JP2009012012A - Pulse arc welding control method and pulse arc welding apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that, in a material having the low specific resistivity such as aluminum, a welding starting end is subjected to insufficient heat input and incomplete penetration under the same condition as that during the stationary welding period, and occurrence of crater at a welding terminating end can be reduced by controlling the welding voltage and the wire feeding rate, however the crater state can not be consistently formed only by making an adjustment so that the welding voltage and the wire feeding rate during the end welding period become those during the stationary welding period to those during the welding completing point of the end welding period. <P>SOLUTION: Excellent welding quality can be realized by performing the welding with the pulse current waveform different from that the stationary welding period during the start welding period and the end welding period according to the set material of a welding wire and the set material of an object to be welded. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pulse arc welding control method and a pulse arc welding apparatus for performing pulse arc welding while feeding a welding wire as a consumable electrode.

In conventional arc welding, when aluminum is arc-welded, the welding voltage supplied to the welded part and the welding wire feed speed are set at the same setting level as that during steady welding during the welding start period. In addition, in the welding end period, for the purpose of crater processing to suppress crater generation, the welding voltage supplied to the welded part during the crater processing period is reduced from the steady setting level to the crater processing setting level. Is known in which the feeding speed is reduced in accordance with the change in the welding voltage (see, for example, Patent Document 1).
JP-A-1-107968

  In the above conventional arc welding, as shown in FIG. 12, the welding voltage and the welding wire feed speed are the same as those in the steady welding period TN at the welding start end portion 103. When welding a material having a low resistivity and a high thermal conductivity, heat input may be insufficient near the welding start end portion 103, resulting in insufficient penetration. In some cases, the bead has a narrow bead width, a high bead height, and a shallow bead appearance.

  Further, in the conventional arc welding, it is possible to reduce the occurrence of the crater 102 at the welding end portion by controlling the welding voltage V and the wire feed speed WS. However, the crater state is stably formed only by adjusting the welding voltage V1 and the wire feed speed WS1 in the steady welding period TN to the welding voltage V2 and the wire feed speed WS2 from the welding end point in the end period. You may not be able to. The reason for this is that when the welding wire is moved in the welding direction at the same welding speed as the steady welding period TN in the end period, the speed at which the welding wire is fed is reduced from the wire feeding speed WS1 to the wire feeding speed WS2. This is because the supply amount of the welding wire is reduced, the bead width is narrowed, and the crater state cannot be stably formed.

  Therefore, in conventional arc welding, there is a possibility that the welding quality cannot be ensured over the entire welding length from the welding start end to the welding end.

  In order to solve the above problems, a pulse arc welding control method of the present invention is a pulse arc welding control method for performing welding by generating an arc between a welding wire mainly composed of aluminum and a workpiece. In the start welding period before the steady welding period, the average welding current is larger than the average welding current in the steady welding period and has a peak higher than the peak current value of the pulse current waveform in the steady welding period. Welding is performed using a pulse current waveform of the current value.

  Further, in addition to the above, the pulse arc welding control method of the present invention changes the average welding current from the average welding current higher than the average welding current in the steady welding period to the average welding current in the steady welding period within the start welding period. The welding speed is controlled to increase from a welding speed lower than the welding speed during the steady welding period toward the welding speed during the steady welding period, and the reduction of the average welding current and the Welding is performed in synchronization with an increase in welding speed.

  In addition to the above, the pulse arc welding control method of the present invention is an arc welding control method for performing welding by generating an arc between a welding wire mainly composed of iron or stainless steel and a workpiece. In the start welding period before the steady welding period, the average welding current has a peak that is smaller than the average welding current in the steady welding period and lower than the peak current value of the pulse current waveform in the steady welding period. Welding is performed using a pulse current waveform of the current value.

  Further, in addition to the above, the pulse arc welding control method of the present invention changes the average welding current from the average welding current lower than the average welding current in the steady welding period to the average welding current in the steady welding period within the start welding period. The welding speed is controlled to increase from a welding speed lower than the welding speed in the steady welding period toward the welding speed in the steady welding period, and the increase in the average welding current and the Welding is performed in synchronization with an increase in welding speed.

  Further, in addition to the above, the pulse arc welding control method of the present invention has an average welding current that is equal to or smaller than an average welding current in the steady welding period in the end welding period after the steady welding period, and Welding is performed with a pulse current waveform having a peak current value lower than the peak current value of the pulse current waveform in the steady welding period.

