JP4657391B2 - Stud welding integrated heat input push-in control method - Google Patents

Description

【００８１】
正常な溶接動作が行われた場合の全入熱量はほぼ一定であるために、この正常な溶接動作が行われる場合の全入熱量を溶接スタッドの径及び被溶接材１４の条件及び溶接姿勢（下向き、横向き等）に応じて選定された検出期間全体の標準入熱量Ｑstにする。
【００８２】
［数２の説明］
以下、図２（Ａ）及び（Ｂ）に示すように、主ア−ク電流・電圧検出開始時点ｔ３から主ア−ク電流・電圧検出終了時点ｔ８までの正常な溶接時の検出期間全体の標準入熱量Ｑstを算出する式について説明する。
数２の右辺の１番目の式によって、検出間隔ごとの入熱量平均値ΔＱavを主ア−ク電流・電圧検出開始時点ｔ３から主ア−ク電流・電圧検出終了時点ｔ８まで積算して検出期間全体の標準入熱量Ｑstを算出する。
【数２】

【００８４】
［数３の説明］
図２（Ａ）及び（Ｂ）に示すように、上記の主ア−ク電流・電圧検出開始時点ｔ３の検出間隔Δｔの検出開始時点はｔ01であり、主ア−ク電流・電圧検出終了時点ｔ８の検出間隔Δｔの検出開始時点はｔ0nである。したがって、１回目の検出間隔Δｔの検出開始時点ｔ01から検出回数ｎ回目の検出間隔Δｔの検出開始時点ｔ0nまでの検出期間全体の標準入熱量Ｑstを、数２の右辺の２番目の式によって算出してもよい。
【００８６】
また、検出期間全体の標準入熱量Ｑstを上記の数２によって算出する代わりに、主ア−ク電流・電圧検出開始時点ｔ３の１回目の検出間隔Δｔから主ア−ク電流・電圧検出終了時点ｔ８の検出回数ｎ回目の検出間隔Δｔまでの検出期間全体の標準入熱量Ｑstを、数３によって算出してもよい。
【数３】

【００９０】
［図３の説明］
図３（Ａ）は、各溶接中の主アーク期間全体の出力電流Ｉｏから検出期間中の溶接電流平均値Ｉavを算出する説明図であり、同図（Ｂ）は、各溶接中の主アーク期間全体の出力端子電圧Ｖｄから検出間隔Δｔごとに検出間隔ごとの主ア−ク電圧平均値Ｖav(Δｔ)を算出する説明図である。
【００９２】
図１で説明した溶接電源装置１として、サイリスタ等の半導体スイッチング素子を用いた略定電流制御方式の電源装置を使用た場合、主アーク電流通電開始時点ｔ２から短絡電流通電終了時点ｔ10までの間、出力電流Ｉｏがほぼ一定に制御された定電流が流れる。
【００９４】
主ア−ク電流通電終了時点即ち短絡電流通電開始時点ｔ９で、押し込み動作を開始して短絡させると、図３（Ａ）に示すように、正常に短絡した瞬間に急峻な電流が流れる。この急峻な電流の増加分は、主アーク電流Ｉａの平均値と比較して無視することができる範囲である。そこで、主アーク期間Ｔａの出力電流Ｉｏは、アーク時も瞬時的な短絡時も略一定であるので、検出間隔ごとの主ア−ク電流平均値Ｉav(Δt)を測定しないで、検出期間中の溶接電圧平均値Ｖavだけを測定してもよい。
【００９５】
次に、図３（Ａ）及び（Ｂ）を参照して、主ア−ク電流・電圧検出開始時点ｔ３から、検出期間全体の標準入熱量Ｑstに達した主ア−ク電流・電圧検出終了時点ｔｎまでの短絡が発生しない積算入熱量Ｑtaを算出する式について説明する。
【００９６】
［数４の説明］
数４の右辺の１番目の式によって、主ア−ク電流・電圧検出開始時点ｔ３から主ア−ク電流・電圧検出終了時点ｔｎまで、検出間隔ごとの入熱量平均値ΔＱavを積算して、積算入熱量Ｑtaを算出する。
【数４】

【００９８】
上記の主ア−ク電流・電圧検出開始時点ｔ３の検出間隔Δｔの検出開始時点はｔ01であり、主ア−ク電流・電圧検出終了時点ｔｎの検出間隔Δｔの検出開始時点はｔ0nである。したがって、１回目の検出間隔Δｔの検出開始時点ｔ01から検出回数ｎ回目の検出間隔Δｔの検出開始時点ｔ0nまでの積算入熱量Ｑtaを、数４の右辺の２番目の式によって算出してもよい。
【０１００】
［数５の説明］
また、積算入熱量Ｑtaを上記の数４によって算出する代わりに、主ア−ク電流・電圧検出開始時点ｔ３の１回目の検出間隔Δｔから主ア−ク電流・電圧検出終了時点ｔｎの検出回数ｎ回目の検出間隔Δｔまでの積算入熱量Ｑtaを、数５によって算出してもよい。
【数５】

【０１０１】
［図４の説明］
図４（Ａ）は、各溶接中の主アーク期間全体の出力電流Ｉｏから検出間隔ごとの主ア−ク電流平均値Ｉav(Δt)を算出する説明図であり、同図（Ｂ）は、各溶接中の主アーク期間全体の出力端子電圧Ｖｄから検出間隔Δｔごとに検出間隔ごとの主ア−ク電圧平均値Ｖav(Δｔ)を算出する説明図である。
【０１０２】
次に、図４（Ａ）及び（Ｂ）を参照して、主ア−ク電流・電圧検出開始時点ｔ３から、検出期間全体の標準入熱量Ｑstに達した主ア−ク電流・電圧検出終了時点ｔｎまでの短絡が発生しない積算入熱量Ｑtaを算出する式について説明する。
【０１０３】
［数６の説明］
積算入熱量Ｑtaは、検出間隔ごとの入熱量平均値ΔＱavを、主ア−ク電流・電圧検出開始時点ｔ３から主ア−ク電流・電圧検出終了時点ｔｎまで、数６の右辺の１番目の式によって算出する。
【数６】

【０１０４】
上記の主ア−ク電流・電圧検出開始時点ｔ３の検出間隔Δｔの検出開始時点はｔ01であり、主ア−ク電流・電圧検出終了時点ｔｎの検出間隔Δｔの検出開始時点はｔ0nである。したがって、１回目の検出間隔Δｔの検出開始時点ｔ01から検出回数ｎ回目の検出間隔Δｔの検出開始時点ｔ0nまでの積算入熱量Ｑtaを、数６の右辺の２番目の式によって算出してもよい。
【０１０６】
［数７の説明］
また、積算入熱量Ｑtaを上記の数４によって算出する代わりに、主ア−ク電流・電圧検出開始時点ｔ３の１回目の検出間隔Δｔから主ア−ク電流・電圧検出終了時点ｔｎの検出回数ｎ回目の検出間隔Δｔまでの積算入熱量Ｑtaを、数７によって算出してもよい。
【数７】

【０１１０】
次に、補助ア−ク期間Ｔｐの補助ア−ク電流・電圧検出開始時点ｔ１から補助ア−ク電流値Ｉｐを測定するとともに、補助ア−ク電圧平均値Ｖav12を測定して補助ア−ク期間積算入熱量Ｑta12を算出する場合について説明する。
【０１１２】
通常のスタッド溶接においては、前述した図２に示した補助ア−ク期間Ｔｐは０.１〜０.２［秒］であり、主アーク期間Ｔａは０.４〜１.５［秒］であり、短絡期間Ｔｓは０.２［秒］位であって、補助ア−ク期間Ｔｐは主アーク期間Ｔａに比べて１／１０程度の通電時間であり、しかも補助ア−ク電流値Ｉｐは主ア−ク電流値Ｉａよりも小であるので、
制御回路を簡単にするために、補助ア−ク期間積算入熱量Ｑta12の算出を省略している。
【０１１４】
しかし、溶接条件によっては、補助ア−ク期間積算入熱量Ｑta12を主アーク期間積算入熱量Ｑta3nに対して無視することができなくなりその場合は、補助ア−ク電流平均値Ｉｐと補助ア−ク電圧平均値と補助ア−ク期間Ｔｐとから補助ア−ク期間積算入熱量Ｑta12を算出する。
補助ア−ク期間Ｔｐは前述したとおり、主アーク期間Ｔａに比べて短時間であるので、補助ア−ク電流平均値Ｉｐと補助ア−ク電圧平均値とは、検出間隔ごとの主ア−ク電流平均値Ｉav(Δt)及び検出間隔ごとの主ア−ク電圧平均値Ｖav(Δｔ)のように、検出間隔Δｔごとに算出する必要はなく、補助ア−ク電流・電圧検出開始時点ｔ１から、補助ア−ク電圧平均値Ｖav12を測定して、この補助ア−ク電圧平均値Ｖav12と補助ア−ク電流値Ｉｐとから、補助ア−ク期間積算入熱量Ｑta12を算出すればよい。
【０１１６】
補助ア−ク期間積算入熱量Ｑta12は、下記の式に示すとおり、補助ア−ク電流・電圧検出開始時点ｔ１から、補助ア−ク電圧平均値Ｖav12を測定して、この補助ア−ク電圧平均値Ｖav12と補助ア−ク電流値Ｉｐと補助ア−ク検出期間Ｔ12との積から算出する。
補助・主アーク期間積算入熱量Ｑta1nは、下記の式に示すとおり、検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)から算出した主アーク期間積算入熱量Ｑta3nと補助ア−ク期間積算入熱量Ｑta12との和となる。
Ｑta12＝Ｖav12・Ｉｐ・Ｔ12
Ｑta1n＝Ｑta12＋Ｑta3n
【０１２０】
［図５の説明］
図５は、主アーク期間Ｔａ中に、引き上げ不良、異常アーク現象による片溶け等によって、スタッド１８が、一時的に、溶融プールに短絡した場合の溶接電圧波形及び溶接電流波形を示す図である。
【０１２２】
主アーク期間Ｔａ中に、引き上げ不良、異常アーク現象、例えば磁気吹きによる片溶け等によってスタッド１８が、一時的に、溶融プールに短絡した場合、検出間隔ごとの短絡発生時の入熱量平均値ΔＱasが低くなるために、主アーク期間Ｔａ中に短絡が多く発生して積算入熱量Ｑtaは減少する。
【０１２４】
主ア−ク電流・電圧検出開始時点ｔ３から積算して、検出期間全体の標準入熱量Ｑstが積算入熱量Ｑtaと一致した時点又は越えた直後の時点ｔｎにおける積算入熱量Ｑtaを、数４乃至数７によって算出する。
【０１２６】
主アーク期間Ｔａ中に短絡が発生した場合の出力端子電圧Ｖｄは、検出間隔ごとの短絡発生時の出力端子電圧平均値Ｖas(Δｔ)となるので、検出期間中の溶接電圧平均値Ｖavは減少する。
また、このときの出力電流Ｉｏは、検出間隔ごとの短絡発生時の出力電流平均値Ｉas(Δｔ)となるが、溶接電源装置の出力特性が定電流特性の場合は、検出期間中の溶接電流平均値Ｉavはほとんど変化することがなく、また溶接電源装置の出力特性が垂下特性のような定電流特性でない場合は、検出期間中の溶接電流平均値Ｉavは多少増加する。
【０１３０】
［図６の説明］
図６（Ａ）は、主アーク期間Ｔａ中に微小短絡が発生した場合の出力電流Ｉｏの波形を示す溶接電流波形図であり、同図（Ｂ）は、主アーク期間Ｔａ中に短絡が発生した場合の出力端子電圧Ｖｄの波形を示す図である。
【０１３２】
上記の図６に示すように、前述した実施例では、太径スタッド溶接のように溶接時間が長くなったとき、貫通溶接のとき、横向き溶接のとき等で微小短絡が頻繁に発生しても、積算入熱量Ｑtaはほとんど減少しない。しかし、これらの微少短絡が頻繁に発生すると、溶接部の欠陥になる可能性が大きい。
【０１３４】
この場合は、検出間隔ごとの入熱量平均値ΔＱavを算出する検出間隔Δｔを、溶接部の欠陥になる可能性のある微小短絡の一回の発生時間よりも小さい数［mSec］程度に定める。
次に、正常な溶接動作が行われた場合の検出間隔ごとの入熱量平均値ΔＱavの適正値を、溶接スタッドの径及び被溶接材１４の条件及び溶接姿勢（下向き、横向き等）に応じて検出間隔ごとの入熱量標準値ΔＱstとして定める。
この予め設定した検出間隔ごとの入熱量平均値ΔＱavを、検出間隔Δｔごとに、検出間隔ごとの入熱量標準値ΔＱstと比較する。
この検出間隔ごとの入熱量平均値ΔＱavが検出間隔ごとの入熱量標準値ΔＱstよりも低下した短絡回数Ｎｓを計数して、この短絡回数Ｎｓが上記の予め設定した標準入熱許容短絡回数Ｎst以上になると溶接不良と判定する。
【０１３６】
上記の判定結果を使用して、数４乃至数１２によって算出する方法の積算入熱量Ｑtaで溶接したスタッド溶接終了時に、微小短絡回数が許容範囲を越えたことを表示したり、さらに入熱を加算したりする。
【０１４０】
［数８乃至数１２の説明］
図４（Ａ）及び（Ｂ）の右端の符号Ｖav及びＩavに示すように、検出期間中の溶接電流平均値Ｉav及び検出期間中の溶接電圧平均値Ｖavを算出し、主アーク入熱標準値設定期間Ｔ38を乗算して積算入熱量Ｑtaを算出してもよい。
【０１４２】
検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)を、検出回数１回からｎ回まで積算して、主アーク期間積算電圧値Ｖta3nを、数８によって算出する。
【数８】

