JP2004249305A

JP2004249305A - Laser welding method and laser welding system

Info

Publication number: JP2004249305A
Application number: JP2003040558A
Authority: JP
Inventors: Kunio Murakami; 邦雄村上; Hirofumi Harada; 裕文原田; Seiji Katayama; 聖ニ片山
Original assignee: Enshu Ltd
Current assignee: Enshu Ltd
Priority date: 2003-02-19
Filing date: 2003-02-19
Publication date: 2004-09-09

Abstract

PROBLEM TO BE SOLVED: To provide a laser welding method, wherein, before a pair of members to be welded are butt-welded, the end surfaces of the members are ground, the butting gap between the members is adjusted, and then the butt-welding is conducted. SOLUTION: In the laser welding method, both end surfaces 10A, 11A, faced to each other, of the pair of members to be welded are ground with a grinding means 80 mounted on a welding head 20 or the like, before a pair of members 10, 11 to be weld, which are held by a fixing jig 70, are butt-welded. After that, the gap between both end surfaces to be butted is adjusted and fixed to have a specified clearance by moving at least one side of the members to be welded by the fixing holder 70. Then, while detecting, with a detecting means 90, a weld line 12 of one or more pairs of members to be welded, the position of the laser head 20 and the output of a laser beam L are controlled to conduct the butt-welding. COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、レーザ発振器を使用したレーザ溶接方法とこのレーザ溶接システムに係り、特に、溶接工程内において、一対の被溶接部材を突合せ溶接するに先立ち、突合せ両端面の隙間や端面状態を検出し、不良ならば突合せ両端面のバリ取り・研削を行うものに関する。
【０００２】
【従来の技術】
従来のレーザ溶接装置は、そのレーザ発振器に炭酸ガスレーザやＹＡＧレーザを使用したものが主流を占めている。また、最近では半導体レーザ素子を多数使用して各レーザ光線を集束した高出力の半導体レーザ発振器が採用されている。この半導体レーザ発振器を使用したレーザ溶接装置は、自動車業界において、車体の軽量化・車体の剛性アップによる安全性の改善、溶接コストの削減に貢献できるものとして期待されている。特に、テーラードブランク材の溶接や薄板鋼の突合せ溶接や重ね合せ溶接を、非接触の片面側溶接で実行できることに優位性が認められている。
【０００３】
上記半導体レーザ溶接装置は、例えば、図１７に示す基本的な構成になっている。半導体レーザ溶接装置１は、半導体レーザ発振器２と、レーザ光の伝送部３と、レーザ光の集光部４と、被溶接部材１０，１１の溶接線１２に対してレーザ光線５を照射する溶接ヘッド６と、この溶接ヘッド６を姿勢制御しながら溶接線に沿って移動する３軸直交移動体７の移動手首８又は多関節ロボットの手首（図示なし）と、被溶接部材１０，１１をクランプする固定治具Ｇとからなる。更に、上記溶接ヘッドには、カメラ９による溶接線１２の検知とレーザ光線５の位置制御及び溶融池の監視による溶接条件制御を行なうべく、レーザ出力制御等の機能を備える他、溶接後の溶接ビートの品質検査機能を備えている。これらの機能を備えた半導体レーザ溶接装置１における溶接ヘッド６により、テーラードブランク材の溶接や薄板鋼の突合せ溶接や重ね合せ溶接等が、非接触の片面側溶接で実行される。
【０００４】
上記半導体レーザ溶接装置及びその他のレーザ溶接装置において、レーザ光線を使用した突合せ溶接には、各種の要求がある。まず、レーザ光線の光軸直径は、０．９ｍｍ程度と小径であることから、突合せ溶接に先立ち、一対の被溶接材（板厚１〜２ｍｍ）の両端面のバラツキは、高精度な隙間寸法（０〜０．２ｍｍ）の初期設定が要求される。このためには、被溶接材の両端面が平滑に研削仕上げされていることが望まれるし、一対の被溶接材の両端面を所定の隙間寸法に微調節・固定させることのできる固定治具が望まれる。そして、一対の被溶接材が薄板で、三次元形状にプレス加工されたものの三次元溶接を実施する場合は、突合せ端面の完全一致と、レーザ光線を溶接線の正確な照射位置へ照射させるための高い位置制御が、更に要求されることになる。
【０００５】
然して、上記一対の被溶接材（板厚１〜２ｍｍ）において、両端面（突合せ面）の隙間寸法（０〜０．２ｍｍ）の初期設定や端面形状にバラツキが有ると、突合せ溶接に溶接不良を発生させることになる。具体的には、一対の被溶接材において、突合せ隙間が無い所では適正とは言えないものの確実な溶接が実行される。しかし、両端面の突合せ隙間寸法が広い所では、溶接抜けによる孔が開き、たちまち溶接不良の原因となる。この溶接不良を解消させるには、（１）溶接端面の全長にわたり同一隙間にするか、（２）溶接端面（突合せ面）の隙間の広・狭に対応してレーザ出力とデフォーカス量の制御又は溶接速度を加減制御する方法が提案されている。
【０００６】
上記（１）において、溶接端面（突合せ面）の全長にわたり同一隙間にする方法は、突合せ溶接に先立つ別工程において、一対の被溶接材の端面に有るバリを砥石で削り取ったり、レーザ光や燃焼ガスでバリを溶かし取る手段が実施されている。このバリ取りされた一対の被溶接材を、溶接工程に搬入して固定治具に固定し、一定の隙間管理のもとにレーザ溶接されている。
【０００７】
また、上記（２）において、溶接端面（突合せ面）の隙間の広・狭に対応してレーザ出力とデフォーカス量の制御又は溶接速度を加減制御する方法は、突合せ面の断面性状に適応した溶接条件で、金属帯同志をレーザ溶接するものである。その詳細は、先行金属ストリップの後端部と後行金属ストリップの先端部とを切断した後、お互いの切断面を突合せ、この突合せ部に沿ってレーザ溶接する溶接機であって、金属ストリップの突合せ面幅方向各位置における破断面の面積率を把握する破断面検出器と、この幅方向各位置におけるバリ発生度合いを測定するバリ検出器と、この幅方向各位置での板厚を測定する板厚測定器と、上記破断面検出器、バリ検出器及び板厚測定器からの信号によりレーザ出力、溶接速度及びフィラ−ワイヤーの供給速度を演算する演算器と、この演算器からの指令により前記レーザ出力、溶接速度及びフィラ−ワイヤーの供給速度を制御する制御器と、を有するものである。この構成により、板破断等のライントラブルが低減する。（例えば、特許文献１参照）
【０００８】
【特許文献１】
特開平８−２９０２８１号公報（第１頁、第２頁、図１）
【０００９】
しかし、上記（１）において、溶接端面の全長にわたり同一隙間とすべく、砥石やレーザ光でバリ取りする方法は、突合せ溶接に先立ち別工程（バリ取り工程）にて行われる。このため、バリ取り装置とこれを設置するスペース及び管理工程が必須になり、初期投資や運転コスト、更に溶接時間の延長を来たしてしまう。また、別工程（バリ取り工程）において、被溶接材の両端面のバリ取りが高精度に行われても、後工程となる溶接工程の固定治具に取り付け直した時、被溶接材全体の撓み・歪み・抉れ等が影響してその被溶接材の両端面の隙間が均一になる事の保証は少ない。このため、バリ取り工程と溶接工程とを別工程の治具にセットし直しての作業では、上記問題点の他、溶接精度を低下させると言う問題が残存する。
【００１０】
更に、上記（２）において、隙間の広・狭に対応してレーザ出力とデフォーカス量の制御又は溶接速度を加減制御する方法は、突合せ面の断面性状に適応した溶接条件で制御し、金属帯同志をレーザ溶接させなければならない。このため、制御系が煩雑になるばかりか高価な制御装置の設備投資を余儀なくされる。また、溶接面は、突合せ隙間が無い所と隙間の広い所では、そのビード幅（肉盛り幅と高さ）が大きく変動することなる。この結果、外観を悪くしたり、溶接強度がビード幅の変化により変動することを意味する。従って、上記突合せ面の断面性状に適応した溶接条件での溶接方法は、一見、無難な溶接が合理的に行えるかに判断される。しかし、本質的に溶接強度が均一な高品質な薄板の突合せ溶接が期待できない。
【００１１】
然るに、薄板の突合せ溶接が求める理想的な溶接条件は、一対の被溶接材において、両端面の突合せされる隙間寸法や端面性状が溶接する全長にわたり均一・同一に保たれた状態とすること。この状態が完全に保証された条件下において、突合せ溶接を実行するとビード幅（肉盛り幅と高さ）の均一・同一な高い溶接品質が得られることである。
【００１２】
【発明が解決しようとする課題】
本発明は、上記従来の各種レーザ溶接装置を採用して実施されるレーザ溶接方法において、起きる突合せ溶接の様々な問題点に鑑みてなされたものである。
【００１３】
本発明における第１の目的は、溶接工程内において、一対の被溶接部材を突合せ溶接するに先立ち、その端面を研削加工した後、突合せ隙間を調節して溶接するレーザ溶接方法を提供するものである。更に、第２の目的は、溶接工程内において、一対の被溶接部材を突合せ溶接するに先立ち、突合せ両端面の隙間寸法や端面状態を検出し、不良ならばその端面を研削加工した後に突合せ隙間を再調節して溶接するレーザ溶接方法を提供するものである。
【００１４】
本発明における第３の目的は、上記第１と第２の目的を達成させるために、溶接工程内において、一対の被溶接部材を突合せ溶接するに先立ち、突合せ両端面を研削する研削手段と、突合せ両端面の当接状態を検出する検出手段と、突合せ両端面の隙間調節を行う固定治具を備えたレーザ溶接システムを提供するものである。
【００１５】
【課題を解決するための手段】
本発明の請求項１のレーザ溶接方法は、一対の被溶接部材の突合せ両端面の隙間を調節・保持する固定治具と、上記一対の被溶接部材の突合せ溶接線に対してレーザ光線を照射する溶接ヘッドと、上記溶接ヘッドに備えて一対の被溶接部材の突合せ両端面を研削する研削手段と、少なくとも上記溶接線及び突合せ隙間・端面状態の検出手段と、溶接ヘッドを姿勢制御しながら溶接線に沿って移動する多関節ロボットの手首又は３軸直交移動体の手首と、からなるレーザ溶接システムを使用したレーザ溶接方法において、
上記固定治具に保持された一対の被溶接部材の突合せ溶接に先行して、上記溶接ヘッド等に備える研削手段により上記一対の被溶接部材の対面する両端面を研削加工し、この後、上記固定治具は被溶接部材の少なくとも片側を可動して突合せ両端面の隙間を所定隙間に調節・固定し、この後、少なくとも一対の被溶接部材の溶接線を検出手段で検出しながら溶接ヘッドの位置制御とレーザ光線の出力制御を行って突合せ溶接を実行させることを特徴とする。
【００１６】
請求項２のレーザ溶接方法は、一対の被溶接部材の突合せ両端面の隙間を調節・保持する固定治具と、上記一対の被溶接部材の突合せ溶接線に対してレーザ光線を照射する溶接ヘッドと、上記溶接ヘッドに備えて一対の被溶接部材の突合せ両端面を研削する研削手段と、少なくとも上記溶接線及び突合せ隙間・端面状態の検出手段と、溶接ヘッドを姿勢制御しながら溶接線に沿って移動する多関節ロボットの手首又は３軸直交移動体の手首と、からなるレーザ溶接システムを使用したレーザ溶接方法において、
上記固定治具に保持された一対の被溶接部材の突合せ溶接に先行して、検出手段で検出した両端面隙間・端面状態が良好の場合は、直ちに、一対の被溶接部材の溶接線を検出手段で検出しながら溶接ヘッドの位置制御とレーザ光線の出力制御を行って突合せ溶接を実行させ、また、検出手段で検出した両端面隙間・端面状態が不良結果の場合は、上記溶接ヘッド等に備える研削手段により上記一対の被溶接部材の対面する両端面を研削加工し、この後、上記固定治具は被溶接部材の少なくとも片側を可動して突合せ両端面の隙間を所定隙間に調節・固定し、この後の再検出で良好となれば、少なくとも一対の被溶接部材の溶接線を検出手段で検出しながら溶接ヘッドの位置制御とレーザ光線の出力制御を行って突合せ溶接を実行させることを特徴とする。
【００１７】
請求項３のレーザ溶接方法は、請求項２のレーザ溶接方法において、上記一対の被溶接部材の両端面に対する研削加工は、１回目の研削加工に基づく隙間・端面の検出不良に続く、２回目の隙間・端面の検出も不良結果となった場合には、端面不良としてワーク払出処理を行なうことを特徴とする。
【００１８】
請求項４のレーザ溶接方法は、請求項１〜３記載のいずれか１項のレーザ溶接方法において、上記一対の被溶接部材の両端面隙間を、工具外径よりもバリ取り代分だけ狭く位置決めし、研削手段は両端面に沿う往動移動だけで両端面のバリ取りを行うことを特徴とする。
【００１９】
請求項５のレーザ溶接方法は、請求項１〜３記載のいずれか１項のレーザ溶接方法において、上記一対の被溶接部材の両端面隙間を、工具外径よりも大きく位置決めし、研削手段は両端面の片面ずつ沿う往動移動と復動移動により両端面のバリ取りを行うことを特徴とする。
【００２０】
請求項６のレーザ溶接システムは、一対の被溶接部材を固定する固定治具と、上記一対の被溶接部材の突合せ溶接線に対してレーザ発振器から導かれるレーザ光線を照射する溶接ヘッドと、上記溶接ヘッドを姿勢制御しながら溶接線に沿って移動させる多関節ロボットの手首又は３軸直交移動体の手首と、上記溶接線を検出する検出手段と、溶融池の監視制御手段と、を備えたレーザ溶接システムにおいて、上記固定治具には，少なくとも一方の被溶接部材を他方の被溶接部材から離接移動させて突合面の隙間調節を行う可動体の調節手段を備え、上記溶接ヘッドには突合せ溶接に先行して溶接線及び一対の被溶接部材の突合せ隙間・端面状態を検出する検出手段と、上記検出手段の検出結果に基づき被溶接部材の両端面を研削する研削手段と、を具備したことを特徴とする。
【００２１】
請求項７のレーザ溶接システムは、請求項６記載のレーザ溶接システムにおいて、上記固定治具に備える可動体は、一対の被溶接部材の突合せ両端面の隙間・端面状態を検出する検出手段と、所定寸法の突合せ隙間に位置決めする位置決め手段と、を備えたことを特徴とする。
【００２２】
請求項８のレーザ溶接システムは、請求項６記載のレーザ溶接システムにおいて、上記固定治具に備える可動体は、一対の被溶接部材の突合せ両端面の隙間・端面状態を検出する検出手段と、この検出手段からの検出情報により所定寸法の突合せ隙間に位置決めする制御手段とにより制御されることを特徴とする。
【００２３】
請求項９のレーザ溶接システムは、請求項６または７または８記載のレーザ溶接システムにおいて、上記固定治具に備える一対の可動体は、その両方を移動させて位置決め制御されることを特徴とする。
【００２４】
請求項１０のレーザ溶接システムは、請求項６記載のレーザ溶接システムにおいて、上記研削手段は、回転軸の先端に工具（回転砥石又は回転切刃）を装着するとともに、溶接ヘッド等の適所に固定的又は可動的（首振り又は進退可能）に配置され、一対の被溶接部材の突合せ両端面に対する研削加工を行なうことを特徴とする。
【００２５】
請求項１１のレーザ溶接システムは、請求項１０記載のレーザ溶接システムにおいて、上記研削手段の工具（回転砥石又は回転切刃）は、被溶接部材の端面を両側から挟持する一対のテーパー環部を備え、これら一対のテ−パー環部の間に砥石又は切刃を備えたことを特徴とする。
【００２６】
【作用】
上記請求項１のレーザ溶接方法によると、固定治具に保持された一対の被溶接部材は、その突合せ溶接に先行して、両端面の隙間を広げ、溶接ヘッド等に備える研削手段により一対の被溶接部材の対面する両端面が研削加工される。これで、両端面はバリ取りされて端面状態が平滑に修正される。この後、上記固定治具は、被溶接部材の少なくとも片側を可動して突合せ両端面の隙間を所定隙間に調節・固定する。その後、すくなくとも一対の被溶接部材の溶接線を検出手段で検出しながら溶接ヘッドの位置制御とレーザ光線の出力制御を行って突合せ溶接が実行される。
【００２７】
しかして、研削手段の研削加工により、一対の被溶接部材の両端面の加工精度のバラツキが高精度に修正される。この後、両端面の隙間寸法と端面状態が最良な条件に設定・調節されるから、どのような端面状態であっても、最適な突合せ溶接が遂行される。
【００２８】
請求項２のレーザ溶接方法によると、固定治具に保持された一対の被溶接部材は、その両端面の突合せ溶接に先行して、固定治具にセットされた一対の被溶接部材の突合せ両端面は、その端面隙間や端面状態（バリの有無等）が溶接ヘッドに取付けた検出手段によって検出される。この検出手段で検出した両端面隙間・端面状態が良好の場合は、直ちに、少なくとも一対の被溶接部材の溶接線を検出手段で検出しながら溶接ヘッドの位置制御とレーザ光線の出力制御を行って突合せ溶接が実行される。
【００２９】
また、上記検出手段で検出した両端面隙間・端面状態が不良結果の場合は、両端面の隙間を広げ、溶接ヘッド等に備える研削手段により一対の被溶接部材の対面する両端面を研削加工する。これで、両端面はバリ取りにより端面状態が平滑に修正される。この後、上記固定治具は被溶接部材の少なくとも片側を可動して突合せ両端面の隙間を所定隙間に調節・固定して再検出される。再検出が良好となれば、少なくとも一対の被溶接部材の溶接線を検出手段で検出しながら溶接ヘッドの位置制御とレーザ光線の出力制御を行って突合せ溶接が実行される。
【００３０】
しかして、一対の被溶接部材の突合せ両端面は、検出手段で検出した両端面隙間・端面状態が良好の場合は、直ちに溶接されるから、効率良く溶接作業が遂行される。また、検出手段で検出した両端面隙間・端面状態が不良の場合は、研削手段の研削加工により、一対の被溶接部材の両端面の加工精度のバラツキが高精度に修正される。この後、両端面の隙間寸法と端面状態が最良な条件に設定・調節されるから、どのような端面状態であっても、最適な突合せ溶接が遂行される。
【００３１】
請求項３のレーザ溶接方法によると、請求項２のレーザ溶接方法において、一対の被溶接部材の両端面に対する研削加工は、１回目の研削加工に基づく隙間・端面の検出で隙間・端面に不良あるとき、２回目の研削加工を続けて行い、この２回目の研削に基づく隙間・端面の検出も不良結果となった場合には、端面不良としてワーク払出処理が行われる。
【００３２】
しかして、一対の被溶接部材の突合せ両端面は、その両端面隙間・端面状態が不良である場合は、最大限に良品とする研削を試みて歩留まりを改善する。また、突合せ溶接に不適当な一対の被溶接部材は、２回目の研削による検出で見切りを付けて溶接することなくワーク払出処理されるから、不要な溶接が低減され、溶接の不良率を著しく削減することができる。
【００３３】
請求項４のレーザ溶接方法は、請求項１〜３記載のいずれか１項のレーザ溶接方法において、上記一対の被溶接部材の両端面隙間を、砥石外径よりもバリ取り代分だけ狭くし、研削手段が両端面に沿う往動移動だけで両端面のバリ取りを行うから、バリ取りのための研削時間が短縮化される。このため、研削工程が介入されても、トータルなレーザ溶接時間の短縮化が図られる。
【００３４】
請求項５のレーザ溶接方法は、請求項１〜３記載のいずれか１項のレーザ溶接方法において、上記一対の被溶接部材の両端面隙間を、砥石外径よりも大きく位置決めし、研削手段が両端面の片面ずつ沿う往動移動と復動移動により両端面のバリ取りを行うから、両端面のバリ取り精度が高められる。このため、突合せ溶接における溶接部（溶接ビード）の品質が高められるとともに、溶接強度も高められる。
【００３５】
請求項６のレーザ溶接システムによると、固定治具には，少なくとも一方の被溶接部材を他方の被溶接部材から離接移動させて突合せ面の隙間調節を行う可動体の調節手段を備え、上記溶接ヘッドには突合せ溶接に先行して溶接線及び一対の被溶接部材の突合せ隙間・端面状態を検出する検出手段と、上記検出手段の検出結果に基づき被溶接部材の両端面を研削する研削手段とを具備したから、上記請求項１〜５に記載したレーザ溶接方法を遂行させることができる。
【００３６】
請求項７のレーザ溶接システムによると、上記請求項６記載のレーザ溶接システムにおいて、固定治具の可動体は、一対の被溶接部材の突合せ両端面の隙間・端面状態を検出する検出手段と、所定寸法の突合せ隙間に位置決めする位置決め手段とを備えているから、一対の被溶接部材の突合せのための両端面の隙間調節と、適切な突合せ溶接が遂行できる。
【００３７】
請求項８のレーザ溶接システムによると、上記請求項６記載のレーザ溶接システムにおいて、固定治具の可動体は、一対の被溶接部材の突合せ両端面の隙間・端面状態を検出する検出手段と、この検出手段からの検出情報により所定寸法の突合せ隙間に位置決めする制御手段とで制御されるから、一対の被溶接部材の突合せのための両端面の隙間調節が高精度に行えるとともに、最適な突合せ溶接が遂行できる。
【００３８】
請求項９のレーザ溶接システムによると、上記請求項６または７または８記載のレーザ溶接システムにおいて、固定治具に備える一対の可動体は、その両方を移動させて位置決め制御されるから、一対の被溶接部材の突合せのための両端面の隙間調節が迅速、且つ短時間に実行でき、溶接作業の効率化が図れる。
【００３９】
請求項１０のレーザ溶接システムによると、上記請求項６記載のレーザ溶接システムにおいて、研削手段は、回転軸の先端に回転砥石又は回転工具を装着するとともに、溶接ヘッド等の適所に固定的又は可動的（首振り又は進退可能）に配置され、一対の被溶接部材の突合せ両端面に対する研削加工を行なうから、一対の被溶接部材の両端面に対する研削・切削が適確且つ、高精度に行われる。
【００４０】
請求項１１のレーザ溶接システムによると、上記請求項１０記載のレーザ溶接システムにおいて、回転砥石又は回転工具によると、一対のテーパー環部が撓み易い薄板となる被溶接部材の端面を両側から挟持しているから、薄板の端面が研削中にビビリ振動や位置ズレを起こさず、一対のテ−パー環部の間にある砥石又は切刃により、精密な端面研削乃至端面切削が行える。
【００４１】
【発明の実施の形態】
以下、本発明に係るレーザ溶接方法とその装置を、例えば、半導体レーザ発振器を使用した実施形態により説明する。図１〜図７は本発明の第１実施形態を示し、図７〜図１２は本発明の第２実施形態を示し、一次元形状部品や三次元形状部品の突合せ溶接を行なうための固定治具を備えたレーザ溶接方法とそのレーザ溶接システムである。また、図１３〜図１６は実施形態のフローチャート図である。
【００４２】
先ず、図１と図３に示す半導体レーザ発振器を使用したレーザ溶接システム１００は、半導体レーザ発振器Ｈと、レーザ光線Ｌの伝送部（光ファイバ）Ｄと、レーザ光線の集光部Ｓと、被溶接部材１０，１１の溶接線１２に対してレーザ光線Ｌを照射する溶接ヘッド２０と、この溶接ヘッド２０を姿勢制御しながら溶接線１２に沿って移動する３軸直交移動体５０に取付けられた手首６０と、このＮＣ制御装置（６軸制御＋研削手段のＳ軸又はＣ軸）６５と、一対の被溶接部材１０，１１をクランプする固定治具７０とから主要部を構成している。上記図１に示すレーザ溶接システム１００の３軸直交移動体５０は、門型フレームＦ１，Ｆ２，Ｆ３に装備したものである。また、図２に示すレーザ溶接システム１００´としても良い。この３軸直交移動体５０´は、移動コラムＦ４に片持支持されたものである。尚、上記レーザ溶接システム１００と同一部材は、同一符号を附して説明を省略している。更に、多関節ロボットの手首に装備させても良い。
【００４３】
