JP7396779B2 - Arc welding control method - Google Patents
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Description
本発明は、短絡期間中は溶接ワイヤの逆送速度を所定逆送値にし、アーク期間中は正送速度を所定正送値にして溶接するアーク溶接制御方法に関するものである。 The present invention relates to an arc welding control method in which the reverse feed speed of a welding wire is set to a predetermined reverse feed value during a short circuit period, and the forward feed speed is set to a predetermined forward feed value during an arc period.
一般的な消耗電極式アーク溶接では、消耗電極である溶接ワイヤを一定速度で送給し、溶接ワイヤと母材との間にアークを発生させて溶接が行なわれる。消耗電極式アーク溶接では、溶接ワイヤと母材とが短絡期間とアーク期間とを交互に繰り返す溶接状態になることが多い。 In general consumable electrode arc welding, welding is performed by feeding a welding wire, which is a consumable electrode, at a constant speed to generate an arc between the welding wire and the base metal. In consumable electrode arc welding, the welding wire and the base metal are often in a welded state in which short circuit periods and arc periods alternate.
溶接品質をさらに向上させるために、溶接ワイヤの送給速度を正送速度と逆送速度とに交互に切り換えて溶接する正逆送給アーク溶接方法が提案されている(例えば、特許文献1参照)。この正逆送給アーク溶接方法では、一定の送給速度の従来技術に比べて、短絡とアークとの繰り返しの周期を安定化することができるので、スパッタ発生量の削減、ビード外観の改善等の溶接品質の向上を図ることができる。 In order to further improve welding quality, a forward and reverse feed arc welding method has been proposed in which the welding wire feed speed is alternately switched between a forward feed speed and a reverse feed speed. ). This forward and reverse feed arc welding method can stabilize the cycle of short-circuit and arc repetition compared to conventional technology with a constant feed speed, reducing the amount of spatter and improving the bead appearance. The welding quality can be improved.
正逆送給アーク溶接においては、アーク期間及び短絡期間の各時間長さが略一定になるために、安定した溶接状態となる。しかし、ワイヤ突き出し長さの変動、溶融池の不規則な運動、送給速度の変動等が発生すると、短絡期間の時間長さが基準時間以上になる長期短絡が発生しやすくなる。長期短絡状態において、アーク発生までの経過時間が長くなるほど溶滴移行状態が不安定になり、溶接状態が悪くなるという問題がある。 In forward and reverse feed arc welding, the lengths of the arc period and the short circuit period are approximately constant, resulting in a stable welding state. However, if fluctuations in the length of the wire protrusion, irregular movements of the molten pool, fluctuations in the feeding speed, etc. occur, long-term short circuits in which the length of the short circuit period exceeds the reference time are likely to occur. In a long-term short-circuit state, there is a problem that the longer the elapsed time until arc generation, the more unstable the droplet transfer state becomes, and the worse the welding state becomes.
そこで、本発明では、正逆送給アーク溶接において、長期短絡が発生しても、溶接状態を安定に保つことができるアーク溶接制御方法を提供することを目的とする。 Therefore, an object of the present invention is to provide an arc welding control method that can maintain a stable welding state even if a long-term short circuit occurs in forward and reverse feed arc welding.
上述した課題を解決するために、請求項1の発明は、
短絡期間中は溶接ワイヤの逆送速度を所定逆送値にし、アーク期間中は正送速度を所定正送値にして溶接するアーク溶接制御方法において、
前記短絡期間の経過時間が基準時間以上の前記短絡期間が所定回数以上連続して発生したときは、次周期の前記短絡期間の開始時点から前記逆送速度の絶対値を前記所定逆送値の絶対値よりも大きくする、
ことを特徴とするアーク溶接制御方法である。
In order to solve the above-mentioned problem, the invention of claim 1:
In an arc welding control method for welding, the reverse feed speed of the welding wire is set to a predetermined reverse feed value during a short circuit period, and the forward feed speed is set to a predetermined forward feed value during an arc period,
When the short circuit period in which the elapsed time of the short circuit period is equal to or longer than the reference time occurs consecutively for a predetermined number of times or more, the absolute value of the reverse feed speed is set to the predetermined reverse feed value from the start of the short circuit period in the next cycle. greater than the absolute value,
This is an arc welding control method characterized by the following.
本発明によれば、正逆送給アーク溶接において、長期短絡が発生しても、溶接状態を安定に保つことができる。 According to the present invention, even if a long-term short circuit occurs in forward and reverse feed arc welding, a stable welding state can be maintained.
以下、図面を参照して本発明の実施の形態について説明する。 Embodiments of the present invention will be described below with reference to the drawings.
[実施の形態1]
図1は、本発明の実施の形態1に係るアーク溶接制御方法を実施するための溶接電源のブロック図である。以下、同図を参照して各ブロックについて説明する。
[Embodiment 1]
FIG. 1 is a block diagram of a welding power source for implementing an arc welding control method according to
電源主回路PMは、3相200V等の商用電源(図示は省略)を入力として、後述する誤差増幅信号Eaに従ってインバータ制御等による出力制御を行い、出力電圧Eを出力する。この電源主回路PMは、図示は省略するが、商用電源を整流する1次整流器、整流された直流を平滑する平滑コンデンサ、平滑された直流を高周波交流に変換する上記の誤差増幅信号Eaによって駆動されるインバータ回路、高周波交流を溶接に適した電圧値に降圧する高周波変圧器、降圧された高周波交流を直流に整流する2次整流器を備えている。 The power supply main circuit PM receives a commercial power supply (not shown) such as a three-phase 200V power supply as an input, performs output control by inverter control, etc. according to an error amplification signal Ea, which will be described later, and outputs an output voltage E. Although not shown, this power supply main circuit PM is driven by a primary rectifier that rectifies commercial power, a smoothing capacitor that smoothes the rectified DC, and the above-mentioned error amplification signal Ea that converts the smoothed DC into high-frequency AC. It is equipped with an inverter circuit, a high-frequency transformer that steps down the high-frequency AC to a voltage value suitable for welding, and a secondary rectifier that rectifies the stepped-down high-frequency AC into DC.
リアクトルWLは、上記の出力電圧Eを平滑する。このリアクトルWLのインダクタンス値は、例えば100μHである。 Reactor WL smoothes the above output voltage E. The inductance value of this reactor WL is, for example, 100 μH.
送給モータWMは、後述する送給制御信号Fcを入力として、正送と逆送とを交互に繰り返して溶接ワイヤ1を送給速度Fwで送給する。送給モータWMには、過渡応答性の速いモータが使用される。溶接ワイヤ1の送給速度Fwの変化率及び送給方向の反転を速くするために、送給モータWMは溶接トーチ4の先端の近くに設置される場合がある。また、送給モータWMを2個使用して、プッシュプル方式の送給系とする場合もある。
The feed motor WM receives a feed control signal Fc, which will be described later, as an input, and feeds the
溶接ワイヤ1は、上記の送給モータWMに結合された送給ロール5の回転によって溶接トーチ4内を送給されて、母材2との間にアーク3が発生する。溶接トーチ4内の給電チップ(図示は省略)と母材2との間には溶接電圧Vwが印加され、溶接電流Iwが通電する。溶接トーチ4の先端からはシールドガスが噴出して、アーク3を大気から遮蔽する。
The
出力電圧設定回路ERは、予め定めた出力電圧設定信号Erを出力する。出力電圧検出回路EDは、上記の出力電圧Eを検出し平滑して、出力電圧検出信号Edを出力する。 The output voltage setting circuit ER outputs a predetermined output voltage setting signal Er. The output voltage detection circuit ED detects and smoothes the above-mentioned output voltage E, and outputs an output voltage detection signal Ed.
電圧誤差増幅回路EVは、上記の出力電圧設定信号Er及び上記の出力電圧検出信号Edを入力として、出力電圧設定信号Er(+)と出力電圧検出信号Ed(-)との誤差を増幅して、電圧誤差増幅信号Evを出力する。 The voltage error amplification circuit EV receives the above output voltage setting signal Er and the above output voltage detection signal Ed as input, and amplifies the error between the output voltage setting signal Er (+) and the output voltage detection signal Ed (-). , outputs a voltage error amplified signal Ev.