  In addition to the above, the pulse arc welding control method of the present invention is configured so that, in the end welding period, the average welding current is changed from the average welding current in the steady welding period to the average welding current at the welding end position in the end welding period. The welding speed is controlled to decrease from the welding speed in the steady welding period toward the welding speed at the welding end position in the end welding period, and the average welding current is reduced and the welding speed is reduced. The welding is performed in synchronism with the reduction.

  The pulse arc welding apparatus of the present invention is a pulse arc welding apparatus that performs welding by generating an arc between a welding wire and a workpiece, and sets the material of the welding wire or the material of the workpiece. And a pulse for each of a start welding period, a steady welding period after the start welding period, and an end welding period after the steady welding period based on the material set in the material setting part. A pulse waveform control unit for outputting a current waveform signal, a material set in the material setting unit, and a signal from the pulse waveform control unit, each of the start welding period, the steady welding period, and the end welding period A welding condition control unit that outputs a signal that controls the pulse current waveform, average welding current, and welding speed over a period, and a switch that controls the pulse current waveform and average welding current An element, an output control unit that controls the switching element based on a signal from the welding condition control unit, a manipulator that holds a welding torch for feeding the welding wire, and a signal from the welding condition control unit A robot controller that controls the welding speed by controlling the operation of the manipulator based on the start welding period and the end welding period according to the set material of the welding wire or the material of the workpiece Then, welding is performed with a pulse current waveform different from the steady welding period.

  In addition to the above, the pulse arc welding apparatus of the present invention has an average during the start welding period when a material mainly composed of aluminum is set as the material of the welding wire or the material of the workpiece by the material setting unit. Welding is performed with a pulse current waveform having a peak current value higher than the average current during the steady welding period and higher than the peak current value of the pulse current waveform during the steady welding period.

  Further, in addition to the above, the pulse arc welding apparatus of the present invention has a start welding period when a material mainly composed of iron or stainless steel is set as the material of the welding wire or the material of the workpiece by the material setting unit. The welding is performed using a pulse current waveform having a peak current value lower than the peak current value of the pulse current waveform in the steady welding period, in which the average welding current is equal to or smaller than the average welding current in the steady welding period. .

  In addition to the above, the pulse arc welding apparatus according to the present invention has an average welding current having a magnitude equal to or smaller than an average welding current in the steady welding period in the end welding period, and a pulse current waveform in the steady welding period. Welding is performed with a pulse current waveform having a peak current value lower than the peak current value.

  According to the present invention, in the start welding period, the steady welding period, and the end welding period, the heat input to the workpiece is appropriately performed by performing welding with the pulse waveform current corresponding to the material of the welding wire or the workpiece. Therefore, good welding quality can be realized from the welding start end portion to the welding end portion.

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

  A pulse arc welding control method and a pulse arc welding apparatus effective for a material having a low specific resistivity such as aluminum and a high thermal conductivity will be described in Embodiment 1, and unlike aluminum, the specific resistivity is high and the thermal conductivity is high. A pulse arc welding control method and a pulse arc welding apparatus effective for iron and stainless steel, which are low-quality materials, will be described in Embodiment 2.

(Embodiment 1)
A pulse arc control method and a pulse arc welding apparatus effective for a material having a low specific resistivity such as aluminum and good thermal conductivity will be described below with reference to FIGS.

  In the present embodiment, a case will be described in which the steady welding period TN comes after the start welding period TS and the end period TN comes after the steady welding period TN. Further, the waveform of the pulse current repeated during the steady welding period TN is called a standard pulse waveform, the peak current of this standard pulse waveform is Ip, and the base current is Ib.

  FIG. 1 is a diagram showing an example of a pulse waveform for deepening an increase in heat input and penetration into a workpiece. FIG. 1A shows a standard pulse waveform. FIGS. 1B and 1C show examples of pulse waveforms that can increase the heat input and deepen the penetration compared to the standard pulse waveform of FIG. The waveform in FIG. 1B is an example of a waveform in which the peak current Ip2 is high and the peak current period and the pulse width PW2 are short compared to the waveform in FIG. The waveform of FIG. 1C is an example of a waveform in which the peak current Ip2 is high, the peak current period and the pulse width PW3 are short, and the base current Ib2 is low compared to the waveform of FIG. Here, the pulse width is PW1> PW2> PW3. Regarding the peak current, Ip <Ip2. Regarding the base current, Ib> Ib2.