検出間隔ごとの主ア−ク電流平均値Ｉav(Δt)を、検出回数１回からｎ回まで積算して、主アーク期間積算電流値Ｉta3nを、数９によって算出する。
【数９】

【０１４４】
数８によって算出した主アーク期間積算電圧値Ｖta3nを検出回数ｎで除算して、検出期間中の溶接電圧平均値Ｖavを、数１０によて算出する。
【数１０】

数９によって算出した主アーク期間積算電流値Ｉta3nを検出回数ｎで除算して、検出期間中の溶接電流の平均値Ｉavを、数１１によって算出する。
【数１１】

【０１４６】
前述した数１０によって算出した検出期間中の溶接電圧平均値Ｖavと数１１によって算出した検出期間中の溶接電流の平均値Ｉavと主アーク積算値検出期間Ｔ3nとを乗算してから、数１２によって、積算入熱量Ｑtaを算出する。
【数１２】

【０１５０】
［請求項４の実施例の説明］
請求項４の方法は、検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)から算出した主アーク期間積算入熱量Ｑta3nが、主アーク期間全体の標準入熱量Ｑst38に達した時点ｔｎで押し込み工程を開始する方法である。
以下、図２乃至図３を参照して、この方法について説明する。
（Ａ）溶接開始前に、数１乃至数３によって、正常な溶接時の主アーク期間全体の標準入熱量Ｑst38を予め設定しておく。
【０１５２】
（Ｂ）補助ア−ク電流通電開始時点ｔ０において、溶接ガン２の起動スイッチ１３を押して補助ア−ク電流Ｉｐの通電を開始するとともに、スタッド１８を被溶接材１４から引き上げて補助ア−クを発生させる。
（Ｃ）補助ア−ク期間Ｔｐが経過した主ア−ク電流通電開始時点ｔ２で、補助ア−ク電流Ｉｐから主ア−ク電流Ｉａに切り換える。
【０１５４】
（Ｄ）図３に示すように、主アーク電流・電圧検出開始時点ｔ３から、検出間隔Δｔごとに、検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)を測定する。
（Ｅ）この検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)と検出期間中の溶接電流平均値Ｉavとの積の検出間隔ごとの入熱量平均値ΔＱavを積算して主アーク期間積算入熱量Ｑta3nを、数４乃至数７のいずれかによって算出する。
【０１５６】
（Ｆ）この主アーク期間積算入熱量Ｑta3nが、予め設定した主アーク期間全体の標準入熱量Ｑst38に達した時点ｔｎで押し込み工程を開始する。
Ｑta3n＞＝Ｑst38
（Ｇ）なお、検出期間中の溶接電流平均値Ｉavは、請求項１２又は請求項１３又は請求項１４の方法で算出した値である。
【０１６０】
［請求項５の実施例の説明］
請求項５の方法は、主アーク期間積算電圧値Ｖta3nが、主アーク期間全体の標準入熱量Ｑst38から算出した検出期間全体の主アーク電圧標準値Ｖst38に達した時点ｔｎで押し込み工程を開始する方法である。
以下、図２乃至図３を参照して、この方法について説明する。
（Ａ）乃至（Ｄ）及び（Ｈ）の説明は、請求項４の実施例の説明と同じなので省略する。
【０１６２】
（Ｅ５）この検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)を積算して主アーク期間積算電圧値Ｖta3nを、数８によって算出する。
（Ｆ５）予め設定した主アーク期間全体の標準入熱量Ｑst38を検出期間中の溶接電流平均値Ｉavで除算した検出期間全体の主アーク電圧標準値Ｖst38を算出する。
Ｖst38＝Ｑst38／Ｉav
【０１６４】
（Ｇ５）この主アーク期間積算電圧値Ｖta3nが、検出期間全体の主アーク電圧標準値Ｖst38に達した時点ｔｎで押し込み工程を開始する。
Ｖta3n＞＝Ｖst38
【０１７０】
［請求項６の実施例の説明］
請求項６の方法は、検出期間全体の主アーク電圧平均値Ｖav3nから算出した主アーク期間積算入熱量Ｑta3nが、主アーク期間全体の標準入熱量Ｑst38に達した時点ｔｎで押し込み工程を開始する方法である。
以下、図２乃至図３を参照して、この方法について説明する。
（Ａ）乃至（Ｄ）及び（Ｈ）の説明は、請求項４の実施例の説明と同じなので省略する。
【０１７２】
（Ｅ６１）この検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)を積算して主アーク期間積算電圧値Ｖta3nを、数８によって算出する。
（Ｅ６２）この主アーク期間積算電圧値Ｖta3nを検出回数ｎで除算して検出期間全体の主アーク電圧平均値Ｖav3n＝Ｖta3n／ｎを、数１０によって算出する。
【０１７４】
（Ｆ６）検出期間全体の主アーク電圧平均値Ｖav3nと検出期間中の溶接電流平均値Ｉavと主アーク積算値検出期間Ｔ3nとの積の主アーク期間積算入熱量Ｑta3nを、数１２よって算出する。
（Ｆ）この主アーク期間積算入熱量Ｑta3nが、予め設定した主アーク期間全体の標準入熱量Ｑst38に達した時点ｔｎで押し込み工程を開始する。
Ｑta3n＞＝Ｑst38
【０１８０】
［請求項７の実施例の説明］
請求項７の方法は、請求項４の検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)から算出した主アーク期間積算入熱量Ｑta3nと補助ア−ク期間積算入熱量Ｑta12との和の補助・主アーク期間積算入熱量Ｑta1nが、補助・主アーク検出期間全体の標準入熱量Ｑst18に達した時点ｔｎで押し込み工程を開始する方法である。
以下、図２乃至図３を参照して、この方法について説明する。
（Ａ７）溶接開始前に、正常な溶接時の補助ア−ク期間Ｔｐ及び補助・主アーク検出期間全体の標準入熱量Ｑst18を予め設定しておく。主アーク期間全体の標準入熱量Ｑst38は、数１乃至数３によって算出する。
【０１８２】
（Ｂ）補助ア−ク電流通電開始時点ｔ０において、溶接ガン２の起動スイッチ１３を押して補助ア−ク電流Ｉｐの通電を開始するとともに、スタッド１８を被溶接材１４から引き上げて補助ア−クを発生させる。
（Ｂ７１）補助ア−ク電流・電圧検出開始時点ｔ１から、補助ア−ク電圧平均値Ｖav12を測定する。
（Ｂ７２）この補助ア−ク電圧平均値Ｖav12と補助ア−ク電流値Ｉｐと補助ア−ク検出期間Ｔ12との積の補助ア−ク期間積算入熱量Ｑta12を算出する。
Ｑta12＝Ｖav12・Ｉｐ・Ｔ12
【０１８４】
（Ｃ）補助ア−ク期間Ｔｐが経過した主ア−ク電流通電開始時点ｔ２で、補助ア−ク電流Ｉｐから主ア−ク電流Ｉａに切り換える。
（Ｄ）主アーク電流・電圧検出開始時点ｔ３から、検出間隔Δｔごとに、検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)を測定する。
【０１８６】
（Ｅ）この検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)と検出期間中の溶接電流平均値Ｉavとの積の検出間隔ごとの入熱量平均値ΔＱavを積算して主アーク期間積算入熱量Ｑta3nを、数４乃至数７のいずれかによって算出する。
（Ｆ７）補助ア−ク期間積算入熱量Ｑta12と主アーク期間積算入熱量Ｑta3nとの和の補助・主アーク期間積算入熱量Ｑta1nが、予め設定した補助・主アーク検出期間全体の標準入熱量Ｑst18に達した時点ｔｎで押し込み工程を開始する。
Ｑta1n＝Ｑta12＋Ｑta3n
Ｑta3n＞＝Ｑst18
（Ｇ）なお、検出期間中の溶接電流平均値Ｉavは、請求項１２又は請求項１３又は請求項１４の方法で算出した値である。
【０１９０】
［請求項８の実施例の説明］
請求項８の方法は、補助・主アーク検出期間全体の標準入熱量Ｑst18から補助ア−ク期間積算入熱量Ｑta12を減算して主アーク期間全体の標準入熱量Ｑst38を算出し、請求項５の主アーク期間積算電圧値Ｖta3nが、この主アーク期間全体の標準入熱量Ｑst38から算出した検出期間全体の主アーク電圧標準値Ｖst38に達した時点ｔｎで押し込み工程を開始する方法である。
以下、図２乃至図３を参照して、この方法について説明する。
（Ａ７）溶接開始前に、正常な溶接時の補助ア−ク期間Ｔｐ及び補助・主アーク検出期間全体の標準入熱量Ｑst18を予め設定しておく。主アーク期間全体の標準入熱量Ｑst38は、数１乃至数３によって算出する。
【０１９２】
（Ｂ）補助ア−ク電流通電開始時点ｔ０において、溶接ガン２の起動スイッチ１３を押して補助ア−ク電流Ｉｐの通電を開始するとともに、スタッド１８を被溶接材１４から引き上げて補助ア−クを発生させる。
（Ｂ７１）補助ア−ク電流・電圧検出開始時点ｔ１から、補助ア−ク電圧平均値Ｖav12を測定する。
【０１９４】
（Ｂ７２）この補助ア−ク電圧平均値Ｖav12と補助ア−ク電流値Ｉｐと補助ア−ク検出期間Ｔ12との積の補助ア−ク期間積算入熱量Ｑta12を算出する。
Ｑta12＝Ｖav12・Ｉｐ・Ｔ12
（Ｂ８）補助・主アーク検出期間全体の標準入熱量Ｑst18から補助ア−ク期間積算入熱量Ｑta12を減算して主ア−ク期間積算入熱量Ｑta3nを算出しておく。
Ｑta3n＝Ｑst18−Ｑta12
【０１９６】
（Ｃ）補助ア−ク期間Ｔｐが経過した主ア−ク電流通電開始時点ｔ２で、補助ア−ク電流Ｉｐから主ア−ク電流Ｉａに切り換える。
（Ｄ）主アーク電流・電圧検出開始時点ｔ３から、検出間隔Δｔごとに、検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)を測定する。
【０１９８】
（Ｅ５）この検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)を積算して主アーク期間積算電圧値Ｖta3nを、数８によって算出する。
（Ｆ８）主アーク期間積算入熱量Ｑta3nを検出期間中の溶接電流平均値Ｉavで除算した検出期間全体の主アーク電圧標準値Ｖst38を算出する。
Ｖst38＝Ｑst38／Ｉav
（Ｇ５）主アーク期間積算電圧値Ｖta3nが、検出期間全体の主アーク電圧標準値Ｖst38に達した時点ｔｎで押し込み工程を開始する。
Ｖta3n＞＝Ｖst38
【０２００】
［請求項９の実施例の説明］
請求項９の方法は、請求項６の検出期間全体の主アーク電圧平均値Ｖav3nから算出した主アーク期間積算入熱量Ｑta3nと補助ア−ク期間積算入熱量Ｑta12との和の補助・主アーク期間積算入熱量Ｑta1nが、補助・主アーク検出期間全体の標準入熱量Ｑst18に達した時点ｔｎで押し込み工程を開始する方法である。
参照して、この方法について説明する。
（Ａ７）溶接開始前に、正常な溶接時の補助ア−ク期間Ｔｐ及び補助・主アーク検出期間全体の標準入熱量Ｑst18を予め設定しておく。主アーク期間全体の標準入熱量Ｑst38は、数１乃至数３によって算出する。
【０２０２】
（Ｂ）補助ア−ク電流通電開始時点ｔ０において、溶接ガン２の起動スイッチ１３を押して補助ア−ク電流Ｉｐの通電を開始するとともに、スタッド１８を被溶接材１４から引き上げて補助ア−クを発生させる。
（Ｂ７１）補助ア−ク電流・電圧検出開始時点ｔ１から、補助ア−ク電圧平均値Ｖav12を測定する。
（Ｂ７２）この補助ア−ク電圧平均値Ｖav12と補助ア−ク電流値Ｉｐと補助ア−ク検出期間Ｔ12との積の補助ア−ク期間積算入熱量Ｑta12を算出する。
Ｑta12＝Ｖav12・Ｉｐ・Ｔ12
【０２０４】
（Ｃ）補助ア−ク期間Ｔｐが経過した主ア−ク電流通電開始時点ｔ２で、補助ア−ク電流Ｉｐから主ア−ク電流Ｉａに切り換える。
（Ｄ）主アーク電流・電圧検出開始時点ｔ３から、検出間隔Δｔごとに、検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)を測定する。
【０２０６】
（Ｅ６１）この検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)を積算して主アーク期間積算電圧値Ｖta3nを、数８によって算出する。
（Ｅ６２）この主アーク期間積算電圧値Ｖta3nを検出回数ｎで除算して検出期間全体の主アーク電圧平均値Ｖav3nを、数１０によって算出する。
【０２０８】
（Ｆ６）検出期間全体の主アーク電圧平均値Ｖav3nと検出期間中の溶接電流平均値Ｉavと主アーク積算値検出期間Ｔ3nとの積の主アーク期間積算入熱量Ｑta3nを、数１２よって算出する。
（Ｇ６）補助ア−ク期間積算入熱量Ｑta12と主アーク期間積算入熱量Ｑta3nとの和の補助・主アーク期間積算入熱量Ｑta1nが、予め設定した補助・主アーク検出期間全体の標準入熱量Ｑst18に達した時点ｔｎで押し込み工程を開始する。
Ｑta1n＞＝Ｑst18
【０２１０】
［請求項１０の実施例の説明］
請求項１０の方法は、請求項４乃至請求項９の方法に加えて、短絡回数Ｎｓが予め設定した回数以上になると溶接不良を表示する方法である。
【０２１２】
請求項１０の方法は、請求項４乃至請求項９の構成要件に加えて、つぎの３つの要件を追加している。
図６に示すように、溶接開始前に、
〓溶接部の欠陥になる可能性のある微小短絡の一回の発生時間よりも短い数［mSec］の検出間隔Δｔ及び
〓検出間隔ごとの入熱量標準値ΔＱst及び
〓正常な溶接時の主アーク期間全体の標準入熱量Ｑst38を確保する標準入熱許容短絡回数Ｎstを予め設定しておく。
【０２１４】
主アーク電流・電圧検出開始時点ｔ３から、検出間隔Δｔごとに、検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)を測定する。
検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)と検出期間中の溶接電流平均値Ｉavとの積の検出間隔ごとの入熱量平均値ΔＱavを算出する。
ΔＱav＝Ｖav(Δt)・Ｉav
この検出間隔ごとの入熱量平均値ΔＱavが、検出間隔ごとの入熱量標準値ΔＱstよりも低下した短絡回数Ｎｓを計数する。ΔＱav＜ΔＱst
この短絡回数Ｎｓが予め設定した標準入熱許容短絡回数Ｎst以上になると、溶接不良を表示する。Ｎｓ＞Ｎst
上記の検出期間中の溶接電流平均値Ｉavは、請求項１２又は請求項１３又は請求項１４の方法で算出した値である。
【０２２０】
［請求項１１の実施例の説明］
請求項１１の方法は、請求項４乃至請求項９の方法に加えて、短絡回数Ｎｓが予め設定した標準入熱許容短絡回数Ｎst以上になると予め設定した時間だけ主アーク電流Ｉａの通電時間を追加する方法である。
請求項１０の方法が、短絡回数Ｎｓが予め設定した標準入熱許容短絡回数Ｎst以上になると溶接不良を表示する方法であるのに対して、請求項１１の方法は、短絡回数Ｎｓが予め設定した標準入熱許容短絡回数Ｎst以上になると予め設定した時間だけ主アーク電流Ｉａの通電時間を追加する方法である。請求項１０の方法その他の構成は、請求項１１の方法と同じなので説明は省略する。
【０２３０】
請求項１２の方法は、請求項４乃至は請求項１１の検出期間中の溶接電流平均値Ｉavとして、定電流出力特性の溶接電源装置に設定した主ア−ク電流設定値を採用している。
【０２３１】
溶接電源装置の出力特性が定電流特性の場合、溶接電源装置に故障が発生しない限り、溶接電源装置に設定した値の検出期間中の溶接電流平均値Ｉavの電流が流れる。
したがって、請求項１２の方法は、信号検出用のリード線を接続して検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)だけを測定すればよいので、大電流の検出期間中の溶接電流平均値Ｉavを測定する溶接電流検出器が不要である。溶接電源装置に故障が発生したときは、検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)に異常が発生するので、この異常を表示させるか又は溶接電源装置の動作を停止させることもできる。
【０２３５】
請求項１３の方法は、請求項４乃至は請求項１１の検出期間中の溶接電流平均値Ｉavとして、主アーク電流・電圧検出開始時点ｔ３から後で測定した定電流出力特性の溶接電源装置から出力する主ア−ク電流測定値を採用している。
【０２３６】
溶接電源装置の出力特性が定電流特性の場合に、出力電流が略一定に維持される。したがって、請求項１３の方法は、検出間隔Δｔごとに、検出間隔ごとの主ア−ク電流平均値Ｉav(Δt)を測定する必要がなく、主アーク安定後に検出期間中の溶接電流平均値Ｉavを少なくとも１回測定すればよいので、回路が簡単になる。
【０２４０】
請求項１４の方法は、請求項４乃至は請求項１１の検出期間中の溶接電流平均値Ｉavとして、主アーク電流・電圧検出開始時点ｔ３から、検出間隔Δｔごとに算出した検出間隔ごとの主ア−ク電流平均値Ｉav(Δt)を採用している。
【０２４１】
この請求項１４の方法は、溶接電源装置の出力特性が定電流特性でない場合であっても、検出間隔Δｔごとに、検出間隔ごとの主ア−ク電流平均値Ｉav(Δt)及び検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)を測定して主アーク期間積算入熱量Ｑta3nを算出することによって、小容量のエンジン発電機等の溶接電源装置に供給する容量が小さい電源装置を用いて、大電流を必要とする太径のスタッドを溶接する場合等で、溶接電源の入力電力の不足によって溶接電源の出力電圧及び出力電流が低下する場合でも、良好な溶接結果を得ることができる。
【０２４５】
請求項１５の方法は、請求項７又は請求項８又は請求項９の補助ア−ク電流値Ｉｐとして、定電流出力特性の溶接電源装置に設定した補助ア−ク電流設定値を採用している。
【０２４６】
溶接電源装置の出力特性が定電流特性の場合に、溶接電源装置に故障が発生しない限り、溶接電源装置に設定した値の補助ア−ク電流値Ｉｐが流れる。したがって、請求項１５の方法は、請求項７又は請求項８又は請求項９の方法において、請求項１２の方法と同様に、信号検出用のリード線を接続して補助ア−ク電圧平均値Ｖav12だけを測定すればよいので、補助ア−ク電流値Ｉｐを測定する溶接電流検出器が不要である。溶接電源装置に故障が発生したときは、検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)に異常が発生するので、この異常を表示させるか又は溶接電源装置の動作を停止させることもできる。
【０２５０】
請求項１６の方法は、請求項７又は請求項８又は請求項９の補助ア−ク電流値Ｉｐとして、補助ア−ク電流・電圧検出開始時点ｔ１から測定した定電流出力特性の溶接電源装置から出力する補助ア−ク電流測定値を採用している。
【０２５１】
溶接電源装置の出力特性が定電流特性の場合に、出力電流が略一定に維持される。したがって、請求項１６の方法は、請求項７又は請求項８又は請求項９の方法の方法において請求項１３の方法と同様に、検出間隔Δｔごとに、補助ア−ク電流平均値Ｉav(Δt)を測定する必要がなく、補助ア−ク安定後に補助ア−ク電流値Ｉｐを少なくとも１回測定すればよいので、回路が簡単になる。
【０２７０】
［図７の説明］
図７は、本発明の方法をディジタル制御で実施するスタッド溶接装置の実施例を示す図である。
【０２７２】
同図のスタッド溶接装置は、溶接電源装置１と溶接ガン２と溶接制御装置３とから形成される。
この溶接電源装置１は、溶接ガン２に補助ア−ク電流Ｉｐと主ア−ク電流Ｉａとから成る溶接電流を出力し、後述する溶接制御装置３から出力されるアナログ信号に応じて、出力電流Ｉｏを制御する電流指令出力回路５と、その電流指令に基づいて溶接電流を制御するサイリスタ等の半導体スイッチング素子からなる溶接電流出力回路１５と、２次ケーブル１７を通ってスタッド１８に出力される出力電流Ｉｏを検出して溶接電流検出信号Ｉｃを出力する溶接電流検出回路ＩＣと、出力端子電圧値Ｖｄを検出して溶接電圧検出信号Ｖｃを出力する溶接電圧検出回路ＶＣとから形成される。
【０２７４】
溶接制御装置３は、溶接電流検出信号Ｉｃをディジタル溶接電流検出信号Ｉddに変換して演算処理回路ＣＰＵに出力するＡ／Ｄ変換回路７と、溶接電圧検出信号Ｖｃをディジタル溶接電圧検出信号Ｖddに変換して演算処理回路ＣＰＵに出力するＡ／Ｄ変換回路８と、ディジタル溶接電流検出信号Ｉddとディジタル溶接電圧検出信号Ｖddとを入力して後述するディジタル出力信号を出力する演算処理回路ＣＰＵと、演算処理回路ＣＰＵのディジタル出力信号Ｉodをアナログ出力信号Ｉoaに変換して電流指令出力回路５に出力するＤ／Ａ変換回路６と、検出値、演算値、溶接結果のデータ等を記憶する記憶回路１１と、これらを表示するディジタルパネル等の表示回路１２とからなる。このＤ／Ａ変換回路６、Ａ／Ｄ変換回路７及びＡ／Ｄ変換回路８は演算処理回路ＣＰＵに内蔵してもよい。
【０２８０】
［図８の説明］
図８は、本発明の方法をアナログ制御で実施するスタッド溶接装置の実施例を示す図である。
【０２８２】
また、この図８の実施例では、図７の実施例のようにマイクロコンピュータを用いた複雑な回路を構成しなくても、電流、電圧検出信号を積分器、乗除算器等のアナログ回路で構成した演算回路を用いて平均入熱を算出し表示することもできる。また、標準値（アナログ回路で構成）と比較して許容範囲からはずれた場合に、異常ランプ、ブザー等で警報を発する。
【０２８４】
まず、起動スイッチ起動スイッチ１３を押すと、溶接シ−ケンス制御回路２１に予め設定した補助ア−ク電流が溶接電流出力回路１５から出力し、スタッド１８が引き上げられ、補助ア−クが発生し、溶接シ−ケンス制御回路２１に予め設定されているパイロット時間経過後、主ア−ク電流に移行する。この補助ア−ク電流から溶接電流移行するとき計測時間設定回路２８からリセット信号が出力され、平滑回路２２、平滑回路２３はリセットされるて、新たに溶接電流検出回路ＩＣ、溶接電圧検出回路ＶＣで検出される溶接電流及び溶接電圧の時間積分を開始する。また、このリセット信号は、補助ア−ク電流出力開始と同期させてもよい。
【０２８６】
次に溶接シ−ケンス制御回路２１に予め設定されている溶接時間経過後に、溶接ガン２によりスタッド１８が押し込まれる。この押し込み動作の開始を計測時間設定回路２８が検出して、平滑回路２２、平滑回路２３にホールド信号を出力する。このホールド信号によって、リセット信号から積分されてきた値を、平滑回路２２、平滑回路２３にホールドする。このホールドされた値は、時間積分された値であるので、それぞれを乗算回路２４によって乗算し、除算回路２９を用いて溶接シ−ケンス制御回路２１で予め設定されている溶接時間（アナログ値）で除算することによって、平均入熱量を算出して、表示回路１２に表示する。また、この算出した平均入熱量を標準入熱設定回路２５で予め設定されている平均入熱の標準値と比較回路２６によって比較し、許容範囲を超えた場合は、警報器２７によって警報する。
【１０００】
【発明の効果】
本発明の共通の効果は次のとおりである。
本発明の方法は、積算入熱量Ｑtaと検出期間全体の標準入熱量Ｑstとを検出するごとに比較し、積算入熱量Ｑtaが検出期間全体の標準入熱量Ｑstに達した時点ｔｎで押し込み工程を開始するので、短絡が発生しても、適切な入熱量を確保することができ、良好な溶接品質を得ることができる。
また、本発明は、良好な溶接品質を得るとともに、各スタッドの溶接ごとに得られたデータは各スタッドの溶接ごとに記憶させておき、このデータを演算処理装置４又は外部記憶装置（例えばメモリカード、フロッピーディスク等）又は直接にパソコン等に出力することによって、パソコン等で各スタッドの溶接作業の溶接品質を容易に確認することができる。また、この各スタッドの溶接ごとに得られたデ−タを集計して統計処理等を行って溶接品質の管理を行うことができる。
【１００４】
請求項４乃至請求項６の方法は、検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)又は検出期間全体の主アーク電圧平均値Ｖav3n又はこの電圧値から算出した主アーク期間積算入熱量Ｑta3nが、主アーク期間全体の標準入熱量Ｑst38又はこの入熱量から算出した検出期間全体の主アーク電圧標準値Ｖst38に達した時点ｔｎで押し込み工程を開始するので、短絡が発生しても、適切な入熱量を確保することができ、良好な溶接品質を得ることができる。
【１００７】
請求項７乃至請求項９の方法は、請求項４乃至請求項６のそれぞれの方法の効果に加えて、補助ア−ク期間Ｔｐの補助ア−ク電流・電圧検出開始時点ｔ１から補助ア−ク電流値Ｉｐを測定するとともに、補助ア−ク電圧平均値Ｖav12を測定して補助ア−ク期間積算入熱量Ｑta12を算出するので、入熱の測定精度が向上する。
【１０１０】
請求項１０の方法は、請求項４乃至請求項９のそれぞれの方法の効果に加えて、溶接部の欠陥になる可能性のある微小短絡の一回の発生時間よりも短い数［mSec］の検出間隔Δｔごとに算出した検出間隔ごとの入熱量平均値ΔＱavが、検出間隔ごとの入熱量標準値ΔＱstよりも低下する短絡回数Ｎｓを計数して、この短絡回数Ｎｓが予め設定した標準入熱許容短絡回数Ｎst以上になると、溶接不良を表示する効果を有している。
【１０１１】
