JP4178854B2

JP4178854B2 - Casting product internal defect inspection support apparatus and method

Info

Publication number: JP4178854B2
Application number: JP2002198567A
Authority: JP
Inventors: 博行石井
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 2002-07-08
Filing date: 2002-07-08
Publication date: 2008-11-12
Anticipated expiration: 2022-07-08
Also published as: JP2004034144A

Description

【０００１】
【発明の属する技術分野】
本発明は、鋳造品にできる鋳巣等の内部欠陥の検査を支援するための技術に関する。
【０００２】
【従来の技術】
鋳造品に現れる欠陥の中には、引け巣等の鋳巣のように、製品の内部に現れる欠陥がある。このような鋳巣等の欠陥は、鋳造品の強度等の性能に悪影響を及ぼす可能性があるので、ないにこしたことはない。しかし、現実問題として鋳巣を皆無にすることは極めて困難なので、製品形状や鋳造の仕方を調整するなどにより、性能に影響が少ない部分（例えば後の機械加工工程で除去する部分など）に鋳巣を集中させるというアプローチがとられている。この場合、生産に向けた設計の段階で、形状や鋳造条件を様々に変えながら試作と検査を繰り返し、最適な条件を探索することになる。
【０００３】
ここで内部欠陥の検査には、古くは製品自体の破壊が必要であった。このような破壊検査は、手間と時間を要する上、精度もあまり高くなく、また破壊検査に用いたワークについては、その後、強度試験等のワーク全体についての試験を行うことができなくなるため、不便な場合があった。
【０００４】
これに対し近年では、Ｘ線を用いた非破壊検査もよく用いられるようになっている。特に最近では、例えば特開平７−１２７５９号公報に開示されるように、Ｘ線ＣＴ（コンピュータ断層）により鋳造品内部の断面を画像化することで、内部欠陥の状況を視覚的に提示するシステムが提案されている。
【０００５】
【発明が解決しようとする課題】
Ｘ線ＣＴを用いた検査は、検査対象の断層画像が得られるので、内部欠陥の有無や位置を視覚的に確認しやすいというメリットがある。
【０００６】
しかしながら、ＣＴ断層画像では、断面上での内部欠陥の位置や大きさは分かるが、内部欠陥の三次元的な位置や大きさを把握することは困難である。また、鋳巣等の内部欠陥は比較的小さいものが多いこともあって、鋳造品全体の検査では小さい間隔で多数の断面を取って断層画像を作成することとなり、これら多数の断層画像を目視で調べるのには多大の時間と労力を要する。
【０００７】
本発明はこのような課題に鑑みなされたものであり、鋳造品の内部欠陥の検査をより容易にする支援装置及び方法を提供することを目的とする。
【０００８】
【課題を解決するための手段】
上記目的を達成するため、本発明に係る装置は、検査対象の鋳造品を実測して形成した該鋳造品の複数の断面の断層画像を受け取り、それら前記複数の断面の断層画像に基づき、前記鋳造品の三次元形状モデルとしてサーフェイスモデルを表示する表示手段と、前記表示手段に表示された前記サーフェイスモデルの面要素のうちユーザに指定された面要素を前記鋳造品の外表面の起点として、既に外表面として認識されている面要素と辺を共有する面要素を新たな外表面として認識する処理を繰り返して前記鋳造品の外表面を抽出する実測モデル形成手段と、前記サーフェイスモデルから、前記外表面として抽出されなかった面要素を前記鋳造品内の空洞を取り囲む面要素として識別する欠陥識別手段と、を備える。
【０００９】
本発明の好適な態様では、前記サーフェイスモデルにおける前記鋳造品の外表面を構成する面要素を半透明とし、前記空洞を取り囲む面要素を前記半透明表示とは異なる色で強調した表示画像を形成する表示画像形成手段を備える。
【００１０】
また、本発明は、検査対象の鋳造品を実測して形成した該鋳造品の複数の断面の断層画像を受け取り、それら前記複数の断面の断層画像に基づき、前記鋳造品のサーフェイスモデルを表示する表示手段と、前記表示手段に表示された前記サーフェイスモデルの面要素のうちユーザに指定された面要素を前記鋳造品の外表面の起点として、既に外表面として認識されている面要素と辺を共有する面要素を新たな外表面として認識する処理を繰り返して前記鋳造品の外表面を抽出する実測モデル形成手段と、前記サーフェイスモデルから、前記外表面として抽出されなかった面要素で囲まれる空間を前記鋳造品内の内部欠陥として識別する欠陥識別手段と、前記鋳造品における目標とする内部欠陥状態の情報を取得し、前記欠陥識別手段で識別した内部欠陥と前記目標とする内部欠陥状態との比較に基づき前記検査対象の鋳造品の良否を判定し、判定結果をユーザに提示する良否判定手段と、を備える。
【００１１】
また、本発明に係る方法は、検査対象の鋳造品を実測して形成した該鋳造品の複数の断面の断層画像を受け取り、それら前記複数の断面の断層画像に基づき、前記鋳造品の三次元形状モデルとしてサーフェイスモデルを表示するステップと、前記表示手段に表示された前記サーフェイスモデルの面要素のうちユーザに指定された面要素を前記鋳造品の外表面の起点として、既に外表面として認識されている面要素と辺を共有する面要素を新たな外表面として認識する処理を繰り返して前記鋳造品の外表面を抽出するステップと、前記サーフェイスモデルから、前記外表面として抽出されなかった面要素を前記鋳造品内の空洞を取り囲む面要素として識別するステップと、を含む。
【００１２】
また本発明に係る方法は、検査対象の鋳造品を実測して形成した該鋳造品の複数の断面の断層画像を受け取り、それら前記複数の断面の断層画像に基づき、前記鋳造品のサーフェイスモデルを形成するステップと、前記サーフェイスモデルを表示手段に表示するサーフェイスモデル表示ステップと、前記表示手段に表示された前記サーフェイスモデルの面要素のうちユーザに指定された面要素を前記鋳造品の外表面の起点として、既に外表面として認識されている面要素と辺を共有する面要素を新たな外表面として認識する処理を繰り返して前記鋳造品の外表面を抽出するステップと、前記サーフェイスモデルから、前記外表面として抽出されなかった面要素で囲まれる空間を前記鋳造品内の内部欠陥として識別するステップと、前記鋳造品における目標とする内部欠陥状態の情報を取得し、前記サーフェイスモデルから識別した内部欠陥と前記目標とする内部欠陥状態との比較に基づき前記検査対象の鋳造品の良否を判定し、その判定結果をユーザに提示するステップと、を含む。