電流検出回路IDは、上記の溶接電流Iwを検出して、電流検出信号Idを出力する。電圧検出回路VDは、上記の溶接電圧Vwを検出して、電圧検出信号Vdを出力する。 The current detection circuit ID detects the above-mentioned welding current Iw and outputs a current detection signal Id. Voltage detection circuit VD detects the above-mentioned welding voltage Vw and outputs voltage detection signal Vd.
短絡判別回路SDは、上記の電圧検出信号Vdを入力として、この値が予め定めた短絡判別値(10V程度)未満のときは短絡期間にあると判別してHighレベルになり、以上のときはアーク期間にあると判別してLowレベルになる短絡判別信号Sdを出力する。 The short-circuit discrimination circuit SD inputs the above-mentioned voltage detection signal Vd, and when this value is less than a predetermined short-circuit discrimination value (approximately 10V), it determines that there is a short-circuit period and becomes High level; It determines that it is in the arcing period and outputs a short circuit determination signal Sd that goes to Low level.
長期短絡判別回路LSDは、上記の短絡判別信号Sdを入力として、短絡判別信号SdがHighレベル(短絡)に変化するとLowレベルにリセットされ、短絡判別信号SdがHighレベルに変化した時点からの経過時間が基準時間に達するとHighレベルにセットされる、長期短絡判別信号Lsdを出力する。 The long-term short circuit determination circuit LSD inputs the above-mentioned short circuit determination signal Sd, and when the short circuit determination signal Sd changes to High level (short circuit), it is reset to Low level, and the progress from the time when the short circuit determination signal Sd changes to High level. When the time reaches the reference time, a long-term short circuit determination signal Lsd is output, which is set to High level.
長期短絡連続発生判別回路NSDは、上記の短絡判別信号Sd及び上記の長期短絡判別信号Lsdを入力として、短絡判別信号SdがLowレベル(アーク)に変化した時点の長期短絡判別信号LsdがHighレベルであることが所定回数連続して発生したときは、Highレベルとなる長期短絡連続発生判別信号Nsdを出力する。したがって、長期短絡連続発生判別信号NsdがHighレベルとなるのは、長期短絡が所定回数連続して発生したときである。 The long-term short circuit continuous occurrence determination circuit NSD inputs the above-mentioned short circuit determination signal Sd and the above-mentioned long-term short circuit determination signal Lsd, and determines that the long-term short circuit determination signal Lsd is at High level at the time when the short circuit determination signal Sd changes to Low level (arc). When this occurs a predetermined number of times in succession, a long-term short circuit continuous occurrence determination signal Nsd that becomes High level is output. Therefore, the long-term short circuit continuous occurrence determination signal Nsd becomes High level when long-term short circuits occur a predetermined number of times in succession.
逆送速度設定回路WRRは、上記の長期短絡判別信号Lsd及び上記の長期短絡連続発生判別信号Nsdを入力として、長期短絡判別信号LsdがLowレベル(通常短絡)であり、かつ、長期短絡連続発生判別信号NsdがLowレベルのときは所定逆送値となり、それ以外のときは所定長期短絡逆送値となる、逆送速度設定信号Wrrを出力する。ここで、所定逆送値及び所定長期短絡逆送値は負の値であり、その絶対値は所定長期短絡逆送値の方が大きくなるように設定される。したがって、
1)短絡期間の経過時間が基準時間以上の長期短絡になった時点から短絡期間が終了するまでの期間中は、逆送速度設定信号Wrrは所定長期短絡逆送値となり、
2)基準時間以上の短絡期間となる長期短絡が所定回数以上連続して発生したときは、次周期の短絡期間の開始時点から短絡期間が終了するまでの期間中は、逆送速度設定信号Wrrは所定長期短絡逆送値となり、
3)直前に長期短絡が所定回数以上連続して発生しておらず、短絡期間の経過時間が基準時間に達していない期間中は、逆送速度設定信号Wrrは所定逆送値となる。
所定逆送値は、平均送給速度(平均溶接電流値)に応じた値として設定される。
The reverse feed speed setting circuit WRR inputs the above-mentioned long-term short-circuit discrimination signal Lsd and the above-mentioned long-term short-circuit continuous occurrence discrimination signal Nsd, and determines whether the long-term short-circuit discrimination signal Lsd is at a low level (normal short circuit) and the long-term short circuit continuous occurrence occurs. When the discrimination signal Nsd is at a low level, a predetermined reverse feed value is output, and in other cases, a reverse feed speed setting signal Wrr is output, which is a predetermined long-term short circuit reverse feed value. Here, the predetermined reverse value and the predetermined long-term short-circuit reverse value are negative values, and the absolute value thereof is set so that the predetermined long-term short-circuit reverse value is larger. therefore,
1) During the period from the time when the elapsed time of the short circuit period becomes a long-term short circuit longer than the reference time until the end of the short circuit period, the reverse feed speed setting signal Wrr becomes a predetermined long-term short circuit reverse feed value,
2) When a long-term short circuit with a short circuit period longer than the reference time occurs consecutively for a predetermined number of times or more, the reverse feed speed setting signal Wrr is activated during the period from the start of the short circuit period of the next cycle to the end of the short circuit period. is the specified long-term short-circuit reverse transmission value,
3) During a period in which a long-term short circuit has not occurred consecutively for a predetermined number of times or more immediately before, and the elapsed time of the short circuit period has not reached the reference time, the reverse feed speed setting signal Wrr becomes the predetermined reverse feed value.
The predetermined reverse feeding value is set as a value according to the average feeding speed (average welding current value).
正送速度設定回路WSRは、上記の逆送速度設定信号Wrrを入力として、逆送速度設定信号Wrrが所定逆送値であるときは所定正送値となり、所定長期短絡逆送値であるときは所定長期短絡正送値となる、正送速度設定信号Wsrを出力する。ここで、所定正送値及び所定長期短絡正送値は正の値であり、その値は所定長期短絡正送値の方が大きくなるように設定される。所定正送値は、平均送給速度(平均溶接電流値)に応じた値として設定される。 The forward feed speed setting circuit WSR inputs the above reverse feed speed setting signal Wrr, and when the reverse feed speed setting signal Wrr is a predetermined reverse feed value, it becomes a predetermined forward feed value, and when it is a predetermined long-term short circuit reverse feed value, it becomes a predetermined forward feed value. outputs a normal feed speed setting signal Wsr that is a predetermined long-term short-circuit normal feed value. Here, the predetermined forward feed value and the predetermined long-term short-circuit forward feed value are positive values, and the values are set so that the predetermined long-term short-circuit forward feed value is larger. The predetermined forward feed value is set as a value according to the average feed speed (average welding current value).
送給速度設定回路FRは、上記の逆送速度設定信号Wrr、上記の正送速度設定信号Wsr及び上記の短絡判別信号Sdを入力として、短絡判別信号SdがHighレベル(短絡期間)のときは逆送速度設定信号Wrrを送給速度設定信号Frとして出力し、短絡判別信号SdがLowレベル(アーク期間)のときは正送速度設定信号Wsrとなる送給速度設定信号Frを出力する。 The feeding speed setting circuit FR inputs the above reverse feeding speed setting signal Wrr, the above forward feeding speed setting signal Wsr, and the above short circuit determination signal Sd, and when the short circuit determination signal Sd is at a High level (short circuit period), The reverse feed speed setting signal Wrr is output as the feed speed setting signal Fr, and when the short circuit determination signal Sd is at a low level (arc period), the feed speed setting signal Fr is output as the forward feed speed setting signal Wsr.
送給制御回路FCは、上記の送給速度設定信号Frを入力として、送給速度設定信号Frの値に相当する送給速度Fwで溶接ワイヤ1を送給するための送給制御信号Fcを上記の送給モータWMに出力する。
The feed control circuit FC inputs the above feed speed setting signal Fr and generates a feed control signal Fc for feeding the
減流抵抗器Rは、上記のリアクトルWLと溶接トーチ4との間に挿入される。この減流抵抗器Rの値は、短絡負荷(0.01~0.03Ω程度)の10倍以上大きな値(0.5~3Ω程度)に設定される。この減流抵抗器Rが通電路に挿入されると、リアクトルWL及び外部ケーブルのリアクトルに蓄積されたエネルギーが急放電される。 The current reducing resistor R is inserted between the reactor WL and the welding torch 4 described above. The value of this current reducing resistor R is set to a value (approximately 0.5 to 3 Ω) that is ten times or more greater than the short circuit load (approximately 0.01 to 0.03 Ω). When this current reducing resistor R is inserted into the current carrying path, the energy stored in the reactor WL and the reactor of the external cable is rapidly discharged.