  The pulse waveforms shown in FIG. 1 (b) and FIG. 1 (c) set a peak current Ip2 higher than the peak current Ip of the standard pulse waveform shown in FIG. 1 (a) repeated during the steady welding period TN. That is, the pulse widths PW2 and PW3, the peak current Ip2, and the base current Ib2 are adjusted so that the separation state is established, that is, one pulse and one drop are realized. Here, the peak current Ip2, the base current Ib2, the pulse widths PW2 and PW3, and the like vary depending on the welding conditions such as the work piece and the welding wire to be used, and can be obtained by, for example, experiments.

  Note that by increasing the peak current, the arc force is strong and the pressing force of the molten pool is strong, so that the amount of penetration can be deepened and heat can be sufficiently input to the work piece.

  Here, when welding an object to be welded mainly of aluminum, since the specific resistivity is low, the thermal conductivity is good, and the material easily escapes heat, conventionally, the bead width is narrow near the welding start end, The bead formation was high in bead height and shallow penetration. However, as in the arc welding control method of the present embodiment, during the start welding period TS, the peak is higher than the standard pulse waveform shown in FIG. 1 (a) as shown in FIG. 1 (b) or FIG. 1 (c). By repeating a pulse waveform with a high current, it is possible to apply heat sharply to the work piece at the welding start part, ensuring a bead formation state with a wide bead width, low bead height, and deep penetration. be able to.

  FIG. 2 is a diagram showing an example of a pulse waveform for reducing the heat input to the work piece and making the penetration shallow. FIG. 2 (a) shows a standard pulse waveform. FIG. 2B and FIG. 2C show examples of pulse waveforms that can reduce the heat input and make the amount of penetration shallower than the standard pulse waveform of FIG. The waveform of FIG. 2 (b) is a waveform with a lower peak current and a longer peak current period and longer pulse width than the waveform of FIG. 2 (a). Further, the waveform of FIG. 2C is a waveform in which the peak current is lower, the peak current period is longer, and the base current is higher than that of the waveform of FIG.

  The pulse waveforms shown in FIG. 2B and FIG. 2C set a peak current Ip3 lower than the peak current Ip of the standard pulse waveform shown in FIG. That is, the pulse widths PW4 and PW5, the peak current Ip3, and the base current Ib3 are adjusted so that the separation state is established, that is, one pulse and one drop are realized. Here, the peak current Ip3, the base current Ib3, the pulse widths PW4, PW5, and the like vary depending on the welding conditions of the work piece, the welding wire used, and the like, and can be obtained, for example, by experiments.

  Note that, by reducing the peak current Ip, the arc force is weak and the pressing force of the molten pool is weakened, so that the amount of penetration can be made shallow and the heat input to the workpiece can be suppressed. Therefore, a material having a low specific resistivity such as aluminum and a high thermal conductivity has a pulse waveform effective near the end of the weld.

  FIG. 3 is a diagram illustrating a welding state and a change in average welding current and welding speed with respect to the welding position in the start welding period TS and the steady welding period TN. Note that the change with respect to the welding position can be regarded as a time change. The welding speed is a speed at which, for example, a welding torch attached to an industrial robot moves in the welding line direction. In FIG. 3, in the start welding period TS, the average welding current and welding speed in the case of setting a pulse waveform capable of deepening the increase in heat input and penetration into the workpiece shown in FIGS. 1B and 1C. In this example, the average welding current and the welding speed are the same in the start welding period TS and the steady welding period TN. Note that the average welding current and the welding voltage change synchronously.

  In the vicinity of the conventional welding start end, when the material of the work piece is aluminum, the specific resistivity is low, the thermal conductivity is good, and the heat easily escapes, so the bead width is narrow, the bead height is high, and the penetration is shallow. It was a bead formation state.

  Therefore, by setting a pulse waveform that can increase the heat input to the work piece and deepen the penetration during the start welding period TS and welding, it is possible to sufficiently input heat to the welding start end and widen the bead width. The bead height is low, the penetration is deep, and the welding quality can be improved. That is, although depending on welding conditions, even if the average welding current is constant between the start welding period TS and the steady welding period TN, the peak current of the pulse current waveform in the start welding period TS is the peak current of the pulse current waveform in the steady welding period TN. The welding quality can be improved by making it higher.