【００１３】
また本発明は、鋳造品の形状情報及び鋳造パラメータに基づき、所定の鋳造シミュレーションを実行し、所望の内部欠陥分布が得られるまで、前記形状情報及び鋳造パラメータの少なくとも１つに修正を加えながらそのシミュレーションを繰り返す鋳造条件探索ステップと、鋳造条件探索ステップで所望の内部欠陥分布をもたらすものとして求められた形状情報及び鋳造パラメータに従って試作品を鋳造する試作ステップと、この試作品を断層画像形成装置で実測し、この試作品の複数の断面の断層画像を形成する試作品実測ステップと、それら複数の断面の断層画像に基づき、試作品のサーフェイスモデルを形成する実測モデル形成ステップと、前記サーフェイスモデルを表示手段に表示するサーフェイスモデル表示ステップと、前記表示手段に表示された前記サーフェイスモデルの面要素のうちユーザに指定された面要素を前記鋳造品の外表面の起点として、既に外表面として認識されている面要素と辺を共有する面要素を新たな外表面として認識する処理を繰り返して前記鋳造品の外表面を抽出する外表面特定ステップと、前記サーフェイスモデルから、前記外表面として抽出されなかった面要素で囲まれる空間を試作品内の内部欠陥として識別する欠陥識別ステップと、鋳造条件探索ステップでの前記シミュレーションの繰り返しにより最終的に得られた内部欠陥分布と、前記サーフェイスモデルから識別した内部欠陥の分布とに基づき、前記シミュレーションの良否判断の基礎となる所定の情報を作成し、ユーザに対して提示するシミュレーション良否情報提示ステップと、を含む。
【００１４】
また本発明は、検査対象の鋳造品を実測して形成した該鋳造品の複数の断面の断層画像を受け取り、それら前記複数の断面の断層画像に基づき、前記鋳造品のサーフェイスモデルを形成するステップと、前記サーフェイスモデルを表示手段に表示するステップと、前記表示手段に表示された前記サーフェイスモデルの面要素のうちユーザに指定された面要素を前記鋳造品の外表面の起点として、既に外表面として認識されている面要素と辺を共有する面要素を新たな外表面として認識する処理を繰り返して前記鋳造品の外表面を抽出するステップと、前記サーフェイスモデルから、前記外表面として抽出されなかった面要素を内部欠陥の面要素と識別するステップとを実行させる。
【００１５】
【発明の実施の形態】
以下、本発明の実施の形態（以下実施形態という）について、図面に基づいて説明する。
【００１６】
図１は、本発明に係る鋳造品製作支援システムの概略構成を示す図である。この図に示すように、このシステムは、Ｘ線ＣＴスキャナ１０と検査支援装置２０とディスプレイ装置４０と入力装置４５とを含む。
【００１７】
Ｘ線ＣＴスキャナ１０は、鋳造品をＸ線にて走査することでＣＴ断層画像を撮影するための装置である。
【００１８】
検査支援装置２０は、ＣＴ断層画像に基づき、鋳造品の内部欠陥検査の助けとなる情報を作成してユーザに提供する装置であり、実測モデル形成部２２と内部欠陥識別部２４と描画部２６と判定処理部２８を備えている。検査支援装置２０は、例えば、パーソナルコンピュータやワークステーションなどの汎用のコンピュータシステムに、以下に説明する実測モデル形成部２２や内部欠陥識別部２４、描画部２６、判定処理部２８などの処理内容を記述したプログラムを実行させることにより実現することができる。
【００１９】
このうち、実測モデル形成部２２は、ＣＴスキャナ１０から入力される断層画像群から、鋳造品の三次元形状モデルを形成する。ここでは、三次元形状モデルとして、鋳造品の表面をポリゴン（多角形面要素）で表したポリゴンサーフェイスモデルを作成する。このような断層画像群からポリゴンモデルを作成するアルゴリズムとしては、例えばマーチング・キューブ法などの従来公知のものを利用することができる。空気と鋳物金属（例えばアルミニウムや鋳鉄など）では、Ｘ線の吸収率が大きく異なるため、ＣＴ断層画像では両者の画素値（ＣＴ値）に大きい差が出る。したがってＣＴ断層画像群からマーチング・キューブ法等の手法でポリゴンモデルを作成すると、鋳造金属部分と空気との境界面がポリゴンデータ化される。すなわち、実測モデル形成部２２で形成されるポリゴンモデルでは、鋳造品と外部との境界面だけでなく、鋳造品内部の鋳巣等の内部欠陥による空洞部分の内面も表現される。
【００２０】
内部欠陥識別部２４は、実測モデル形成部２２が形成した三次元形状モデルから、鋳造品内の内部欠陥に該当する部分を識別する。ここでは、ポリゴンサーフェイスモデルから、鋳造品の外部（外気）との境界面（外表面と呼ぶ）に該当するポリゴン群を抽出し、残ったポリゴン群を内部欠陥の空洞部分との境界面と認識する。
【００２１】
描画部２６は、実測モデル形成部２２で形成した三次元形状モデルをレンダリングして表示画像を形成する手段であり、特に本実施形態では、内部欠陥識別部２４の識別結果を利用して、内部欠陥部分を視認しやすく強調した表示画像を生成する。
【００２２】
判定処理部２８は、内部欠陥識別部２４の識別結果に基づき、検査対象の鋳造品の内部欠陥状態が適切な状態であるかどうかを判定する。判定処理部２８はあらかじめ本装置内に登録された判定基準に従って、その判定を行う。
【００２３】
ディスプレイ装置４０は、検査支援装置２０の生成する表示画面を表示する装置であり、例えば描画部２６が生成した鋳造品の三次元画像の表示を行う。入力装置４５は、例えばキーボードやポインティングデバイスなど、検査支援装置２０に対するデータや指示の入力を受け付ける装置である。
【００２４】
次に、図２を参照して、このシステムによる鋳造品の内部欠陥検査支援処理の手順を説明する。
【００２５】
まずこのシステムでは、Ｘ線ＣＴ装置１０により、検査対象の鋳造品の所定間隔（例えば１ｍｍなど。この間隔は、作成したい３次元形状モデルの精度による）の断面をそれぞれ走査し、それら各断面の断層画像を作成する（Ｓ１０）。この結果得られた各断面の断層画像のデータは、検査支援装置２０に入力される。検査支援装置２０の実測モデル形成部２２は、それら断層画像群から、マーチングキューブズ法などのアルゴリズムを用いて、検査対象の鋳造品のポリゴンサーフェイスモデルを形成する（Ｓ１２）。次に、内部欠陥識別部２４がこのポリゴンサーフェイスモデルから、鋳造品内の内部欠陥に該当する部分を識別する（Ｓ２０）。このステップＳ２０の処理内容の一例をステップＳ２２〜Ｓ２６として示している。この処理例では、ポリゴンサーフェイスモデルから、鋳造品の外部（外気）との境界面（外表面と呼ぶ）に該当するポリゴン群を抽出し、残ったポリゴン群を内部欠陥の空洞部分との境界面と認識する。ここでは、外表面の認識処理のために、まずポリゴンサーフェイスモデルをディスプレイ装置４０に表示し、その表示上でユーザに鋳造品の外表面に該当するポリゴンの指定を求める（Ｓ２２）。