トランジスタTRは、上記の減流抵抗器Rと並列に接続されて、後述する駆動信号Drに従ってオン又はオフ制御される。 The transistor TR is connected in parallel with the current reducing resistor R described above, and is controlled to be turned on or off according to a drive signal Dr, which will be described later.
くびれ検出回路NDは、上記の短絡判別信号Sd、上記の電圧検出信号Vd及び上記の電流検出信号Idを入力として、短絡判別信号SdがHighレベル(短絡期間)であるときの電圧検出信号Vdの電圧上昇値が基準値に達した時点でくびれの形成状態が基準状態になったと判別してHighレベルとなり、短絡判別信号SdがLowレベル(アーク期間)に変化した時点でLowレベルになるくびれ検出信号Ndを出力する。また、短絡期間中の電圧検出信号Vdの微分値がそれに対応した基準値に達した時点でくびれ検出信号NdをHighレベルに変化させるようにしても良い。さらに、電圧検出信号Vdの値を電流検出信号Idの値で除算して溶滴の抵抗値を算出し、この抵抗値の微分値がそれに対応する基準値に達した時点でくびれ検出信号NdをHighレベルに変化させるようにしても良い。 The constriction detection circuit ND inputs the short circuit determination signal Sd, the voltage detection signal Vd, and the current detection signal Id, and detects the voltage detection signal Vd when the short circuit determination signal Sd is at a high level (short circuit period). Constriction detection determines that the constriction formation state has reached the standard state when the voltage rise value reaches the reference value and becomes High level, and becomes Low level when the short circuit determination signal Sd changes to Low level (arc period) Outputs signal Nd. Furthermore, the constriction detection signal Nd may be changed to High level at the time when the differential value of the voltage detection signal Vd during the short-circuit period reaches the corresponding reference value. Furthermore, the resistance value of the droplet is calculated by dividing the value of the voltage detection signal Vd by the value of the current detection signal Id, and when the differential value of this resistance value reaches the corresponding reference value, the constriction detection signal Nd is calculated. It may be changed to High level.
低レベル電流設定回路ILRは、予め定めた低レベル電流設定信号Ilrを出力する。電流比較回路CMは、この低レベル電流設定信号Ilr及び上記の電流検出信号Idを入力として、Id<IlrのときはHighレベルになり、Id≧IlrのときはLowレベルになる電流比較信号Cmを出力する。 The low level current setting circuit ILR outputs a predetermined low level current setting signal Ilr. The current comparison circuit CM inputs this low-level current setting signal Ilr and the above-mentioned current detection signal Id, and generates a current comparison signal Cm that becomes High level when Id<Ilr and becomes Low level when Id≧Ilr. Output.
駆動回路DRは、上記の電流比較信号Cm及び上記のくびれ検出信号Ndを入力として、くびれ検出信号NdがHighレベルに変化するとLowレベルに変化し、その後に電流比較信号CmがHighレベルに変化するとHighレベルに変化する駆動信号Drを上記のトランジスタTRのベース端子に出力する。したがって、この駆動信号Drはくびれが検出されるとLowレベルになり、トランジスタTRがオフ状態になり通電路に減流抵抗器Rが挿入されるので、短絡負荷を通電する溶接電流Iwは急減する。そして、急減した溶接電流Iwの値が低レベル電流設定信号Ilrの値まで減少すると、駆動信号DrはHighレベルになり、トランジスタTRがオン状態になるので、減流抵抗器Rは短絡されて通常の状態に戻る。 The drive circuit DR inputs the above current comparison signal Cm and the above constriction detection signal Nd, changes to Low level when the constriction detection signal Nd changes to High level, and then changes to Low level when current comparison signal Cm changes to High level. A drive signal Dr that changes to High level is output to the base terminal of the transistor TR. Therefore, when a constriction is detected, the drive signal Dr becomes Low level, the transistor TR is turned off, and the current reducing resistor R is inserted into the current carrying path, so the welding current Iw that conducts the short-circuited load suddenly decreases. . Then, when the rapidly decreased value of welding current Iw decreases to the value of low-level current setting signal Ilr, drive signal Dr becomes High level and transistor TR is turned on, so current reducing resistor R is short-circuited and normal Return to state.
電流制御設定回路ICRは、上記の短絡判別信号Sd、上記の低レベル電流設定信号Ilr、上記のくびれ検出信号Nd及び上記の長期短絡判別信号Lsdを入力として、以下の処理を行い、電流制御設定信号Icrを出力する。
1)短絡判別信号SdがLowレベル(アーク期間)のときは、低レベル電流設定信号Ilrとなる電流制御設定信号Icrを出力する。
2)短絡判別信号SdがHighレベル(短絡期間)に変化すると、予め定めた初期期間中は予め定めた初期電流設定値となり、その後は予め定めた短絡時傾斜で予め定めた短絡時ピーク設定値まで上昇してその値を維持する電流制御設定信号Icrを出力する。
3)その後に、くびれ検出信号NdがHighレベルに変化すると、低レベル電流設定信号Ilrの値となる電流制御設定信号Icrを出力する。
4)短絡期間中に長期短絡判別信号LsdがHighレベルになると、予め定めた短絡解除電流値となる電流制御設定信号Icrを出力する。
The current control setting circuit ICR receives the above short circuit discrimination signal Sd, the above low level current setting signal Ilr, the above constriction detection signal Nd, and the above long term short circuit discrimination signal Lsd, performs the following processing, and sets the current control. A signal Icr is output.
1) When the short circuit determination signal Sd is at a low level (arc period), a current control setting signal Icr that becomes a low level current setting signal Ilr is output.
2) When the short-circuit discrimination signal Sd changes to High level (short-circuit period), the current becomes the predetermined initial setting value during the predetermined initial period, and thereafter the current changes to the predetermined short-circuit peak setting value with the predetermined short-circuit slope. It outputs a current control setting signal Icr that increases to a value of 1 and maintains that value.
3) After that, when the constriction detection signal Nd changes to High level, the current control setting signal Icr having the value of the low-level current setting signal Ilr is output.
4) When the long-term short-circuit discrimination signal Lsd becomes High level during the short-circuit period, a current control setting signal Icr having a predetermined short-circuit release current value is output.
電流誤差増幅回路EIは、上記の電流制御設定信号Icr及び上記の電流検出信号Idを入力として、電流制御設定信号Icr(+)と電流検出信号Id(-)との誤差を増幅して、電流誤差増幅信号Eiを出力する。 The current error amplification circuit EI receives the above current control setting signal Icr and the above current detection signal Id, amplifies the error between the current control setting signal Icr (+) and the current detection signal Id (-), and outputs a current. Outputs an error amplified signal Ei.
電流降下時間設定回路TDRは、予め定めた電流降下時間設定信号Tdrを出力する。 The current drop time setting circuit TDR outputs a predetermined current drop time setting signal Tdr.
小電流期間回路STDは、上記の短絡判別信号Sd及び上記の電流降下時間設定信号Tdrを入力として、短絡判別信号SdがLowレベル(アーク期間)に変化した時点から電流降下時間設定信号Tdrによって定まる時間が経過した時点でHighレベルになり、その後に短絡判別信号SdがHighレベル(短絡期間)になるとLowレベルになる小電流期間信号Stdを出力する。 The small current period circuit STD inputs the short circuit determination signal Sd and the current drop time setting signal Tdr, and is determined by the current drop time setting signal Tdr from the time when the short circuit determination signal Sd changes to Low level (arc period). It outputs a small current period signal Std which becomes High level when the time elapses, and then becomes Low level when the short circuit discrimination signal Sd becomes High level (short circuit period).
