JP3951931B2

JP3951931B2 - Welding control method and consumable electrode type pulse arc welding apparatus

Info

Publication number: JP3951931B2
Application number: JP2003032147A
Authority: JP
Inventors: 篤寛川本; 仁志西村; 晶中川; 稔朗正井; 明尚島田
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2003-02-10
Filing date: 2003-02-10
Publication date: 2007-08-01
Anticipated expiration: 2023-02-10
Also published as: JP2004237356A

Description

【０００１】
【発明の属する技術分野】
本発明は、消耗電極（以下、ワイヤと称する）を自動送給し、ワイヤと溶接母材（以下、母材と称する）間にピーク電流とベース電流とを交互に繰り返し供給して溶接出力制御を行う溶接制御方法及び消耗電極式パルスアーク溶接装置に関するものである。
【０００２】
【従来の技術】
近年では生産性を向上させるために溶接の低スパッタに対する要求が一段と高まってきている。特にアークスタート時及びワークの位置ズレ等による突出し長さが変化するときの低スパッタ化が要求されている。
【０００３】
従来の消耗電極式パルスアーク溶接機は、短絡発生時に短絡発生直前の溶接電流にかかわらず所定の第一の電流傾度で溶接電流を上昇し所定の電流値に到達すると第一の傾きと異なる所定の第二の電流傾度で溶接電流を上昇させ短絡開放時の溶接電流を低下させることでスパッタの抑制を行っていた。（例えば特許文献１参照）
図３は上記従来の消耗電極式パルスアーク溶接機を示しており、１は入力電源、２は第１整流部、３はインバータ回路部、４は主変圧器、５は第２整流部、６はリアクタ、７は溶接電圧検出部、８はアーク短絡判定部、９は溶接電流検出部、２２はトーチ、２３はワイヤ、２４は母材、２５はワイヤ送給装置、３１は第一傾度設定部、３２は第二傾度設定部、３３は屈曲点判定回路部、３４は第二のスイッチング回路部、３５は第一のスイッチング回路部、３６は増幅部である。
【０００４】
以上のように構成された消耗電極式パルスアーク溶接機について説明する。所定の第二の電流傾度を第一の電流傾度より小さくしておくと、短絡発生時の溶接電流値が所定の第一傾度で上昇し所定の電流値に到達すると第二傾度に切り替えるため短絡開放時の溶接電流値が高くなるのを抑制する。これによりスパッタの多量発生を抑制すると共に溶接を安定させていた。
【０００５】
【特許文献１】
特許第３１５６０３３号公報
【０００６】
【発明が解決しようとする課題】
しかし、従来の消耗電極式パルスアーク溶接機は通常溶接時のスパッタ抑制は可能となったが、アークスタート時及びワークの位置ズレ等の突出し長さが変化する時等のアークが不安定となる場合にはスパッタが多いという課題を有していた。
【０００７】
このようなアークが不安定となる場合には短絡発生のタイミングはベース期間に限定されない。つまりピーク期間中あるいはピーク電流への立ち上がり傾斜部、ピーク期間からの立下り傾斜部の溶接電流値が高い場合にも短絡発生するため、その電流値から電流を上昇させると短絡開放時の電流は高くなりスパッタが増加するからである。
【０００８】
本発明は、上記アーク不安定時のスパッタを抑制する溶接制御方法および消耗電極式パルスアーク溶接機を提供することを目的とする。
【０００９】
【課題を解決するための手段】
上記目的を達成するために、本発明は、短絡発生直前の溶接電流値に応じて短絡中の溶接電流波形を切り替えスパッタの発生を抑制するものである。この制御方法により、短絡発生直前の溶接電流が低い場合は短絡中の溶接電流波形を上昇させ、高い場合は上昇させないことで短絡開放時の溶接電流値を抑制できるためスパッタを抑制できる。
【００１０】
また、本発明は、短絡発生直前の溶接電流が予め設定した所定値と比較し前記所定値より高い場合と低い場合で短絡中の溶接電流波形を切り替えるものである。
【００１１】
また、本発明の溶接制御方法は、前記の短絡時の溶接電流波形を切り替える所定値を、ワイヤ送給量あるいはワイヤ径あるいはワイヤ材質の少なくとも一つに応じて設定するものである。
【００１２】
また、本発明は、短絡開放後を時間起点として予め設定した所定時間中は予め設定した所定の電圧値あるいは所定の電流値のいずれか一方に制御し短絡開放後のアーク長を保持するものである。これにより短絡開放後のアーク長を保持し、短絡の連続発生を抑制する。
【００１３】
また、本発明は短絡開放後を時間起点として予め設定した所定時間中は予め設定した所定の電圧あるいは所定の電流のいずれか一方に制御しその後所定の電圧制御あるいは電流制御を開始する際に段階的にスロープ制御し急峻な電圧変化あるいは電流変化を抑制するものである。
【００１４】
【発明の実施の形態】
（実施の形態１）
本実施の形態において従来例と同様の構成については同一の番号を付して詳細な説明を省略する。
【００１５】
図１において、溶接電圧を検出する溶接電圧検出部７と、溶接電流を検出する溶接電流検出部９と、前記溶接電圧検出部７の出力により溶接状態がアークあるいは短絡を判別するアーク短絡判別部８と、短絡時に時間経過と共に電流値を上昇する電流上昇設定部１１と、短絡時に時間経過と共に電流値を上昇させない電流下降設定部１２と、前記電流上昇設定部１１の出力と前記電流下降設定部１２の出力と前記溶接電流検出部９の出力を入力とし短絡発生直前の溶接電流が予め設定した電流値より高い場合は前記電流下降設定部１２からの入力を低い場合は前記電流上昇設定部１１からの入力を選択制御して出力する短絡電流制御部１０と、前記短絡電流制御部１０の出力と前記アーク短絡判別部８の出力を入力とし短絡時に前記短絡電流制御部１０の出力を選択制御して出力する出力制御部１４を示す。
【００１６】
以上のように構成された本実施の形態について、その動作を説明する。
【００１７】
溶接電流検出部９で検出した信号と短絡電流制御部１０内で予め設定した電流値とを比較し短絡発生直前の溶接電流が予め設定した所定値と比較し前記所定値より高い場合は電流上昇設定部１１からの入力を出力し時間経過と共に溶接電流を上昇させるように電流制御し、前記所定値より低い場合は電流下降設定部１２からの入力を出力し時間経過と共に溶接電流を上昇させないように電流制御し、短絡発生直前の溶接電流値により短絡時の溶接電流波形を切り替えることによりスパッタ発生を抑制できる。尚電流下降設定部１２では上昇も下降もせずに直前の電流値に等しい値を維持しても良いし、所定時間下降させた後に上昇させても良い。
【００１８】
（実施の形態２）
本実施の形態において実施の形態１と同様の構成については同一の番号を付して詳細な説明を省略する。
【００１９】
図２においてワイヤ送給量あるいはワイヤ径あるいはワイヤ材質等の溶接条件を設定する溶接条件設定部１８と、前記溶接条件設定部１８の出力を入力としてワイヤ送給量あるいはワイヤ径あるいはワイヤ材質の少なくとも一つに応じて短絡時の溶接電流波形を切り替える電流値を設定する前記短絡電流制御部１０を備えている。
【００２０】
実施の形態１と異なる点は、電流上昇設定部１１からの出力と電流下降設定部１２からの出力を切り替える電流値をワイヤ送給量あるいはワイヤ径あるいはワイヤ材質の少なくとも一つに応じて設定する点である。これにより、溶接条件毎に最適な上下限値を設定することでスパッタを更に抑制できる。
【００２１】
（実施の形態３）
本実施の形態において実施の形態１及び２と同様の構成については同一の番号を付して詳細な説明を省略する。
【００２２】
図２において前記出力制御部１４は短絡開放後を時間起点として予め設定した所定時間を計時する時間計時部１６を備え、前記時間計時部１６が設定する所定時間中は予め設定した所定の電圧値あるいは所定の電流値のいずれか一方に溶接出力を制御し前記出力制御部１４に出力する短絡開放制御部１５を備えている。
【００２３】
実施の形態１及び２と異なる点は、前記時間計時部１６にて設定される期間は短絡開放制御部１５によって電圧制御あるいは電流制御することで短絡開放後のアーク長を保持することができ短絡の連続発生を抑制できスパッタを更に抑制できる。
【００２４】
（実施の形態４）
本実施の形態において実施の形態１及び２、３と同様の構成については同一の番号を付して詳細な説明を省略する。
【００２５】
図２において前記出力制御部１４は前記短絡開放制御部１５による制御を行った後所定の電圧制御あるいは電流制御を開始する際に段階的に電流あるいは電圧をスロープ制御するスロープ制御部１７を備えている。
【００２６】
実施の形態１及び２、３と異なる点は前記短絡開放制御部１５による制御後の急峻な電圧変化あるいは電流変化を抑制できる。電圧あるいは電流の急峻な変化を抑制することにより溶融プールの振動を抑制し短絡の連続発生を抑制できスパッタを更に抑制できる。
【００２７】
【発明の効果】
本発明は、アークスタート時及びワークの位置ズレ等の突出し長さが変化する時等のアークが不安定となる場合に発生するスパッタを抑制することができ、溶接品質を向上することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態１を示すブロック回路図