請求項１１の方法は、請求項４乃至請求項９のそれぞれの方法の効果に加えて、請求項１０と同様に計数した短絡回数Ｎｓが、予め設定した標準入熱許容短絡回数Ｎst以上になると、予め設定した時間だけ主アーク電流Ｉａの通電時間を追加することによって、溶接不良を防止する効果を有している。
【１０１２】
請求項１２の方法は、信号検出用のリード線を接続して検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)だけを測定すればよいので、大電流の検出期間中の溶接電流平均値Ｉavを測定する溶接電流検出器が不要である。溶接電源装置に故障が発生したときは、検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)に異常が発生するので、この異常を表示させるか又は溶接電源装置の動作を停止させることもできる。
【１０１３】
請求項１３の方法は、検出間隔Δｔごとに、検出間隔ごとの主ア−ク電流平均値Ｉav(Δt)を測定する必要がなく、主アーク安定後に検出期間中の溶接電流平均値Ｉavを少なくとも１回測定すればよいので、回路が簡単になる。
【１０１４】
請求項１４の方法は、溶接電源装置の出力特性が定電流特性でない場合であっても、検出間隔Δｔごとに、検出間隔ごとの主ア−ク電流平均値Ｉav(Δt)及び検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)を測定して主アーク期間積算入熱量Ｑta3nを算出することによって、小容量のエンジン発電機等の溶接電源装置に供給する容量が小さい電源装置を用いて、大電流を必要とする太径のスタッドを溶接する場合等で、溶接電源の入力電力の不足によって溶接電源の出力電圧及び出力電流が低下する場合でも、良好な溶接結果を得ることができる。
【１０１５】
請求項１５の方法は、請求項７又は請求項８又は請求項９の方法において、請求項１２の方法と同様に、信号検出用のリード線を接続して補助ア−ク電圧平均値Ｖav12だけを測定すればよいので、補助ア−ク電流値Ｉｐを測定する溶接電流検出器が不要である。溶接電源装置に故障が発生したときは、検出間隔ごとの主ア−ク電圧平均値Ｖav(Δt)に異常が発生するので、この異常を表示させるか又は溶接電源装置の動作を停止させることもできる。
【１０１６】
請求項１６の方法は、請求項７又は請求項８又は請求項９の方法の方法において請求項１３の方法と同様に、検出間隔Δｔごとに、補助ア−ク電流平均値Ｉav(Δt)を測定する必要がなく、補助ア−ク安定後に補助ア−ク電流値Ｉｐを少なくとも１回測定すればよいので、回路が簡単になる。
【図面の簡単な説明】
【図１】図１は、溶接電圧、溶接電流及び主アーク電流期間を監視する従来方法を実施するスタッド溶接装置のブロック図である。
【図２】図２（Ａ）は、正常な溶接時の主アーク期間全体の出力電流Ｉｏから検出期間中の溶接電流平均値Ｉavを算出する説明図であり、同図（Ｂ）は、正常な溶接時の主アーク期間全体の出力端子電圧Ｖｄから検出間隔Δｔごとに検出間隔ごとの主ア−ク電圧平均値Ｖav(Δｔ)を算出する説明図であり、同図（Ｃ）は正常な溶接時のスタッド引き上げ距離を示す図である。
【図３】図３（Ａ）は、各溶接中の主アーク期間全体の出力電流Ｉｏから検出期間中の溶接電流平均値Ｉavを算出する説明図であり、同図（Ｂ）は、各溶接中の主アーク期間全体の出力端子電圧Ｖｄから検出間隔Δｔごとに検出間隔ごとの主ア−ク電圧平均値Ｖav(Δｔ)を算出する説明図である。
【図４】図４（Ａ）は、各溶接中の主アーク期間全体の出力電流Ｉｏから検出間隔ごとの主ア−ク電流平均値Ｉav(Δt)を算出する説明図であり、同図（Ｂ）は、各溶接中の主アーク期間全体の出力端子電圧Ｖｄから検出間隔Δｔごとに検出間隔ごとの主ア−ク電圧平均値Ｖav(Δｔ)を算出する説明図である。
【図５】図５は、主アーク期間Ｔａ中に、引き上げ不良、異常アーク現象による片溶け等によって、スタッド１８が、一時的に、溶融プールに短絡した場合の溶接電圧波形及び溶接電流波形を示す図である。
【図６】図６（Ａ）は、主アーク期間Ｔａ中に微小短絡が発生した場合の出力電流Ｉｏの波形を示す溶接電流波形図であり、同図（Ｂ）は、主アーク期間Ｔａ中に短絡が発生した場合の出力端子電圧Ｖｄの波形を示す図である。
【図７】図７は、本発明の方法をディジタル制御で実施するスタッド溶接装置の実施例を示す図である。
【図８】図８は、本発明の方法をアナログ制御で実施するスタッド溶接装置の実施例を示す図である。
【符号の説明】
１…溶接電源装置
２…溶接ガン
３…溶接制御装置
４…演算処理回路
５…電流指令出力回路
６…Ｄ／Ａ変換回路
７、８…Ａ／Ｄ変換回路
１１…記憶回路
１２…表示回路
１３…起動スイッチ
１４…被溶接材
１５…溶接電流出力回路
１６…制御ケーブル
１７…２次ケーブル
１８…スタッド
２０…入熱演算回路
２１…溶接シ−ケンス制御回路
２２、２３…平滑回路
２４…乗算回路
２５…標準入熱設定回路
２６…比較回路
２７…警報器
２８…計測時間設定回路
２９…除算回路
３０…三相電源
３６、４４…フィルタ回路
３７、４５…増幅回路
３９…基準溶接電圧設定回路
４０…比較器
４１…警報器
４２、４３…接続線
ＣＰＵ…演算処理回路
Ｉ1(t)…時刻ｔの溶接電流値
Ｉａ…主ア−ク電流／主ア−ク電流値
ＩＣ…溶接電流検出回路
Ｉｃ…溶接電流検出信号
Ｉｏ…出力電流／出力電流値
Ｉｐ…補助ア−ク電流／補助ア−ク電流値
Ｉｓ…短絡電流
Ｉas(Δｔ)…検出間隔ごとの短絡発生時の出力電流平均値
Ｉav…検出期間中の溶接電流平均値
Ｉav(Δｔ)…検出間隔ごとの主ア−ク電流平均値
Ｉta3n…主アーク期間積算電流値
Ｎｓ…短絡回数
Ｎst…標準入熱許容短絡回数
ｎ …（検出間隔Δｔの）検出回数
Ｑｒ…所要の入熱
Ｑst…検出期間全体の標準入熱量
Ｑta…積算入熱量
Ｑta12…補助ア−ク期間積算入熱量
Ｑst18…（予め設定した）補助・主アーク検出期間全体の標準入熱量
Ｑst38…（予め設定した）主アーク期間全体の標準入熱量
Ｑta1n…補助・主アーク期間積算入熱量
Ｑta3n…主アーク期間積算入熱量
ΔＱas…検出間隔ごとの短絡発生時の入熱量平均値
ΔＱav…検出間隔ごとの入熱量平均値
ΔＱst…検出間隔ごとの入熱量標準値
Ｔ12…補助ア−ク検出期間
Ｔ38…主アーク入熱標準値設定期間
Ｔ3n…主アーク積算値検出期間
ｔ０…補助ア−ク電流通電開始時点
ｔ１…補助ア−ク電流・電圧検出開始時点
ｔ２…主ア−ク電流通電開始時点
ｔ３…主ア−ク電流・電圧検出開始時点
ｔ８…主ア−ク電流・電圧検出終了時点
ｔ９…主ア−ク電流通電終了時点／短絡電流通電開始時点
ｔ10…出力電流通電終了時点／短絡電流通電終了時点
ｔ01乃至ｔ0n…各検出間隔Δｔの検出開始時点
Ｔａ…主アーク期間
Ｔｐ…補助ア−ク期間
Ｔｓ…短絡期間
ｔｎ…積算入熱量Ｑtaが予め設定した検出期間全体の標準入熱量Ｑstに達した時点
又は主アーク期間積算電圧値Ｖta3nが予め設定した検出期間全体の主アーク電圧標準値Ｖst38に達した時点
Δｔ…検出間隔
Δｔ＝１乃至Δｔ＝ｎ…１回目乃至Ｎ回目の検出
Δｔ・ｎ…主アーク検出期間
Ｖ1(t)…時刻ｔの溶接電圧値
Ｖav…検出期間中の溶接電圧平均値
Ｖav12…補助ア−ク電圧平均値
Ｖas(Δｔ)…検出間隔ごとの短絡発生時の出力端子電圧平均値
Ｖav(Δｔ)…検出間隔ごとの主ア−ク電圧平均値
ＶＣ…溶接電圧検出回路
Ｖｃ…溶接電圧検出信号
Ｖｄ…出力端子電圧／出力端子電圧値
Ｖｅ…適正溶接電圧平均値
Ｖst38…検出期間全体の主アーク電圧標準値
Ｖav3n…検出期間全体の主アーク電圧平均値
Ｖta3n…主アーク期間積算電圧値
ΔＶｅ…適正溶接電圧範囲の許容値[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control method for integrating the heat input during the pull-up period of stud welding and starting pushing.
[0002]
[Prior art]
In stud welding, in order to secure the welding quality by pulling up the stud from the work piece and then pushing the stud into the work piece by a predetermined pushing amount, It is important to obtain Qr (referred to as required heat input). If the welding conditions such as heat input are not appropriate and the required heat input Qr cannot be obtained, for example, if the welding current value is lower than the appropriate value, if the lifting distance is short, or if the welding posture is poor During the pulling up period, the molten surface of the stud comes into contact with the molten pool of the material to be welded and a short circuit occurs.
When this short circuit occurs, the proper arc voltage value Va does not continue sufficiently, resulting in insufficient heat input, and it becomes impossible to push in a required push amount during pushing, resulting in poor welding.
[0004]
Therefore, in order to determine whether the required heat input Qr is obtained and the quality of welding is ensured, in recent years, the following method has been proposed.
[Prior art 1]
The technique disclosed in Japanese Patent Application Laid-Open No. 61-242766 uses an electromagnetic oscillograph to measure and record a welding current and a welding voltage, in particular, a short-circuit current during indentation at the end of welding, and performs quality judgment.
[Prior Art 2]
Japanese Patent Application Laid-Open No. 1-154877 detects the movement amount of the stud and the waveforms of the gun coil voltage and the welding current, and the peak of the surge current when the push start point, the output stop point of the gun coil voltage, and the welding current is short-circuited. The success or failure of the welding result has been determined from the temporal positional relationship between any two of the three points.
[0006]
[Prior Art 3]
The technique of Japanese Examined Patent Publication No. 3-72388 detects the stud moving amount (pushing amount) and compares the moving amount in the stud pushing process with a standard value to determine the quality.
[Prior Art 4]
The technology disclosed in Japanese Patent Laid-Open No. 7-144275 detects the arc voltage and the moving state of the stud, measures the arc voltage within 0.3 seconds before the start of indentation, and fuses when a short circuit occurs and the welding voltage decreases. Defects are judged.
[0008]
[Prior Art 5]
In the technique of Japanese Patent Application Publication No. 58-500209, a microprocessor is used to control the welding current to calculate each of the welding current average value, welding voltage average value, and welding current energizing time, and multiply these three values. The amount of heat input is calculated and the welding current average value, welding voltage average value, welding current energization time, and heat input amount are stored and displayed.
Further, at the end of the main arc period Ta, if the set value of the welding current is compared with the actual value and is less than the set value, the main arc period Ta is extended to control the required heat input Qr. ing.
[0010]
[Prior Art 6]
In the technique disclosed in Japanese Patent Application Laid-Open No. 62-296966, an arc voltage value Va in an auxiliary arc (hereinafter referred to as auxiliary arc) period Tp is detected and compared with a preset reference voltage. If the surface of the welded material is contaminated with grease, etc., the amount of energy required to burn the pollutant on the surface of the welded material by increasing the welding current value or the welding voltage value to be energized or both Supply.
In addition, the amount of energy required to bake contaminants on the surface of the material to be welded differs for each welding, but in this prior art 6, the amount of energy required to bake contaminants on the surface of the material to be welded increases. Even so, the heat input supplied during the main arc period Ta does not decrease below the preset required heat input Qr.
[0030]
[Explanation of FIG. 1]
FIG. 1 is a block diagram of a stud welding apparatus that implements a conventional method created by the applicant to monitor welding voltage, welding current, and main arc current duration in accordance with the prior art described above.
The figure shows a welding power source 1 having a substantially constant current characteristic, which is constituted by a thyristor or the like with a three-phase power source 30 as an input, a welding gun 2, a “−” terminal of the output terminal of the welding power source 1, and the welding gun 2. A connection cable for connecting the secondary cable 17 connected between the two, the welded material 14 such as a steel structure for welding the stud, and the “+” terminal of the output terminal of the welding power source 1 and the welded material 14. It is a block diagram of the stud welding apparatus formed with 42, 43 grade | etc.,.
[0032]
In the figure, the output terminal voltage Vd detected by the welding voltage detection circuit VC connected to the output terminal of the welding power source apparatus 1 is averaged by the filter circuit 36, amplified by the amplification circuit 37, and displayed by the display circuit 12. .
The reference welding voltage setting circuit 39 sets an appropriate welding voltage average value Ve when an appropriate welding voltage is obtained.
The output signal of the amplification circuit 37 and the appropriate welding voltage average value Ve are compared by the comparator 40. When the absolute value of the difference is outside the appropriate welding voltage range allowable value ΔVe, the alarm device 41 is activated. Alarm.
[0034]
Furthermore, in the welding power source apparatus 1, the welding current detection circuit IC detects the output current Io output to the stud 18 through the secondary cable 17, and outputs the welding current detection signal Ic. The welding current detection signal Ic is averaged by the filter circuit 44, amplified by the amplifier circuit 45, and displayed by the display circuit 12.
In the welding power source device 1 described above, in order to monitor the required heat input Qr during the pulling period, the output terminal voltage value Vd, the output current value Io, and the main arc current period Ta of the welding power source device during the pulling period are displayed. Displayed on the circuit 12.
[0040]
[Problems to be solved by the invention]
In the prior art 1 to the prior art 4 described above, the quality determination is performed by paying attention to the stud push-in time. In these methods, even if the arc is normally started, if a short circuit occurs in the first half of the main arc period Ta, sufficient heat input can be obtained if the short circuit does not occur in the second half of the main arc period Ta. However, it is difficult to find the welding defect by the above method. Similarly, when the arc start is delayed and the arc generation net time during the main arc period Ta is shortened, a sufficient heat input cannot be obtained, resulting in poor welding. It was difficult to find a defect.
[0041]
Further, the above-described conventional techniques 1 to 5 have the following problems.