電源特性切換回路SWは、上記の電流誤差増幅信号Ei、上記の電圧誤差増幅信号Ev、上記の短絡判別信号Sd及び上記の小電流期間信号Stdを入力として、以下の処理を行い、誤差増幅信号Eaを出力する。
1)短絡判別信号SdがHighレベル(短絡期間)に変化した時点から、短絡判別信号SdがLowレベル(アーク期間)に変化して予め定めた遅延期間が経過した時点までの期間中は、電流誤差増幅信号Eiを誤差増幅信号Eaとして出力する。
2)その後の大電流アーク期間中は、電圧誤差増幅信号Evを誤差増幅信号Eaとして出力する。
3)その後のアーク期間中に小電流期間信号StdがHighレベルとなる小電流アーク期間中は、電流誤差増幅信号Eiを誤差増幅信号Eaとして出力する。
この回路によって、溶接電源の特性は、短絡期間、遅延期間及び小電流アーク期間中は定電流特性となり、それ以外の大電流アーク期間中は定電圧特性となる。
The power supply characteristic switching circuit SW receives the above current error amplification signal Ei, the above voltage error amplification signal Ev, the above short circuit determination signal Sd, and the above small current period signal Std, performs the following processing, and converts the error amplification signal. Output Ea.
1) During the period from the time when the short circuit determination signal Sd changes to High level (short circuit period) to the time when the short circuit determination signal Sd changes to Low level (arc period) and a predetermined delay period has elapsed, the current The error amplified signal Ei is output as the error amplified signal Ea.
2) During the subsequent large current arc period, the voltage error amplification signal Ev is output as the error amplification signal Ea.
3) During the small current arcing period in which the small current period signal Std becomes High level during the subsequent arcing period, the current error amplification signal Ei is outputted as the error amplification signal Ea.
With this circuit, the characteristics of the welding power source are constant current characteristics during the short circuit period, delay period, and small current arc period, and constant voltage characteristics during the other large current arc periods.
図2は、本発明の実施の形態1に係るアーク溶接制御方法を示す通常短絡のときの図1の溶接電源における各信号のタイミングチャートである。同図(A)は送給速度Fwの時間変化を示し、同図(B)は溶接電流Iwの時間変化を示し、同図(C)は溶接電圧Vwの時間変化を示し、同図(D)は短絡判別信号Sdの時間変化を示し、同図(E)は小電流期間信号Stdの時間変化を示し、同図(F)は長期短絡判別信号Lsdの時間変化を示し、同図(G)は長期短絡連続発生判別信号Nsdの時間変化を示す。以下、同図を参照して各信号の動作について説明する。 FIG. 2 is a timing chart of each signal in the welding power source of FIG. 1 during a normal short circuit, showing the arc welding control method according to the first embodiment of the present invention. The same figure (A) shows the time change of the feeding speed Fw, the same figure (B) shows the time change of the welding current Iw, the same figure (C) shows the time change of the welding voltage Vw, the same figure (D ) shows the time change of the short-circuit discrimination signal Sd, the same figure (E) shows the time change of the small current period signal Std, the same figure (F) shows the time change of the long-term short circuit discrimination signal Lsd, the same figure (G ) shows the time change of the long-term short circuit continuous occurrence determination signal Nsd. The operation of each signal will be explained below with reference to the same figure.
同図は、時刻t1~t2の短絡期間が、直前に長期短絡が所定回数以上連続して発生しておらず、短絡期間の経過時間が基準時間未満となる通常短絡の場合である。したがって、同図は従来技術に相当する。同図(F)に示す長期短絡判別信号Lsd及び同図(G)に示す長期短絡連続発生判別信号Nsdは、Lowレベルのままである。 In this figure, the short circuit period from time t1 to t2 is a normal short circuit in which a long-term short circuit has not occurred immediately before a predetermined number of times or more and the elapsed time of the short circuit period is less than the reference time. Therefore, the figure corresponds to the prior art. The long-term short circuit determination signal Lsd shown in (F) of the same figure and the long-term short circuit continuous occurrence determination signal Nsd shown in (G) of the same figure remain at the Low level.
同図(A)に示す送給速度Fwは、図1の送給速度設定回路FRから出力される送給速度設定信号Frの値に制御される。送給速度Fwは、短絡期間中は負の値の逆送速度となり、アーク期間中は正の値の正送速度となる。送給速度Fwは、正負の台形波形となる。 The feed rate Fw shown in FIG. 1A is controlled by the value of the feed rate setting signal Fr output from the feed rate setting circuit FR of FIG. The feeding speed Fw becomes a negative reverse feeding speed during the short circuit period, and a positive forward feeding speed during the arcing period. The feeding speed Fw has a positive and negative trapezoidal waveform.
[時刻t1~t2の通常短絡期間の動作]
正送期間中の時刻t1において短絡が発生すると、同図(C)に示すように、溶接電圧Vwは数Vの短絡電圧値に急減するので、同図(D)に示すように、短絡判別信号SdがHighレベル(短絡期間)に変化する。これに応動して、同図(A)に示すように、送給速度Fwは正の値の正送速度から傾斜を有して負の値の逆送速度へと変化し、時刻t2にアークが発生するまでこの値を維持する。正送速度は図1の正送速度設定信号Wsrによって設定され、逆送速度は図1の逆送速度設定信号Wrrによって設定される。この短絡期間は、上述したように、直前に長期短絡が所定回数以上連続して発生しておらず、短絡期間の経過時間が基準時間未満となる通常短絡であるので、逆送速度設定信号Wrrは所定逆送値となる。正送速度から0までの傾斜及び0から逆送速度までの傾斜は、図1の送給モータWMの過渡特性によって決まる。これらの傾斜を所望値に設定しても良い。この各傾斜期間は、例えば1msである。
[Operation during the normal short circuit period from time t1 to t2]
When a short circuit occurs at time t1 during the forward feed period, the welding voltage Vw suddenly decreases to a short circuit voltage value of several volts, as shown in (C) of the same figure. The signal Sd changes to High level (short circuit period). In response to this, as shown in the same figure (A), the feeding speed Fw changes from the forward feeding speed with a positive value to the reverse feeding speed with a negative value with an inclination, and at time t2, the feeding speed Fw changes from the forward feeding speed with a positive value to the reverse feeding speed with a negative value. This value is maintained until this occurs. The forward feed speed is set by the forward feed speed setting signal Wsr shown in FIG. 1, and the reverse feed speed is set by the reverse feed speed setting signal Wrr shown in FIG. As mentioned above, this short circuit period is a normal short circuit in which a long-term short circuit has not occurred consecutively for a predetermined number of times or more immediately before, and the elapsed time of the short circuit period is less than the reference time, so the reverse feed speed setting signal Wrr becomes a predetermined reverse value. The slope from the normal feed speed to 0 and the slope from 0 to the reverse feed speed are determined by the transient characteristics of the feed motor WM shown in FIG. These slopes may be set to desired values. Each ramp period is, for example, 1 ms.
同図(B)に示すように、時刻t1~t2の短絡期間中の溶接電流Iwは、予め定めた初期期間中は予め定めた初期電流値となる。その後、溶接電流Iwは、予め定めた短絡時傾斜で上昇し、予め定めた短絡時ピーク値に達するとその値を維持する。 As shown in FIG. 3B, the welding current Iw during the short-circuit period from time t1 to t2 has a predetermined initial current value during a predetermined initial period. Thereafter, the welding current Iw increases at a predetermined short-circuit slope, and when it reaches a predetermined short-circuit peak value, it maintains that value.
同図(C)に示すように、溶接電圧Vwは、溶接電流Iwが短絡時ピーク値となるあたりから上昇する。これは、溶接ワイヤ1の逆送及び溶接電流Iwによるピンチ力の作用により、溶接ワイヤ1の先端の溶滴にくびれが次第に形成されるためである。
As shown in FIG. 3C, the welding voltage Vw increases from around the point where the welding current Iw reaches its peak value at the time of short circuit. This is because a constriction is gradually formed in the droplet at the tip of the
その後に溶接電圧Vwの電圧上昇値が基準値に達すると、くびれの形成状態が基準状態になったと判別して、図1のくびれ検出信号NdはHighレベルに変化する。 After that, when the voltage increase value of the welding voltage Vw reaches the reference value, it is determined that the constriction formation state has reached the reference state, and the constriction detection signal Nd in FIG. 1 changes to High level.