上記３軸直交移動体５０，５０´は、左右（Ｘ軸）、前後（Ｙ軸）、上下（Ｚ軸）の３軸方向に移動制御される。また、３軸直交移動体５０，５０´に取付けられた手首６０は、溶接ヘッド２０に対する旋回動（Ｔ軸）、首振動（Ｒ軸とＢ軸）と、研削手段８０の昇降動（Ｓ軸）との４軸制御を行う。勿論、研削手段８０は、昇降動（Ｓ軸）に替えて、旋回動（Ｃ軸）としても良い。上記溶接ヘッド２０には、突合せ溶接に先行して一対の被溶接部材１０，１１の両端面１０Ａ，１１Ａを研削加工する研削手段８０と、上記一対の被溶接部材１０，１１の溶接線１２の検出手段９０及び溶融池Ｃｏの監視制御手段９０と、溶接ビードＢの形状を検出する溶接欠陥検出手段ＢＤと、これらの計測結果をリアルタイムにフイ−ドバックして溶接ビードＢを最適形状に創出すべく、レーザ光線Ｌの出力制御や溶接線（溶融池）等の位置制御について溶接条件制御するレーザ溶接制御装置ＬＣとを備えている。尚、上記溶接線１２の検出手段９０及び溶融池Ｃｏの監視制御手段９０は、同一符号９０で示した。その理由は、同一手段で両方の機能を果すからであり、同一の構成としても良いし、別手段に独立させた構成としても良い。
【００４４】
続いて、上記各構成ユニットの詳細を説明する。まず、半導体レーザ発振器Ｈは、多数のレーザ半導体からのレーザ光線を、偏光カップリングと、波長カップリングと、ＬＤスタックと、ビームシェーバーと、集光レンズ等の集束手段を介して、光束直径０．９×２．０ｍｍ程度の楕円形スポットのレーザ光線Ｌに集束される。ここでのレーザ出力は、少なくとも３ｋＷ以上の照射エネルギを発射するものである。勿論、本発明はレーザ発振器について、半導体型に限定されず、他の方式のものが適用できる。
【００４５】
上記溶接ヘッド２０に配置した研削手段８０は、突合せ溶接に先行して一対の被溶接部材１０，１１の両端面１０Ａ，１１Ａを研削する機能を持っている。上記研削手段８０は、図１と図３に示すように、溶接ヘッド２０の筐体２１における溶接線１２の方向に沿う側の側面に配置されており、昇降駆動ユニットＤＵのシリンダＣ２にて上下方向Ｃｏに昇降可能となっている。この昇降駆動ユニットＤＵは、ＮＣ制御装置６５からの昇降切替え指令Ｓ１を受けると昇降切換弁Ｖ１が働き、シリンダＣ１への圧縮空気Ｅｏの供給方向を切替える。これにより、研削手段８０は、実線示の研削位置（ーＺ軸方向）と、一点鎖線示８０´の回避位置（上限位置）の間を昇降位置決めされる。
【００４６】
勿論、上記昇降駆動ユニットＤＵは、旋回駆動ユニットとし、研削手段８０を実線示の研削位置（ーＺ軸方向）と、ニ点鎖線示８０”の回避位置（旋回位置）の間を旋回位置決めさせる構成としても良い。更に、上記研削手段８０は、その筐体８０Ａの内部に電動モータ又はエアーモータ等の回転駆動部８１を備え、回転軸８２の先端に備えるチャック８３に研削工具（ダブルカットのエンドミル）Ｋ１を着脱可能に、又はチャック８３を使用せずに固着させた形態で備えている。勿論、上記研削工具Ｋ１は、各種タイプの工具との頻繁な交換動作を行う場合には、自動工具交換装置（図示なし）を近傍に備え、この機能により自動交換動作を行わせても良い。
【００４７】
上記研削工具（ダブルカットのエンドミル）Ｋ１と、被溶接部材１０，１１の両端面１０Ａ，１１Ａとの隙間寸法Ｘの関係は、例えば、研削工具Ｋ１の直径よりもやや小さ目の隙間寸法Ｘに調節した両端面１０Ａ，１１Ａを研削加工することができる。これにより、両端面１０Ａ，１１Ａの研削効率が高められるし、研削後の両端面１０Ａ，１１Ａの接合性（隙間寸法Ｘが全長にわたり均一となる）が良好となる。勿論、図１１に示すように、両端面１０Ａ，１１Ａの隙間寸法Ｘを、研削工具Ｋ１の直径よりも大きく開き、研削工具Ｋ１の往復動で片面ずつを研削する方法によっても良い。
【００４８】
また、上記研削手段８０において、研削工具Ｋ１に替えて切削工具Ｋ２を回転軸８２に装着し、切削作業により、一対の被溶接部材１０，１１の両端面１０Ａ，１１Ａを切削加工する機能にしても良い。上記研削工具Ｋ１乃至は切削工具Ｋ２は、通常の形状は円柱形をなしている。この円柱形の工具によると、特に、薄板の端面研削や端面切削を行うと、薄板の端面が研削中にビビリ振動や位置ズレを起こすことがある。
【００４９】
そこで、図３の拡大図に示すように、一対のテーパー環部Ｔを付設し、撓み易い薄板となる被溶接部材１０，１１の端面１０Ａ，１１Ａを両側から挟持させる構成とするのが好ましい。上記一対のテ−パー環部Ｔの間にある砥石Ｋ１又は切刃Ｋ２により、精密な端面研削乃至端面切削が行えるように改良されている。
【００５０】
上記固定治具７０は、図４と図５に示す第１の実施手段のように、被溶接部材１０，１１の片側１０を固定する固着体７１と、被溶接部材１０，１１の他方の片側１１を移動可能に固定する可動体７２とからなる。上記可動体７２は、ＮＣ制御装置６５からの移動指令Ｓ２により切換弁Ｖ２を作動させてエア源Ｅｏからの圧縮空気をシリンダＣ１に方向変更して送り込み、治具開き・治具閉じ動作を行わせる。
【００５１】
勿論、固定治具７０は、図６と図７に示す第２の実施手段のように、固着体７１にもＮＣ制御装置６５からの移動指令Ｓ２により切換弁Ｖ２，Ｖ３を作動させてエア源Ｅｏからの圧縮空気をシリンダＣ１，Ｃ２に方向変更して送り込み、治具開き・治具閉じ動作を行わせる。この両側移動方式によると、２組必要になるものの、動作でも時間を半分に短縮できる効果が得られる。尚、図５と図６に示すように、被溶接部材１０，１１の端面１０Ａ，１１Ａは、検出手段９０（溶接線検出用カメラと共用）により、端面及び端面状態が検出される。その出力情報Ｇ１は、隙間処理部ＤＧに送り込まれて数値化され、レーザ溶接制御装置ＬＣとＮＣ制御装置６５に送り込まれて処理される。
【００５２】
上記固定治具７０は、図８と図９に示す第３の実施手段のように、被溶接部材１０，１１の片側１０を固定する固着体７１と、被溶接部材１０，１１の他方の片側１１を移動可能に固定する可動体７２とからなる。上記可動体７２は、ＮＣ制御装置６５からの移動指令Ｓ２によりサーボモータＳＭ１を正逆回転して固着体７１の方向に接近・離反するように１軸移動される。その移動量はエンコーダＥにより、ＮＣ制御装置６５へフィードバック信号Ｆ１を送り返して制御されている。これにより、被溶接部材１０，１１の隙間Ｘは、溶接線１２の検出手段９０により検出され、ＮＣ制御装置６５へのフィードバック信号Ｆ１によってその隙間が数値化され、所定数値の隙間Ｘとなるように、サーボモータＳＭ１を正逆回転して固着体７１の方向に１軸移動されるように構成されている。
【００５３】
勿論、固定治具７０は、図１０に示す第４の実施手段のように、固着体７１も可動体７１とすることができる。この両側可動式にすると、両側の可動体７１，７２にサーボモータＳＭ１とエンコーダＥを設置することになる。この両側移動方式によると、サーボモータＳＭ１等の駆動系とこの制御系が２組必要になるものの、ゆっくりしたサーボモータＳＭ１の指令動作でも、隙間調節作用の時間を半分に短縮できる効果が得られる。尚、図９と図１０に示すように、被溶接部材１０，１１の端面１０Ａ，１１Ａは、検出手段９０（溶接線検出用カメラと共用）により、端面及び端面状態が検出される。その出力情報Ｇ１は、隙間処理部ＤＧに送り込まれて数値化され、レーザ溶接制御装置ＬＣとＮＣ制御装置６５に送り込まれて処理される。
【００５４】
上記本発明のレーザ溶接システム１００，１００´において、固定治具７０と研削手段８０との構成により、一対の被溶接部材１０，１１の両端面１０Ａ，１１Ａを研削加工する第１の研削方法を以下に説明する。
（１）一対の被溶接部材１０，１１の隙間Ｘを研削工具Ｋ１の工具径に合わせる（実際には工具径よりも微量だけ小さ目）べく、ＮＣ制御装置６５からの移動指令Ｓ２により、シリンダＣ１又はサーボモータＳＭ１の前進駆動は固着体７１の方向に１軸移動させる。
（２）続いて、図３に示すように、研削手段８０を実線示の研削位置（ーＺ軸方向）とするとともに、被溶接部材１０，１１の両端面１０Ａ，１１Ａの隙間Ｘに研削工具Ｋ１を進入させる。そして、この研削手段８０は、両端面１０Ａ，１１Ａに沿って予め教示された研削工具Ｋ１の移動プログラム（二次元又は三次元）により、二次元又は三次形状の両端面１０Ａ，１１Ａを高精度に研削加工する。
（３）研削後は、図３に示すように、ＮＣ制御装置６５からの上昇指令Ｓ１により、研削手段８０を破線の後退位置（上限位置）とする。
（４）そして、上記被溶接部材１０，１１の両端面１０Ａ，１１Ａを図１又は図１２に示すように、溶接線１２に対して溶接ヘッド２０によるレーザ溶接が実行される。
（５）尚、上記レーザ溶接に先立ち、更に、図５と図１２に示すように、工程を追加することもできる。それは、溶接線１２の検出手段９０により一対の被溶接部材１０，１１の突合せ両端面１０Ａ，１１Ａの隙間Ｘ１が検出される。この検出信号Ｇ１は、隙間処理部ＤＧに送り込まれて数値化され、所定寸法の突合せ隙間Ｘ１となるように、ＮＣ制御装置６５が固着体７１の方向に可動体７２を位置制御する。
【００５５】
上記被溶接部材１０，１１の溶接線１２を検出する検出手段９０及び溶融池Ｃｏの監視制御手段９０は、図１に示すように、溶接ヘッド２０の片側に、溶接線の検出手段９０及び溶融池の監視制御手段９０となるカメラＣとして配置されている。上記溶接線の検出手段９０及び溶融池の監視制御手段９０は、公知手段と同一構成であり、同一作用を行うものであるから、その詳細説明を省略する。また、溶接欠陥検出手段ＢＤについても、公知手段と同一構成であり、同一作用を行うものであるから、その詳細説明を省略する。
【００５６】
本発明のレーザ溶接システム１００，１００´は、上記のように構成されており、以下のように一対の被溶接材１０，１１に対する突合せ溶接が、本発明に係る新規なレーザ溶接方法により実施される。
【００５７】
まず、本発明レーザ溶接方法の基本思想について、その動作手順の概容を図１３に示すフローチャートにより説明する。
（１）運転の「開始」２１０により、被溶接部材１０，１１の「ワークセット」２１１を行う。この「ワークセット」２１１により、突合せ溶接に先立つ「端面検出と研削の要否」判定とその実行が行われる。その手順は、▲１▼固定治具上の被溶接部材１０，１１を位置決め・クランプしながら端面隙間を所定値に管理する。▲２▼隙間の検出器（カメラ）で突合せの端面隙間と端面荒さを検出する。▲３▼端面不良が見られた時は、研削手段で端面研削を実行する。この研削時は、バキュームで研削切粉を吸引処理する。▲４▼再度、端面検出を行い。良好ならば溶接工程に移行する。不良ならば、溶接中断する。
（２）次に、「溶接実行」２１２を行う。この溶接時には、▲１▼溶接部の溶融池の幅を監視制御手段９０（ＣＭＯＳカメラ等）で監視し、この結果によりレーザ出力を調節する。▲２▼また、溶接線１２とレーザ照射位置のズレを検出手段９０（アナログカメラ）で監視し、照射位置の補正を行う。
（３）溶接が完了すると、「ワークリセット」２１３となり、「終了」２１４になる。
【００５８】
上記レーザ溶接方法の実施形態について、図１４〜図１６のフローチャートとレーザ溶接システム１００により、更に具体的に説明する。
（１）はじめに、被溶接部材１０，１１の「ワークセット」３１０（２１１）を行う。ここでは、「治具へワーク搬入」３１１の指令を受けて、固定治具７０へワーク搬入が実行される。
（２）次に、「治具にてワークの位置決め、クランプ」３１２を行う。ここでは、ワークを位置決めブロックに突き当てクランプした後、ブロックを抜き、固定治具７０を開端まで作動させる。
（３）続いて、「カメラで溶接線のチェック（軸移動）」３１３を行う。ここでは、加工プログラムに従って、レーザ溶接システム１００を運転制御し、溶接線１２の検出手段９０から情報を取り込む。
（４）続いて、「突合せ良好」３１４の判定を行う。ここでは、カメラから得られた画像処理を行い、両端面の隙間と端面荒さを判定する。そして、良好・不良の判定結果を制御系に送る。
（５）続いて、「ＮＧ１回目」３１５の判定を行う。ここでは、突合せ状態のＮＧが１回目ならば研削加工を行い。２回目のＮＧならば、研削や溶接をせずワーク払出しの「ＮＧ処理」３１６を行なう。但し、ＮＧ処理を行なう回数は可変である。
（６）続いて、「リュータにて切削治具初期位置へ」３１７の処理を行う。ここでは、固定治具７０を開口端まで移動させて所定の端面隙間とし、リュ−タ（研削手段）により端面を研削する。研削後は位置決めブロックを外し、ワークアンクランプとする。次に、リュ−タをセット状態からリセット状態とする。
（７）続いて、「溶接実行」３１８（２１２）を行う。
（８）続いて、溶接ヘッド並びに被溶接部材１０，１１を「溶接開始位置へ位置決め」３１９を行う。
（９）続いて、「レーザＯＮ」３２０を実行する。これと同時に溶融池の「画像処理」３２１が制御系からの指令により実行される。また、レーザ光線Ｌの照射位置補正を行うための溶接線１２の検出が検出手段９０により同時実行される。（この詳細説明は後記する）。
（１０）上記「画像処理」３２１の実行は「ＣＭＯＳカメラで溶融池画像取込み」３２２として行われる。
（１１）そして、レーザ溶接制御装置ＬＣ内の「パソコンで溶融池の幅検出」３２３が行われる。ここでは、パソコンで画像処理し、溶融池Ｃｏの幅を算出する。これと並行して「溶接実行（軸移動）」３２５が行われている。
（１２）更に、上記溶融池Ｃｏの幅算出に基づき「レーザの出力を制御」３２４が行われる。ここでは、溶接端に到達すると「レーザＯＦＦ」３２６の指令が発せられる。
（１３）ここで、溶接終了となる。また、画像処理も「照射終了」３２７となり、「画像終了」３２８となる。しかし、「照射終了」３２７が否定されておれば、「レーザＯＦＦ」３２６となっていなければ、引き続き溶接が続行していて「ＣＭＯＳカメラで溶融池画像取込み」３２２が実行される。
また、「レーザＯＦＦ」３２６の指令を受けて「ワークリセット」３２９（２１３）となる。
【００５９】
上記レーザ溶接方法の実施形態において、図１６のフローチャートにより、上記レーザ光線の照射位置補正を説明する。
（９）「画像処理」３２１がレーザ溶接制御装置ＬＣからの指令により実行される。これで、レーザ光線Ｌの照射位置補正を行うための溶接線１２の検出が検出手段９０により実行される。
（１０）その実行は「アナログカメラで溶接線画像取込み」３３０を行う。
（１１）そして、「画像処理装置で溶接線とレーザのズレの検出」３３１が行われる。
（１２）そして、「検出結果を制御装置へ転送」３３２される。これで、画像処理装置とレーザ溶接システム１００との座標系を考慮して計算し、被溶接部材１０，１１の突合せ端面１０Ａ，１１Ａの溶接線１２からのズレ量が補正される。
（１３）「照射終了」３２７からの終了信号で、溶接線１２の補正指令も終了される。最終的に溶接工程が「終了」３３３となる。
【００６０】
本発明は、以上説明した実施形態に限定されることなく、発明の要旨内での設計変更や構成要素の変更及び組合せの変更が自由に行える。例えば、研削工程と溶接工程における細かな段取や溶接手順は、上記実施形態に限定されない。具体的には、固定治具７０に保持される一対の被溶接部材１０，１１は、その突合せ溶接に先行して、その端面隙間や端面状態の検出を行うことなく、無条件で両端面の隙間を広げ、溶接ヘッドに備える研削手段８０により一対の被溶接部材の対面する両端面を研削加工させてから溶接工程に入っても良い。これによるときも、一対の被溶接部材の両端面の加工精度のバラツキが高精度に修正できる。この後、両端面の隙間寸法と端面状態が最良な条件に設定・調節されるから、どのような端面状態であっても、最適な突合せ溶接が遂行できる。
【００６１】
更に、研削手段８０は、その詳細な構成や取付け位置を溶接ヘッド２０に限定されず、任意・適宜に変更できる。また、被溶接部材１０，１１の形状は、一次元形状部品から三次元形状部品までの任意形状を対象とすることができ、これらの突合せ溶接を行なうことができる。
【００６２】
そして、上記検出手段９０や監視制御手段９０や溶接欠陥検出手段ＢＤは、個々独立した実施装置として説明した。これらの各装置は、ハイブリッド化して装置を１つにまとめて小型化することが可能である。これにより、複合溶接ヘッドをより一層に、コンパクトなものにすることができる。更に、レーザ発振器は、半導体レーザに限定されず、炭酸ガスレーザやＹＡＧレーザにおいても実施可能である。更に、溶融池の監視制御手段９０は、本発明を遂行するに当り絶対的に必要なものではなく、その機能を停止乃至廃止し、溶接線の検出手段９０だけを機能させた状態での本発明の遂行が可能である。
【００６３】
【発明の効果】
以上、詳述したように、本発明に係るレーザ溶接方法とその溶接システムによると、下記の効果を発揮する。
【００６４】
まず、上記請求項１のレーザ溶接方法によると、固定治具に保持された一対の被溶接部材は、その突合せ溶接に先行して、両端面の隙間を広げ、溶接ヘッド等に備える研削手段により一対の被溶接部材の対面する両端面を研削加工されるから、一対の被溶接部材の両端面の加工精度のバラツキが高精度に修正できる。この後、両端面の隙間寸法と端面状態が最良な条件に設定・調節されるから、どのような端面状態であっても、最適な突合せ溶接が遂行できる。
【００６５】
請求項２のレーザ溶接方法によると、一対の被溶接部材の突合せ両端面は、検出手段で検出した両端面隙間・端面状態が良好の場合は、直ちに溶接されるから、効率良く溶接作業が遂行できる。また、検出手段で検出した両端面隙間・端面状態が不良の場合は、研削手段の研削加工により、一対の被溶接部材の両端面の加工精度のバラツキが高精度に修正されてから、両端面の隙間寸法と端面状態が最良な条件に設定・調節されるから、どのような端面状態であっても、最適な突合せ溶接が遂行できる。
【００６６】
請求項３のレーザ溶接方法によると、請求項２のレーザ溶接方法において、一対の被溶接部材の突合せ両端面は、その両端面隙間・端面状態が不良である場合は、最大限に良品研削を試みて歩留まりが改善できる。また、突合せ溶接に不適当な一対の被溶接部材は、２回目の研削による検出で見切りを付けて溶接することなくワーク払出処理されるから、不要な溶接の低減と溶接の不良率を著しく削減することができる。
【００６７】
請求項４のレーザ溶接方法は、請求項１〜３記載のいずれか１項のレーザ溶接方法において、上記一対の被溶接部材の両端面隙間を、砥石外径よりもバリ取り代分だけ狭くし、研削手段が両端面に沿う往動移動だけで両端面のバリ取りを行うから、バリ取りのための研削時間が短縮化される。このため、研削工程が介入されても、トータルなレーザ溶接時間の短縮化が図られる。
【００６８】
請求項５のレーザ溶接方法は、請求項１〜３記載のいずれか１項のレーザ溶接方法において、上記一対の被溶接部材の両端面隙間を、砥石外径よりも大きく位置決めし、研削手段が両端面の片面ずつ沿う往動移動と復動移動により両端面のバリ取りを行うから、両端面のバリ取り精度が高められる。このため、突合せ溶接における溶接部（溶接ビード）の品質が高められるとともに、溶接強度も高められる。
【００６９】
請求項６のレーザ溶接システムによると、固定治具には，少なくとも一方の被溶接部材を他方の被溶接部材から離接移動させて突合せ面の隙間調節を行う可動体の調節手段を備え、上記溶接ヘッドには突合せ溶接に先行して溶接線及び一対の被溶接部材の突合せ隙間・端面状態を検出する検出手段と、上記検出手段の検出結果に基づき被溶接部材の両端面を研削する研削手段とを具備したから、上記請求項１〜５に記載したレーザ溶接方法を遂行させることができる。
【００７０】
請求項７のレーザ溶接システムによると、上記請求項６記載のレーザ溶接システムにおいて、固定治具の可動体は、一対の被溶接部材の突合せ両端面の隙間・端面状態を検出する検出手段と、所定寸法の突合せ隙間に位置決めする位置決め手段とを備えているから、一対の被溶接部材の突合せのための両端面の隙間調節と、適切な突合せ溶接が遂行できる。
【００７１】
請求項８のレーザ溶接システムによると、上記請求項６記載のレーザ溶接システムにおいて、固定治具の可動体は、一対の被溶接部材の突合せ両端面の隙間・端面状態を検出する検出手段と、この検出手段からの検出情報により所定寸法の突合せ隙間に位置決めする制御手段とで制御されるから、一対の被溶接部材の突合せのための両端面の隙間調節が高精度に行えるとともに、最適な突合せ溶接が遂行できる。
【００７２】
請求項９のレーザ溶接システムによると、上記請求項６または７記載のレーザ溶接システムにおいて、固定治具に備える一対の可動体は、その両方を移動させて位置決め制御されるから、一対の被溶接部材の突合せのための両端面の隙間調節が迅速、且つ短時間に実行でき、溶接作業の効率化ができる。
【００７３】
請求項１０のレーザ溶接システムによると、上記請求項６記載のレーザ溶接システムにおいて、研削手段は、回転軸の先端に回転砥石又は回転工具を装着するとともに、溶接ヘッド等の適所に固定的又は可動的（首振り又は進退可能）に配置され、一対の被溶接部材の突合せ両端面に対する研削加工を行なうから、一対の被溶接部材の両端面に対する研削・切削が適確且つ、高精度にできる。
【００７４】
請求項１１のレーザ溶接システムによると、上記請求項９記載のレーザ溶接システムにおいて、回転砥石又は回転工具によると、一対のテーパー環部が撓み易い薄板となる被溶接部材の端面を両側から挟持しているから、薄板の端面が研削中にビビリ振動や位置ズレを起こさず、一対のテ−パー環部の間にある砥石又は切刃により、精密な端面研削乃至端面切削ができる。
【図面の簡単な説明】
【図１】本発明のレーザ溶接システムの全体と要部を示す斜視図である。
【図２】本発明のレーザ溶接システムの変形例を示す斜視図である。
【図３】本発明のレーザ溶接システムの研削状態の斜視図である。
【図４】本発明の第１実施形態を示し、レーザ溶接システムの固定治具の斜視図である。
【図５】本発明の第１実施形態を示し、レーザ溶接システムの固定治具の平面図である。
【図６】本発明の第２実施形態を示し、レーザ溶接システムの固定治具の平面図である。
【図７】本発明の第３実施形態を示し、レーザ溶接システムの固定治具の斜視図である。
【図８】本発明の第３実施形態を示し、レーザ溶接システムの固定治具の斜視図である。
【図９】本発明の第３実施形態を示し、レーザ溶接システムの固定治具の平面図である。
【図１０】本発明の第４実施形態を示し、レーザ溶接システムの固定治具の平面図である。
【図１１】本発明のレーザ溶接システムの研削状態の斜視図である。
【図１２】本発明の実施形態を示し、溶接部の溶接状態を示す斜視図である。
【図１３】本発明の第１実施形態のレーザ溶接方法の基本的フローチャート図である。
【図１４】本発明の第２実施形態のレーザ溶接方法の具体的フローチャート図である。
【図１５】本発明の第２実施形態のレーザ溶接方法の具体的フローチャート図である。
【図１６】本発明の第２実施形態のレーザ溶接方法の具体的フローチャート図である。
【図１７】従来のレーザ溶接システムの全体システム図である。
【符号の説明】
１０，１１被溶接部材（通常の薄板）
１０Ａ，１１Ａ両端面
１２溶接線
２０溶接ヘッド
５０，５０´ ３軸直交移動体
６０手首
６５ＮＣ制御装置（６軸制御）
７０固定治具
７１固着体
７２可動体
８０研削手段
８１回転駆動部
９０溶接線の監視制御手段（溶融池の監視制御手段）
１００，１００´ レーザ溶接システム
Ｂ溶接ビード
ＢＤ溶接欠陥検出手段
Ｃカメラ
Ｃ１，Ｃ２シリンダ
Ｃｏ溶融池
Ｄ伝送部（光ファイバ）
ＤＵ昇降駆動ユニット
Ｅエンコーダ
Ｅｏ圧縮空気
ＬＣレーザ溶接制御装置
Ｌ溶接用のレーザ光線
Ｋ１研削工具
Ｋ２切削工具
Ｈ半導体レーザ発振器
ＳＭ１サーボモータ
Ｖ２，ｖ３切換弁
Ｘ隙間
Ｘ１突合せ隙間[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser welding method using a laser oscillator and this laser welding system, and in particular, detects a gap and an end surface state of both ends of a butt before butt welding a pair of welded members in a welding process. If it is defective, it relates to a device that deburrs and grinds both butt ends.
[0002]
[Prior art]
Conventional laser welding apparatuses mainly use carbon dioxide lasers or YAG lasers as their laser oscillators. Recently, a high-power semiconductor laser oscillator that uses a large number of semiconductor laser elements and focuses each laser beam has been adopted. The laser welding apparatus using this semiconductor laser oscillator is expected in the automobile industry to contribute to the improvement of safety by reducing the weight of the vehicle body and the rigidity of the vehicle body, and the reduction of welding costs. In particular, it has been recognized that superiority can be achieved by non-contact single-sided welding for tailored blank material welding, butt welding and lap welding of sheet steel.