【図２】本発明の実施の形態２を示すブロック回路図
【図３】従来例を示すブロック回路図
【符号の説明】
１・・入力電源
２・・第一整流部
３・・インバータ部
４・・変圧器
５・・第二整流部
６・・リアクタ
７・・溶接電圧検出部
８・・アーク短絡判定部
９・・溶接電流検出部
１０・・短絡電流制御部
１１・・電流上昇設定部
１２・・電流下降設定部
１３・・アーク期間制御部
１４・・出力制御部
１５・・短絡開放制御部
１６・・時間計時部
１７・・スロープ制御部
１８・・溶接条件設定部
２２・・トーチ
２３・・ワイヤ
２４・・母材
２５・・ワイヤ送給装置[0001]
BACKGROUND OF THE INVENTION
The present invention automatically feeds a consumable electrode (hereinafter referred to as a wire), and repeatedly supplies a peak current and a base current between the wire and a welding base material (hereinafter referred to as a base material) to control welding output. The present invention relates to a welding control method and a consumable electrode type pulse arc welding apparatus.
[0002]
[Prior art]
In recent years, in order to improve productivity, the demand for low spatter of welding has further increased. In particular, low spattering is required at the time of arc start and when the protrusion length changes due to a workpiece misalignment or the like.
[0003]
The conventional consumable electrode type pulse arc welder increases the welding current at a predetermined first current gradient regardless of the welding current immediately before the occurrence of the short circuit when a short circuit occurs and reaches a predetermined current value. Sputtering was suppressed by increasing the welding current with the second current gradient and decreasing the welding current when the short circuit was opened. (For example, see Patent Document 1)
FIG. 3 shows the conventional consumable electrode type pulse arc welding machine, wherein 1 is an input power source, 2 is a first rectifier, 3 is an inverter circuit unit, 4 is a main transformer, 5 is a second rectifier, Is a reactor, 7 is a welding voltage detector, 8 is an arc short-circuit detector, 9 is a welding current detector, 22 is a torch, 23 is a wire, 24 is a base material, 25 is a wire feeder, and 31 is a first gradient setting. , 32 is a second gradient setting unit, 33 is a bending point determination circuit unit, 34 is a second switching circuit unit, 35 is a first switching circuit unit, and 36 is an amplification unit.
[0004]
The consumable electrode type pulse arc welder configured as described above will be described. If the predetermined second current gradient is made smaller than the first current gradient, the welding current value at the time of occurrence of the short-circuit rises at the predetermined first gradient, and when it reaches the predetermined current value, the short-circuit is switched to the second gradient. The welding current value at the time of opening is suppressed from increasing. As a result, a large amount of spatter was suppressed and welding was stabilized.
[0005]
[Patent Document 1]
Japanese Patent No. 3156033 [0006]
[Problems to be solved by the invention]
However, the conventional consumable electrode type pulse arc welder has made it possible to suppress spatter during normal welding, but the arc becomes unstable at the time of arc start and when the protruding length of the work position shift etc. changes. In some cases, the problem was that there was a lot of sputtering.
[0007]
When such an arc becomes unstable, the timing of occurrence of a short circuit is not limited to the base period. In other words, even when the welding current value is high during the peak period or at the rising slope to the peak current and the falling slope from the peak period, a short circuit will occur. This is because it increases and spatter increases.
[0008]
It is an object of the present invention to provide a welding control method and a consumable electrode type pulse arc welding machine that suppresses sputtering when the arc is unstable.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention suppresses the occurrence of spatter by switching the welding current waveform during the short circuit according to the welding current value immediately before the occurrence of the short circuit. By this control method, when the welding current immediately before the occurrence of the short circuit is low, the welding current waveform during the short circuit is increased, and when the welding current is high, the welding current value at the time of short circuit opening can be suppressed by suppressing the welding current value.