くびれ検出信号NdがHighレベルになったことに応動して、図1の駆動信号DrはLowレベルになるので、図1のトランジスタTRはオフ状態となり図1の減流抵抗器Rが通電路に挿入される。同時に、図1の電流制御設定信号Icrが低レベル電流設定信号Ilrの値に小さくなる。このために、同図(B)に示すように、溶接電流Iwは短絡時ピーク値から低レベル電流値へと急減する。そして、溶接電流Iwが低レベル電流値まで減少すると、駆動信号DrはHighレベルに戻るので、トランジスタTRはオン状態となり減流抵抗器Rは短絡される。同図(B)に示すように、溶接電流Iwは、電流制御設定信号Icrが低レベル電流設定信号Ilrのままであるので、アーク再発生から予め定めた遅延期間が経過するまでは低レベル電流値を維持する。したがって、トランジスタTRは、くびれ検出信号NdがHighレベルに変化した時点から溶接電流Iwが低レベル電流値に減少するまでの期間のみオフ状態となる。同図(C)に示すように、溶接電圧Vwは、溶接電流Iwが小さくなるので一旦減少した後に急上昇する。上述した各パラメータは、例えば以下の値に設定される。初期電流=40A、初期期間=0.5ms、短絡時傾斜=180A/ms、短絡時ピーク値=400A、低レベル電流値=50A、遅延期間=0.5ms。 In response to the constriction detection signal Nd going high, the drive signal Dr in FIG. 1 goes low, so the transistor TR in FIG. 1 turns off and the current reducing resistor R in FIG. inserted. At the same time, the current control setting signal Icr in FIG. 1 is reduced to the value of the low level current setting signal Ilr. For this reason, as shown in the same figure (B), the welding current Iw rapidly decreases from the peak value at the time of short circuit to the low level current value. Then, when the welding current Iw decreases to a low level current value, the drive signal Dr returns to High level, so the transistor TR is turned on and the current reducing resistor R is short-circuited. As shown in the same figure (B), since the current control setting signal Icr remains at the low level current setting signal Ilr, the welding current Iw is a low level current until a predetermined delay period elapses from the re-occurrence of the arc. Maintain value. Therefore, the transistor TR is in an off state only during the period from when the constriction detection signal Nd changes to High level until the welding current Iw decreases to a low level current value. As shown in FIG. 3C, the welding voltage Vw decreases once and then rises rapidly because the welding current Iw becomes smaller. Each of the parameters described above is set to the following values, for example. Initial current = 40A, initial period = 0.5ms, slope during short circuit = 180A/ms, peak value during short circuit = 400A, low level current value = 50A, delay period = 0.5ms.
[時刻t2~t3のアーク期間の動作]
時刻t2において、溶接ワイヤの逆送及び溶接電流Iwの通電によるピンチ力によってくびれが進行してアークが発生すると、同図(C)に示すように、溶接電圧Vwは数十Vのアーク電圧値に急増するので、同図(D)に示すように、短絡判別信号SdがLowレベル(アーク期間)に変化する。これに応動して、同図(A)に示すように、送給速度Fwは負の値の逆送速度から傾斜を有して正の値の正送速度へと変化し、時刻t3に短絡が発生するまでこの値を維持する。このアーク期間の開始時点における逆送速度は所定逆送値であるので、正送速度は所定正送値となる。逆送速度から0までの傾斜及び0から正送速度までの傾斜は、図1の送給モータWMの過渡特性によって決まる。これらの傾斜を所望値に設定しても良い。この各傾斜期間は、例えば1msである。
[Operation during the arc period from time t2 to t3]
At time t2, when the constriction progresses and an arc is generated due to the pinch force caused by the reverse feeding of the welding wire and the application of the welding current Iw, the welding voltage Vw increases to an arc voltage value of several tens of V, as shown in FIG. As a result, the short circuit determination signal Sd changes to Low level (arc period) as shown in FIG. In response to this, as shown in the same figure (A), the feeding speed Fw changes from the reverse feeding speed with a negative value to the forward feeding speed with a positive value with an inclination, and at time t3, a short circuit occurs. This value is maintained until this occurs. Since the reverse feed speed at the start of this arc period is the predetermined reverse feed value, the forward feed speed becomes the predetermined forward feed value. The slope from the reverse feed speed to 0 and the slope from 0 to the forward feed speed are determined by the transient characteristics of the feed motor WM shown in FIG. These slopes may be set to desired values. Each ramp period is, for example, 1 ms.
時刻t2においてアークが発生すると、同図(C)に示すように、溶接電圧Vwは数十Vのアーク電圧値に急増する。他方、同図(B)に示すように、溶接電流Iwは、時刻t2~t21の遅延期間の間は低レベル電流値を継続する。その後、時刻t21から溶接電流Iwは急速に増加してピーク値となり、その後は徐々に減少する大電流値となる。この時刻t21~t22の大電流アーク期間中は、図1の電圧誤差増幅信号Evによって溶接電源のフィードバック制御が行われるので、定電圧特性となる。したがって、大電流アーク期間中の溶接電流Iwの値はアーク負荷によって変化する。 When an arc occurs at time t2, the welding voltage Vw rapidly increases to an arc voltage value of several tens of volts, as shown in FIG. On the other hand, as shown in FIG. 3B, the welding current Iw continues at a low level current value during the delay period from time t2 to t21. Thereafter, the welding current Iw rapidly increases from time t21 to a peak value, and then gradually decreases to a large current value. During the large current arcing period from time t21 to time t22, feedback control of the welding power source is performed using the voltage error amplification signal Ev shown in FIG. 1, so that a constant voltage characteristic is achieved. Therefore, the value of welding current Iw during the high current arc period changes depending on the arc load.
時刻t2にアークが発生してから図1の電流降下時間設定信号Tdrによって定まる電流降下時間が経過する時刻t23において、同図(E)に示すように、小電流期間信号StdがHighレベルに変化する。これに応動して、溶接電源は定電圧特性から定電流特性に切り換えられる。このために、同図(B)に示すように、溶接電流Iwは低レベル電流値に低下し、短絡が発生する時刻t3までその値を維持する。同様に、同図(C)に示すように、溶接電圧Vwも低下する。小電流期間信号Stdは、時刻t3に短絡が発生するとLowレベルに戻る。 At time t23, when the current drop time determined by the current drop time setting signal Tdr in FIG. 1 has elapsed since the arc occurred at time t2, the small current period signal Std changes to High level, as shown in FIG. 1(E). do. In response to this, the welding power source is switched from constant voltage characteristics to constant current characteristics. For this reason, as shown in FIG. 3B, the welding current Iw decreases to a low level current value and maintains that value until time t3 when a short circuit occurs. Similarly, as shown in the same figure (C), the welding voltage Vw also decreases. The small current period signal Std returns to the Low level when a short circuit occurs at time t3.
各パラメータの数値例を以下に示す。
所定逆送速度=-40m/min、所定正送値=70m/min
Numerical examples of each parameter are shown below.
Predetermined reverse feed speed = -40m/min, predetermined forward feed value = 70m/min
図3は、本発明の実施の形態1に係るアーク溶接制御方法を示す長期短絡のときの図1の溶接電源における各信号のタイミングチャートである。同図(A)は送給速度Fwの時間変化を示し、同図(B)は溶接電流Iwの時間変化を示し、同図(C)は溶接電圧Vwの時間変化を示し、同図(D)は短絡判別信号Sdの時間変化を示し、同図(E)は小電流期間信号Stdの時間変化を示し、同図(F)は長期短絡判別信号Lsdの時間変化を示し、同図(G)は長期短絡連続発生判別信号Nsdの時間変化を示す。同図の説明において、図2と同一の点については説明を繰り返さない。以下、同図を参照して、図2とは異なる点を中心に各信号の動作について説明する。 FIG. 3 is a timing chart of each signal in the welding power source of FIG. 1 during a long-term short circuit, showing the arc welding control method according to the first embodiment of the present invention. The same figure (A) shows the time change of the feeding speed Fw, the same figure (B) shows the time change of the welding current Iw, the same figure (C) shows the time change of the welding voltage Vw, the same figure (D ) shows the time change of the short-circuit discrimination signal Sd, the same figure (E) shows the time change of the small current period signal Std, the same figure (F) shows the time change of the long-term short circuit discrimination signal Lsd, the same figure (G ) shows the time change of the long-term short circuit continuous occurrence determination signal Nsd. In the explanation of this figure, the explanation of the same points as in FIG. 2 will not be repeated. Hereinafter, with reference to the figure, the operation of each signal will be explained focusing on the points different from those in FIG. 2.