When through welding is frequently performed at a construction site (when a stud is welded to a steel frame from a deck plate laid on a steel frame), there is a gap (clearance) between the deck plate and the material to be welded (such as a steel frame). The measured lift amount is the distance from the position on the deck plate to the lifted position. This distance is longer than the distance from the work piece (steel frame or the like) by the clearance and the thickness of the deck plate.
[0042]
The clearance is generally 1 to 2 mm, but it can occur frequently more than that. When this clearance is long, the distance between the raised stud tip and the surface of the work piece (steel frame, etc.) is longer than the preset lifting amount, so the arc length becomes long and the arc becomes unstable. Therefore, sufficient heat input cannot be obtained. Further, the pushing amount from the time when the stud comes into contact with the material to be welded is actually shorter than the set pushing amount by the clearance and the thickness of the deck plate. Therefore, when the clearance becomes long, the pushing becomes insufficient.
[0043]
Moreover, in the method of the prior art 4, since the movement amount of the welding gun movable part (chuck side) is detected, for example, if the chuck for fixing the stud to the welding gun is loose, an auxiliary arc is generated. In addition, when the stud is pulled up to a preset lifting position at the same time as the auxiliary arc current is supplied, a short circuit occurs because the stud does not slip and cannot be pulled up by the set value.
[0044]
In addition, when welding occurs momentarily at the arc start and the generation of the arc is delayed, the chuck and the stud slip when the stud is pulled up. Even if such slippage occurs, the method for detecting the amount of pushing movement described above cannot detect the position of the stud accurately, so that even if a welding failure occurs, it is possible to find a welding failure. Have difficulty.
[0045]
In the method of the prior art 5, since the amount of energy is calculated at the end of the welding cycle, the amount of energy cannot be controlled even if the amount of energy is found to be excessive at the end.
[0046]
In the method of the prior art 6, since the heat input during the main arc period Ta is not monitored, if the arc is unstable and a short circuit occurs during the main arc period, the required heat input Qr cannot be obtained. In particular, short-circuiting is likely to occur during welding, such as through welding, resulting in insufficient heat input.
[0048]
Therefore, the conventional techniques 1 to 6 described above cannot accurately supply the required heat input Qr.
[0051]
[Means for Solving the Problems]
The present invention relates to a stud welding in which a stud is pulled up from a workpiece to be welded and an arc is generated, and then the stud is pushed into the workpiece by a predetermined pushing amount and welded. Set the standard heat input for the entire period in advance, switch from the auxiliary arc current to the main arc current, and from the main arc current / voltage detection start point, Predetermined For each detection interval, The main arc voltage average value at each detection interval and the main arc current average value at each detection interval are calculated. , The main arc period integrated voltage value is calculated by integrating the main arc voltage average value of each detection interval, the main arc period integrated current value is calculated by integrating the main arc current average value of each detection interval, Dividing the main arc period integrated current value by the main arc integrated value detection period to calculate the welding current average value, When the main arc period integrated voltage value reaches the value of the main arc voltage standard value for the entire detection period obtained by dividing the standard heat input for the entire set main arc period by the calculated welding current average value, the pushing step This is a heat input integrated push-in control method for stud welding that starts the process.
[0052]
According to a second aspect of the present invention, in the stud welding in which the stud is pulled up from the workpiece to be welded and an arc is generated, and then the stud is pushed into the workpiece by a predetermined pushing amount and welded. Set the standard heat input for the entire main arc period in advance, switch from the auxiliary arc current to the main arc current, and from the start of main arc current / voltage detection, Predetermined Each detection interval Main arc voltage average value of detection interval and main arc current average value of each detection interval To calculate A main arc period integrated voltage value is calculated by integrating the main arc voltage average value at each detection interval, and the main arc period integrated voltage value is divided by the main arc integrated value detection period to obtain a welding voltage for the entire detection period. An average value is calculated, a main arc current average value at each detection interval is integrated to calculate a main arc period integrated current value, and the main arc period integrated current value is divided by the main arc integrated value detection period. Calculating the welding current average value over the entire detection period, and calculating the main arc period integrated heat input by the product of the welding voltage average value, the welding current average value and the main arc integrated value detection period, It is a heat input integrated push-in control method of stud welding that starts a push-in process when the main arc period accumulated heat input reaches the standard heat input.
[0070]
DETAILED DESCRIPTION OF THE INVENTION
According to the stud welding integrated heat input push-in control method of the present invention, the main arc period integrated heat input Qta3n calculated from the main arc voltage average value Vav (Δt) for each detection interval described in claim 4 is the main arc period. This is a method of starting the pushing step at the time tn when the entire standard heat input amount Qst38 is reached, and is as follows.
(A) Before the start of welding, as shown in FIG. 2, the standard heat input amount Qst38 for the entire main arc period during normal welding is set in advance using Equations 1 to 3.
(B) At the start time t0 of the auxiliary arc current energization, the start-up switch 13 of the welding gun 2 is pushed to start energization of the auxiliary arc current Ip, and the stud 18 is pulled up from the work piece 14 to assist the auxiliary arc. Is generated.
(C) The auxiliary arc current Ip is switched to the main arc current Ia at the main arc current energization start time t2 when the auxiliary arc period Tp has elapsed.
(D) As shown in FIG. 3, from the main arc current / voltage detection start time t3, the main arc current average value Iav (Δt) for each detection interval and the main arc for each detection interval for each detection interval Δt. The average voltage Vav (Δt) is measured.
(E) Detection of the product of the main arc voltage average value Vav (Δt) for each detection interval and the welding current average value Iav during the detection period or the main arc current average value Iav (Δt) for each detection interval The heat input average value ΔQav for each interval is integrated to calculate the main arc period integrated heat input Qta3n.
(F) The pushing process is started at time tn when this main arc period integrated heat input Qta3n reaches the standard heat input Qst38 for the entire main arc period set in advance.
[0071]
【Example】
In the stud welding, the start switch 13 of the welding gun 2 is pushed to start energization of the auxiliary arc current Ip, and the stud 18 is pulled up from the workpiece 14 to generate the auxiliary arc.
Next, when the filter auxiliary arc period Tp elapses, the auxiliary arc current Ip is switched to the main arc current Ia, and after the preset main arc period Ta elapses, the arc generating stud is The welding material is pushed into a short circuit with the welding material, the short-circuit current Is is applied for a preset short-circuit period Ts, the welding current is cut off, and the welding is terminated.
[0072]
[Explanation of FIG. 2]
FIG. 2 (A) is an explanatory diagram for calculating the welding current average value Iav during the detection period from the output current Io of the entire main arc period during normal welding, and FIG. 2 (B) is a diagram during normal welding. It is explanatory drawing which calculates the main arc voltage average value Vav ((DELTA) t) for every detection interval for every detection interval (DELTA) t from the output terminal voltage Vd of the whole main arc period, The figure (C) is a stud at the time of normal welding It is a figure which shows the raising distance.
[0074]
As shown in FIG. 5A, at the start time t0 of the auxiliary arc current energization, the start switch 13 is pushed to start energization of the auxiliary arc current Ip, and the stud 18 is pulled up from the workpiece 14 to assist. Generate an arc.
[0076]
From this auxiliary arc current energization start time t0 or a main arc current energization start time t2 described later, a welding voltage value V1 at each time t is detected by a welding current detection circuit IC and a welding voltage detection circuit VC shown in FIG. (t) and the welding current value I1 (t) at each time t are detected at a preset detection interval Δt, and the main arc voltage average value Vav (Δt) for each detection interval for each detection interval Δt. And the main arc current average value Iav (Δt) is calculated.
[0078]
Next, the auxiliary arc current Ip is switched to the main arc current Ia at the main arc current energization start time t2. During the main arc heat input standard value setting period T38 from the main arc current / voltage detection start time t3 immediately after the main arc current energization start time t2 to the main arc current / voltage detection end time t8, The welding voltage value V1 (t) at time t is detected, and the main arc voltage average value Vav (Δt) for each detection interval when no short circuit occurs is calculated. Similarly, the welding current value I1 (t) at each time t is detected, and the main arc current average value Iav (Δt) for each detection interval when no short circuit occurs is calculated.
[0080]
[Explanation of Equation 1]
From the main arc current / voltage detection start time t3 to the main arc current / voltage detection end time t8, the main arc voltage average value Vav (Δt) for each detection interval and the detection interval Δt The main arc current average value Iav (Δt) for each detection interval is calculated, and the heat input average value ΔQav for each detection interval is calculated by Equation (1).
[Expression 1]