[0003]
The semiconductor laser welding apparatus has a basic configuration shown in FIG. 17, for example. A semiconductor laser welding apparatus 1 is a welding that irradiates a laser beam 5 to a semiconductor laser oscillator 2, a laser beam transmission unit 3, a laser beam condensing unit 4, and a welding line 12 of members to be welded 10 and 11. The head 6, the moving wrist 8 of the three-axis orthogonal moving body 7 that moves along the welding line while controlling the posture of the welding head 6 or the wrist (not shown) of the articulated robot, and the members to be welded 10 and 11 are clamped And a fixing jig G. Further, the welding head has functions such as laser output control in order to detect the welding line 12 by the camera 9, control the position of the laser beam 5, and control welding conditions by monitoring the molten pool. It has a beat quality inspection function. The welding head 6 in the semiconductor laser welding apparatus 1 having these functions performs tailored blank material welding, butt welding of thin steel plates, lap welding, and the like by non-contact one-side welding.
[0004]
In the semiconductor laser welding apparatus and other laser welding apparatuses, there are various requirements for butt welding using a laser beam. First, since the optical axis diameter of the laser beam is as small as about 0.9 mm, the variation between both end surfaces of the pair of materials to be welded (plate thickness of 1 to 2 mm) is a highly accurate gap dimension prior to butt welding. An initial setting of (0 to 0.2 mm) is required. For this purpose, it is desired that both end faces of the workpiece are ground smoothly, and a fixing jig capable of finely adjusting and fixing the end faces of the pair of workpieces to a predetermined gap size. Is desired. And when carrying out 3D welding of a pair of materials to be welded that are thin plates and pressed into a 3D shape, the exact match of the butt end faces and the irradiation of the laser beam to the exact irradiation position of the welding line High position control is further required.
[0005]
However, in the above-mentioned pair of materials to be welded (plate thickness of 1 to 2 mm), if there are variations in the initial setting of the clearance dimension (0 to 0.2 mm) or the end face shape of both end faces (butting faces), poor welding in butt welding Will be generated. Specifically, in a pair of materials to be welded, reliable welding is performed although it is not appropriate where there is no butt gap. However, in a place where the butt gap size between both end faces is wide, a hole due to welding is opened, which causes a welding failure. In order to eliminate this welding failure, (1) the same gap is provided over the entire length of the weld end face, or (2) the laser output and the defocus amount are controlled in accordance with the wide / narrow gap of the weld end face (butting face). Alternatively, a method for controlling the welding speed is proposed.
[0006]
In the above (1), the method of making the same gap over the entire length of the welding end surface (butting surface) is to separate the burrs on the end surfaces of the pair of materials to be welded with a grindstone, laser light or combustion in a separate process prior to butt welding. Means have been implemented to dissolve burrs with gas. The pair of materials to be deburred are carried into a welding process, fixed to a fixing jig, and laser-welded under a certain clearance control.
[0007]
In (2) above, the method of controlling the laser output and defocus amount or adjusting the welding speed in accordance with the wide / narrow gap of the weld end face (butting face) is adapted to the cross-sectional properties of the butt face. Laser welding of metal bands is performed under welding conditions. The details are a welding machine that cuts the rear end portion of the preceding metal strip and the front end portion of the subsequent metal strip, then butts each other's cut surface and laser welds along the butt portion. A fracture surface detector that grasps the area ratio of the fracture surface at each position in the width direction of the abutting surface, a burr detector that measures the degree of burr occurrence at each position in the width direction, and the thickness at each position in the width direction is measured. A plate thickness measuring device, a calculator that calculates the laser output, welding speed, and filler wire supply speed based on the signals from the fracture surface detector, burr detector, and plate thickness measuring device, and a command from this calculator And a controller for controlling the laser output, the welding speed, and the supply speed of the filler wire. With this configuration, line troubles such as plate breakage are reduced. (For example, see Patent Document 1)
[0008]
[Patent Document 1]
JP-A-8-290281 (first page, second page, FIG. 1)
[0009]
However, in the above (1), the method of deburring with a grindstone or a laser beam so as to have the same gap over the entire length of the weld end face is performed in a separate process (deburring process) prior to the butt welding. For this reason, a deburring device, a space for installing the deburring device, and a management process become indispensable, resulting in an increase in initial investment, operation cost, and welding time. Moreover, even if deburring of both end faces of the welded material is performed with high accuracy in a separate process (deburring process), when it is reattached to the fixing jig of the welding process, which is a subsequent process, There is little guarantee that the gaps between the two end faces of the welded material will be uniform due to the influence of bending, distortion, twisting, etc. For this reason, in the operation | work which resets a deburring process and a welding process to the jig | tool of another process, the problem of reducing a welding precision other than the said problem remains.
[0010]
Further, in the above (2), the method of controlling the laser output and the defocus amount or adjusting the welding speed in accordance with the wide / narrow gap is controlled by welding conditions adapted to the cross-sectional properties of the butt surface, The belts must be laser welded. This complicates the control system and necessitates capital investment for expensive control devices. In addition, the bead width (building width and height) of the welded surface varies greatly between a place where there is no butt gap and a place where the gap is wide. As a result, it means that the appearance is deteriorated and the welding strength varies due to the change in the bead width. Therefore, the welding method under the welding conditions adapted to the cross-sectional properties of the abutting surfaces is judged at first glance to be able to reasonably perform safe welding. However, butt welding of high-quality thin plates with essentially uniform welding strength cannot be expected.
[0011]
However, the ideal welding conditions required for the butt welding of thin plates are to maintain a uniform and identical state over the entire length of the welded gaps and end face properties in a pair of materials to be welded. When butt welding is performed under the condition in which this state is completely guaranteed, uniform and identical high weld quality with a bead width (building width and height) can be obtained.
[0012]
[Problems to be solved by the invention]
The present invention has been made in view of various problems of butt welding that occur in a laser welding method carried out by employing the above-described conventional various laser welding apparatuses.
[0013]
The first object of the present invention is to provide a laser welding method in which, in a welding process, prior to butt welding a pair of members to be welded, after grinding the end surfaces thereof, the butt gap is adjusted and welding is performed. is there. Furthermore, the second object is to detect the gap size and the end face state of both ends of the butt before the butt welding of the pair of members to be welded in the welding process. The present invention provides a laser welding method in which welding is adjusted again.
[0014]
In order to achieve the first and second objects, the third object of the present invention is a grinding means for grinding both butt end faces prior to butt welding a pair of welded members in the welding process, The present invention provides a laser welding system including a detecting means for detecting a contact state between both end surfaces of a butt and a fixing jig for adjusting a clearance between both ends of the butt.
[0015]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a laser welding method for irradiating a laser beam to a fixing jig for adjusting / holding a gap between both end faces of a pair of welded members and a butt welding line of the pair of welded members. Welding head, grinding means for grinding the butt end faces of a pair of welded members in preparation for the welding head, detection means for at least the welding line and butt gap / end face state, and welding while controlling the attitude of the welding head In a laser welding method using a laser welding system comprising a wrist of an articulated robot that moves along a line or a wrist of a three-axis orthogonal moving body,
Prior to the butt welding of the pair of members to be welded held by the fixing jig, both facing surfaces of the pair of members to be welded are ground by grinding means provided in the welding head or the like, and thereafter The fixing jig moves at least one side of the member to be welded and adjusts and fixes the gap between the butt end faces to a predetermined gap, and then detects the welding line of at least a pair of members to be welded by the detecting means while detecting the welding line of the welding head. Butt welding is performed by performing position control and laser beam output control.
[0016]
The laser welding method according to claim 2 includes a fixing jig that adjusts and holds a gap between butt end faces of a pair of welded members, and a welding head that irradiates a laser beam to a butt weld line of the pair of welded members. And a grinding means for grinding the butt end faces of a pair of members to be welded in preparation for the welding head, at least the means for detecting the welding line and the butt gap / end face state, and along the welding line while controlling the attitude of the welding head. In a laser welding method using a laser welding system comprising: a wrist of an articulated robot that moves by moving a wrist or a wrist of a three-axis orthogonal moving body;