  FIG. 4 is a diagram illustrating a welding state and a change in average welding current and welding speed with respect to the welding position in the start welding period TS and the steady welding period TN. In FIG. 4, in the start welding period TS, in addition to setting a pulse waveform that can deepen the increase in heat input or penetration into the workpiece as shown in FIGS. 1B and 1C, welding is started. Sometimes, welding is started at an average welding current IS higher than the average welding current IN and welding speed SN and a welding speed SS lower than the welding speed SN, and from the position PS, which is the starting position of the start welding period TS, the steady welding period TN. Toward the position P1 which is the starting position of the welding temperature, the average welding current IS is decreased with a predetermined inclination so as to become the average welding current IN, and the welding speed SS is increased with a predetermined inclination so as to become the welding speed SN. Control is in progress. Here, the decrease in average welding current and the increase in welding speed are controlled to be synchronized.

  The average welding current can be reduced by reducing the peak current, shortening the peak period, reducing the base current, or the like. Moreover, although the average welding current and the welding speed are changed with a predetermined inclination, the predetermined inclination can be obtained by experiments or the like based on welding conditions, for example.

  And by performing such control in the start welding period TS, heat input control can be performed more sufficiently than the welding control method described with reference to FIG. 3, and the bead formation state at the welding start end can be further improved. can do. Further, since the pulse parameters that are not normally adjusted can be adjusted, the range of heat input adjustment is widened, that is, the options are increased, and the welding quality can be improved.

  FIG. 5 is a diagram showing a change and welding state of the average welding current and welding speed with respect to the welding position in the start welding period TS and the steady welding period TN. In FIG. 5, in addition to performing welding by setting a pulse waveform capable of deepening the increase in heat input and penetration into the workpiece shown in FIGS. 1B and 1C in the start welding period TS. At the start of welding, the average welding current IN and the average welding current IS higher than the welding speed SN and the welding speed SS lower than the welding speed SN are set to a constant welding length until a certain time TS2 elapses from the starting position PS of the starting welding period TS. Continue until position P1 when welding. After that, from the position P1 to the position P2, which is the start position of the steady welding period TN, the average welding current IS is decreased with a predetermined inclination so as to become the average welding current IN, and the welding speed SS is changed to the welding speed SN. Control is performed so as to increase at a predetermined inclination.

  And by performing such control in the start welding period TS, the heat input control can be performed sufficiently more than the welding control method described with reference to FIG. Can be better. Moreover, since the range of heat input adjustment with respect to a bead formation state or a welding state spreads, welding quality can be improved.

  FIG. 6 is a diagram showing a change and welding state of the average welding current and the welding speed with respect to the welding position in the steady welding period TN and the end welding period TE. Note that the change with respect to the welding position can be regarded as a time change. The welding speed is a speed at which, for example, a welding torch attached to an industrial robot moves in the welding line direction. In FIG. 6, in the end welding period TE, the average welding current and welding speed in the case of setting a pulse waveform capable of reducing the heat input to the workpiece and reducing the penetration shown in FIGS. 2 (b) and 2 (c). In this example, the average welding current and the welding speed are the same in the steady welding period TN and the end welding period TE.

  And, by setting the pulse waveform that can reduce the heat input to the work piece to be reduced and penetration during the end welding period TE, the heat input to the work piece can be reduced and the arc force can be reduced. Since it can reduce, the pressing force to a molten pool falls, a digging state can be reduced and welding quality can be improved.

  FIG. 7 is a diagram illustrating changes in the average welding current and the welding speed with respect to the welding position in the steady welding period TN and the end welding period TE. In FIG. 7, in the end welding period TE, in addition to setting the pulse waveform that can reduce the heat input to the work piece shown in FIG. 2B and FIG. From the position P11, which is the end position of TN and the start position of the end welding period TE, to the position PE, which is the end position of the end welding period TE, with a predetermined inclination so that the average welding current IN becomes the average welding current IE. In addition, control is performed such that the welding speed is decreased from the welding speed SN to the welding speed SE with a predetermined inclination. Note that the average welding current and the welding speed are controlled to be synchronized.

  Further, by performing such control during the end welding period TE, heat input control can be performed more sufficiently than the welding control method described with reference to FIG. 6, so that the bead formation state of the welding end portion can be further improved. Can do. Moreover, since the range of heat input adjustment with respect to a bead formation state or a welding state spreads, welding quality can be improved.