同図は、時刻t1~t2の短絡期間が、直前に長期短絡が所定回数以上連続して発生しておらず、短絡期間の経過時間が基準時間以上となる長期短絡の場合である。したがって、長期短絡は連続していないので、同図(G)に示すように、長期短絡連続発生判別信号NsdはLowレベルのままである。 This figure shows a case where the short circuit period from time t1 to t2 is a long-term short circuit in which a long-term short circuit has not occurred consecutively for a predetermined number of times or more immediately before, and the elapsed time of the short circuit period is equal to or longer than the reference time. Therefore, since the long-term short circuits are not continuous, the long-term short circuit continuous occurrence determination signal Nsd remains at the Low level, as shown in FIG.
[時刻t1~t2の長期短絡期間の動作]
正送期間中の時刻t1において短絡が発生すると、同図(C)に示すように、溶接電圧Vwは数Vの短絡電圧値に急減するので、同図(D)に示すように、短絡判別信号SdがHighレベル(短絡期間)に変化する。これに応動して、同図(A)に示すように、送給速度Fwは正の値の正送速度から傾斜を有して負の値の逆送速度へと変化し、時刻t2にアークが発生するまでこの値を維持する。この短絡期間は、上述したように、直前に長期短絡が所定回数以上連続して発生しておらず、短絡期間の経過時間が時刻t11に基準時間以上となる長期短絡の場合である。したがって、同図(A)に示すように、時刻t1~t11までの期間中の送給速度Fwの逆送速度は、所定逆送値となる。そして、時刻t11において、短絡期間の経過時間が基準時間に達すると、同図(F)に示すように、長期短絡判別信号LsdがHighレベルに変化する。これに応動して、同図(A)に示すように、送給速度Fwの逆送速度は、所定長期短絡逆送値へと絶対値が大きくなる。この結果、溶接ワイヤの逆送速度が加速されるので、長期短絡は時刻t2において早期に解除される。長期短絡判別信号Lsdは、時刻t3に次周期の短絡が発生した時点でLowレベルに戻る。
[Operation during the long-term short circuit period from time t1 to t2]
When a short circuit occurs at time t1 during the forward feed period, the welding voltage Vw suddenly decreases to a short circuit voltage value of several volts, as shown in (C) of the same figure. The signal Sd changes to High level (short circuit period). In response to this, as shown in the same figure (A), the feeding speed Fw changes from the forward feeding speed with a positive value to the reverse feeding speed with a negative value with an inclination, and at time t2, the feeding speed Fw changes from the forward feeding speed with a positive value to the reverse feeding speed with a negative value. This value is maintained until this occurs. As described above, this short-circuit period is a long-term short-circuit in which a long-term short circuit has not occurred consecutively for a predetermined number of times or more immediately before, and the elapsed time of the short-circuit period is equal to or longer than the reference time at time t11. Therefore, as shown in FIG. 3A, the reverse feed rate of the feed rate Fw during the period from time t1 to t11 becomes a predetermined reverse feed value. Then, at time t11, when the elapsed time of the short-circuit period reaches the reference time, the long-term short-circuit discrimination signal Lsd changes to High level, as shown in FIG. In response to this, the absolute value of the reverse feed rate of the feed rate Fw increases to a predetermined long-term short-circuit reverse feed value, as shown in FIG. As a result, the reverse feed speed of the welding wire is accelerated, so that the long-term short circuit is quickly canceled at time t2. The long-term short circuit determination signal Lsd returns to the Low level when the next cycle of short circuit occurs at time t3.
同図(B)に示すように、時刻t1~t11の短絡期間中の溶接電流Iwは、予め定めた初期期間中は予め定めた初期電流値となる。その後、溶接電流Iwは、予め定めた短絡時傾斜で上昇し、予め定めた短絡時ピーク値に達するとその値を維持する。時刻t11において同図(F)に示す長期短絡判別信号LsdがHighレベルになると、溶接電流Iwは予め定めた短絡解除電流値へと大きくなる。長期短絡のときは、溶滴移行状態が不安定になっているので、溶滴のくびれを検出することなくアークが発生することになる。このために、時刻t2にアークが発生したときの溶接電流Iwは、短絡解除電流値となることが多い。短絡解除電流値は、例えば500Aである。 As shown in FIG. 3B, the welding current Iw during the short-circuit period from time t1 to t11 has a predetermined initial current value during a predetermined initial period. Thereafter, the welding current Iw increases at a predetermined short-circuit slope, and when it reaches a predetermined short-circuit peak value, it maintains that value. At time t11, when the long-term short circuit determination signal Lsd shown in FIG. In the case of a long-term short circuit, the droplet transfer state is unstable, so an arc will occur without detecting the constriction of the droplet. For this reason, the welding current Iw when an arc occurs at time t2 often has a short-circuit release current value. The short circuit release current value is, for example, 500A.
同図(C)に示すように、溶接電圧Vwは、時刻t1~t2の短絡期間中は数Vの短絡電圧値となる。 As shown in FIG. 3C, the welding voltage Vw has a short-circuit voltage value of several volts during the short-circuit period from time t1 to t2.
[時刻t2~t3のアーク期間の動作]
時刻t2において、溶接ワイヤの逆送及び溶接電流Iwの通電によるピンチ力によってアークが発生すると、同図(C)に示すように、溶接電圧Vwは数十Vのアーク電圧値に急増するので、同図(D)に示すように、短絡判別信号SdがLowレベル(アーク期間)に変化する。これに応動して、同図(A)に示すように、送給速度Fwは負の値の逆送速度から傾斜を有して正の値の正送速度へと変化し、時刻t3に短絡が発生するまでこの値を維持する。このアーク期間の開始時点における逆送速度は所定長期短絡逆送値であるので、正送速度は所定長期短絡正送値となる。
[Operation during the arc period from time t2 to t3]
At time t2, when an arc is generated by the pinch force caused by the reverse feeding of the welding wire and the application of the welding current Iw, the welding voltage Vw rapidly increases to an arc voltage value of several tens of V, as shown in FIG. As shown in FIG. 3D, the short circuit determination signal Sd changes to Low level (arc period). In response to this, as shown in the same figure (A), the feeding speed Fw changes from the reverse feeding speed with a negative value to the forward feeding speed with a positive value with an inclination, and at time t3, a short circuit occurs. This value is maintained until this occurs. Since the reverse feed speed at the start of this arc period is the predetermined long-term short-circuit reverse feed value, the forward feed speed becomes the predetermined long-term short-circuit forward feed value.
時刻t2においてアークが発生すると、同図(C)に示すように、溶接電圧Vwは数十Vのアーク電圧値に急増する。 When an arc occurs at time t2, the welding voltage Vw rapidly increases to an arc voltage value of several tens of volts, as shown in FIG.
同図(B)に示すように、溶接電流Iwは、時刻t2時点での短絡解除電流値から徐々に減少する。時刻t2~t21のアーク期間中は、図1の電圧誤差増幅信号Evによって溶接電源のフィードバック制御が行われるので、定電圧特性となる。したがって、この期間中の溶接電流Iwの値はアーク負荷によって変化する。 As shown in FIG. 3B, the welding current Iw gradually decreases from the short-circuit release current value at time t2. During the arcing period from time t2 to time t21, feedback control of the welding power source is performed by the voltage error amplification signal Ev shown in FIG. 1, so that a constant voltage characteristic is achieved. Therefore, the value of welding current Iw during this period changes depending on the arc load.
時刻t2にアークが発生してから図1の電流降下時間設定信号Tdrによって定まる電流降下時間が経過する時刻t21において、同図(E)に示すように、小電流期間信号StdがHighレベルに変化する。これに応動して、溶接電源は定電圧特性から定電流特性に切り換えられる。このために、同図(B)に示すように、溶接電流Iwは低レベル電流値に低下し、短絡が発生する時刻t3までその値を維持する。同様に、同図(C)に示すように、溶接電圧Vwも低下する。小電流期間信号Stdは、時刻t3に短絡が発生するとLowレベルに戻る。 At time t21, when the current drop time determined by the current drop time setting signal Tdr in FIG. 1 has elapsed since the arc occurred at time t2, the small current period signal Std changes to High level, as shown in FIG. 1(E). do. In response to this, the welding power source is switched from constant voltage characteristics to constant current characteristics. For this reason, as shown in FIG. 3B, the welding current Iw decreases to a low level current value and maintains that value until time t3 when a short circuit occurs. Similarly, as shown in the same figure (C), the welding voltage Vw also decreases. The small current period signal Std returns to the Low level when a short circuit occurs at time t3.