Prior to the butt welding of the pair of welded members held by the fixing jig, when the gap between both end faces detected by the detecting means is good, the weld line of the pair of welded members is immediately detected. The position of the welding head and the output control of the laser beam are controlled while being detected by the means, and butt welding is performed, and if the gap / end face condition detected by the detection means is a defective result, the welding head or the like is Grinding means are provided to grind the opposite end faces of the pair of welded members, and then the fixing jig moves at least one side of the welded members to adjust and fix the gap between the butt end faces to a predetermined gap. If the subsequent re-detection is satisfactory, the welding head position control and the laser beam output control are performed while detecting the welding lines of at least a pair of members to be welded by the detection means. And butterflies.
[0017]
The laser welding method according to claim 3 is the laser welding method according to claim 2, wherein the grinding of the both end faces of the pair of members to be welded follows the gap / end face detection failure based on the first grinding process. If the gap / end face detection results in a failure, the workpiece payout process is performed as an end face failure.
[0018]
The laser welding method according to claim 4 is the laser welding method according to any one of claims 1 to 3, wherein a gap between both end faces of the pair of members to be welded is narrower than a tool outer diameter by a deburring allowance. The grinding means deburrs both end surfaces only by forward movement along both end surfaces.
[0019]
The laser welding method according to claim 5 is the laser welding method according to any one of claims 1 to 3, wherein the gap between both end faces of the pair of members to be welded is positioned larger than the outer diameter of the tool, and the grinding means is Both end surfaces are deburred by forward movement and backward movement along each side of both end surfaces.
[0020]
The laser welding system according to claim 6 is a fixing jig for fixing a pair of members to be welded, a welding head for irradiating a laser beam guided from a laser oscillator to a butt welding line of the pair of members to be welded, and the above A wrist of an articulated robot that moves the welding head along the welding line while controlling the posture or a wrist of a three-axis orthogonal moving body, a detection unit that detects the welding line, and a monitoring control unit for the molten pool In the laser welding system, the fixing jig is provided with a movable body adjusting means for adjusting the clearance of the abutting surface by moving at least one member to be welded away from the other member to be welded. Prior to butt welding, detecting means for detecting the welding line and the butt gap / end face state of the pair of welded members, and grinding means for grinding both end faces of the welded member based on the detection results of the detecting means , Characterized by comprising a.
[0021]
The laser welding system according to claim 7 is the laser welding system according to claim 6, wherein the movable body provided in the fixing jig includes a detecting unit that detects a gap and an end surface state of the butt end faces of the pair of welded members; Positioning means for positioning in a butt gap of a predetermined dimension.
[0022]
The laser welding system according to claim 8 is the laser welding system according to claim 6, wherein the movable body provided in the fixing jig includes a detecting unit that detects a gap / end surface state between both ends of the pair of welded members; It is controlled by the control means which positions in the butt gap of a predetermined dimension by the detection information from this detection means.
[0023]
The laser welding system according to claim 9 is the laser welding system according to claim 6, 7, or 8, wherein the pair of movable bodies provided in the fixing jig is positioned and controlled by moving both of them. .
[0024]
The laser welding system according to claim 10 is the laser welding system according to claim 6, wherein the grinding means is equipped with a tool (a rotating grindstone or a rotating cutting blade) at the tip of the rotating shaft and fixed at an appropriate position such as a welding head. It is characterized in that it is arranged to be movable or movable (can be swung or moved back and forth), and grinding is performed on both end faces of the pair of welded members.
[0025]
The laser welding system according to claim 11 is the laser welding system according to claim 10, wherein the tool (rotary grindstone or rotary cutting blade) of the grinding means includes a pair of tapered ring portions that sandwich the end face of the member to be welded from both sides. And a grindstone or a cutting blade is provided between the pair of taper ring portions.
[0026]
[Action]
According to the laser welding method of the first aspect, the pair of members to be welded held by the fixing jig widen the gap between both end faces before the butt welding, and the pair of members to be welded by the grinding means provided in the welding head or the like. The opposite end faces of the member to be welded are ground. Thus, both end faces are deburred and the end face state is corrected smoothly. Thereafter, the fixing jig moves at least one side of the member to be welded, and adjusts and fixes the gap between the butt end faces to a predetermined gap. Thereafter, butt welding is performed by controlling the position of the welding head and controlling the output of the laser beam while detecting at least the welding lines of the pair of members to be welded by the detecting means.
[0027]
Therefore, the variation in the processing accuracy of the both end faces of the pair of welded members is corrected with high accuracy by the grinding process of the grinding means. Thereafter, the gap dimension and the end face state of both end faces are set and adjusted to the optimum conditions, so that optimum butt welding is performed regardless of the end face state.
[0028]
According to the laser welding method of claim 2, the pair of welded members held by the fixing jig are butt ends of the pair of welded members set on the fixing jig prior to the butt welding of both end faces thereof. The surface is detected by detecting means attached to the welding head for the end surface gap and the end surface state (presence or absence of burrs). If the gaps and end face states detected by the detection means are good, immediately perform welding head position control and laser beam output control while detecting at least the welding lines of the pair of welded members by the detection means. Butt welding is performed.
[0029]
In addition, when the both end face gap and the end face state detected by the detecting means are defective, the both end face gaps are widened and the facing end faces of the pair of members to be welded are ground by the grinding means provided in the welding head or the like. . As a result, both end surfaces are smoothly corrected by deburring. Thereafter, the fixing jig is re-detected by moving at least one side of the member to be welded and adjusting and fixing the gap between both end faces to a predetermined gap. If the re-detection is good, the butt welding is performed by performing the position control of the welding head and the output control of the laser beam while detecting the welding line of at least a pair of members to be welded by the detecting means.
[0030]
Thus, the butt end faces of the pair of members to be welded are immediately welded when the gaps and end face states detected by the detecting means are good, so that the welding operation is performed efficiently. In addition, when the both end face gaps and end face states detected by the detecting means are poor, the grinding accuracy of the pair of welded members is corrected with high precision by the grinding process of the grinding means. Thereafter, the gap dimension and the end face state of both end faces are set and adjusted to the optimum conditions, so that optimum butt welding is performed regardless of the end face state.
[0031]
According to the laser welding method of claim 3, in the laser welding method of claim 2, the grinding of the both end faces of the pair of members to be welded is defective in the gap / end face by detecting the gap / end face based on the first grinding process. In some cases, the second grinding process is continued, and when the gap / end face detection based on the second grinding also results in a failure result, the workpiece payout process is performed as an end face failure.
[0032]
Therefore, if the gap between both end faces of the pair of welded members and the state of the end faces are poor, the yield is improved by trying to grind them to the highest quality. In addition, since a pair of welded members that are inappropriate for butt welding are subjected to workpiece discharge processing without being cut off and welded by the second grinding detection, unnecessary welding is reduced, and the defective rate of welding is remarkably increased. Can be reduced.
[0033]
The laser welding method according to claim 4 is the laser welding method according to any one of claims 1 to 3, wherein a gap between both end faces of the pair of members to be welded is made smaller than a grindstone outer diameter by a deburring allowance. Since the grinding means deburrs both end surfaces only by forward movement along both end surfaces, the grinding time for deburring is shortened. For this reason, even if the grinding process is intervened, the total laser welding time can be shortened.
[0034]
The laser welding method according to claim 5 is the laser welding method according to any one of claims 1 to 3, wherein the gaps on both ends of the pair of members to be welded are positioned larger than the outer diameter of the grindstone, and the grinding means Since both end surfaces are deburred by forward movement and backward movement along each side of both end surfaces, the deburring accuracy of both end surfaces can be improved. For this reason, the quality of the welded portion (weld bead) in butt welding is enhanced, and the welding strength is also enhanced.
[0035]
According to the laser welding system of claim 6, the fixing jig is provided with a movable body adjusting means for adjusting the clearance between the butted surfaces by moving at least one of the members to be welded away from the other member to be welded. Prior to butt welding, the welding head includes a detecting means for detecting a welding line and a butt gap / end face state of a pair of welded members, and a grinding means for grinding both end faces of the welded member based on the detection result of the detecting means. Therefore, the laser welding method according to any one of claims 1 to 5 can be performed.
[0036]