このように指定されたポリゴンを起点に、既に外表面として認識されているポリゴンに連結する（すなわち辺を共有する）ポリゴンを探索してこれを新たに外表面として認識する（Ｓ２４）。すなわち、探索して得たポリゴンが外表面に該当する旨を所定の記憶装置に記憶する。この処理を、新たに外表面と認識されるポリゴンが増えなくなるところまで繰り返すと、鋳造品の外表面に該当するポリゴンをすべて抽出できる。鋳造品の場合、外表面でない境界面（すなわち鋳造品の内表面）は、内部欠陥と考えてよい。したがって、外表面のポリゴンをすべて抽出した後で、外表面である旨の情報が記憶されていないポリゴンは、内部欠陥である空洞を取り囲むポリゴンと考えることができる。したがって、この処理例では、ステップＳ２２でユーザに指定されたポリゴンに連結するポリゴンをすべて抽出した後に、抽出されずに残った各ポリゴンを鋳造品の内部欠陥に対応するポリゴンとして識別する（Ｓ２６）。なお、このように内部欠陥の面を表すポリゴンが識別されると、それらを相互に連結するポリゴンの組に分けることで、個々の内部欠陥（空洞）を識別することもできる。これにより、個々の内部欠陥の位置や体積などの物理量を求める処理が可能となる。
【００２６】
このように内部欠陥が識別できると、描画部２６による三次元画像生成や、判定処理部２８による良否判定が可能になる。例えば、これら２つの処理をユーザが選択できるようにすることも可能である。
【００２７】
描画部２６の処理としては、まず内部欠陥識別部２４が識別した外表面の各ポリゴン群を半透明に設定する（Ｓ３０）。すなわち、外表面と認識したポリゴンに対し、０より大きく１より小さい所定値の透過係数（透過係数０は完全に透明、透過係数１は完全に不透明）を設定する。また、内部欠陥に対応する各ポリゴンを、外表面のポリゴンの色（半透明）に対して区別しやすい所定の色に設定する（Ｓ３２）。そして、この設定に従って、描画部２６は鋳造品のポリゴンサーフェイスモデルをレンダリングし、その結果の三次元画像をディスプレイ装置４０に表示する（Ｓ３４）。このようにして作成される三次元画像では、鋳造品の形状が半透明で表示され、鋳造品内部にある鋳巣等の欠陥がその半透明の鋳造品形状表示を透かして明確に視認できるように表示される。このように、内部欠陥の位置や形状を三次元表示することができるので、ユーザにとって内部欠陥の数や個々の位置、形状、大きさなどを直感的に把握しやすいというメリットがある。また、入力装置４５から視点位置や視線方向等の描画パラメータの指定を動的に受け付け可能とし、その指定に応じて動的にサーフェイスモデルのレンダリングを行うようにすることも好適である。このように向き等を様々に変えながら三次元表示を行うことで、内部欠陥の三次元的な位置がより把握しやすくなる。
【００２８】
また、判定処理部２８では、例えば、内部欠陥識別部２４で識別した内部欠陥群が、あらかじめ登録しておいた判定基準を満足するかどうかを判定する（Ｓ３６）。
【００２９】
例えば、鋳巣等の内部欠陥を製品性能に悪影響のない部分に集中させる設計アプローチをとる場合、判定基準として、製品形状の中で内部欠陥を集中させる集中目標領域をあらかじめ設定しておけばよい。この場合、その集中目標領域外に内部欠陥が存在する場合、その検査対象を不良と判定する、などの判定を行えばよい。この場合、内部欠陥識別部２４で識別した各内部欠陥のポリゴンの位置情報から、各内部欠陥の三次元位置を知ることができるので、この三次元位置の情報から、その判定基準を満足するかどうかを判定することができる。なお、判定基準の情報として、集中目標領域の代わりに、その集中目標領域以外の領域を、できるだけ内部欠陥が存在しないようにしたい領域、として設定してもよい。また、構造上絶対内部欠陥が存在してはいけない禁止領域をあらかじめ設定し、この領域内に内部欠陥があれば不良と判定する手法も可能である。
【００３０】
また、別の判定手法として、内部欠陥についての量的評価値が、判定基準としてあらかじめ定めた上限値以下に収まっているかどうかを判定する手法が考えられる。ここで、内部欠陥についての量的評価値としては、例えば、内部欠陥の総数、総体積、総表面積、最大体積（すべての内部欠陥の中で体積が最大のものの体積）、最大表面積、などの様々なものが考えられる。これら量的評価値の１つに基づき判定するだけでなく、複数の量的評価値の組合せで判定することも可能である。
【００３１】
また、上記二つの判定手法の折衷的な手法として、上述の集中目標領域の外の領域における内部欠陥の量的評価値を評価する手法も好適である。この場合例えば、集中目標領域外の内部欠陥の総体積（又は最大体積、総数など）が所定上限値以下であれば、検査対象を良品と判定するなどの処理となる。もちろん、集中目標領域外の内部欠陥について複数の量的評価値を調べ、それら各評価値の組合せが所定の良品基準を満足する場合に、良品と判定するような方式でもよい。また、上述の集中目標領域と禁止領域の両方を設定し、集中目標領域と禁止領域のいずれでもない範囲に対して量的評価値による判定基準を設定するなどの判定方式も好適である。
【００３２】
検査支援装置２０は、このようにして判定処理部２８が求めた判定結果を、ディスプレイ装置４０に表示する（Ｓ３８）。
【００３３】
なお、描画部２６による内部欠陥を視認可能とした三次元画像表示と、判定処理部２８による判定結果とを、例えばウインドウシステムなどを用いて同時にディスプレイ装置４０に表示することも可能である。
【００３４】
このように、本実施形態のシステムによれば、鋳造品の断層画像から三次元形状モデルを形成し、この三次元形状モデルから内部欠陥を識別して表示したり、あるいはこれら内部欠陥の状況が許容範囲内であるかを判定したりすることができる。ユーザは、このような三次元画像表示や判定結果表示を参照して、検査対象の鋳造品の鋳巣等の内部欠陥の状態の良否を確認することができる。したがって、試作段階でこのシステムを利用すれば、試作品の内部欠陥状態の検査が従来に比べて格段に容易になり、試作・検査・設計調整（鋳造パラメータや設計形状の調整・変更）に要するサイクルを短縮することができる。
【００３５】
次に図３及び図４を参照して、上記実施形態の変形例について説明する。
【００３６】
図３は、この変形例のシステム構成を示す図であり、図１に示した上記実施形態の構成要素に相当する構成要素には、図１と同じ符号を付して詳細な説明を省略する。
【００３７】
この変形例のシステムは、鋳造部門等における鋳造プロセス設計のための試作サイクルの支援を目指したものである。この変形例では、上記実施形態のシステム構成に加え、検査支援装置２０に鋳造シミュレータ２９を設けている。
【００３８】
