unit that obtains a second movement pitch by dividing the welding section distance by the first division value;
A display unit for displaying information;
The arc welding apparatus according to claim 6, wherein the first movement pitch and the second movement pitch are displayed on the display unit. A welding power supply device for supplying electric power between the welding electrode and a welding object, a manipulator having a welding torch for holding the welding electrode, and a control device for controlling the operation of the manipulator, The welding is performed by generating an arc between the electrode and the object to be welded, and after the welding torch is moved to the welding position and welding is performed, the arc is maintained or the arc is maintained. Arc welding apparatus that performs welding again at the next welding position separated by a predetermined movement pitch, and repeats these,
A setting unit for setting the first movement pitch;
A storage unit for storing the teaching program;
A first calculation unit that calculates a welding section distance that is a distance from a welding start position to a welding end position based on a teaching program stored in the storage unit;
A second calculation unit that calculates a first division value by dividing the welding section distance calculated by the first calculation unit by the first movement pitch set by the setting unit;
A third calculation unit for obtaining a second movement pitch by dividing the welding section distance calculated by the first calculation unit by the first division value calculated by the second calculation unit;
An arc welding apparatus for performing welding with the second movement pitch as the predetermined movement pitch. The arc welding apparatus according to claim 8, further comprising a display unit that displays information, wherein the first moving pitch and the second moving pitch are displayed on the display unit. The arc welding apparatus according to any one of claims 6 to 9, wherein in the first division value calculation unit, the first division value is rounded up, down, or rounded to a positive integer greater than zero.

Images