JP7516231B2 - Layered manufacturing device, layered manufacturing method, and program - Google Patents
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- 238000004519 manufacturing process Methods 0.000 title claims description 53
- 238000002844 melting Methods 0.000 claims description 71
- 230000008018 melting Effects 0.000 claims description 71
- 238000011156 evaluation Methods 0.000 claims description 62
- 238000000034 method Methods 0.000 claims description 42
- 239000000463 material Substances 0.000 claims description 40
- 239000000654 additive Substances 0.000 claims description 39
- 230000000996 additive effect Effects 0.000 claims description 39
- 230000008569 process Effects 0.000 claims description 38
- 238000007639 printing Methods 0.000 claims description 29
- 230000008859 change Effects 0.000 claims description 25
- 238000010438 heat treatment Methods 0.000 claims description 17
- 238000004458 analytical method Methods 0.000 claims description 16
- 230000002123 temporal effect Effects 0.000 claims description 16
- 238000000465 moulding Methods 0.000 claims description 13
- 238000007711 solidification Methods 0.000 claims description 13
- 230000008023 solidification Effects 0.000 claims description 13
- 230000004044 response Effects 0.000 claims description 5
- 238000004590 computer program Methods 0.000 claims 1
- 238000010309 melting process Methods 0.000 description 12
- 238000009826 distribution Methods 0.000 description 9
- 238000010586 diagram Methods 0.000 description 8
- 239000011295 pitch Substances 0.000 description 6
- 239000002184 metal Substances 0.000 description 5
- 239000000843 powder Substances 0.000 description 5
- 238000012805 post-processing Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 230000001419 dependent effect Effects 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000012768 molten material Substances 0.000 description 2
- 230000007423 decrease Effects 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/25—Process efficiency
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Description
本発明の実施形態は、積層造形装置、積層造形方法、およびプログラムに関する。 Embodiments of the present invention relate to an additive manufacturing device, an additive manufacturing method, and a program.
積層造形技術は、素材に金属粉末や金属ワイヤなどの材料を使い、溶融熱源としてレーザーや電子ビームを用いることを特徴とする。そのため、構造物を目的の形状に対してニアネットシェイプに製造できる可能性はある。しかしながら、現状は、完全なニアネットシェイプに造形物を製作することは困難である。それは、造形時に生じる造形物の面外変形が原因である。そのため、造形物にはこの面外変形を抑制するためのサポートを取り付けるのが一般的である。 Additive manufacturing technology is characterized by using materials such as metal powder and metal wire as the raw material, and using a laser or electron beam as the melting heat source. This makes it possible to manufacture structures to a near net shape of the desired shape. However, currently it is difficult to manufacture objects to a perfect near net shape. This is due to out-of-plane deformation of the object that occurs during manufacturing. For this reason, it is common to attach supports to the object to suppress this out-of-plane deformation.
上述したサポートは、造形終了後に加工にて取り除く必要があるため、後工程の増加が問題となっている。後工程の増加を避けるためには、サポートの使用は望ましくない。 The supports mentioned above need to be removed by processing after the modeling is complete, which increases the number of post-processing steps, and this is a problem. To avoid this increase in post-processing steps, the use of supports is not recommended.
一方で、面外変形が特に問題となる場所がオーバーハング部（例えばベース部から突出している部分）であることから、造形物の造形方向を変えることでオーバーハング部が生じることを避ける方法や、オーバーハング部に限らず一般的な方法として、ビーム照射領域を分割することで変形を抑制する方法、温度を調整することで変形を抑制する方法などが報告されている。しかしながら、面外変形の原因は、造形物内に生じる熱ひずみの偏りであり、すなわち、凝固時の温度分布の偏りである。そのため、上述した各種の方法は、オーバーハング部に面外変形が生じるという根本的な問題を解決するものではない。 On the other hand, because out-of-plane deformation is particularly problematic in overhanging parts (for example, parts protruding from the base), methods that have been reported include changing the molding direction of the molded object to avoid the occurrence of overhanging parts, as well as general methods not limited to overhanging parts, such as dividing the beam irradiation area to suppress deformation, and adjusting the temperature to suppress deformation. However, the cause of out-of-plane deformation is the unevenness of thermal strain that occurs within the molded object, that is, the unevenness of the temperature distribution during solidification. Therefore, the various methods mentioned above do not solve the fundamental problem of out-of-plane deformation occurring in overhanging parts.