[0010]
In the present invention, the welding current waveform during the short circuit is switched between a case where the welding current immediately before the occurrence of the short circuit is higher than the predetermined value and a case where the welding current is lower than the predetermined value.
[0011]
In the welding control method of the present invention, the predetermined value for switching the welding current waveform at the time of the short circuit is set according to at least one of a wire feed amount, a wire diameter, and a wire material.
[0012]
In addition, the present invention controls the arc length after opening the short circuit by controlling it to either a predetermined voltage value or a predetermined current value set in advance for a predetermined time period after the short circuit is opened. is there. As a result, the arc length after opening the short circuit is maintained, and continuous occurrence of short circuits is suppressed.
[0013]
Further, the present invention provides a step when the predetermined voltage control or the current control is started after the predetermined voltage or the predetermined current is controlled for a predetermined time set in advance after the short circuit is opened. The slope is controlled to suppress steep voltage changes or current changes.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
In the present embodiment, the same components as those in the conventional example are denoted by the same reference numerals, and detailed description thereof is omitted.
[0015]
In FIG. 1, a welding voltage detection unit 7 for detecting a welding voltage, a welding current detection unit 9 for detecting a welding current, and an arc short circuit determination unit for determining whether the welding state is an arc or a short circuit based on the output of the welding voltage detection unit 7. 8, a current rise setting unit 11 that increases the current value with the lapse of time at the time of the short circuit, a current decrease setting unit 12 that does not increase the current value with the lapse of time at the time of the short circuit, an output of the current rise setting unit 11, and the current decrease setting When the output of the part 12 and the output of the welding current detection part 9 are input and the welding current immediately before the occurrence of the short circuit is higher than a preset current value, the input from the current drop setting part 12 is low and the current increase setting part The short-circuit current control unit 10 that selectively controls and outputs the input from 11, and the output of the short-circuit current control unit 10 and the output of the arc short-circuit determination unit 8 are input to the short-circuit current at the time of short circuit. Shows the output control unit 14 for selecting and outputting control the output of the control unit 10.
[0016]
The operation of the embodiment configured as described above will be described.
[0017]
The signal detected by the welding current detection unit 9 is compared with a current value preset in the short-circuit current control unit 10, and the current rises when the welding current immediately before the occurrence of the short-circuit is higher than the predetermined value compared with a predetermined value. An input from the setting unit 11 is output and current control is performed so as to increase the welding current as time elapses. When the current is lower than the predetermined value, an input from the current decrease setting unit 12 is output so as not to increase the welding current as time elapses. Therefore, the occurrence of spatter can be suppressed by switching the welding current waveform at the time of the short circuit according to the welding current value immediately before the occurrence of the short circuit. The current drop setting unit 12 may maintain a value equal to the previous current value without increasing or decreasing, or may increase after decreasing for a predetermined time.