この鋳造シミュレータ２９は、鋳造欠陥の発生位置や形状、大きさなどを求めるためのシミュレーション演算を行う手段であり、製品（鋳造品）の設計形状や鋳造パラメータ（例えば湯の温度や注入場所など）に従って解析用のモデルを作成し、このモデルに対して凝固解析等の公知の解析演算を行う。このシミュレーションのアルゴリズムとしては、特開２００１−２８７０２３など、従来からある様々なアルゴリズムを利用することができる。
【００３９】
検査支援装置２０に設けられたハードディスクドライブ等の記憶部３０には、鋳造品の設計形状データ３２や、その鋳造品を鋳造する際の鋳造パラメータ３４、鋳造シミュレータ２９によるシミュレーション結果３６などが記憶される。
【００４０】
図４に示すように、このシステムでは、まず、設計部門がＣＡＤシステムで作成した鋳造品の設計形状データを受け取り、記憶部３０に記憶する（Ｓ４０）。次に、ユーザが、鋳造シミュレータ２９を起動し、このシミュレータ２９に対し、鋳造条件として、シミュレーション対象とする設計形状データ３２と、各種の鋳造パラメータ３４と、を設定する（Ｓ４２）。鋳造シミュレータ２９は、この設定に従って解析モデルを作成して所定の鋳造シミュレーションを実行し（Ｓ４４）、そのシミュレーション結果をディスプレイ装置４０に表示する。ユーザはこのシミュレーション結果を見て、内部欠陥の状況を含む鋳造状態が良好なものであるかどうかを調べ、鋳造条件が適切であったか否かを判断する（Ｓ４６）。ここで、シミュレーション結果の鋳造状態が良好でない場合は、ステップＳ４２に戻って設計形状データや鋳造パラメータなどに調整を加え、シミュレーション（Ｓ４４）を行う。これを良好なシミュレーション結果が得られるまで繰り返す。良好なシミュレーション結果が得られたときの設計形状データ３２や鋳造パラメータ３４、シミュレーション結果３６は、記憶部３０に保存されており、後で利用可能となっている。
【００４１】
このようにして良好なシミュレーション結果が得られると、そのときの鋳造条件（設計形状データ及び鋳造パラメータ）に従って、試作品を鋳造する（Ｓ４８）。そして、上述の実施形態と同様、Ｘ線ＣＴスキャナ１０によりその試作品の断層画像を作成し（Ｓ５０）、これら断層画像群をもとに実測モデル形成部２２で試作品の三次元形状モデルを作成し（Ｓ５２）、この三次元形状モデルから内部欠陥識別部２４で内部欠陥の識別を行う（Ｓ５４）。そして、本実施形態では、判定処理部２８が、この内部欠陥の識別結果を、シミュレーション結果３６における内部欠陥の状態と比較し、その良否を判定する（Ｓ５６）。ここでは、例えば、シミュレーション結果３６における内部欠陥の発生位置分布と実測モデルから求めた内部欠陥の位置分布とを比較し、それら両分布の差が所定の許容範囲以内かどうかを判定する（Ｓ５８）。このとき、内部欠陥の位置だけでなく大きさも考慮する判定処理を採用することも好適である。実測した内部欠陥の状態が、ステップＳ４６で良好と判定したシミュレーション結果と類似であれば、良好な試作結果が得られたものと判断できる。なお、ステップＳ５６，Ｓ５８の代わりに、上記実施形態で例示したような判断基準に従って実測モデルの内部欠陥状態の良否を判定してもよい。そして、この判定の結果をディスプレイ装置４０に表示し、ユーザの判断を仰ぐ。
【００４２】
ユーザは、この判定結果の表示を見て、試作品の内部欠陥の状態が良好であるか否かを判断し、良好でない場合は、ステップＳ４２に戻って設計形状データや鋳造パラメータの鋳造条件の調整・変更を行い、以降の処理を繰り返す。
【００４３】
このように、この変形例のシステムでは、シミュレーションによる設計・鋳造パラメータの練り上げと、試作品実測によるその設計・鋳造パラメータの有効性の検証とをスムーズな流れで実行でき、鋳造品生産のサイクルの短縮に寄与できる。
【００４４】
また、この変形例では、試作品の実測モデルから求めた内部欠陥の分布とシミュレーション結果との比較ができるので、両者の差が大きい場合や、鋳造条件を様々に変えてもなかなか両者が近くならない場合などには、鋳造シミュレータ２９のシミュレーションアルゴリズムの改良が必要などの判断を行うことができる。
【図面の簡単な説明】
【図１】本発明の好適な実施形態のシステム構成の一例を示す図である。
【図２】実施形態のシステムの処理手順を示すフローチャートである。
【図３】変形例のシステム構成を示す図である。
【図４】変形例の処理手順を示すフローチャートである。
【符号の説明】
１０Ｘ線ＣＴスキャナ、２０検査支援装置、２２実測モデル形成部、２４内部欠陥識別部、２６描画部、２８判定処理部、２９鋳造シミュレータ、３０記憶部、３２設計形状データ、３４鋳造パラメータ、３６シミュレーション結果、４０ディスプレイ装置、４５入力装置。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for supporting inspection of internal defects such as a cast hole formed in a cast product.
[0002]
[Prior art]
Among the defects that appear in the casting, there are defects that appear inside the product, such as a hollow such as a shrinkage cavity. Such a defect such as a cast hole may adversely affect performance such as the strength of the cast product, so it has never been missed. However, as a practical problem, it is extremely difficult to eliminate the cast hole. Therefore, by adjusting the product shape and casting method, it is possible to cast on parts that have little effect on performance (for example, parts to be removed in a subsequent machining process). The approach is to concentrate the nest. In this case, at the stage of design for production, trial production and inspection are repeated while changing the shape and casting conditions in various ways to search for optimum conditions.