  FIG. 8 is a diagram illustrating a welding state and a change in average welding current and welding speed with respect to the welding position in the steady welding period TN and the end welding period TE. In FIG. 8, in addition to setting the pulse waveform that can reduce the heat input to the work piece shown in FIGS. 2B and 2C and shallow the penetration in the end welding period TE, the steady welding period From the position P11 which is the end position of TN and the start position of the end welding period TE to the position P12 which is a position in the middle of the end welding period TE, a predetermined slope is set so that the average welding current IE becomes the average welding current IE. And at a predetermined inclination so that the welding speed SN becomes the welding speed SE, and thereafter, from the position P12 that is in the middle of the end welding period TE to the end position PE of the end welding period TE, Control is performed to keep the average welding current IE and the welding speed SE constant.

  And by performing such control in the end welding period TE, the heat input control can be sufficiently performed as compared with the welding control method described with reference to FIG. 7, so that the bead formation state of the welding end portion is further improved. Can do. Moreover, since the range of heat input adjustment with respect to a bead formation state or a welding state spreads, welding quality can be improved.

  In the above, the control of the welding current and the welding speed has been described with reference to FIGS. 1 to 8. Here, an example of a pulse arc welding apparatus for performing the above-described arc welding control method will be described with reference to FIG. To do.

  FIG. 9 is a diagram showing a schematic configuration of the pulse arc welding apparatus. The pulse arc welding apparatus mainly includes a welding machine 20 and a robot 21.

  In the welding machine 20, the electric power from the input power source 1 is rectified by the primary rectification unit 2, converted into alternating current by the switching element 3, stepped down by the transformer 4, and rectified by the secondary rectification unit 5 and DCL (inductor) 6. The welding arc 14 is applied between the welding wire 14 and the workpiece 17 and the welding arc 16 is generated between the welding wire 14 and the workpiece 17 to perform welding. Further, the welding machine 20 includes an output control unit 7 for controlling the switching element 3, a welding condition output unit 8 for outputting a control signal to the output control unit 7, a material of a welding wire to be used or a workpiece 17 to be welded. A material setting unit 9 for setting the material, a wire feeding control unit 11 for controlling the wire feeding device 13, and a pulse waveform output unit 18 are provided. The pulse waveform output unit 18 receives a signal from the material setting unit 9 and is set in advance for each material, and each of the start period TS, steady welding period TN, and end period TE stored in a storage unit (not shown). In this period, information on the pulse current waveform such as the peak current value, base current value, and peak period in the period is selected and output to the welding condition output unit 8.

  The robot 21 is mainly composed of a manipulator 12 and a robot control unit 10. The manipulator 12 is provided with a wire feeding device 13 for feeding the welding wire 14 to the workpiece 17 and a welding torch 15.

  When the material of the welding wire 14 or the material of the workpiece 17 is set in the material setting unit 9, a signal corresponding to the set material is output to the welding condition output unit 8 and the pulse waveform output unit 18. Then, the welding condition output unit 8 that has received the signal from the material setting unit 9 and the signal from the pulse waveform output unit 18 sets the welding start period TS and the steady welding period TN set in advance for each material based on this signal. And a pulse current waveform signal in the welding end period TE and a signal related to the average welding current IE are output to the output control unit 7. And the output control part 7 controls the waveform of the average welding current IE and a pulse current by controlling the switching element 3 based on the signal from the welding condition output part 8. FIG.

  Further, the welding condition output unit 8 controls a signal for controlling the welding speed in the welding start period TS set for each material in advance based on the signal from the material setting unit 9 and the welding speed in the steady welding period TN. A signal and a signal for controlling the welding speed in the welding end period TE are output to the robot controller 10. The robot control unit 10 controls the manipulator 12 based on the signal from the welding condition output unit 8 to control the welding speed of the workpiece 17 in the welding direction, that is, the moving speed of the welding wire 14 in the welding direction. Is done.

  Further, the welding condition output unit 8 outputs a signal for controlling the feeding speed of the welding wire 14 having a unitary relationship with the welding current to the wire feeding control unit 11, and the wire feeding control unit 11 performs the welding condition output unit 8. The feeding speed of the welding wire 14 is controlled by controlling the wire feeding device 13 based on the signal from.

  Here, for example, when the material setting unit 9 sets the material of the welding wire 14 or the material of the workpiece 17 to be a material mainly composed of aluminum, FIG. 1, FIG. 2, and FIG. Control of the average welding current, the pulse current waveform, and the welding speed described with reference to FIG.

  In addition, each component which comprises the arc welding apparatus shown in FIG. 9 may each be comprised independently, and you may make it comprise combining a some component.