According to the laser welding system of claim 7, in the laser welding system of claim 6, the movable body of the fixing jig includes detection means for detecting a gap / end surface state of the butt end faces of the pair of welded members; Since positioning means for positioning in a butt gap of a predetermined size is provided, it is possible to adjust gaps at both end faces for butting a pair of members to be welded and appropriate butt welding.
[0037]
According to the laser welding system of claim 8, in the laser welding system of claim 6, the movable body of the fixing jig includes a detecting unit that detects a gap / end surface state of both end faces of the pair of welded members; Since the detection information from the detection means is controlled by a control means for positioning in a butt gap of a predetermined dimension, the gap between both end faces for butting a pair of welded members can be adjusted with high accuracy, and an optimum butt is obtained. Welding can be carried out.
[0038]
According to the laser welding system of claim 9, in the laser welding system of claim 6, 7, or 8, the pair of movable bodies provided in the fixing jig are positioned and controlled by moving both of them. The clearance adjustment between the both end faces for the butting of the members to be welded can be performed quickly and in a short time, and the efficiency of the welding work can be improved.
[0039]
According to the laser welding system of claim 10, in the laser welding system of claim 6, the grinding means attaches a rotating grindstone or a rotating tool to the tip of the rotating shaft and is fixed or movable at an appropriate position such as a welding head. Since it is arranged on the target (can be swung or moved back and forth) and grinds both end surfaces of the pair of welded members, the grinding and cutting of both end surfaces of the pair of welded members are performed accurately and with high accuracy. .
[0040]
According to the laser welding system of claim 11, in the laser welding system of claim 10, according to the rotating grindstone or the rotating tool, the end faces of the member to be welded which are thin plates in which the pair of tapered ring portions are easily bent are sandwiched from both sides. Therefore, the end face of the thin plate does not cause chatter vibration or misalignment during grinding, and precise end face grinding or end face cutting can be performed with a grindstone or a cutting blade between a pair of taper rings.
[0041]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a laser welding method and apparatus according to the present invention will be described by way of an embodiment using a semiconductor laser oscillator, for example. 1 to 7 show a first embodiment of the present invention, and FIGS. 7 to 12 show a second embodiment of the present invention. A fixed jig for performing butt welding of one-dimensional shaped parts and three-dimensional shaped parts. A laser welding method and a laser welding system including the tool. 13 to 16 are flowcharts of the embodiment.
[0042]
First, a laser welding system 100 using the semiconductor laser oscillator shown in FIGS. 1 and 3 includes a semiconductor laser oscillator H, a laser beam L transmission unit (optical fiber) D, a laser beam condensing unit S, The welding head 20 irradiates the welding line 12 of the welding members 10 and 11 with the laser beam L, and the three-axis orthogonal moving body 50 that moves along the welding line 12 while controlling the attitude of the welding head 20. The wrist 60, the NC control device (6-axis control + S-axis or C-axis of the grinding means) 65, and a fixing jig 70 that clamps the pair of members to be welded 10 and 11 constitute a main part. The three-axis orthogonal moving body 50 of the laser welding system 100 shown in FIG. 1 is mounted on the portal frames F1, F2, and F3. Moreover, it is good also as laser welding system 100 'shown in FIG. The three-axis orthogonal moving body 50 ′ is cantilevered by the moving column F4. The same members as those of the laser welding system 100 are denoted by the same reference numerals and description thereof is omitted. Furthermore, you may equip with the wrist of an articulated robot.
[0043]
The three-axis orthogonal moving bodies 50 and 50 ′ are controlled to move in three axial directions, ie, left and right (X axis), front and rear (Y axis), and vertical (Z axis). Further, the wrist 60 attached to the three-axis orthogonal moving bodies 50 and 50 ′ is a swiveling motion (T-axis), neck vibration (R-axis and B-axis) with respect to the welding head 20, and lifting / lowering motion (S-axis) of the grinding means 80. 4 axis control. Of course, the grinding means 80 may be swiveled (C-axis) instead of moving up and down (S-axis). The welding head 20 includes a grinding means 80 for grinding both end faces 10A and 11A of the pair of welded members 10 and 11 prior to the butt welding, and a welding line 12 of the pair of welded members 10 and 11. The detection means 90 and the weld pool Co monitoring control means 90, the weld defect detection means BD for detecting the shape of the weld bead B, and the measurement results are fed back in real time to create the weld bead B in an optimum shape. Therefore, a laser welding control device LC that controls the welding conditions for the output control of the laser beam L and the position control of the weld line (molten pool) or the like is provided. Note that the detection means 90 for the weld line 12 and the monitoring control means 90 for the weld pool Co are indicated by the same reference numeral 90. The reason is that both functions are performed by the same means, and the same configuration may be used, or a configuration independent of another means may be used.
[0044]
Next, details of each of the constituent units will be described. First, the semiconductor laser oscillator H converts a laser beam from a large number of laser semiconductors into a beam diameter of 0 through focusing means such as a polarization coupling, a wavelength coupling, an LD stack, a beam shaver, and a condenser lens. The laser beam L is focused on an elliptical spot of about 9 × 2.0 mm. The laser output here emits irradiation energy of at least 3 kW or more. Of course, the present invention is not limited to the semiconductor type of the laser oscillator, and other types can be applied.
[0045]
The grinding means 80 arranged on the welding head 20 has a function of grinding both end faces 10A, 11A of the pair of welded members 10, 11 prior to the butt welding. As shown in FIGS. 1 and 3, the grinding means 80 is disposed on the side surface of the casing 21 of the welding head 20 on the side along the direction of the weld line 12, and is moved up and down by the cylinder C2 of the lifting drive unit DU. It can be moved up and down in the direction Co. When the elevation drive unit DU receives the elevation switching command S1 from the NC controller 65, the elevation switching valve V1 operates to switch the supply direction of the compressed air Eo to the cylinder C1. As a result, the grinding means 80 is moved up and down between the grinding position indicated by the solid line (−Z-axis direction) and the avoidance position (upper limit position) indicated by the alternate long and short dash line 80 ′.
[0046]
Of course, the elevating drive unit DU is a swivel drive unit, and the grinding means 80 is swiveled between a grinding position indicated by a solid line (−Z-axis direction) and an avoidance position (turning position) indicated by a two-dot chain line 80 ″. Furthermore, the grinding means 80 includes a rotation drive unit 81 such as an electric motor or an air motor inside the housing 80A, and a grinding tool (double-cut) is attached to the chuck 83 provided at the tip of the rotation shaft 82. End mill) K1 is detachably attached or fixed without using the chuck 83. Of course, the grinding tool K1 is automatically used when it is frequently exchanged with various types of tools. A tool changer (not shown) may be provided nearby and an automatic change operation may be performed by this function.
[0047]
The relationship of the gap dimension X between the grinding tool (double-cut end mill) K1 and both end faces 10A, 11A of the members to be welded 10, 11 is adjusted to, for example, the gap dimension X slightly smaller than the diameter of the grinding tool K1. The both end faces 10A and 11A can be ground. Thereby, the grinding efficiency of both end surfaces 10A and 11A is improved, and the joining properties (gap size X is uniform over the entire length) of both end surfaces 10A and 11A after grinding are improved. Of course, as shown in FIG. 11, the gap dimension X between the both end faces 10A, 11A may be opened larger than the diameter of the grinding tool K1, and one side may be ground by reciprocating movement of the grinding tool K1.
[0048]
Further, in the grinding means 80, a cutting tool K2 is mounted on the rotary shaft 82 instead of the grinding tool K1, and the both end faces 10A, 11A of the pair of welded members 10, 11 are cut by a cutting operation. Also good. The grinding tool K1 or the cutting tool K2 has a cylindrical shape as a normal shape. According to this cylindrical tool, particularly when end face grinding or end face cutting of a thin plate is performed, the end surface of the thin plate may cause chatter vibrations or misalignment during grinding.
[0049]
Therefore, as shown in the enlarged view of FIG. 3, it is preferable that a pair of tapered ring portions T are provided so that the end faces 10A and 11A of the welded members 10 and 11 that are thin plates that are easily bent are sandwiched from both sides. The grindstone K1 or the cutting edge K2 between the pair of taper ring portions T is improved so that precise end face grinding or end face cutting can be performed.
[0050]
The fixing jig 70 includes a fixed body 71 for fixing one side 10 of the members 10 and 11 to be welded and the other side of the members 10 and 11 to be welded, as in the first embodiment shown in FIGS. And a movable body 72 that movably fixes 11. The movable body 72 operates the switching valve V2 in response to the movement command S2 from the NC control device 65, changes the direction of the compressed air from the air source Eo to the cylinder C1, and feeds the jig to open and close the jig. Make it.
[0051]
Of course, the fixing jig 70 operates the switching valves V2 and V3 on the fixed body 71 by the movement command S2 from the NC controller 65 as in the second embodiment shown in FIGS. The direction of the compressed air from Eo is sent to the cylinders C1 and C2 by changing the direction, and the jig opening / closing operation is performed. According to this both-side moving method, although two sets are required, the effect of shortening the time by half can be obtained even in the operation. As shown in FIGS. 5 and 6, the end faces and end face states of the end faces 10A and 11A of the members to be welded 10 and 11 are detected by the detecting means 90 (shared with the welding line detection camera). The output information G1 is sent to the gap processing unit DG and digitized, and sent to the laser welding control device LC and the NC control device 65 for processing.