[0081]
Since the total heat input when the normal welding operation is performed is substantially constant, the total heat input when the normal welding operation is performed is determined based on the diameter of the welding stud, the condition of the workpiece 14 and the welding posture ( The standard heat input Qst for the entire detection period selected according to the downward, horizontal, etc.).
[0082]
[Explanation of Equation 2]
Hereinafter, as shown in FIGS. 2A and 2B, the entire detection period during normal welding from the main arc current / voltage detection start time t3 to the main arc current / voltage detection end time t8 is as follows. An expression for calculating the standard heat input Qst will be described.
Using the first expression on the right side of Equation 2, the heat input average value ΔQav for each detection interval is integrated from the main arc current / voltage detection start time t3 to the main arc current / voltage detection end time t8 to detect the detection period. The overall standard heat input Qst is calculated.
[Expression 2]

[0084]
[Explanation of Equation 3]
As shown in FIGS. 2A and 2B, the detection start time point of the detection interval Δt of the main arc current / voltage detection start time point t3 is t01, and the main arc current / voltage detection end time point. The detection start time of the detection interval Δt at t8 is t0n. Accordingly, the standard heat input amount Qst of the entire detection period from the detection start time t01 of the first detection interval Δt to the detection start time t0n of the nth detection interval Δt is calculated by the second equation on the right side of Equation 2. May be.
[0086]
Further, instead of calculating the standard heat input Qst for the entire detection period by the above equation 2, the main arc current / voltage detection end time is calculated from the first detection interval Δt of the main arc current / voltage detection start time t3. The standard heat input Qst for the entire detection period up to the detection interval Δt of the detection number n8 at t8 may be calculated by Equation 3.
[Equation 3]

[0090]
[Explanation of FIG. 3]
FIG. 3A is an explanatory diagram for calculating the welding current average value Iav during the detection period from the output current Io of the entire main arc period during each welding, and FIG. 3B shows the main arc during each welding. It is explanatory drawing which calculates the main arc voltage average value Vav ((DELTA) t) for every detection interval for every detection interval (DELTA) t from the output terminal voltage Vd of the whole period.
[0092]
In the case where a substantially constant current control type power supply device using a semiconductor switching element such as a thyristor is used as the welding power supply device 1 described with reference to FIG. 1, the main arc current energization start time t2 to the short-circuit current energization end time t10 A constant current with the output current Io controlled to be substantially constant flows.
[0094]
When the push-in operation is started and short-circuited at the main arc current energization end time, that is, at the short-circuit current energization start time t9, as shown in FIG. This steep increase in current is in a range that can be ignored compared to the average value of the main arc current Ia. Therefore, since the output current Io during the main arc period Ta is substantially constant during both the arc and the momentary short-circuit, the main arc current average value Iav (Δt) for each detection interval is not measured and the output current Io is detected during the detection period. Only the welding voltage average value Vav may be measured.
[0095]
Next, with reference to FIGS. 3A and 3B, from the main arc current / voltage detection start time point t3, the main arc current / voltage detection end that has reached the standard heat input Qst for the entire detection period. An expression for calculating the integrated heat input amount Qta that does not cause a short circuit until time tn will be described.
[0096]
[Explanation of Equation 4]
From the main arc current / voltage detection start time t3 to the main arc current / voltage detection end time tn, the heat input average value ΔQav for each detection interval is integrated by the first expression on the right side of Equation 4, The integrated heat input Qta is calculated.
[Expression 4]

[0098]
The detection start time of the detection interval Δt of the main arc current / voltage detection start time t3 is t01, and the detection start time of the detection interval Δt of the main arc current / voltage detection end time tn is t0n. Therefore, the integrated heat input amount Qta from the detection start time t01 of the first detection interval Δt to the detection start time t0n of the detection interval Δt of the number of detections may be calculated by the second equation on the right side of Equation 4. .
[0100]
[Explanation of Equation 5]
Further, instead of calculating the integrated heat input amount Qta by the above equation 4, the number of detections of the main arc current / voltage detection end time tn from the first detection interval Δt at the main arc current / voltage detection start time t3. The integrated heat input Qta up to the n-th detection interval Δt may be calculated by Equation 5.
[Equation 5]

[0101]
[Explanation of FIG. 4]
FIG. 4A is an explanatory diagram for calculating the main arc current average value Iav (Δt) for each detection interval from the output current Io of the entire main arc period during each welding, and FIG. It is explanatory drawing which calculates the main arc voltage average value Vav ((DELTA) t) for every detection interval for every detection interval (DELTA) t from the output terminal voltage Vd of the whole main arc period in each welding.
[0102]
Next, referring to FIGS. 4A and 4B, from the main arc current / voltage detection start time point t3, the main arc current / voltage detection ends when it reaches the standard heat input Qst for the entire detection period. An expression for calculating the integrated heat input amount Qta that does not cause a short circuit until time tn will be described.
[0103]
[Explanation of Equation 6]
The cumulative heat input amount Qta is the first heat input average value ΔQav at each detection interval from the main arc current / voltage detection start time t3 to the main arc current / voltage detection end time tn. Calculated by the formula.
[Formula 6]