  As described above, according to the arc welding control method and the pulse arc welding control apparatus of the present embodiment, for example, when performing the overlap fillet or the horizontal fillet welding, the material of the base material that is the workpiece 17 is determined. By performing arc welding in the welding start period TS and / or the welding end period TE according to the specific resistivity and thermal conductivity, at a pulse waveform current or welding speed different from the pulse waveform current in the steady welding period TN A uniform weld quality can be realized over the entire weld length from the weld start end to the weld end.

(Embodiment 2)
A pulse arc welding control method effective for iron or stainless steel, which is a material having a high specific resistivity and low thermal conductivity unlike aluminum, will be described below. In addition, about the location similar to Embodiment 1, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted. The main difference from the first embodiment is the welding current in the start welding period TS, and more specifically, the pulse current waveform.

  FIG. 3 is a diagram illustrating a welding state and a change in average welding current and welding speed with respect to the welding position in the start welding period TS and the steady welding period TN. Note that the change with respect to the welding position can be regarded as a time change. The welding speed is a speed at which, for example, a welding torch attached to an industrial robot moves in the welding line direction. As will be described later, the pulse current waveform in the start welding period TS is different from that in the first embodiment, but the average welding current is the same as that in the first embodiment.

  In FIG. 3, in the start welding period TS, welding is performed by setting a pulse current waveform that can reduce the heat input to the workpieces shown in FIGS. 2B and 2C and shallow the penetration. It is an example of an average welding current and welding speed.

  In the vicinity of the conventional welding start end, too much heat is input to the work piece, the molten metal in the steady welding period TN is drawn to the welding start end, the bead width near the welding start end is wide, and the bead in the steady welding period TN It was a bead formation state that became thin.

  By setting a pulse current waveform that can reduce the heat input to the work piece and reducing the penetration during the start welding period TS, it is possible to suppress the heat input near the welding start end, and melt during the steady welding period TN. It is possible to suppress the metal from being pulled, to make the bead width uniform from the vicinity of the welding start end portion to the steady welding period TN, and to improve the welding quality.

  FIG. 10 is a diagram illustrating a welding state and a change in average welding current and welding speed with respect to the welding position in the start welding period TS and the steady welding period TN. In FIG. 10, in addition to setting a pulse waveform that can reduce the heat input to the work piece shown in FIG. 2 (b) and FIG. 2 (c) and shallow the penetration in the start welding period TS, Welding is started at an average welding current IS2 and a welding speed SS lower than the average welding current IN and welding speed SN in the steady welding period TN, and further, the steady welding period TN is started from a position PS that is a start position of the start welding period TS. Control is performed such that the average welding current IS2 increases to the average welding current IN from the average welding current IS2 toward the position P1, which is the position, and increases at a predetermined inclination from the welding speed SS to the welding speed SN. Is going. The increase in average welding current and the increase in welding speed are controlled to be synchronized.

  Further, by performing such control during the start welding period TS, heat input control can be performed more sufficiently than the welding control method described with reference to FIG. 3, so that the bead formation state at the welding start end can be further improved. Can do. Moreover, since the range of heat input adjustment with respect to a bead formation state or a welding state spreads, welding quality can be improved.

  FIG. 11 is a diagram illustrating a welding state and a change in average welding current and welding speed with respect to the welding position in the start welding period TS and the steady welding period TS. In FIG. 11, in addition to performing welding by setting a pulse waveform that can reduce the heat input to the work piece shown in FIGS. 2B and 2C and shallow the penetration in the start welding period TS. At the start of welding, the average welding current IN and welding speed SS lower than the average welding current IN and welding speed SN in the steady welding period TN are set to a certain welding length until a certain time TS1 elapses from the starting position PS of the starting welding period TS. Continue until it reaches the position P1 in the case of welding, and then increase from the position P1 toward the position P2, which is the starting position of the steady welding period TN, with a predetermined slope from the welding current IS2 to the welding current IN, In addition, control is performed to increase the welding speed SS from the welding speed SS to a welding speed SN with a predetermined inclination.

  And, by performing such control during the start welding period TS, heat input control can be performed more sufficiently than the welding control method described with reference to FIG. 10, so that the bead formation state at the welding start end is further improved. Can do. Moreover, since the range of heat input adjustment with respect to a bead formation state or a welding state spreads, welding quality can be improved.

  In addition, even in the welding of iron or stainless steel, which is a material having a high specific resistivity different from that of aluminum, by applying the pulse arc welding control method described in the first embodiment during the welding end period, the same as in the first embodiment. The welding quality can be improved.