[0052]
The fixing jig 70 includes a fixed body 71 for fixing one side 10 of the members to be welded 10 and 11 and the other side of the members to be welded 10 and 11, as in the third embodiment shown in FIGS. And a movable body 72 that movably fixes 11. The movable body 72 is moved by one axis so that the servo motor SM1 rotates forward and backward in accordance with a movement command S2 from the NC control device 65 so as to approach and separate in the direction of the fixed body 71. The amount of movement is controlled by the encoder E by sending back a feedback signal F1 to the NC controller 65. As a result, the gap X between the members to be welded 10 and 11 is detected by the detection means 90 of the welding line 12, and the gap is digitized by the feedback signal F1 to the NC control device 65 so that the gap X becomes a predetermined numerical value. Further, the servo motor SM 1 is rotated forward and backward to move one axis in the direction of the fixed body 71.
[0053]
Of course, in the fixing jig 70, the fixed body 71 can also be the movable body 71 as in the fourth implementation means shown in FIG. When the both-side movable type is adopted, the servo motor SM1 and the encoder E are installed on the movable bodies 71 and 72 on both sides. According to this two-sided movement method, two sets of drive systems such as the servo motor SM1 and the control system are required, but the effect of reducing the time for adjusting the gap by half can be obtained even with a slow command operation of the servo motor SM1. . 9 and 10, the end faces 10A and 11A of the members 10 and 11 to be welded are detected by the detecting means 90 (shared with the welding line detection camera). The output information G1 is sent to the gap processing unit DG and digitized, and sent to the laser welding control device LC and the NC control device 65 for processing.
[0054]
In the laser welding system 100, 100 ′ of the present invention, a first grinding method for grinding both end faces 10A, 11A of the pair of welded members 10, 11 by the configuration of the fixing jig 70 and the grinding means 80 is provided. This will be described below.
(1) In order to adjust the gap X between the pair of members to be welded 10 and 11 to the tool diameter of the grinding tool K1 (actually a small amount smaller than the tool diameter), the cylinder C1 is operated by a movement command S2 from the NC controller 65. Alternatively, the forward drive of the servo motor SM1 moves one axis in the direction of the fixed body 71.
(2) Subsequently, as shown in FIG. 3, the grinding means 80 is set to the grinding position indicated by the solid line (−Z-axis direction), and the grinding tool is inserted into the gap X between the both end faces 10A, 11A of the members 10 and 11 to be welded. Enter K1. And this grinding means 80 is highly accurate in the two-dimensional or tertiary shape both-end surface 10A, 11A with the movement program (two-dimensional or three-dimensional) of the grinding tool K1 taught beforehand along the both-end surface 10A, 11A. Grind.
(3) After grinding, as shown in FIG. 3, the grinding means 80 is set to the retracted position (upper limit position) shown by the broken line by the ascending command S 1 from the NC controller 65.
(4) Then, laser welding by the welding head 20 is performed on the weld line 12 at both end faces 10A, 11A of the members to be welded 10, 11 as shown in FIG.
(5) Prior to the laser welding, as shown in FIGS. 5 and 12, a process can be added. The detection means 90 of the welding line 12 detects the gap X1 between the butt end faces 10A, 11A of the pair of welded members 10, 11. The detection signal G1 is sent to the gap processing unit DG and digitized, and the NC control device 65 controls the position of the movable body 72 in the direction of the fixed body 71 so that the butt gap X1 has a predetermined size.
[0055]
As shown in FIG. 1, the detection means 90 for detecting the weld line 12 of the members to be welded 10 and 11 and the monitoring control means 90 for the molten pool Co are provided on one side of the welding head 20 with the welding line detection means 90 and the melting line. It is arranged as a camera C serving as a pond monitoring control means 90. The weld line detection means 90 and the molten pool monitoring control means 90 have the same configuration as the known means and perform the same operation, and thus detailed description thereof will be omitted. Also, the welding defect detection means BD has the same configuration as that of the known means and performs the same action, so that detailed description thereof is omitted.
[0056]
The laser welding system 100, 100 ′ of the present invention is configured as described above, and butt welding with respect to a pair of materials to be welded 10, 11 is performed by the novel laser welding method according to the present invention as follows. The
[0057]
First, the basic concept of the laser welding method of the present invention will be described with reference to the flowchart shown in FIG.
(1) “Work set” 211 of the welded members 10 and 11 is performed by “start” 210 of operation. By this “work set” 211, “end face detection and necessity of grinding” determination and execution prior to butt welding are performed. The procedure is as follows: (1) The end face clearance is controlled to a predetermined value while positioning and clamping the members to be welded 10 and 11 on the fixing jig. {Circle around (2)} A gap detector (camera) detects the end face gap and the end face roughness. {Circle around (3)} When end face defects are found, end face grinding is performed by a grinding means. At the time of this grinding, the grinding chips are sucked with vacuum. (4) Perform end face detection again. If it is satisfactory, the process proceeds to the welding process. If defective, stop welding.
(2) Next, “welding” 212 is performed. At the time of this welding, (1) the width of the molten pool in the welded portion is monitored by the monitoring control means 90 (CMOS camera or the like), and the laser output is adjusted based on the result. (2) Further, the deviation between the welding line 12 and the laser irradiation position is monitored by the detecting means 90 (analog camera), and the irradiation position is corrected.
(3) When the welding is completed, “work reset” 213 and “end” 214 are obtained.
[0058]
The embodiment of the laser welding method will be described more specifically with reference to the flowcharts of FIGS. 14 to 16 and the laser welding system 100.
(1) First, “work set” 310 (211) of the members to be welded 10 and 11 is performed. Here, in response to a command “work load into the jig” 311, the work is loaded into the fixed jig 70.
(2) Next, “positioning and clamping of workpiece with jig” 312 is performed. Here, after the work is brought into contact with the positioning block and clamped, the block is removed and the fixing jig 70 is operated to the open end.
(3) Subsequently, “check welding line (axis movement) with camera” 313 is performed. Here, the operation of the laser welding system 100 is controlled according to the machining program, and information is acquired from the detection means 90 of the weld line 12.
(4) Subsequently, “good match” 314 is determined. Here, the image processing obtained from the camera is performed to determine the gap between the both end faces and the end face roughness. Then, the determination result of good / bad is sent to the control system.
(5) Subsequently, “NG first time” 315 is determined. Here, if the NG in the butt state is the first time, grinding is performed. If it is NG for the second time, “NG treatment” 316 for workpiece discharge is performed without grinding or welding. However, the number of times the NG process is performed is variable.
(6) Subsequently, the process of “To the cutting jig initial position with a router” 317 is performed. Here, the fixing jig 70 is moved to the opening end to form a predetermined end face gap, and the end face is ground by a router (grinding means). After grinding, remove the positioning block and use the workpiece unclamp. Next, the router is changed from the set state to the reset state.
(7) Subsequently, “welding execution” 318 (212) is performed.
(8) Subsequently, “positioning to the welding start position” 319 is performed on the welding head and the members to be welded 10 and 11.
(9) Subsequently, “Laser ON” 320 is executed. At the same time, “image processing” 321 of the molten pool is executed according to a command from the control system. Further, the detection means 90 simultaneously detects the welding line 12 for correcting the irradiation position of the laser beam L. (This detailed description will be described later).
(10) The execution of the “image processing” 321 is performed as “Taking a molten pool image with a CMOS camera” 322.
(11) The “weld pool width detection by personal computer” 323 in the laser welding control device LC is performed. Here, image processing is performed with a personal computer, and the width of the molten pool Co is calculated. In parallel with this, “welding execution (axis movement)” 325 is performed.
(12) Further, “control of laser output” 324 is performed based on the calculation of the width of the molten pool Co. Here, when reaching the welding end, a command of “laser OFF” 326 is issued.
(13) Here, welding ends. Further, the image processing is also “irradiation end” 327 and “image end” 328. However, if “irradiation end” 327 is denied, if “laser OFF” 326 is not reached, welding continues and “take molten pool image capture with CMOS camera” 322 is executed.
In response to a command of “laser OFF” 326, “work reset” 329 (213) is obtained.
[0059]
In the embodiment of the laser welding method, the irradiation position correction of the laser beam will be described with reference to the flowchart of FIG.
(9) “Image processing” 321 is executed by a command from the laser welding control device LC. Thus, the detection unit 90 detects the welding line 12 for correcting the irradiation position of the laser beam L.
(10) The execution is “weld line image capture with analog camera” 330.
(11) Then, “detection of misalignment between welding line and laser by image processing apparatus” 331 is performed.
(12) Then, “Transfer detection result to control device” 332. Thus, calculation is performed in consideration of the coordinate system between the image processing apparatus and the laser welding system 100, and the amount of deviation from the welding line 12 of the butted end faces 10A and 11A of the members to be welded 10 and 11 is corrected.
(13) With the end signal from “irradiation end” 327, the correction command for the welding line 12 is also ended. Finally, the welding process is “finished” 333.
[0060]