[0104]
The detection start time of the detection interval Δt of the main arc current / voltage detection start time t3 is t01, and the detection start time of the detection interval Δt of the main arc current / voltage detection end time tn is t0n. Therefore, the integrated heat input amount Qta from the detection start time t01 of the first detection interval Δt to the detection start time t0n of the detection number Δt of detection times may be calculated by the second expression on the right side of Equation 6. .
[0106]
[Explanation of Equation 7]
Further, instead of calculating the integrated heat input amount Qta by the above equation 4, the number of detections of the main arc current / voltage detection end time tn from the first detection interval Δt at the main arc current / voltage detection start time t3. The integrated heat input amount Qta up to the nth detection interval Δt may be calculated by Equation 7.
[Expression 7]

[0110]
Next, the auxiliary arc current value Ip is measured from the auxiliary arc current / voltage detection start time t1 in the auxiliary arc period Tp, and the auxiliary arc voltage average value Vav12 is measured to measure the auxiliary arc current. The case where the period integrated heat input Qta12 is calculated will be described.
[0112]
In normal stud welding, the auxiliary arc period Tp shown in FIG. 2 described above is 0.1 to 0.2 [seconds], and the main arc period Ta is 0.4 to 1.5 [seconds]. Yes, the short-circuit period Ts is about 0.2 [seconds], the auxiliary arc period Tp is about 1/10 of the energization time compared to the main arc period Ta, and the auxiliary arc current value Ip is Since it is smaller than the main arc current value Ia,
In order to simplify the control circuit, the calculation of the auxiliary arc period integrated heat input Qta12 is omitted.
[0114]
However, depending on the welding conditions, the auxiliary arc period cumulative heat input Qta12 cannot be ignored with respect to the main arc period cumulative heat input Qta3n. In this case, the auxiliary arc current average value Ip and the auxiliary arc An auxiliary arc period integrated heat input Qta12 is calculated from the voltage average value and the auxiliary arc period Tp.
As described above, since the auxiliary arc period Tp is shorter than the main arc period Ta, the auxiliary arc current average value Ip and the auxiliary arc voltage average value are the main arc at each detection interval. Unlike the average current value Iav (Δt) and the main arc voltage average value Vav (Δt) for each detection interval, it is not necessary to calculate every detection interval Δt, and the auxiliary arc current / voltage detection start time t1 From this, the auxiliary arc voltage average value Vav12 is measured, and the auxiliary arc period integrated heat input Qta12 is calculated from the auxiliary arc voltage average value Vav12 and the auxiliary arc current value Ip.
[0116]
As shown in the following formula, the auxiliary arc period integrated heat input Qta12 is obtained by measuring the auxiliary arc voltage average value Vav12 from the auxiliary arc current / voltage detection start time t1, and calculating the auxiliary arc voltage. It is calculated from the product of the average value Vav12, the auxiliary arc current value Ip, and the auxiliary arc detection period T12.
Auxiliary / main arc period integrated heat input Qta1n is calculated based on the main arc period integrated heat input Qta3n calculated from the main arc voltage average value Vav (Δt) at each detection interval as shown in the following equation. It is the sum of the heat input Qta12.
Qta12 = Vav12 ・ Ip ・ T12
Qta1n = Qta12 + Qta3n
[0120]
[Explanation of FIG. 5]
FIG. 5 is a diagram showing a welding voltage waveform and a welding current waveform when the stud 18 is temporarily short-circuited to the molten pool due to poor pulling, partial melting due to an abnormal arc phenomenon, etc. during the main arc period Ta. .
[0122]
During the main arc period Ta, if the stud 18 is temporarily short-circuited to the molten pool due to poor pulling, abnormal arc phenomenon, for example, single melting due to magnetic blowing, etc., the heat input average value ΔQas when a short-circuit occurs at every detection interval Therefore, many short circuits occur during the main arc period Ta, and the integrated heat input Qta decreases.
[0124]
Accumulated from the main arc current / voltage detection start time t3, the accumulated heat input Qta at the time tn when the standard heat input Qst for the entire detection period coincides with the integrated heat input Qta or immediately after it is exceeded Calculation is performed using Equation (7).
[0126]
When the short circuit occurs during the main arc period Ta, the output terminal voltage Vd becomes the output terminal voltage average value Vas (Δt) at the occurrence of the short circuit for each detection interval, so the welding voltage average value Vav during the detection period decreases. To do.
Further, the output current Io at this time is the output current average value Ias (Δt) at the occurrence of a short circuit for each detection interval. When the output characteristic of the welding power source device is a constant current characteristic, the welding current during the detection period The average value Iav hardly changes, and when the output characteristic of the welding power source device is not a constant current characteristic such as a drooping characteristic, the welding current average value Iav during the detection period slightly increases.
[0130]
[Explanation of FIG. 6]
FIG. 6A is a welding current waveform diagram showing a waveform of the output current Io when a minute short circuit occurs during the main arc period Ta, and FIG. 6B shows a short circuit occurring during the main arc period Ta. It is a figure which shows the waveform of the output terminal voltage Vd at the time of doing.
[0132]
As shown in FIG. 6 above, in the above-described embodiment, even when a short-circuit occurs frequently, such as when welding time becomes long, as in large-diameter stud welding, through welding, sideways welding, etc. The accumulated heat input Qta hardly decreases. However, if these micro short-circuits occur frequently, there is a high possibility of defects in the welds.
[0134]
In this case, the detection interval Δt for calculating the heat input average value ΔQav for each detection interval is set to a number [mSec] that is smaller than a single occurrence time of a micro short circuit that may cause a defect in the weld.
Next, an appropriate value of the heat input average value ΔQav for each detection interval when a normal welding operation is performed is determined in accordance with the diameter of the welding stud, the condition of the material to be welded 14 and the welding posture (downwardly, laterally, etc.). It is determined as a heat input standard value ΔQst for each detection interval.
This preset heat input average value ΔQav for each detection interval is compared with the heat input standard value ΔQst for each detection interval Δt.
The number of short circuits Ns in which the heat input average value ΔQav at each detection interval is lower than the heat input standard value ΔQst at each detection interval is counted, and this short circuit number Ns is equal to or greater than the preset standard heat input allowable short circuit number Nst. When it becomes, it determines with a welding defect.
[0136]
Using the above determination results, it is displayed that the number of micro short-circuits has exceeded the allowable range at the end of stud welding where welding is performed with the integrated heat input amount Qta of the method calculated by Equations 4 to 12, and heat input is further performed. Or add.
[0140]
[Explanation of Equations 8 to 12]
4A and 4B, the welding current average value Iav during the detection period and the welding voltage average value Vav during the detection period are calculated, and the main arc heat input standard value is calculated. The integrated heat input Qta may be calculated by multiplying the set period T38.
[0142]
The main arc voltage average value Vav (Δt) at each detection interval is integrated from the number of detection times 1 to n, and the main arc period integrated voltage value Vta3n is calculated by Equation 8.
[Equation 8]

The main arc current average value Iav (Δt) for each detection interval is integrated from the number of detection times 1 to n, and the main arc period integrated current value Ita3n is calculated by Equation 9.
[Equation 9]

[0144]
The main arc period integrated voltage value Vta3n calculated by Equation 8 is divided by the number of detections n, and the welding voltage average value Vav during the detection period is calculated by Equation 10.
[Expression 10]

The main arc period integrated current value Ita3n calculated by Expression 9 is divided by the number of detections n, and the average value Iav of the welding current during the detection period is calculated by Expression 11.
## EQU11 ##

[0146]
After multiplying the welding voltage average value Vav during the detection period calculated by Equation 10 and the average value Iav of the welding current during the detection period calculated by Equation 11 and the main arc integrated value detection period T3n, Equation 12 The integrated heat input amount Qta is calculated.
[Expression 12]