上述した各パラメータの数値例を以下に示す。
所定逆送速度=-40m/min、所定長期短絡逆送値=-60m/min、所定正送値=70m/min、所定長期短絡正送値=80m/min、基準時間=10ms
Numerical examples of each of the above-mentioned parameters are shown below.
Predetermined reverse feed speed = -40 m/min, predetermined long-term short circuit reverse feed value = -60 m/min, predetermined forward feed value = 70 m/min, predetermined long-term short circuit forward feed value = 80 m/min, reference time = 10 ms
上述した実施の形態1によれば、正逆送給アーク溶接において、短絡期間の経過時間が基準時間以上になると逆送速度の絶対値を大きくし、続くアーク期間中の正送速度を所定正送値よりも大きくする。 正逆送給アーク溶接において、ワイヤ突き出し長さの変動、溶融池の不規則な運動、送給速度の変動等が発生すると、短絡期間の時間長さが基準時間以上になる長期短絡が発生しやすくなる。長期短絡状態において、アーク発生までの経過時間が長くなるほど溶滴移行状態が不安定になり、溶接状態が悪くなる。したがって、長期短絡状態になった場合は、速やかに長期短絡状態を解除してアーク発生状態へと導く必要がある。本実施の形態では、長期短絡状態になると、逆送速度を大きくすることによって、早期に長期短絡状態を解除することができる。反面、逆送速度が大きくなると、平均送給速度が変化することになり、溶接ビードが悪くなる問題が発生する。本実施の形態では、逆送速度を大きくした場合には、次周期の正送速度を連動して大きくするようにしている。これにより、平均送給速度の変動を抑制している。この結果、本実施の形態では、長期短絡が発生しても、溶接状態を安定に保つことができ、溶接ビードも良好にすることができる。 According to the first embodiment described above, in forward and reverse feed arc welding, when the elapsed time of the short circuit period exceeds the reference time, the absolute value of the reverse feed speed is increased, and the forward feed speed during the subsequent arc period is increased to a predetermined normal value. Make it larger than the sending price. During forward and reverse feed arc welding, if fluctuations in wire protrusion length, irregular movement of the molten pool, fluctuations in feed speed, etc. occur, long-term short circuits will occur where the length of the short circuit period exceeds the standard time. It becomes easier. In a long-term short circuit state, the longer the elapsed time until arc generation, the more unstable the droplet transfer state becomes, and the worse the welding state becomes. Therefore, when a long-term short circuit occurs, it is necessary to quickly release the long-term short circuit and lead to an arcing state. In this embodiment, when a long-term short-circuit condition occurs, the long-term short-circuit condition can be canceled early by increasing the reverse feeding speed. On the other hand, if the reverse feed speed increases, the average feed speed will change, causing a problem of poor weld beads. In this embodiment, when the reverse feed speed is increased, the forward feed speed of the next cycle is increased in conjunction with the increase. This suppresses fluctuations in the average feeding speed. As a result, in this embodiment, even if a long-term short circuit occurs, the welding state can be kept stable and the weld bead can also be made good.
図4は、本発明の実施の形態1に係るアーク溶接制御方法を示す長期短絡が連続して発生したときの図1の溶接電源における各信号のタイミングチャートである。同図(A)は送給速度Fwの時間変化を示し、同図(B)は溶接電流Iwの時間変化を示し、同図(C)は溶接電圧Vwの時間変化を示し、同図(D)は短絡判別信号Sdの時間変化を示し、同図(E)は小電流期間信号Stdの時間変化を示し、同図(F)は長期短絡判別信号Lsdの時間変化を示し、同図(G)は長期短絡連続発生判別信号Nsdの時間変化を示す。同図の説明において、図2と同一の点については説明を繰り返さない。以下、同図を参照して、図2とは異なる点を中心に各信号の動作について説明する。 FIG. 4 is a timing chart of each signal in the welding power source of FIG. 1 when long-term short circuits occur successively, illustrating the arc welding control method according to the first embodiment of the present invention. The same figure (A) shows the time change of the feeding speed Fw, the same figure (B) shows the time change of the welding current Iw, the same figure (C) shows the time change of the welding voltage Vw, the same figure (D ) shows the time change of the short-circuit discrimination signal Sd, the same figure (E) shows the time change of the small current period signal Std, the same figure (F) shows the time change of the long-term short circuit discrimination signal Lsd, the same figure (G ) shows the time change of the long-term short circuit continuous occurrence determination signal Nsd. In the explanation of this figure, the explanation of the same points as in FIG. 2 will not be repeated. Hereinafter, with reference to the figure, the operation of each signal will be explained focusing on the points different from those in FIG. 2.
同図は、時刻t1~t2の短絡期間の直前に長期短絡が所定回数以上連続して発生した場合である。したがって、同図(G)に示すように、長期短絡連続発生判別信号Nsdは、時刻t1以前においてHighレベルとなっており、時刻t2においてLowレベルに戻る。 This figure shows a case where long-term short circuits occur consecutively for a predetermined number of times or more immediately before the short circuit period from time t1 to t2. Therefore, as shown in FIG. 3G, the long-term short circuit continuous occurrence determination signal Nsd is at High level before time t1, and returns to Low level at time t2.
[時刻t1~t2の短絡期間の動作]
正送期間中の時刻t1において短絡が発生すると、同図(C)に示すように、溶接電圧Vwは数Vの短絡電圧値に急減するので、同図(D)に示すように、短絡判別信号SdがHighレベル(短絡期間)に変化する。これに応動して、同図(A)に示すように、送給速度Fwは正の値の正送速度から傾斜を有して負の値の逆送速度へと変化し、時刻t2にアークが発生するまでこの値を維持する。時刻t1において同図(G)に示す長期短絡連続発生判別信号NsdがHighレベルであるので、同図(A)に示すように、送給速度Fwの逆送速度は、短絡期間の開始時点から所定逆送値よりも大きな値の所定長期短絡逆送値となる。長期短絡が連続して発生している場合には、溶接状態が不安定になっているので、次の短絡も長期短絡状態になる可能性が高い。そこで、短絡の発生時点から逆送速度を通常値よりも大きくすることによって、長期短絡状態になることを抑制している。この結果、時刻t1~t2の短絡期間は、通常短絡期間となっている。これ以外の各信号の動作は、図2と同様であるので、説明は繰り返さない。上記の所定回数は、例えば2~5回程度である。
[Operation during the short circuit period from time t1 to t2]
When a short circuit occurs at time t1 during the forward feed period, the welding voltage Vw suddenly decreases to a short circuit voltage value of several volts, as shown in (C) of the same figure. The signal Sd changes to High level (short circuit period). In response to this, as shown in the same figure (A), the feeding speed Fw changes from the forward feeding speed with a positive value to the reverse feeding speed with a negative value with an inclination, and at time t2, the feeding speed Fw changes from the forward feeding speed with a positive value to the reverse feeding speed with a negative value. This value is maintained until this occurs. At time t1, the long-term short circuit continuous occurrence determination signal Nsd shown in (G) of the same figure is at High level, so as shown in (A) of the same figure, the reverse feeding speed of the feeding speed Fw is changed from the start of the short circuit period. The predetermined long-term short-circuit reverse transmission value is larger than the predetermined reverse transmission value. If long-term short circuits occur continuously, the welding condition has become unstable, so there is a high possibility that the next short circuit will also be a long-term short circuit condition. Therefore, by setting the reverse feed speed higher than the normal value from the point at which the short circuit occurs, the occurrence of a long-term short circuit state is suppressed. As a result, the short circuit period from time t1 to t2 is a normal short circuit period. The operation of each signal other than this is the same as that in FIG. 2, so the description will not be repeated. The above predetermined number of times is, for example, about 2 to 5 times.