The present invention is not limited to the embodiments described above, and design changes, component changes, and combinations can be freely made within the spirit of the invention. For example, detailed setup and welding procedures in the grinding process and the welding process are not limited to the above embodiment. Specifically, the pair of members to be welded 10 and 11 held by the fixing jig 70 are unconditionally positioned on both end surfaces without detecting the end surface gap or the end surface state prior to the butt welding. The welding process may be started after the gaps are widened and both end faces facing the pair of members to be welded are ground by the grinding means 80 provided in the welding head. Even in this case, variations in the processing accuracy of both end faces of the pair of welded members can be corrected with high accuracy. Thereafter, the gap dimension and the end face state of both end faces are set and adjusted to the optimum conditions, so that the optimum butt welding can be performed regardless of the end face state.
[0061]
Further, the detailed configuration and mounting position of the grinding means 80 are not limited to the welding head 20 and can be arbitrarily and appropriately changed. Further, the shapes of the members to be welded 10 and 11 can be any shape from a one-dimensionally shaped part to a three-dimensionally shaped part, and butt welding of these parts can be performed.
[0062]
And the said detection means 90, the monitoring control means 90, and the welding defect detection means BD were demonstrated as an independent implementation apparatus. Each of these devices can be hybridized to reduce the size by combining the devices into one. Thereby, a composite welding head can be made still more compact. Further, the laser oscillator is not limited to a semiconductor laser, and can be implemented by a carbon dioxide laser or a YAG laser. Furthermore, the molten pool monitoring and controlling means 90 is not absolutely necessary for carrying out the present invention, and the function is stopped or abolished and only the welding line detecting means 90 is operated. The invention can be carried out.
[0063]
【The invention's effect】
As described above in detail, the laser welding method and the welding system according to the present invention exhibit the following effects.
[0064]
First, according to the laser welding method of the first aspect, the pair of members to be welded held by the fixing jig is subjected to a grinding means provided in a welding head or the like by widening the gap between both end surfaces prior to the butt welding. Since the opposite end faces of the pair of welded members are ground, the variation in the processing accuracy of the end faces of the pair of welded members can be corrected with high accuracy. Thereafter, the gap dimension and the end face state of both end faces are set and adjusted to the optimum conditions, so that the optimum butt welding can be performed regardless of the end face state.
[0065]
According to the laser welding method of the second aspect, the butt end faces of the pair of members to be welded are immediately welded when the both end face gaps and end face states detected by the detecting means are good, so that the welding operation is performed efficiently. it can. In addition, if the gaps and end face states detected by the detecting means are poor, the processing accuracy variation of the both end faces of the pair of welded members is corrected with high precision by grinding of the grinding means. Therefore, the optimum butt welding can be performed regardless of the end face state.
[0066]
According to the laser welding method of claim 3, in the laser welding method of claim 2, when the butt end faces of the pair of members to be welded are poor in both end face clearance and end face state, the non-defective product is ground to the maximum. Try to improve yield. In addition, a pair of workpieces that are inappropriate for butt welding are processed by the workpiece removal without being cut off and welded by the second grinding detection, thus reducing unnecessary welding and reducing the welding defect rate. can do.
[0067]
The laser welding method according to claim 4 is the laser welding method according to any one of claims 1 to 3, wherein a gap between both end faces of the pair of members to be welded is made smaller than a grindstone outer diameter by a deburring allowance. Since the grinding means deburrs both end surfaces only by forward movement along both end surfaces, the grinding time for deburring is shortened. For this reason, even if the grinding process is intervened, the total laser welding time can be shortened.
[0068]
The laser welding method according to claim 5 is the laser welding method according to any one of claims 1 to 3, wherein the gaps on both ends of the pair of members to be welded are positioned larger than the outer diameter of the grindstone, and the grinding means Since both end surfaces are deburred by forward movement and backward movement along each side of both end surfaces, the deburring accuracy of both end surfaces can be improved. For this reason, the quality of the welded portion (weld bead) in butt welding is enhanced, and the welding strength is also enhanced.
[0069]
According to the laser welding system of claim 6, the fixing jig is provided with a movable body adjusting means for adjusting the clearance between the butted surfaces by moving at least one of the members to be welded away from the other member to be welded. Prior to butt welding, the welding head includes a detecting means for detecting a welding line and a butt gap / end face state of a pair of welded members, and a grinding means for grinding both end faces of the welded member based on the detection result of the detecting means. Therefore, the laser welding method according to any one of claims 1 to 5 can be performed.
[0070]
According to the laser welding system of claim 7, in the laser welding system of claim 6, the movable body of the fixing jig includes detection means for detecting a gap / end surface state of the butt end faces of the pair of welded members; Since positioning means for positioning in a butt gap of a predetermined size is provided, it is possible to adjust gaps at both end faces for butting a pair of members to be welded and appropriate butt welding.
[0071]
According to the laser welding system of claim 8, in the laser welding system of claim 6, the movable body of the fixing jig includes a detecting unit that detects a gap / end surface state of both end faces of the pair of welded members; Since the detection information from the detection means is controlled by a control means for positioning in a butt gap of a predetermined dimension, the gap between both end faces for butting a pair of welded members can be adjusted with high accuracy, and an optimum butt is obtained. Welding can be carried out.
[0072]
According to the laser welding system of claim 9, in the laser welding system of claim 6 or 7, the pair of movable bodies provided in the fixing jig are positioned and controlled by moving both of them. The clearance adjustment between both end faces for the butt of the members can be executed quickly and in a short time, and the efficiency of the welding work can be improved.
[0073]
According to the laser welding system of claim 10, in the laser welding system of claim 6, the grinding means attaches a rotating grindstone or a rotating tool to the tip of the rotating shaft and is fixed or movable at an appropriate position such as a welding head. Since the two end faces of the pair of members to be welded are subjected to grinding, the grinding and cutting of both ends of the pair of members to be welded can be performed accurately and with high accuracy.
[0074]
According to the laser welding system of claim 11, in the laser welding system of claim 9, according to the rotating grindstone or the rotating tool, the end faces of the member to be welded that are a thin plate in which the pair of tapered ring portions are easily bent are sandwiched from both sides. Therefore, the end face of the thin plate does not cause chatter vibration or misalignment during grinding, and precise end face grinding or end face cutting can be performed with a grindstone or a cutting blade between a pair of taper rings.
[Brief description of the drawings]
FIG. 1 is a perspective view showing the entire and main part of a laser welding system of the present invention.
FIG. 2 is a perspective view showing a modification of the laser welding system of the present invention.
FIG. 3 is a perspective view of the laser welding system of the present invention in a ground state.
FIG. 4 is a perspective view of a fixing jig of the laser welding system according to the first embodiment of the present invention.
FIG. 5 is a plan view of a fixing jig of the laser welding system according to the first embodiment of the present invention.
FIG. 6 is a plan view of a fixing jig of a laser welding system according to a second embodiment of the present invention.
FIG. 7 is a perspective view of a fixing jig of a laser welding system according to a third embodiment of the present invention.
FIG. 8 is a perspective view of a fixing jig of a laser welding system according to a third embodiment of the present invention.
FIG. 9 is a plan view of a fixing jig of a laser welding system according to a third embodiment of the present invention.
FIG. 10 is a plan view of a fixing jig of a laser welding system according to a fourth embodiment of the present invention.
FIG. 11 is a perspective view of a ground state of the laser welding system of the present invention.
FIG. 12 is a perspective view showing an embodiment of the present invention and showing a welded state of a welded portion.
FIG. 13 is a basic flowchart of the laser welding method according to the first embodiment of the present invention.
FIG. 14 is a specific flowchart of the laser welding method according to the second embodiment of the present invention.
FIG. 15 is a specific flowchart of the laser welding method according to the second embodiment of the present invention.
FIG. 16 is a specific flowchart of the laser welding method according to the second embodiment of the present invention.
FIG. 17 is an overall system diagram of a conventional laser welding system.
[Explanation of symbols]
10,11 Welded member (normal thin plate)
10A, 11A Both end faces
12 Welding line
20 Welding head
50, 50 '3-axis orthogonal moving body
60 wrists
65 NC controller (6-axis control)
70 Fixing jig
71 Adhering body
72 Movable body
80 Grinding means
81 Rotation drive
90 Welding line monitoring control means (molten pool monitoring control means)
100,100 'laser welding system
B weld bead
BD Weld defect detection means
C camera
C1, C2 cylinder
Co molten pool
D Transmission unit (optical fiber)
DU lifting drive unit
E Encoder
Eo Compressed air
LC laser welding controller
L Laser beam for welding
K1 grinding tool
K2 cutting tool
H Semiconductor laser oscillator
SM1 servo motor
V2, v3 selector valve
X gap
X1 butt gap