[0003]
Here, in the inspection of internal defects, it was necessary to destroy the product itself. Such destructive inspection requires labor and time, is not very accurate, and the work used for the destructive inspection cannot be tested after the entire work such as a strength test. There was a case.
[0004]
On the other hand, in recent years, nondestructive inspection using X-rays is often used. Particularly recently, as disclosed in, for example, Japanese Patent Application Laid-Open No. 7-12759, a system for visually presenting the state of internal defects by imaging a cross section inside a cast product by X-ray CT (computer tomography). Has been proposed.
[0005]
[Problems to be solved by the invention]
The inspection using the X-ray CT has a merit that it is easy to visually confirm the presence or absence and position of an internal defect because a tomographic image to be inspected is obtained.
[0006]
However, in the CT tomographic image, the position and size of the internal defect on the cross section can be understood, but it is difficult to grasp the three-dimensional position and size of the internal defect. In addition, internal defects such as cast holes are often relatively small, and in the inspection of the entire cast product, a tomographic image is created by taking a large number of cross sections at a small interval. It takes a lot of time and effort to investigate with.
[0007]
The present invention has been made in view of such problems, and an object thereof is to provide a support device and method that make it easier to inspect internal defects of a cast product.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, an apparatus according to the present invention receives tomographic images of a plurality of cross sections of a cast product formed by actually measuring a cast product to be inspected, and based on the tomographic images of the plurality of cross sections, Display means for displaying a surface model as a three-dimensional shape model of a casting, and a surface element designated by the user among surface elements of the surface model displayed on the display means as a starting point of the outer surface of the casting, already the measured model forming means for extracting the recognized surface elements that share surface element and edges are the outer surface of the casting by repeating the process of recognizing a new outer surface as an outer surface, from the surface model, said the surface element that has not been extracted as an outer surface and a defect identification means for identifying a surface element surrounding the cavity in the casting.
[0009]
In a preferred embodiment of the present invention, before Symbol surface elements constituting an outer surface of the castings in the surface model and the semi-transparent display image highlighted in a different color from that of the semi-transparent display of the face elements surrounding the said cavity Display image forming means for forming the image .
[0010]
Further, the present invention receives tomographic images of a plurality of cross sections of the cast product formed by actually measuring a cast product to be inspected, and displays a surface model of the cast product based on the tomographic images of the plurality of cross sections. The surface element and the side already recognized as the outer surface, with the surface element designated by the user among the surface elements of the surface model displayed on the display means and the display means as the starting point of the outer surface of the casting Measurement model forming means for extracting the outer surface of the casting by repeating the process of recognizing the shared surface element as a new outer surface, and a space surrounded by the surface elements not extracted as the outer surface from the surface model A defect identification means for identifying the internal defect in the cast product, and information on a target internal defect state in the cast product, and the defect identification means identifies To determine the quality of the inspected casting based on a comparison of the internal fault condition of the internal defect and the target comprises a quality determination means for presenting the determination result to the user.
[0011]
Further, the method according to the present invention receives a tomographic image of a plurality of cross sections of the cast product formed by actually measuring a cast product to be inspected, and based on the tomographic images of the plurality of cross sections, the three-dimensional of the cast product A step of displaying a surface model as a shape model , and the surface element designated by the user among the surface elements of the surface model displayed on the display means is already recognized as an outer surface as a starting point of the outer surface of the casting. Extracting the outer surface of the casting by repeating the process of recognizing a surface element that shares a side with a surface element that is a new outer surface, and the surface element that has not been extracted as the outer surface from the surface model the containing and identifying as a surface element surrounding the cavity in the casting.
[0012]
Further, the method according to the present invention receives tomographic images of a plurality of cross sections of the cast product formed by actually measuring a cast product to be inspected, and based on the tomographic images of the plurality of cross sections, a surface model of the cast product is obtained. forming, said a surface model display step of displaying a surface model on the display means, the display means displayed user-specified surface elements an outer surface of the casting of the surface elements of the surface model Extracting the outer surface of the cast product by repeating the process of recognizing as a new outer surface a surface element that shares a side with a surface element that has already been recognized as the outer surface, and starting from the surface model, identifying a space enclosed by the surface element that has not been extracted as the outer surface as an internal defect in said casting, said casting Information on the target internal defect state is obtained, and the quality of the casting to be inspected is determined based on a comparison between the internal defect identified from the surface model and the target internal defect state, and the determination result is Presenting to the user.
[0013]
Further, the present invention executes a predetermined casting simulation based on the shape information and casting parameters of the cast product, and corrects at least one of the shape information and the casting parameters until a desired internal defect distribution is obtained. A casting condition search step that repeats the simulation, a prototype step that casts a prototype according to the shape information and casting parameters required to provide a desired internal defect distribution in the casting condition search step, and the prototype using the tomographic image forming apparatus A prototype measurement step for actually measuring and forming a tomographic image of a plurality of cross sections of the prototype, a measurement model forming step for forming a surface model of the prototype based on the tomographic images of the plurality of cross sections, and the surface model A surface model display step for displaying on the display means, and the display Among the surface elements of the surface model displayed on the stage, the surface element designated by the user is used as the starting point of the outer surface of the casting, and a surface element that shares a side with the surface element that has already been recognized as the outer surface is newly added. An outer surface specifying step of extracting the outer surface of the cast product by repeating the process of recognizing the outer surface, and a space surrounded by the surface elements not extracted as the outer surface from the surface model. Pass / fail judgment of the simulation based on the defect identification step for identifying as a defect, the internal defect distribution finally obtained by repeating the simulation in the casting condition search step, and the distribution of the internal defect identified from the surface model A simulation pass / fail information presentation step that creates predetermined information that is the basis of the process and presents it to the user , Including the.
[0014]
The present invention also includes a step of receiving tomographic images of a plurality of cross sections of the cast product formed by actually measuring a cast product to be inspected, and forming a surface model of the cast product based on the tomographic images of the plurality of cross sections. A step of displaying the surface model on the display means, and a surface element designated by the user among the surface elements of the surface model displayed on the display means as a starting point of the outer surface of the cast product. Extracting the outer surface of the cast product by repeating the process of recognizing a surface element that shares a side with the surface element recognized as a new outer surface, and is not extracted as the outer surface from the surface model. the surface element to execute and identifying the face elements of internal defects.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.
[0016]
FIG. 1 is a diagram showing a schematic configuration of a cast product production support system according to the present invention. As shown in this figure, this system includes an X-ray CT scanner 10, an examination support device 20, a display device 40, and an input device 45.