  Further, the configuration of the pulse arc welding apparatus for performing the pulse arc welding control of the present embodiment is the same as that of the first embodiment described with reference to FIG. 9, and iron that is a material having a high specific resistivity in a storage unit (not shown). The pulse arc welding control method of the present embodiment can be realized by storing information on the pulse waveform when welding stainless steel or stainless steel.

  Regarding the arc welding control method when performing the fillet fillet or horizontal fillet welding using the consumable electrode of the present invention, it is possible to ensure proper heat input to the work piece at the welding start end and at the welding end. Arc welding that prevents excessive heat input to the work piece and realizes uniform weld quality over the entire area of overlap fillet welding and horizontal fillet from the welding start end to the welding end It is possible to provide a control method. It is useful for a welding apparatus that performs arc welding while continuously feeding a welding wire that is a consumable electrode.

(A) The figure which shows the standard pulse waveform in Embodiment 1 of this invention (b) The figure which shows the example of the pulse waveform which can deepen the increase in heat input and the amount of penetration in Embodiment 1 of this invention (c) This invention The figure which shows another example of the pulse waveform which can deepen the increase in heat input and the amount of penetration in Embodiment 1 of this (A) The figure which shows the standard pulse waveform in Embodiment 1 and Embodiment 2 of this invention (b) The pulse waveform which can reduce the heat input and the amount of penetration in Embodiment 1 and Embodiment 2 of this invention shallowly (C) The figure which shows another example of the pulse waveform which can reduce the heat input reduction and penetration amount in Embodiment 1 and Embodiment 2 of this invention The figure which shows the welding current with respect to the welding position of the start welding period and steady welding period in Embodiment 1 and Embodiment 2 of this invention, the change of a welding speed, and a welding state. The figure which shows the welding current with respect to the welding position of the start welding period in the Embodiment 1 of this invention, and a regular welding period, the change of welding speed, and a welding state. The figure which shows the welding current with respect to the welding position of the start welding period in the Embodiment 1 of this invention, and a regular welding period, the change of welding speed, and a welding state. The figure which shows the welding current with respect to the welding position and the welding state with respect to the welding position in the steady welding period and end welding period in Embodiment 1 and Embodiment 2 of this invention, and a welding state. The figure which shows the welding current with respect to the welding position in the steady welding period in Embodiment 1 of this invention, and an end welding period, the change of welding speed, and a welding state. The figure which shows the welding current with respect to the welding position in the steady welding period in Embodiment 1 of this invention, and an end welding period, the change of welding speed, and a welding state. The figure which shows schematic structure of the pulse arc welding apparatus in Embodiment 1 and Embodiment 2 of this invention The figure which shows the welding current and the change of a welding speed with respect to the welding position of the start welding period in the Embodiment 2 of this invention and a regular welding period, and a welding state. The figure which shows the welding current and the change of a welding speed with respect to the welding position of the start welding period in the Embodiment 2 of this invention and a regular welding period, and a welding state. (A) The figure which shows the change of the welding voltage from the welding start of the conventional arc welding to the end of welding (b) The figure which shows the change of the welding wire feed signal from the welding start of the conventional arc welding to the end of welding (c) The figure which shows the welding state of the conventional arc welding (d) The figure which shows the welding state of the conventional arc welding

Explanation of symbols

Ip peak current Ip2 peak current (higher than Ip)
Ip3 peak current (lower than Ip)
Ib base current Ib2 base current (lower than Ib)
Ib3 Base current (higher than Ib)
PW1, PW2, PW3, PW4, PW5 Pulse width PFRQ Pulse frequency TN Steady welding period TS Start welding period TS2 Constant time TE End welding period IN Average welding current (steady welding period)
IS average welding current (start welding period)
IE average welding current (end welding period)
SN welding speed (steady welding period)
SS welding speed (start welding period)
SE welding speed (end welding period)
P1, P2, P11, P12 Position V1 Welding voltage (steady welding period)
V2 Welding voltage (End welding period)
WS1 Wire feed speed (steady welding period)
WS2 Wire feed speed (end welding period)
DESCRIPTION OF SYMBOLS 1 Input power supply 2 Primary rectification part 3 Switching element 4 Transformer 5 Secondary rectification part 6 DCL
DESCRIPTION OF SYMBOLS 7 Output control part 8 Welding condition output part 9 Material setting part 10 Robot control part 11 Wire feeding control part 12 Manipulator 13 Wire feeding apparatus 14 Welding wire 15 Welding torch 16 Welding arc 17 Workpiece 18 Pulse waveform output part 20 Welding Machine 21 Robot 101 Workpiece 102 Welding end (crater)
103 Weld start