[0018]
(Embodiment 2)
In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0019]
In FIG. 2, a welding condition setting unit 18 for setting a welding condition such as a wire feeding amount, a wire diameter, or a wire material, and an output of the welding condition setting unit 18 are input, and at least a wire feeding amount, a wire diameter, or a wire material is input. The short-circuit current control unit 10 that sets a current value for switching the welding current waveform at the time of a short circuit according to one is provided.
[0020]
The difference from the first embodiment is that the current value for switching the output from the current rise setting unit 11 and the output from the current fall setting unit 12 is set according to at least one of the wire feed amount, the wire diameter, and the wire material. Is a point. Thereby, sputter | spatter can further be suppressed by setting the optimal upper and lower limit value for every welding condition.
[0021]
(Embodiment 3)
In the present embodiment, the same configurations as those in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.
[0022]
In FIG. 2, the output control unit 14 includes a time measuring unit 16 that measures a predetermined time set in advance from the time when the short circuit is opened, and a predetermined voltage value set in advance during the predetermined time set by the time measuring unit 16. Or the short circuit open | release control part 15 which controls a welding output to any one of predetermined electric current values and outputs it to the said output control part 14 is provided.
[0023]
The difference from the first and second embodiments is that the arc length after the short circuit is opened can be maintained by performing voltage control or current control by the short circuit opening control unit 15 during the period set by the time counting unit 16. Can be suppressed, and sputtering can be further suppressed.
[0024]
(Embodiment 4)
In the present embodiment, the same configurations as those of the first, second, and third embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.
[0025]
In FIG. 2, the output control unit 14 includes a slope control unit 17 that performs slope control of current or voltage in a stepwise manner when predetermined voltage control or current control is started after control by the short-circuit opening control unit 15. Yes.
[0026]
A difference from the first, second, and third embodiments is that a rapid voltage change or current change after control by the short-circuit opening control unit 15 can be suppressed. By suppressing a steep change in voltage or current, vibration of the molten pool can be suppressed, continuous occurrence of short circuits can be suppressed, and sputtering can be further suppressed.
[0027]
【The invention's effect】
INDUSTRIAL APPLICABILITY The present invention can suppress spatter that occurs when the arc becomes unstable, such as when the arc starts and when the protruding length of the workpiece is shifted, etc., and can improve welding quality.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram showing a first embodiment of the present invention. FIG. 2 is a block circuit diagram showing a second embodiment of the present invention. FIG. 3 is a block circuit diagram showing a conventional example.
1 .. Input power source 2 .. First rectification unit 3 .. Inverter unit 4 .. Transformer 5 .. Second rectification unit 6 .. Reactor 7 .. Welding voltage detection unit 8. Welding current detection unit 10 .. Short circuit current control unit 11 .. Current rise setting unit 12 .. Current fall setting unit 13 .. Arc period control unit 14 .. Output control unit 15 .. Short circuit open control unit 16. Section 17 Slope control section 18 Welding condition setting section 22 Torch 23 Wire 24 Base material 25 Wire feeder