[0017]
The X-ray CT scanner 10 is an apparatus for taking a CT tomographic image by scanning a casting with X-rays.
[0018]
The inspection support device 20 is a device that creates information for assisting the inspection of internal defects of cast products based on CT tomographic images and provides the information to the user. The actual measurement model forming unit 22, the internal defect identifying unit 24, and the drawing unit 26 are provided. The determination processing unit 28 is provided. For example, the inspection support apparatus 20 adds processing contents such as an actual measurement model forming unit 22, an internal defect identification unit 24, a drawing unit 26, and a determination processing unit 28 described below to a general-purpose computer system such as a personal computer or a workstation. This can be realized by executing the described program.
[0019]
Among these, the actual measurement model forming unit 22 forms a three-dimensional shape model of a cast product from the tomographic image group input from the CT scanner 10. Here, a polygon surface model in which the surface of the cast product is represented by a polygon (polygonal surface element) is created as a three-dimensional shape model. As an algorithm for creating a polygon model from such a group of tomographic images, for example, a conventionally known algorithm such as a marching cube method can be used. Since the X-ray absorption rate differs greatly between air and cast metal (for example, aluminum or cast iron), a large difference appears between the pixel values (CT values) in the CT tomographic image. Therefore, when a polygon model is created from a CT tomographic image group by a marching cube method or the like, the boundary surface between the cast metal portion and air is converted to polygon data. That is, in the polygon model formed by the actual measurement model forming unit 22, not only the boundary surface between the cast product and the outside, but also the inner surface of the hollow portion due to internal defects such as a cast hole inside the cast product is expressed.
[0020]
The internal defect identifying unit 24 identifies a portion corresponding to the internal defect in the cast product from the three-dimensional shape model formed by the actual measurement model forming unit 22. Here, a polygon group corresponding to the boundary surface (referred to as the outer surface) with the outside (outside air) of the casting is extracted from the polygon surface model, and the remaining polygon group is recognized as the boundary surface with the cavity portion of the internal defect. To do.
[0021]
The drawing unit 26 is a unit that renders the three-dimensional shape model formed by the actual measurement model forming unit 22 to form a display image. In particular, in the present embodiment, the drawing unit 26 uses the identification result of the internal defect identifying unit 24 to generate an internal image. A display image in which the defective portion is easily visually recognized and emphasized is generated.
[0022]
The determination processing unit 28 determines whether the internal defect state of the casting to be inspected is an appropriate state based on the identification result of the internal defect identification unit 24. The determination processing unit 28 performs the determination according to the determination criteria registered in advance in the apparatus.
[0023]
The display device 40 is a device that displays a display screen generated by the inspection support device 20, and displays, for example, a three-dimensional image of a cast product generated by the drawing unit 26. The input device 45 is a device that receives input of data and instructions to the examination support device 20 such as a keyboard and a pointing device.
[0024]
Next, with reference to FIG. 2, the procedure of the internal defect inspection support process of the cast product by this system will be described.
[0025]
First, in this system, the X-ray CT apparatus 10 scans a cross section of a predetermined interval (for example, 1 mm, etc., depending on the accuracy of the three-dimensional shape model to be created) of the casting to be inspected, and A tomographic image is created (S10). The data of the tomographic image of each cross section obtained as a result is input to the examination support apparatus 20. The actual measurement model forming unit 22 of the inspection support apparatus 20 forms a polygon surface model of a cast product to be inspected from the tomographic image group using an algorithm such as a marching cubes method (S12). Next, the internal defect identifying unit 24 identifies a portion corresponding to the internal defect in the casting from the polygon surface model (S20). An example of the processing content of step S20 is shown as steps S22 to S26. In this processing example, a polygon group corresponding to the boundary surface (referred to as the outer surface) with the outside (outside air) of the casting is extracted from the polygon surface model, and the remaining polygon group is the boundary surface with the cavity portion of the internal defect. Recognize. Here, for the recognition process of the outer surface, first, the polygon surface model is displayed on the display device 40, and on the display, the user is requested to specify the polygon corresponding to the outer surface of the cast product (S22). Using the polygon designated in this way as a starting point, a polygon connected to the polygon already recognized as the outer surface (that is, sharing a side) is searched for and newly recognized as the outer surface (S24). That is, the fact that the polygon obtained by searching corresponds to the outer surface is stored in a predetermined storage device. If this process is repeated until there are no more polygons recognized as the outer surface, all the polygons corresponding to the outer surface of the cast product can be extracted. In the case of a cast product, the boundary surface that is not the outer surface (ie, the inner surface of the cast product) may be considered as an internal defect. Therefore, after extracting all the polygons on the outer surface, the polygons for which information indicating the outer surface is not stored can be considered as polygons surrounding a cavity that is an internal defect. Therefore, in this processing example, after all the polygons connected to the polygon designated by the user are extracted in step S22, each remaining polygon that is not extracted is identified as a polygon corresponding to the internal defect of the cast product (S26). . When the polygons representing the surface of the internal defect are identified in this way, individual internal defects (cavities) can be identified by dividing them into a set of polygons that are connected to each other. Thereby, it is possible to obtain a physical quantity such as the position and volume of each internal defect.
[0026]
If the internal defect can be identified in this way, it is possible to generate a three-dimensional image by the drawing unit 26 and determine whether the determination unit 28 is good or bad. For example, the user can select these two processes.
[0027]
As processing of the drawing unit 26, first, each polygon group on the outer surface identified by the internal defect identifying unit 24 is set to be translucent (S30). That is, a transmission coefficient having a predetermined value larger than 0 and smaller than 1 is set for the polygon recognized as the outer surface (transmission coefficient 0 is completely transparent and transmission coefficient 1 is completely opaque). In addition, each polygon corresponding to the internal defect is set to a predetermined color that can be easily distinguished from the color (translucent) of the polygon on the outer surface (S32). In accordance with this setting, the drawing unit 26 renders a polygonal surface model of the cast product, and displays the resulting three-dimensional image on the display device 40 (S34). In the three-dimensional image created in this way, the shape of the cast product is displayed in a translucent manner, and defects such as a cast hole inside the cast product can be clearly seen through the translucent cast product shape display. Is displayed. Thus, since the position and shape of the internal defect can be displayed three-dimensionally, there is an advantage that the number of internal defects and the position, shape, size, etc. of the internal defect can be easily grasped by the user. It is also preferable that designation of drawing parameters such as a viewpoint position and a line-of-sight direction can be dynamically accepted from the input device 45 and the surface model is dynamically rendered according to the designation. By performing the three-dimensional display while changing the orientation and the like in this way, it becomes easier to grasp the three-dimensional position of the internal defect.