[時刻t2~t3のアーク期間の動作]
時刻t2において、溶接ワイヤの逆送及び溶接電流Iwの通電によるピンチ力によってアークが発生すると、同図(C)に示すように、溶接電圧Vwは数十Vのアーク電圧値に急増するので、同図(D)に示すように、短絡判別信号SdがLowレベル(アーク期間)に変化する。これに応動して、同図(A)に示すように、送給速度Fwは負の値の逆送速度から傾斜を有して正の値の正送速度へと変化し、時刻t3に短絡が発生するまでこの値を維持する。このアーク期間の開始時点における逆送速度は所定逆送値であるので、正送速度は所定正送値となる。時刻t2にアークが発生した時点において、同図(F)に示す長期短絡判別信号LsdはLowレベルであるので、同図(G)に示すように、長期短絡連続発生判別信号NsdはLowレベルに戻る。すなわち、時刻t2~t3のアーク期間中の動作は、図2と同様であるので、説明は繰り返さない。
[Operation during the arc period from time t2 to t3]
At time t2, when an arc is generated by the pinch force caused by the reverse feeding of the welding wire and the application of the welding current Iw, the welding voltage Vw rapidly increases to an arc voltage value of several tens of V, as shown in FIG. As shown in FIG. 3D, the short circuit determination signal Sd changes to Low level (arc period). In response to this, as shown in the same figure (A), the feeding speed Fw changes from the reverse feeding speed with a negative value to the forward feeding speed with a positive value with an inclination, and at time t3, a short circuit occurs. This value is maintained until this occurs. Since the reverse feed speed at the start of this arc period is the predetermined reverse feed value, the forward feed speed becomes the predetermined forward feed value. At the time when the arc occurs at time t2, the long-term short circuit determination signal Lsd shown in FIG. return. That is, the operation during the arc period from time t2 to time t3 is the same as that in FIG. 2, so the description will not be repeated.
上述した実施の形態1によれば、基準時間以上の前記短絡期間が所定回数以上連続して発生したときは、次周期の短絡期間の開始時点から逆送速度の絶対値を所定逆送値の絶対値よりも大きくする。長期短絡が所定回数以上連続して発生している場合には、溶接状態が不安定になっているので、次の短絡も長期短絡状態になる可能性が高い。そこで、短絡の発生時点から逆送速度を通常値よりも大きくすることによって、長期短絡状態になることを抑制している。これにより、本実施の形態では、長期短絡が連続して発生している状態から早期に抜け出すことができるので、溶接不良となることを抑制することができる。 According to the first embodiment described above, when the short-circuit period longer than the reference time occurs consecutively for a predetermined number of times or more, the absolute value of the reverse feed speed is set to the predetermined reverse feed value from the start of the short-circuit period of the next cycle. Make it larger than the absolute value. If long-term short circuits occur consecutively for a predetermined number of times or more, the welding state has become unstable, so there is a high possibility that the next short circuit will also be a long-term short circuit state. Therefore, by setting the reverse feed speed higher than the normal value from the point at which the short circuit occurs, the occurrence of a long-term short circuit state is suppressed. As a result, in the present embodiment, it is possible to quickly escape from a state in which long-term short circuits occur continuously, and therefore it is possible to suppress welding defects.
1 溶接ワイヤ
2 母材
3 アーク
4 溶接トーチ
5 送給ロール
CM 電流比較回路
Cm 電流比較信号
DR 駆動回路
Dr 駆動信号
E 出力電圧
Ea 誤差増幅信号
ED 出力電圧検出回路
Ed 出力電圧検出信号
EI 電流誤差増幅回路
Ei 電流誤差増幅信号
ER 出力電圧設定回路
Er 出力電圧設定信号
EV 電圧誤差増幅回路
Ev 電圧誤差増幅信号
FC 送給制御回路
Fc 送給制御信号
FR 送給速度設定回路
Fr 送給速度設定信号
Fw 送給速度
ICR 電流制御設定回路
Icr 電流制御設定信号
ID 電流検出回路
Id 電流検出信号
ILR 低レベル電流設定回路
Ilr 低レベル電流設定信号
Iw 溶接電流
LSD 長期短絡判別回路
Lsd 長期短絡判別信号
ND くびれ検出回路
Nd くびれ検出信号
NSD 長期短絡連続発生判別回路
Nsd 長期短絡連続発生判別信号
PM 電源主回路
R 減流抵抗器
SD 短絡判別回路
Sd 短絡判別信号
STD 小電流期間回路
Std 小電流期間信号
SW 電源特性切換回路
TDR 電流降下時間設定回路
Tdr 電流降下時間設定信号
TR トランジスタ
VD 電圧検出回路
Vd 電圧検出信号
Vw 溶接電圧
WL リアクトル
WM 送給モータ
WRR 逆送速度設定回路
Wrr 逆送速度設定信号
WSR 正送速度設定回路
Wsr 正送速度設定信号
1 welding wire
2 Base material
3 arc
4 welding torch
5 Feed roll CM Current comparison circuit Cm Current comparison signal DR Drive circuit Dr Drive signal E Output voltage Ea Error amplification signal ED Output voltage detection circuit Ed Output voltage detection signal EI Current error amplification circuit Ei Current error amplification signal ER Output voltage setting circuit Er Output voltage setting signal EV Voltage error amplification circuit Ev Voltage error amplification signal FC Feed control circuit Fc Feed control signal FR Feed rate setting circuit Fr Feed rate setting signal Fw Feed rate ICR Current control setting circuit Icr Current control setting Signal ID Current detection circuit Id Current detection signal ILR Low level current setting circuit Ilr Low level current setting signal Iw Welding current LSD Long term short circuit determination circuit Lsd Long term short circuit determination signal ND Waist detection circuit Nd Waist detection signal NSD Long term short circuit continuous occurrence determination circuit Nsd Long-term short circuit continuous occurrence determination signal PM Main power supply circuit R Current reducing resistor SD Short circuit determination circuit Sd Short circuit determination signal STD Small current period circuit Std Small current period signal SW Power supply characteristic switching circuit TDR Current drop time setting circuit Tdr Current drop time setting signal TR Transistor VD Voltage detection circuit Vd Voltage detection signal Vw Welding voltage WL Reactor WM Feed motor WRR Reverse feed speed setting circuit Wrr Reverse feed speed setting signal WSR Forward feed speed setting circuit Wsr Forward feed speed setting signal
Claims (1)
前記短絡期間の経過時間が基準時間以上の前記短絡期間が所定回数以上連続して発生したときは、次周期の前記短絡期間の開始時点から前記逆送速度の絶対値を前記所定逆送値の絶対値よりも大きくする、
ことを特徴とするアーク溶接制御方法。 In an arc welding control method for welding, the reverse feed speed of the welding wire is set to a predetermined reverse feed value during a short circuit period, and the forward feed speed is set to a predetermined forward feed value during an arc period,
When the short circuit period in which the elapsed time of the short circuit period is equal to or longer than the reference time occurs consecutively for a predetermined number of times or more, the absolute value of the reverse feed speed is set to the predetermined reverse feed value from the start of the short circuit period in the next cycle. greater than the absolute value,
An arc welding control method characterized by:
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| JP2004298924A (en) | 2003-03-31 | 2004-10-28 | Daihen Corp | Method for controlling feeding of wire in arc welding accompanied with short circuit |
| JP2007216268A (en) | 2006-02-17 | 2007-08-30 | Matsushita Electric Ind Co Ltd | Arc welding control method and arc welding apparatus |
| US20130180971A1 (en) | 2012-01-17 | 2013-07-18 | Lincoln Global, Inc. | Systems and methods to feed wire within a welder |
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| JP2016144826A (en) | 2015-02-02 | 2016-08-12 | 株式会社ダイヘン | Output control method for pulse arc welding |
| JP2016168617A (en) | 2015-03-13 | 2016-09-23 | パナソニックIpマネジメント株式会社 | Arc-welding control method |
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| JP2004298924A (en) | 2003-03-31 | 2004-10-28 | Daihen Corp | Method for controlling feeding of wire in arc welding accompanied with short circuit |
| JP2007216268A (en) | 2006-02-17 | 2007-08-30 | Matsushita Electric Ind Co Ltd | Arc welding control method and arc welding apparatus |
| US20130180971A1 (en) | 2012-01-17 | 2013-07-18 | Lincoln Global, Inc. | Systems and methods to feed wire within a welder |
| JP2016026880A (en) | 2014-06-24 | 2016-02-18 | 株式会社ダイヘン | Pulsed arc welding output control method |
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