Claims

A welding control method in which a peak current and a base current are repeatedly supplied in a pulse shape between a welding wire and a welding base material, and a welding current waveform during a short circuit is switched according to a welding current value immediately before the occurrence of the short circuit.

The welding control method according to claim 1, wherein the welding current immediately before the occurrence of the short circuit is compared with a predetermined value set in advance, and the welding current waveform during the short circuit is switched when the welding current is higher and lower than the predetermined value.

The welding control method according to claim 1 or 2, wherein a current value for switching a welding current waveform during a short circuit is individually set according to at least one of a wire feed amount, a wire diameter, and a wire material.

The welding control method according to claim 1 or 2, wherein one of a predetermined voltage value and a predetermined current value that are set in advance is controlled during a predetermined time that is set after a short circuit is opened as a time starting point.

Controls either a preset voltage or a preset current for a preset time starting from the time when the short circuit is opened, and then slopes step by step when starting a preset voltage control or current control. The welding control method according to claim 1, wherein the welding control method controls and suppresses a steep voltage change or current change.

A welding voltage detection unit that detects a welding voltage, a welding current detection unit that detects a welding current, an arc short-circuit determination unit that determines whether the welding state is an arc or a short circuit based on the output of the welding voltage detection unit, and over time when a short circuit occurs A current increase setting unit that increases the current value, a current decrease setting unit that does not increase the current value with time at the time of a short circuit, an output of the current increase setting unit, an output of the current decrease setting unit, and the welding current detection unit When the welding current immediately before the input and short-circuit occurrence is higher than the preset current value, the input from the current drop setting unit is selected and output from the current rise setting unit when the welding current is low. An output control for selecting and outputting the output of the short-circuit current control unit at the time of a short-circuit, using the output of the short-circuit current control unit, the output of the short-circuit current control unit and the output of the arc short-circuit determination unit as inputs A consumable electrode type that controls the current so as not to increase the welding current over time if the welding current immediately before the occurrence of a short circuit is higher than the predetermined value compared with a predetermined value, and increases the welding current if low Pulse arc welding equipment.

7. The consumable electrode type pulse arc welding apparatus according to claim 6, wherein the short-circuit current control unit individually sets a current value for switching a welding current waveform during the short-circuit according to at least one of a wire feed amount, a wire diameter, and a wire material. .

The output control unit includes a time counting unit that measures a predetermined time set in advance from the time when the short circuit is opened, and controls the voltage to either a predetermined voltage value or a predetermined current value during the predetermined time. 8. A consumable electrode type pulse according to claim 6 or 7, further comprising a short circuit opening control unit for outputting to the output control unit, wherein the control is performed to either a predetermined voltage value or a predetermined current value during a predetermined time after the short circuit is opened. Arc welding equipment.

The output control unit includes a slope control unit that performs slope control of current or voltage stepwise when starting predetermined voltage control or current control after performing control by the short-circuit opening control unit, and the short-circuit opening control The consumable electrode type pulse arc welding apparatus according to any one of claims 6 to 8, which suppresses a steep voltage change or current change after control by the unit.