[0028]
Further, in the determination processing unit 28, for example, it is determined whether or not the internal defect group identified by the internal defect identifying unit 24 satisfies a previously registered determination criterion (S36).
[0029]
For example, when taking a design approach that concentrates internal defects such as cast holes in parts that do not adversely affect product performance, it is sufficient to set in advance a concentration target area that concentrates internal defects in the product shape as a criterion. . In this case, if an internal defect exists outside the concentrated target area, a determination such as determining that the inspection target is defective may be performed. In this case, since the three-dimensional position of each internal defect can be known from the position information of the polygon of each internal defect identified by the internal defect identification unit 24, whether the determination criterion is satisfied from the information of this three-dimensional position Whether it can be determined. Note that instead of the concentrated target area, information other than the concentrated target area may be set as determination criterion information as an area where it is desired to have as few internal defects as possible. In addition, it is possible to set a prohibited area in which an absolute internal defect should not exist in the structure in advance, and determine that a defect is present if there is an internal defect in this area.
[0030]
As another determination method, a method for determining whether or not the quantitative evaluation value of the internal defect is within an upper limit value determined in advance as a determination criterion is conceivable. Here, as the quantitative evaluation values for internal defects, for example, the total number of internal defects, the total volume, the total surface area, the maximum volume (the volume of all internal defects having the largest volume), the maximum surface area, etc. Various things are possible. In addition to determination based on one of these quantitative evaluation values, it is also possible to determine by a combination of a plurality of quantitative evaluation values.
[0031]
Further, as an eclectic method of the above two determination methods, a method of evaluating a quantitative evaluation value of internal defects in a region outside the above-described concentrated target region is also suitable. In this case, for example, if the total volume (or maximum volume, total number, etc.) of internal defects outside the concentration target area is equal to or less than a predetermined upper limit value, the inspection target is determined to be non-defective. Of course, a method may be used in which a plurality of quantitative evaluation values are examined for internal defects outside the concentration target area, and a combination of these evaluation values is determined as a non-defective product when a predetermined non-defective product standard is satisfied. A determination method is also suitable in which both the concentrated target area and the prohibited area described above are set, and a determination criterion based on a quantitative evaluation value is set for a range that is neither the concentrated target area nor the prohibited area.
[0032]
The examination support apparatus 20 displays the determination result obtained by the determination processing unit 28 in this way on the display apparatus 40 (S38).
[0033]
The three-dimensional image display in which the internal defect by the drawing unit 26 can be visually recognized and the determination result by the determination processing unit 28 can be simultaneously displayed on the display device 40 by using, for example, a window system.
[0034]
As described above, according to the system of the present embodiment, a three-dimensional shape model is formed from a tomographic image of a cast product, and internal defects are identified and displayed from the three-dimensional shape model, or the status of these internal defects is determined. It can be determined whether it is within an allowable range. The user can confirm the quality of the state of an internal defect such as a cast hole of a casting to be inspected with reference to such a three-dimensional image display and determination result display. Therefore, if this system is used at the prototype stage, the inspection of the internal defect state of the prototype becomes much easier than before, and it is necessary for trial production, inspection, and design adjustment (adjustment and change of casting parameters and design shape). The cycle can be shortened.
[0035]
Next, a modification of the above embodiment will be described with reference to FIGS.
[0036]
FIG. 3 is a diagram showing the system configuration of this modification. Components corresponding to the components of the above-described embodiment shown in FIG. 1 are assigned the same reference numerals as those in FIG. .
[0037]
This modified system is intended to support a trial cycle for casting process design in a casting department or the like. In this modification, a casting simulator 29 is provided in the inspection support apparatus 20 in addition to the system configuration of the above embodiment.
[0038]
This casting simulator 29 is a means for performing a simulation calculation for obtaining the occurrence position, shape, size, etc. of a casting defect, and the design shape and casting parameters (for example, hot water temperature, pouring location, etc.) of the product (casting product). A model for analysis is created according to the above, and a known analysis operation such as solidification analysis is performed on this model. As the simulation algorithm, various conventional algorithms such as JP-A-2001-287023 can be used.
[0039]
A storage unit 30 such as a hard disk drive provided in the inspection support device 20 stores design shape data 32 of a cast product, casting parameters 34 when the cast product is cast, a simulation result 36 by a casting simulator 29, and the like. The
[0040]
As shown in FIG. 4, in this system, first, the design shape data of the cast product created by the design department using the CAD system is received and stored in the storage unit 30 (S40). Next, the user activates the casting simulator 29, and sets the design shape data 32 to be simulated and various casting parameters 34 as casting conditions for the simulator 29 (S42). The casting simulator 29 creates an analysis model according to this setting, executes a predetermined casting simulation (S44), and displays the simulation result on the display device 40. The user looks at the simulation result to check whether the casting state including the state of the internal defect is good, and determines whether the casting condition is appropriate (S46). Here, if the cast state of the simulation result is not good, the process returns to step S42, and adjustments are made to the design shape data, casting parameters, etc., and a simulation (S44) is performed. This is repeated until a good simulation result is obtained. The design shape data 32, the casting parameters 34, and the simulation results 36 when a good simulation result is obtained are stored in the storage unit 30 and can be used later.
[0041]
When a good simulation result is obtained in this way, a prototype is cast according to the casting conditions (design shape data and casting parameters) at that time (S48). Then, as in the above-described embodiment, a tomographic image of the prototype is created by the X-ray CT scanner 10 (S50), and the three-dimensional shape model of the prototype is created by the actual measurement model forming unit 22 based on these tomographic image groups. An internal defect is identified from the three-dimensional shape model by the internal defect identification unit 24 (S54). In the present embodiment, the determination processing unit 28 compares the identification result of the internal defect with the state of the internal defect in the simulation result 36, and determines the quality (S56). Here, for example, the internal defect occurrence position distribution in the simulation result 36 is compared with the internal defect position distribution obtained from the actual measurement model, and it is determined whether or not the difference between the two distributions is within a predetermined allowable range (S58). . At this time, it is also preferable to employ a determination process that considers not only the position of the internal defect but also the size. If the actually measured state of the internal defect is similar to the simulation result determined to be good in step S46, it can be determined that a good prototype result has been obtained. Instead of steps S56 and S58, the quality of the internal defect state of the actually measured model may be determined according to the determination criteria exemplified in the above embodiment. And the result of this determination is displayed on the display apparatus 40, and a user's determination is asked.