[0150]
[Explanation of embodiment of claim 4]
According to the method of claim 4, the main arc period integrated heat input Qta3n calculated from the main arc voltage average value Vav (Δt) at every detection interval is pushed in at the time tn when the standard heat input Qst38 of the entire main arc period reaches. It is a method of starting a process.
Hereinafter, this method will be described with reference to FIGS.
(A) Before starting welding, the standard heat input Qst38 for the entire main arc period at the time of normal welding is set in advance by Equations 1 to 3.
[0152]
(B) At the start time t0 of the auxiliary arc current energization, the start-up switch 13 of the welding gun 2 is pushed to start energization of the auxiliary arc current Ip, and the stud 18 is pulled up from the work piece 14 to assist the auxiliary arc. Is generated.
(C) The auxiliary arc current Ip is switched to the main arc current Ia at the main arc current energization start time t2 when the auxiliary arc period Tp has elapsed.
[0154]
(D) As shown in FIG. 3, from the main arc current / voltage detection start time t3, the main arc voltage average value Vav (Δt) for each detection interval is measured for each detection interval Δt.
(E) Integration of the main arc period by integrating the heat input average value ΔQav for each detection interval of the product of the main arc voltage average value Vav (Δt) for each detection interval and the welding current average value Iav during the detection period. The amount of heat input Qta3n is calculated by any one of Equations 4 to 7.
[0156]
(F) The pushing process is started at time tn when this main arc period integrated heat input Qta3n reaches the standard heat input Qst38 for the entire main arc period set in advance.
Qta3n> = Qst38
(G) The welding current average value Iav during the detection period is a value calculated by the method of claim 12, claim 13, or claim 14.
[0160]
[Explanation of embodiment of claim 5]
The method of claim 5 is a method in which the pushing process is started at a time point tn when the main arc period integrated voltage value Vta3n reaches the main arc voltage standard value Vst38 for the entire detection period calculated from the standard heat input Qst38 for the entire main arc period. It is.
Hereinafter, this method will be described with reference to FIGS.
The description of (A) to (D) and (H) is the same as the description of the embodiment of claim 4 and will be omitted.
[0162]
(E5) The main arc voltage average value Vav (Δt) at each detection interval is integrated to calculate the main arc period integrated voltage value Vta3n by the equation (8).
(F5) The main arc voltage standard value Vst38 for the entire detection period is calculated by dividing the standard heat input Qst38 for the entire main arc period set in advance by the welding current average value Iav during the detection period.
Vst38 = Qst38 / Iav
[0164]
(G5) The pushing process is started at time tn when the main arc period integrated voltage value Vta3n reaches the main arc voltage standard value Vst38 for the entire detection period.
Vta3n> = Vst38
[0170]
[Explanation of embodiment of claim 6]
The method of claim 6 is a method of starting the pushing process at a time point tn when the main arc period integrated heat input Qta3n calculated from the main arc voltage average value Vav3n of the entire detection period reaches the standard heat input Qst38 of the entire main arc period. It is.
Hereinafter, this method will be described with reference to FIGS.
The description of (A) to (D) and (H) is the same as the description of the embodiment of claim 4 and will be omitted.
[0172]
(E61) The main arc voltage average value Vav (Δt) at each detection interval is integrated to calculate the main arc period integrated voltage value Vta3n by the equation (8).
(E62) The main arc period integrated voltage value Vta3n is divided by the number of detections n, and the main arc voltage average value Vav3n = Vta3n / n for the entire detection period is calculated by Equation 10.
[0174]
(F6) The main arc period integrated heat input Qta3n, which is the product of the main arc voltage average value Vav3n over the entire detection period, the welding current average value Iav during the detection period, and the main arc integrated value detection period T3n, is calculated by Equation 12.
(F) The pushing process is started at time tn when this main arc period integrated heat input Qta3n reaches the standard heat input Qst38 for the entire main arc period set in advance.
Qta3n> = Qst38
[0180]
[Explanation of Embodiment of Claim 7]
The method of claim 7 is the sum of the main arc period integrated heat input Qta3n calculated from the main arc voltage average value Vav (Δt) for each detection interval of claim 4 and the auxiliary arc period integrated heat input Qta12. This is a method in which the pushing process is started at the time tn when the auxiliary heat input Qta1n reaches the standard heat input Qst18 for the entire auxiliary / main arc detection period.
Hereinafter, this method will be described with reference to FIGS.
(A7) Before starting welding, the auxiliary arc period Tp during normal welding and the standard heat input Qst18 for the entire auxiliary / main arc detection period are set in advance. The standard heat input amount Qst38 for the entire main arc period is calculated by Equation 1 to Equation 3.
[0182]
(B) At the start time t0 of the auxiliary arc current energization, the start-up switch 13 of the welding gun 2 is pushed to start energization of the auxiliary arc current Ip, and the stud 18 is pulled up from the work piece 14 to assist the auxiliary arc. Is generated.
(B71) The auxiliary arc voltage average value Vav12 is measured from the auxiliary arc current / voltage detection start time t1.
(B72) An auxiliary arc period integrated heat input Qta12, which is the product of the auxiliary arc voltage average value Vav12, the auxiliary arc current value Ip, and the auxiliary arc detection period T12, is calculated.
Qta12 = Vav12 ・ Ip ・ T12
[0184]
(C) The auxiliary arc current Ip is switched to the main arc current Ia at the main arc current energization start time t2 when the auxiliary arc period Tp has elapsed.
(D) From the main arc current / voltage detection start time t3, the main arc voltage average value Vav (Δt) for each detection interval is measured for each detection interval Δt.
[0186]
(E) Integration of the main arc period by integrating the heat input average value ΔQav for each detection interval of the product of the main arc voltage average value Vav (Δt) for each detection interval and the welding current average value Iav during the detection period. The amount of heat input Qta3n is calculated by any one of Equations 4 to 7.
(F7) Auxiliary arc period accumulated heat input Qta12 and main arc period accumulated heat input Qta3n sum of auxiliary arc period accumulated heat input Qta1n is a preset standard heat input Qst18 for the entire auxiliary / main arc detection period The pushing process is started at the time point tn when the pressure reaches.
Qta1n = Qta12 + Qta3n
Qta3n> = Qst18
(G) The welding current average value Iav during the detection period is a value calculated by the method of claim 12, claim 13, or claim 14.
[0190]
[Explanation of Embodiment of Claim 8]
The method of claim 8 calculates the standard heat input Qst38 for the entire main arc period by subtracting the auxiliary arc period integrated heat input Qta12 from the standard heat input Qst18 for the entire auxiliary / main arc detection period. This is a method of starting the pushing process at the time tn when the main arc period integrated voltage value Vta3n reaches the main arc voltage standard value Vst38 for the entire detection period calculated from the standard heat input Qst38 for the entire main arc period.
Hereinafter, this method will be described with reference to FIGS.
(A7) Before starting welding, the auxiliary arc period Tp during normal welding and the standard heat input Qst18 for the entire auxiliary / main arc detection period are set in advance. The standard heat input amount Qst38 for the entire main arc period is calculated by Equation 1 to Equation 3.
[0192]
(B) At the start time t0 of the auxiliary arc current energization, the start-up switch 13 of the welding gun 2 is pushed to start energization of the auxiliary arc current Ip, and the stud 18 is pulled up from the work piece 14 to assist the auxiliary arc. Is generated.
(B71) The auxiliary arc voltage average value Vav12 is measured from the auxiliary arc current / voltage detection start time t1.
[0194]
(B72) An auxiliary arc period integrated heat input Qta12, which is the product of the auxiliary arc voltage average value Vav12, the auxiliary arc current value Ip, and the auxiliary arc detection period T12, is calculated.
Qta12 = Vav12 ・ Ip ・ T12
(B8) The main arc period cumulative heat input Qta3n is calculated by subtracting the auxiliary arc period cumulative heat input Qta12 from the standard heat input Qst18 of the entire auxiliary / main arc detection period.
Qta3n = Qst18-Qta12
[0196]
(C) The auxiliary arc current Ip is switched to the main arc current Ia at the main arc current energization start time t2 when the auxiliary arc period Tp has elapsed.
(D) From the main arc current / voltage detection start time t3, the main arc voltage average value Vav (Δt) for each detection interval is measured for each detection interval Δt.
[0198]
(E5) The main arc voltage average value Vav (Δt) at each detection interval is integrated to calculate the main arc period integrated voltage value Vta3n by the equation (8).
(F8) The main arc voltage standard value Vst38 for the entire detection period is calculated by dividing the main arc period integrated heat input Qta3n by the welding current average value Iav during the detection period.
Vst38 = Qst38 / Iav
(G5) The pushing process is started at time tn when the main arc period integrated voltage value Vta3n reaches the main arc voltage standard value Vst38 for the entire detection period.
Vta3n> = Vst38
[0200]
[Explanation of embodiment of claim 9]
The method of claim 9 is the sum of the main arc period integrated heat input Qta3n calculated from the main arc voltage average value Vav3n of the entire detection period of claim 6 and the auxiliary arc period integrated heat input Qta12. This is a method in which the pushing process is started at time tn when the integrated heat input Qta1n reaches the standard heat input Qst18 for the entire auxiliary / main arc detection period.
This method will be described with reference to FIG.
(A7) Before starting welding, the auxiliary arc period Tp during normal welding and the standard heat input Qst18 for the entire auxiliary / main arc detection period are set in advance. The standard heat input amount Qst38 for the entire main arc period is calculated by Equation 1 to Equation 3.
[0202]
(B) At the start time t0 of the auxiliary arc current energization, the start-up switch 13 of the welding gun 2 is pushed to start energization of the auxiliary arc current Ip, and the stud 18 is pulled up from the work piece 14 to assist the auxiliary arc. Is generated.
(B71) The auxiliary arc voltage average value Vav12 is measured from the auxiliary arc current / voltage detection start time t1.
(B72) An auxiliary arc period integrated heat input Qta12, which is the product of the auxiliary arc voltage average value Vav12, the auxiliary arc current value Ip, and the auxiliary arc detection period T12, is calculated.
Qta12 = Vav12 ・ Ip ・ T12
[0204]
(C) The auxiliary arc current Ip is switched to the main arc current Ia at the main arc current energization start time t2 when the auxiliary arc period Tp has elapsed.
(D) From the main arc current / voltage detection start time t3, the main arc voltage average value Vav (Δt) for each detection interval is measured for each detection interval Δt.
[0206]
(E61) The main arc voltage average value Vav (Δt) at each detection interval is integrated to calculate the main arc period integrated voltage value Vta3n by the equation (8).
(E62) The main arc period integrated voltage value Vta3n is divided by the number of detections n, and the main arc voltage average value Vav3n for the entire detection period is calculated by Equation (10).
[0208]
(F6) The main arc period integrated heat input Qta3n, which is the product of the main arc voltage average value Vav3n over the entire detection period, the welding current average value Iav during the detection period, and the main arc integrated value detection period T3n, is calculated by Equation 12.
(G6) Auxiliary arc period integrated heat input Qta12 and main arc period integrated heat input Qta3n sum of auxiliary arc period integrated heat input Qta1n is a preset standard heat input Qst18 for the entire auxiliary / main arc detection period The pushing process is started at the time point tn when the pressure reaches.
Qta1n> = Qst18
[0210]
[Explanation of Embodiment of Claim 10]
In addition to the methods of claims 4 to 9, the method of claim 10 is a method of displaying a welding failure when the number of short circuits Ns exceeds a preset number.
[0212]
The method of claim 10 adds the following three requirements in addition to the components of claims 4 to 9.
As shown in FIG. 6, before starting welding,
The detection interval Δt of a number [mSec] shorter than a single occurrence time of a micro short-circuit that may become a defect of the weld
標準 Standard heat input ΔQst for each detection interval
(2) The standard heat input allowable short-circuit number Nst that secures the standard heat input Qst38 for the entire main arc period during normal welding is set in advance.
[0214]
From the main arc current / voltage detection start time t3, the main arc voltage average value Vav (Δt) for each detection interval is measured for each detection interval Δt.
A heat input average value ΔQav for each detection interval of the product of the main arc voltage average value Vav (Δt) for each detection interval and the welding current average value Iav during the detection period is calculated.
ΔQav = Vav (Δt) ・ Iav
The number Ns of short circuits in which the heat input average value ΔQav at each detection interval is lower than the heat input standard value ΔQst at each detection interval is counted. ΔQav <ΔQst
When this short circuit number Ns is equal to or greater than a preset standard heat input allowable short circuit number Nst, a welding failure is displayed. Ns> Nst
The welding current average value Iav during the detection period is a value calculated by the method of claim 12, claim 13, or claim 14.
[0220]
[Explanation of Embodiment of Claim 11]
In addition to the methods of claims 4 to 9, the method of claim 11 increases the energization time of the main arc current Ia for a preset time when the number of short circuits Ns is equal to or greater than the preset standard heat input allowable short circuit number Nst. How to add.
The method of claim 10 is a method of displaying a welding failure when the number of short circuits Ns is equal to or greater than a preset standard heat input allowable number of short circuits Nst, whereas the method of claim 11 is that the number of short circuits Ns is preset. This is a method of adding the energization time of the main arc current Ia for a preset time when the standard heat input allowable short-circuit count Nst is reached. The method and other configurations of the tenth aspect are the same as those of the method of the eleventh aspect, and thus the description thereof is omitted.
[0230]
The method of claim 12 employs the main arc current set value set in the welding power source device of constant current output characteristics as the welding current average value Iav during the detection period of claims 4 to 11. .
[0231]
When the output characteristic of the welding power supply device is a constant current characteristic, a current of the welding current average value Iav flows during the detection period of the value set in the welding power supply device unless a failure occurs in the welding power supply device.
Therefore, the method of claim 12 is only required to measure the main arc voltage average value Vav (Δt) for each detection interval by connecting a signal detection lead wire, so that welding during the detection period of a large current is performed. A welding current detector for measuring the current average value Iav is unnecessary. When a failure occurs in the welding power supply device, an abnormality occurs in the main arc voltage average value Vav (Δt) at every detection interval, so this abnormality may be displayed or the operation of the welding power supply device may be stopped. it can.
[0235]
The method of claim 13 is a welding power source apparatus having a constant current output characteristic measured later from the main arc current / voltage detection start time t3 as the welding current average value Iav during the detection period of claims 4 to 11. The main arc current measurement value to be output is adopted.
[0236]
When the output characteristic of the welding power source device is a constant current characteristic, the output current is maintained substantially constant. Therefore, the method of claim 13 does not need to measure the main arc current average value Iav (Δt) for each detection interval at every detection interval Δt, and the welding current average value Iav during the detection period after the main arc is stabilized. Can be measured at least once, which simplifies the circuit.
[0240]
According to a fourteenth aspect of the present invention, the welding current average value Iav during the detection period of the fourth to eleventh aspects is calculated as a main current at every detection interval calculated from the main arc current / voltage detection start time t3 at every detection interval Δt. The arc current average value Iav (Δt) is adopted.
[0241]
In the method of claim 14, even if the output characteristic of the welding power source is not a constant current characteristic, the main arc current average value Iav (Δt) for each detection interval and the detection interval for each detection interval Δt. The main arc voltage average value Vav (Δt) is measured to calculate the main arc period integrated heat input Qta3n, thereby using a power supply device having a small capacity to be supplied to a welding power supply device such as a small capacity engine generator. Even when a large-diameter stud that requires a large current is to be welded, even when the output voltage and output current of the welding power source decrease due to a lack of input power of the welding power source, good welding results can be obtained. .
[0245]
The method of claim 15 employs the auxiliary arc current set value set in the welding power source device of constant current output characteristics as the auxiliary arc current value Ip of claim 7 or claim 8 or claim 9. Yes.
[0246]
When the output characteristic of the welding power source device is a constant current characteristic, the auxiliary arc current value Ip of the value set in the welding power source device flows unless a failure occurs in the welding power source device. Therefore, the method of claim 15 is the method of claim 7 or claim 8 or claim 9, similar to the method of claim 12, by connecting a lead wire for signal detection to the average value of the auxiliary arc voltage. Since only Vav12 needs to be measured, a welding current detector for measuring the auxiliary arc current value Ip is unnecessary. When a failure occurs in the welding power supply device, an abnormality occurs in the main arc voltage average value Vav (Δt) at every detection interval, so this abnormality may be displayed or the operation of the welding power supply device may be stopped. it can.
[0250]
The method according to claim 16 is a welding power source apparatus having a constant current output characteristic measured from the auxiliary arc current / voltage detection start time t1 as the auxiliary arc current value Ip according to claim 7, 8 or 9. Auxiliary arc current measurement value output from is adopted.
[0251]
When the output characteristic of the welding power source device is a constant current characteristic, the output current is maintained substantially constant. Therefore, the method of claim 16 is the same as the method of claim 13 in the method of claim 7 or claim 8 or claim 9, and the auxiliary arc current average value Iav (Δt at every detection interval Δt. ) Need not be measured, and the auxiliary arc current value Ip only needs to be measured at least once after the auxiliary arc is stabilized, thereby simplifying the circuit.
[0270]
[Explanation of FIG. 7]
FIG. 7 is a diagram showing an embodiment of a stud welding apparatus for carrying out the method of the present invention by digital control.
[0272]
The stud welding device shown in FIG. 1 is formed of a welding power source device 1, a welding gun 2, and a welding control device 3.
This welding power source device 1 outputs a welding current composed of an auxiliary arc current Ip and a main arc current Ia to a welding gun 2 and outputs it in accordance with an analog signal output from a welding control device 3 described later. The current command output circuit 5 that controls the current Io, the welding current output circuit 15 that includes a semiconductor switching element such as a thyristor that controls the welding current based on the current command, and the secondary cable 17 are output to the stud 18. The welding current detection circuit IC that detects the output current Io and outputs the welding current detection signal Ic, and the welding voltage detection circuit VC that detects the output terminal voltage value Vd and outputs the welding voltage detection signal Vc. .
[0274]
The welding control device 3 converts the welding current detection signal Ic into a digital welding current detection signal Idd and outputs it to the arithmetic processing circuit CPU, and the welding voltage detection signal Vc into the digital welding voltage detection signal Vdd. An A / D conversion circuit 8 for converting and outputting to the arithmetic processing circuit CPU; an arithmetic processing circuit CPU for inputting a digital welding current detection signal Idd and a digital welding voltage detection signal Vdd and outputting a digital output signal described later; A D / A conversion circuit 6 that converts the digital output signal Iod of the arithmetic processing circuit CPU into an analog output signal Ioa and outputs it to the current command output circuit 5, and a storage circuit that stores detection values, calculation values, welding result data, and the like 11 and a display circuit 12 such as a digital panel for displaying them. The D / A conversion circuit 6, the A / D conversion circuit 7, and the A / D conversion circuit 8 may be built in the arithmetic processing circuit CPU.
[0280]
[Explanation of FIG. 8]
FIG. 8 is a view showing an embodiment of a stud welding apparatus for carrying out the method of the present invention by analog control.
[0282]
Further, in the embodiment of FIG. 8, the current and voltage detection signals are output by analog circuits such as an integrator and a multiplier / divider without using a complicated circuit using a microcomputer as in the embodiment of FIG. The average heat input can also be calculated and displayed using the configured arithmetic circuit. In addition, an alarm is issued with an abnormal lamp, buzzer, etc. when it deviates from the permissible range compared to the standard value (configured with an analog circuit).
[0284]
First, when the start switch start switch 13 is pressed, the auxiliary arc current preset in the welding sequence control circuit 21 is output from the welding current output circuit 15, the stud 18 is pulled up, and the auxiliary arc is generated. After the pilot time preset in the welding sequence control circuit 21 has elapsed, the main arc current is entered. When a transition is made from the auxiliary arc current to the welding current, a reset signal is output from the measurement time setting circuit 28, the smoothing circuit 22 and the smoothing circuit 23 are reset, and a new welding current detection circuit IC and welding voltage detection circuit VC. The time integration of the welding current and welding voltage detected in step 1 is started. The reset signal may be synchronized with the start of auxiliary arc current output.
[0286]
Next, after the welding time preset in the welding sequence control circuit 21 has elapsed, the stud 18 is pushed in by the welding gun 2. The measurement time setting circuit 28 detects the start of the pushing operation, and outputs a hold signal to the smoothing circuit 22 and the smoothing circuit 23. By this hold signal, the value integrated from the reset signal is held in the smoothing circuit 22 and the smoothing circuit 23. Since the held values are time-integrated values, they are multiplied by the multiplication circuit 24, and the welding time (analog value) preset by the welding sequence control circuit 21 using the division circuit 29 is used. By dividing by, the average heat input is calculated and displayed on the display circuit 12. Further, the calculated average heat input is compared with a standard value of average heat input preset in the standard heat input setting circuit 25 by the comparison circuit 26, and an alarm is issued by the alarm device 27 when exceeding the allowable range.
[1000]
【The invention's effect】
The common effects of the present invention are as follows.
The method of the present invention compares the accumulated heat input Qta and the standard heat input Qst for the entire detection period each time it is detected, and the pushing process is performed at time tn when the integrated heat input Qta reaches the standard heat input Qst for the entire detection period. Since it starts, even if a short circuit occurs, an appropriate amount of heat input can be secured and good welding quality can be obtained.
Further, according to the present invention, good welding quality is obtained, and data obtained for each stud welding is stored for each stud welding, and this data is stored in the arithmetic processing unit 4 or an external storage device (for example, a memory). Card, floppy disk, etc.) or output directly to a personal computer or the like, it is possible to easily confirm the welding quality of each stud welding operation on the personal computer or the like. Further, the data obtained for each welding of each stud can be aggregated and statistical processing or the like can be performed to manage the welding quality.
[1004]
The main arc voltage average value Vav (Δt) for each detection interval, the main arc voltage average value Vav3n for the entire detection period, or the main arc period integrated heat input calculated from this voltage value. Even if a short circuit occurs, Qta3n starts at the time tn when the standard heat input Qst38 for the entire main arc period or the main arc voltage standard value Vst38 for the entire detection period calculated from this heat input is reached. A sufficient heat input can be ensured, and good welding quality can be obtained.
[1007]
In addition to the effects of the respective methods of claims 4 to 6, the methods of claims 7 to 9 include the auxiliary arc from the auxiliary arc current / voltage detection start time t1 in the auxiliary arc period Tp. Since the auxiliary arc voltage average value Vav12 is measured and the auxiliary arc period integrated heat input Qta12 is calculated while measuring the auxiliary arc voltage Ip, the heat input measurement accuracy is improved.
[1010]
In addition to the effects of the methods of claims 4 to 9, the method of claim 10 has a number [mSec] shorter than a single occurrence time of a micro short circuit that may become a defect in a weld. The heat input average value ΔQav for each detection interval calculated for each detection interval Δt counts the number of short circuits Ns that is lower than the heat input standard value ΔQst for each detection interval, and the number of short circuits Ns is a preset standard heat input. When the allowable number of short-circuits is greater than or equal to Nst, there is an effect of displaying poor welding.
[1011]
In the method of claim 11, in addition to the effects of the methods of claims 4 to 9, the number of short circuits Ns counted in the same manner as in claim 10 is equal to or greater than a preset standard heat input allowable short circuit number Nst. By adding the energizing time of the main arc current Ia for a preset time, there is an effect of preventing welding failure.
[1012]
In the method of claim 12, since only the main arc voltage average value Vav (Δt) for each detection interval needs to be measured by connecting a signal detection lead wire, the welding current average during the large current detection period is sufficient. A welding current detector for measuring the value Iav is not necessary. When a failure occurs in the welding power supply device, an abnormality occurs in the main arc voltage average value Vav (Δt) at every detection interval, so this abnormality may be displayed or the operation of the welding power supply device may be stopped. it can.
[1013]
The method of claim 13 does not need to measure the main arc current average value Iav (Δt) for each detection interval at every detection interval Δt, and at least the welding current average value Iav during the detection period after the main arc is stabilized. Since only one measurement is required, the circuit is simplified.
[1014]
According to the method of claim 14, even if the output characteristic of the welding power source device is not a constant current characteristic, the main arc current average value Iav (Δt) for each detection interval and the detection interval for each detection interval Δt. By measuring the main arc voltage average value Vav (Δt) and calculating the main arc period cumulative heat input Qta3n, a power supply device having a small capacity supplied to a welding power supply device such as a small capacity engine generator is used. Even when a large-diameter stud that requires a large current is to be welded, even when the output voltage and output current of the welding power source are reduced due to a lack of input power of the welding power source, good welding results can be obtained.
[1015]
The method of claim 15 is the same as the method of claim 12 in the method of claim 7 or claim 8 or claim 9, wherein only the auxiliary arc voltage average value Vav12 is obtained by connecting a signal detection lead wire. Therefore, a welding current detector for measuring the auxiliary arc current value Ip is unnecessary. When a failure occurs in the welding power supply device, an abnormality occurs in the main arc voltage average value Vav (Δt) at every detection interval, so this abnormality may be displayed or the operation of the welding power supply device may be stopped. it can.
[1016]
In the method of claim 16, the auxiliary arc current average value Iav (Δt) is calculated for each detection interval Δt in the method of claim 7, claim 8 or claim 9, as in the method of claim 13. There is no need to measure, and the auxiliary arc current value Ip may be measured at least once after the auxiliary arc is stabilized, so that the circuit is simplified.
[Brief description of the drawings]
FIG. 1 is a block diagram of a stud welding apparatus that implements a conventional method for monitoring welding voltage, welding current, and main arc current duration.
FIG. 2 (A) is an explanatory diagram for calculating a welding current average value Iav during a detection period from an output current Io of the entire main arc period during normal welding, and FIG. It is explanatory drawing which calculates the main arc voltage average value Vav (Δt) for every detection interval for every detection interval Δt from the output terminal voltage Vd of the whole main arc period at the time of simple welding, and FIG. It is a figure which shows the stud raising distance at the time of welding.
FIG. 3 (A) is an explanatory diagram for calculating a welding current average value Iav during a detection period from an output current Io of the entire main arc period during each welding, and FIG. 3 (B) shows each welding. It is explanatory drawing which calculates the main arc voltage average value Vav ((DELTA) t) for every detection interval for every detection interval (DELTA) t from the output terminal voltage Vd of the whole inside main arc period.
FIG. 4 (A) is an explanatory diagram for calculating a main arc current average value Iav (Δt) for each detection interval from the output current Io of the entire main arc period during each welding; B) is an explanatory diagram for calculating the main arc voltage average value Vav (Δt) for each detection interval from the output terminal voltage Vd of the entire main arc period during each welding for each detection interval Δt.
FIG. 5 shows a welding voltage waveform and a welding current waveform when the stud 18 is temporarily short-circuited to the molten pool due to poor pulling, partial melting due to an abnormal arc phenomenon, etc. during the main arc period Ta. FIG.
FIG. 6 (A) is a welding current waveform diagram showing a waveform of an output current Io when a micro short circuit occurs during the main arc period Ta, and FIG. 6 (B) is a diagram during the main arc period Ta. It is a figure which shows the waveform of the output terminal voltage Vd when a short circuit generate | occur | produces in.
FIG. 7 is a diagram showing an embodiment of a stud welding apparatus for performing the method of the present invention by digital control.
FIG. 8 is a diagram showing an embodiment of a stud welding apparatus for performing the method of the present invention by analog control.
[Explanation of symbols]
1 ... Welding power supply
2 ... Welding gun
3 ... Welding control device
4 ... Arithmetic processing circuit
5 ... Current command output circuit
6 ... D / A conversion circuit
7, 8 ... A / D conversion circuit
11 ... Memory circuit
12 ... Display circuit
13 ... Start-up switch
14 ... Material to be welded
15 ... Welding current output circuit
16 ... Control cable
17 ... Secondary cable
18 ... Stud
20 ... Heat input arithmetic circuit
21 ... Welding sequence control circuit
22, 23 ... Smoothing circuit
24. Multiplier circuit
25 ... Standard heat input setting circuit
26: Comparison circuit
27 ... Alarm
28 ... Measurement time setting circuit
29: Dividing circuit
30 ... Three-phase power supply
36, 44 ... Filter circuit
37, 45 ... Amplifier circuit
39 ... Reference welding voltage setting circuit
40 ... Comparator
41 ... Alarm
42, 43 ... connection line
CPU: Arithmetic processing circuit
I1 (t) ... welding current value at time t
Ia: main arc current / main arc current value
IC: Welding current detection circuit
Ic: Welding current detection signal
Io ... Output current / Output current value
Ip: Auxiliary arc current / Auxiliary arc current value
Is ... Short-circuit current
Ias (Δt): Average output current when a short circuit occurs at each detection interval
Iav: welding current average value during the detection period
Iav (Δt): Main arc current average value at every detection interval
Ita3n ... Main arc period integrated current value
Ns: Number of short circuits
Nst ... Standard heat input allowable short circuit count
n ... number of detections (of detection interval Δt)
Qr ... Required heat input
Qst: Standard heat input for the entire detection period
Qta ... Integrated heat input
Qta12 ... Auxiliary arc period integrated heat input
Qst18 ... Standard heat input for the entire auxiliary / main arc detection period (preset)
Qst38 ... Standard heat input for the entire main arc period (preset)
Qta1n ... Auxiliary / main arc period integrated heat input
Qta3n ... Integrated heat input during the main arc period
ΔQas: Average value of heat input when a short circuit occurs at each detection interval
ΔQav ... Average heat input per detection interval
ΔQst: heat input standard value at every detection interval
T12: Auxiliary arc detection period
T38 ... Main arc heat input standard value setting period
T3n ... Main arc integrated value detection period
t0: Auxiliary arc current energization start time
t1: Auxiliary arc current / voltage detection start time
t2: Main arc current energization start point
t3: Main arc current / voltage detection start time
t8: Main arc current / voltage detection end point
t9: Main arc current energization end time / short-circuit current energization start time
t10: Output current energization end / short-circuit current energization end
t01 to t0n: detection start time of each detection interval Δt
Ta ... Main arc period
Tp: Auxiliary arc period
Ts ... Short-circuit period
tn: When the integrated heat input Qta reaches the standard heat input Qst over the preset detection period
Or when the main arc period integrated voltage value Vta3n reaches the main arc voltage standard value Vst38 for the entire preset detection period.
Δt ... Detection interval
Δt = 1 to Δt = n... 1st to Nth detection
Δt · n ... Main arc detection period
V1 (t) ... welding voltage value at time t
Vav: welding voltage average value during the detection period
Vav12: Auxiliary arc voltage average value
Vas (Δt): Output terminal voltage average value when a short circuit occurs at each detection interval
Vav (Δt): Main arc voltage average value at every detection interval
VC: Welding voltage detection circuit
Vc: Welding voltage detection signal
Vd: Output terminal voltage / Output terminal voltage value
Ve: Average value of appropriate welding voltage
Vst38 ... Main arc voltage standard value for the entire detection period
Vav3n: Main arc voltage average value over the entire detection period
Vta3n: Integrated voltage value during the main arc period
ΔVe ... Allowable welding voltage range