Claims (10)

A pulse arc welding control method for performing welding by generating an arc between a welding wire mainly composed of aluminum and a workpiece,
In the start welding period before the steady welding period, the average welding current is equal to or higher than the average welding current in the steady welding period, and the pulse has a peak current value higher than the peak current value of the pulse current waveform in the steady welding period. A pulse arc welding control method for performing welding with a current waveform. Within the start welding period, the average welding current is controlled to decrease from the average welding current higher than the average welding current in the steady welding period toward the average welding current in the steady welding period, and the welding speed is controlled in the steady welding period. The welding is performed in such a manner that the welding speed is controlled to increase from a welding speed lower than the welding speed toward the welding speed in the steady welding period, and the reduction in the average welding current and the increase in the welding speed are synchronized. Pulse arc welding control method. An arc welding control method for performing welding by generating an arc between a welding wire mainly composed of iron or stainless steel and an object to be welded,
In the start welding period before the steady welding period, the average welding current is a pulse having a peak current value that is equal to or lower than the average welding current in the steady welding period and lower than the peak current value of the pulse current waveform in the steady welding period. A pulse arc welding control method for performing welding with a current waveform. Within the start welding period, the average welding current is controlled to increase from the average welding current lower than the average welding current during the steady welding period toward the average welding current during the steady welding period, and the welding speed is controlled during the steady welding period. The welding is performed in such a manner that the welding speed is controlled to increase from a welding speed lower than the welding speed toward the welding speed in the steady welding period, and the increase in the average welding current and the increase in the welding speed are synchronized. Pulse arc welding control method. In the end welding period after the steady welding period, the average welding current is equal to or less than the average welding current in the steady welding period, and the pulse current has a peak current value lower than the peak current value of the pulse current waveform in the steady welding period. The pulse arc welding control method according to any one of claims 1 to 4, wherein welding is performed using a waveform. In the end welding period, the average welding current is controlled so as to decrease from the average welding current in the steady welding period toward the average welding current at the welding end position in the end welding period, and the welding speed is controlled in the steady welding period. 6. The pulse arc according to claim 5, wherein the welding is controlled so as to decrease toward a welding speed at a welding end position in the end welding period, and welding is performed by synchronizing the reduction of the average welding current and the reduction of the welding speed. Welding control method. A pulse arc welding apparatus for performing welding by generating an arc between a welding wire and a workpiece,
A material setting section for setting the material of the welding wire or the material of the workpiece;
Pulse waveforms for outputting respective pulse current waveform signals in a start welding period, a steady welding period after the start welding period, and an end welding period after the steady welding period based on the material set in the material setting unit An output section;
A signal from the material setting unit and a signal from the pulse waveform output unit are input, and a pulse current waveform, an average welding current, and a welding speed in each of the start welding period, the steady welding period, and the end welding period. A welding condition output section for outputting a signal for controlling
A switching element that controls the pulse current waveform and the average welding current;
An output control unit for controlling the switching element based on a signal from the welding condition output unit;
A manipulator holding a welding torch for feeding the welding wire;
A robot controller that controls the welding speed by controlling the operation of the manipulator based on a signal from the welding condition output unit;
A pulse arc welding apparatus for performing welding with a pulse current waveform different from that in the steady welding period in the start welding period and the end welding period in accordance with a welding wire material or a workpiece material to be set. When a material mainly composed of aluminum is set as the material of the welding wire or the material of the workpiece by the material setting unit, the output control unit controls the switching element based on the signal from the welding condition output unit, The welding is performed with a pulse current waveform having a peak current value higher than the peak current value of the pulse current waveform in the steady welding period, in which the average welding current is equal to or higher than the average welding current in the steady welding period in the start welding period. 7. The pulse arc welding apparatus according to 7. When the material setting unit sets the material of the welding wire or the material to be welded as the main component of iron or stainless steel, the output control unit controls the switching element based on the signal from the welding condition output unit. Thus, in the start welding period, welding is performed with a pulse current waveform having a peak current value that is lower than the average welding current in the steady welding period and that is lower than the peak current value of the pulse current waveform in the steady welding period. The pulse arc welding apparatus according to claim 7. The welding is performed with a pulse current waveform having a peak current value lower than a peak current value of the pulse current waveform in the steady welding period, in which the average welding current is equal to or lower than the average welding current in the steady welding period in the end welding period. The pulse arc welding apparatus according to any one of 7 to 9.

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