[0042]
The user looks at the display of the determination result to determine whether or not the state of the internal defect of the prototype is good. If not, the process returns to step S42 and the casting condition of the design shape data and casting parameters is set. Make adjustments and changes, and repeat the following processing.
[0043]
In this way, in this modified system, the design / casting parameters can be refined by simulation and the effectiveness of the design / casting parameters can be verified by actual measurement of the prototype in a smooth flow. Can contribute to shortening.
[0044]
In addition, in this modified example, the distribution of the internal defects obtained from the actual measurement model of the prototype can be compared with the simulation result. Therefore, when the difference between the two is large or the casting conditions are changed variously, the two are not close to each other. In some cases, it can be determined that the simulation algorithm of the casting simulator 29 needs to be improved.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of a system configuration according to a preferred embodiment of the present invention.
FIG. 2 is a flowchart illustrating a processing procedure of the system according to the embodiment.
FIG. 3 is a diagram showing a system configuration of a modified example.
FIG. 4 is a flowchart illustrating a processing procedure of a modification example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 X-ray CT scanner, 20 Inspection assistance apparatus, 22 Actual measurement model formation part, 24 Internal defect identification part, 26 Drawing part, 28 Judgment processing part, 29 Casting simulator, 30 Storage part, 32 Design shape data, 34 Casting parameter, 36 Simulation results, 40 display devices, 45 input devices.

Claims

Display that receives tomographic images of a plurality of cross sections of the cast product formed by actually measuring a cast product to be inspected, and displays a surface model as a three-dimensional shape model of the cast product based on the tomographic images of the plurality of cross sections Means,
Of the surface elements of the surface model displayed on the display means, the surface element specified by the user is the starting point of the outer surface of the casting, and the surface element shares an edge with the surface element that has already been recognized as the outer surface. Measured model forming means for extracting the outer surface of the casting by repeating the process of recognizing as a new outer surface ,
Defect identifying means for identifying a surface element not extracted as the outer surface from the surface model as a surface element surrounding a cavity in the casting ,
A cast product internal defect inspection support device.

The apparatus of claim 1 , comprising:
The surface elements constituting an outer surface of the casting before Symbol surface models and translucent, the display image forming means for forming a display image highlighted in a different color from that of the semi-transparent display of the face elements surrounding the said cavity casting inner defect inspection support apparatus, characterized in that it comprises.

Display means for receiving a tomographic image of a plurality of cross sections of the cast product formed by actually measuring a cast product to be inspected, and displaying a surface model of the cast product based on the tomographic images of the plurality of cross sections ;
Of the surface elements of the surface model displayed on the display means, the surface element specified by the user is the starting point of the outer surface of the casting, and the surface element shares an edge with the surface element that has already been recognized as the outer surface. Measured model forming means for extracting the outer surface of the casting by repeating the process of recognizing as a new outer surface ,
Defect identifying means for identifying, as an internal defect in the casting, a space surrounded by surface elements not extracted as the outer surface from the surface model ;
Obtaining information on the target internal defect state in the cast product, determining the quality of the cast product to be inspected based on a comparison between the internal defect state identified by the defect identification means and the target internal defect state, Pass / fail judgment means for presenting the judgment result to the user;
A cast product internal defect inspection support device.

Receiving a tomographic image of a plurality of cross sections of the cast product formed by actually measuring a cast product to be inspected, and displaying a surface model as a three-dimensional shape model of the cast product based on the tomographic images of the plurality of cross sections When,
Of the surface elements of the surface model displayed on the display means, the surface element specified by the user is the starting point of the outer surface of the casting, and the surface element shares an edge with the surface element that has already been recognized as the outer surface. Repeating the process of recognizing as a new outer surface to extract the outer surface of the casting,
Identifying from the surface model a surface element not extracted as the outer surface as a surface element surrounding a cavity in the casting ;
A method for supporting inspection of internal defects in castings.

Receiving a tomographic image of a plurality of cross sections of the cast product formed by actually measuring a cast product to be inspected, and forming a surface model of the cast product based on the tomographic images of the plurality of cross sections;
A surface model display step for displaying the surface model on a display means;
Of the surface elements of the surface model displayed on the display means, the surface element specified by the user is the starting point of the outer surface of the casting, and the surface element shares an edge with the surface element that has already been recognized as the outer surface. Repeating the process of recognizing as a new outer surface to extract the outer surface of the casting,
Identifying a space surrounded by surface elements not extracted as the outer surface from the surface model as an internal defect in the casting;
Obtaining information on the target internal defect state in the cast product, determining the quality of the cast product to be inspected based on a comparison between the internal defect identified from the surface model and the target internal defect state, Presenting the determination result to the user;
A method for supporting inspection of internal defects in castings.

A casting condition in which a predetermined casting simulation is executed based on the shape information and casting parameters of the cast product, and the simulation is repeated while correcting at least one of the shape information and the casting parameters until a desired internal defect distribution is obtained. A search step;
A prototype step of casting a prototype according to the shape information and casting parameters determined to provide the desired internal defect distribution in the casting condition search step;
A prototype measurement step for measuring the prototype with a tomographic image forming apparatus and forming a tomographic image of a plurality of cross sections of the prototype,
Based on the tomographic images of the plurality of cross sections, an actual measurement model forming step for forming a prototype surface model,
A surface model display step for displaying the surface model on a display means;
Of the surface elements of the surface model displayed on the display means, the surface element specified by the user is the starting point of the outer surface of the casting, and the surface element shares an edge with the surface element that has already been recognized as the outer surface. An outer surface identification step of extracting the outer surface of the casting by repeating the process of recognizing as a new outer surface;
From the surface model, and the defect identification identifying space enclosed by the surface element that has not been extracted as the outer surface as an internal defect in the prototype,
Based on the internal defect distribution finally obtained by repeating the simulation in the casting condition search step and the internal defect distribution identified from the surface model, predetermined information that is the basis for the pass / fail judgment of the simulation is created. And a simulation quality information presentation step to be presented to the user,
A method for supporting inspection of internal defects in castings.

Computer system,
Receiving a tomographic image of a plurality of cross sections of the cast product formed by actually measuring a cast product to be inspected, and forming a surface model of the cast product based on the tomographic images of the plurality of cross sections;
Displaying the surface model on a display means;
Of the surface elements of the surface model displayed on the display means, the surface element specified by the user is the starting point of the outer surface of the casting, and the surface element shares an edge with the surface element that has already been recognized as the outer surface. Repeating the process of recognizing as a new outer surface to extract the outer surface of the casting,
Identifying , from the surface model, a surface element not extracted as the outer surface from a surface element of an internal defect ;
A program that executes