Claims (2)

In stud welding, in which the stud is pulled up from the work piece and an arc is generated, and then the stud is pushed into the work piece by a predetermined push amount, the standard for the entire main arc period during normal welding before welding is started. The amount of heat input is set in advance, the auxiliary arc current is switched to the main arc current, and the main arc at each detection interval is set for each predetermined detection interval from the start of main arc current / voltage detection . An average voltage value and a main arc current average value at each detection interval are calculated , and a main arc voltage average value at each detection interval is integrated to calculate a main arc period integrated voltage value. The main arc current average value is integrated to calculate the main arc period integrated current value, the main arc period integrated current value is divided by the main arc integrated value detection period to calculate the welding current average value, and the main arc period integrated value is calculated. The voltage value is When the standard heat input for the entire main arc period is divided by the average welding current value calculated above, the main arc voltage standard value for the entire detection period is reached. Control method. In stud welding, in which the stud is pulled up from the work piece and an arc is generated, and then the stud is pushed into the work piece by a predetermined push amount, the standard for the entire main arc period during normal welding before welding is started. The amount of heat input is set in advance, the auxiliary arc current is switched to the main arc current, and the main arc at each detection interval is set for each predetermined detection interval from the start of main arc current / voltage detection . An average voltage value and a main arc current average value at each detection interval are calculated, a main arc voltage average value at each detection interval is integrated to calculate a main arc period integrated voltage value, and the main arc period integration is calculated. The voltage value is divided by the main arc integrated value detection period to calculate the average welding voltage for the entire detection period, and the main arc current average value for each detection interval is integrated to calculate the main arc period integrated current value. The main arc period integration The current value is divided by the main arc integrated value detection period to calculate the average welding current value for the entire detection period, and the product of the welding voltage average value, the welding current average value, and the main arc integrated value detection period is used as the main value. A stud welding integrated heat input push-in control method for calculating an arc period accumulated heat input, and starting a pushing process when the main arc period accumulated heat input reaches the standard heat input.

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