Claims

A fixing jig that adjusts and holds the gap between the butt end faces of the pair of welded members, a welding head that irradiates a laser beam to the butt welding line of the pair of welded members, and a pair provided in the welding head Grinding means for grinding both butt end faces of the welded member, detection means for at least the welding line and butt gap / end face state, and the wrist of an articulated robot that moves along the welding line while controlling the position of the welding head or In a laser welding method using a laser welding system comprising a wrist of a three-axis orthogonal moving body,
Prior to the butt welding of the pair of members to be welded held by the fixing jig, both facing surfaces of the pair of members to be welded are ground by grinding means provided in the welding head or the like, and thereafter The fixing jig moves at least one side of the member to be welded and adjusts and fixes the gap between the butt end faces to a predetermined gap, and then detects the welding line of at least a pair of members to be welded by the detecting means while A laser welding method comprising performing butt welding by performing position control and laser beam output control.

A fixing jig that adjusts and holds the gap between the butt end faces of the pair of welded members, a welding head that irradiates a laser beam to the butt welding line of the pair of welded members, and a pair provided in the welding head Grinding means for grinding both butt end faces of the welded member, detection means for at least the welding line and butt gap / end face state, and the wrist of an articulated robot that moves along the welding line while controlling the position of the welding head or In a laser welding method using a laser welding system comprising a wrist of a three-axis orthogonal moving body,
Prior to the butt welding of the pair of welded members held by the fixing jig, when the gap between both end faces detected by the detecting means is good, the weld line of the pair of welded members is immediately detected. The position of the welding head and the output control of the laser beam are controlled while being detected by the means, and butt welding is performed, and if the gap / end face condition detected by the detection means is a defective result, the welding head or the like is Grinding means are provided to grind the opposite end faces of the pair of welded members, and then the fixing jig moves at least one side of the welded members to adjust and fix the gap between the butt end faces to a predetermined gap. If the subsequent re-detection is satisfactory, the welding head position control and the laser beam output control are performed while detecting the welding lines of at least a pair of members to be welded by the detection means. Laser welding method and butterflies.

Grinding to both end faces of the pair of members to be welded will result in defective end faces if the second gap / end face detection results in a poor result following the first gap / end face detection failure. 3. The laser welding method according to claim 2, wherein a workpiece dispensing process is performed.

The gap between both ends of the pair of members to be welded is positioned narrower than the outer diameter of the tool by the amount of deburring, and the grinding means deburrs both ends only by forward movement along both ends. The laser welding method according to any one of claims 1 to 3.

The gap between both end faces of the pair of welded members is positioned larger than the outer diameter of the tool, and the grinding means deburrs both end faces by forward movement and backward movement along each one face of both end faces. The laser welding method according to any one of claims 1 to 3.

A fixing jig for fixing a pair of members to be welded, a welding head for irradiating a laser beam guided from a laser oscillator to a butt welding line of the pair of members to be welded, and a welding line while controlling the posture of the welding head In the laser welding system, comprising: a wrist of an articulated robot that moves along a wrist or a wrist of a three-axis orthogonal moving body; a detection unit that detects the welding line; and a monitoring control unit for a molten pool. Includes a movable body adjusting means for adjusting the gap of the butt surface by moving at least one of the members to be welded away from the other member to be welded. A detecting means for detecting a butt gap / end face state of a pair of members to be welded, and a grinding means for grinding both end faces of the members to be welded based on a detection result of the detecting means are provided. Over laser welding system.

The movable body provided in the fixing jig includes a detecting unit that detects a gap / end surface state of both end surfaces of a pair of members to be welded, and a positioning unit that positions the butting gap of a predetermined size. The laser welding system according to claim 6.

The movable body provided in the fixing jig is
It is controlled by a detecting means for detecting a gap / end face state of both end faces of a pair of welded members, and a control means for positioning in a butt gap of a predetermined size based on detection information from the detecting means. Item 7. The laser welding system according to Item 6.

The laser welding system according to claim 6, wherein the pair of movable bodies provided in the fixing jig are controlled in position by moving both of them.

The grinding means is equipped with a tool (rotary grindstone or rotary cutting blade) at the tip of the rotary shaft, and is fixedly or movablely (movable or swung back and forth) at a suitable position such as a welding head, and a pair of welds The laser welding system according to claim 6, wherein grinding is performed on both end surfaces of the butt of the member.

The tool (rotary grindstone or rotary cutting blade) of the grinding means includes a pair of tapered ring portions that sandwich the end face of the member to be welded from both sides, and includes a grindstone or cutting blade between the pair of taper ring portions. The laser welding system according to claim 10.