本発明が解決しようとする課題は、積層造形物のオーバーハング部を造形する際の面外変形の発生を抑制することのできる、積層造形装置、積層造形方法、およびプログラムを提供することにある。 The problem that the present invention aims to solve is to provide an additive manufacturing device, an additive manufacturing method, and a program that can suppress the occurrence of out-of-plane deformation when manufacturing an overhanging portion of an additive manufacturing object.
実施形態の積層造形装置は、材料に対して熱源を走査することにより積層造形物を造形する積層造形装置において、前記積層造形物の下方に空間がある部分であるオーバーハング部が造形される工程において前記熱源の走査に応じて変化しうる少なくとも前記オーバーハング部の温度場の時間的変化を造形条件ごとに評価する温度評価手段と、前記温度評価手段により評価された造形条件ごとの温度場の時間的変化に基づき、前記オーバーハング部が造形される工程において前記熱源により材料が溶融して形成される溶融部がその凝固過程で力学的溶融温度に達する際に、既に凝固している前記オーバーハング部の既造形部のうちの少なくとも温度場が力学的溶融温度以上に保持されている既造形部分と前記溶融部とが力学的溶融温度の温度領域内に収まる温度場を保ちながら力学的溶融温度未満に冷却される造形条件を決定する造形条件決定手段と、前記造形条件決定手段により決定された造形条件に基づき、前記熱源の走査を実施する熱源走査手段と、を具備する。 An embodiment of an additive manufacturing apparatus is an additive manufacturing apparatus that manufactures an additive manufacturing object by scanning a heat source with respect to a material, and is equipped with a temperature evaluation means that evaluates, for each manufacturing condition, a change in temperature field over time of at least the overhang portion, which may change in response to scanning of the heat source, in a process of manufacturing an overhang portion, which is a portion having a space below the additive manufacturing object; a manufacturing condition determination means that determines, based on the change in temperature field over time for each manufacturing condition evaluated by the temperature evaluation means, manufacturing conditions under which, when a molten portion formed by melting material by the heat source in the process of manufacturing the overhang portion reaches a mechanical melting temperature during its solidification process, at least a pre-manufactured portion of the overhang portion that has already solidified, whose temperature field is maintained at or above the mechanical melting temperature and the molten portion are cooled to below the mechanical melting temperature while maintaining a temperature field that falls within a temperature range of the mechanical melting temperature; and a heat source scanning means that scans the heat source based on the manufacturing conditions determined by the manufacturing condition determination means.
本発明によれば、積層造形物のオーバーハング部を造形する際の面外変形の発生を抑制することができる。 The present invention makes it possible to suppress the occurrence of out-of-plane deformation when forming the overhang portion of a layered object.
以下、実施の形態について、図面を参照して説明する。 The following describes the embodiment with reference to the drawings.
図１は、実施形態に係る三次元積層造形装置が積層造形物を造形する様子を示す積層造形物の斜視図である。また、図２（ａ）は同積層造形物の平面図、図２（ｂ）は同積層造形物の側面図である。 Figure 1 is a perspective view of a layered object showing how a three-dimensional additive manufacturing device according to an embodiment manufactures the layered object. Also, Figure 2(a) is a plan view of the same layered object, and Figure 2(b) is a side view of the same layered object.
なお、本例は、説明を理解しやすいものとするため、簡易な造形物を造形する場合の一例を示しているが、実施形態に係る三次元積層造形装置は、より複雑な形状を有する構造物（例えば、湾曲部を有するタービンのブレード、配管、格子状の構造物など）を造形することが可能である。 In order to make the explanation easier to understand, this example shows an example of manufacturing a simple object, but the 3D additive manufacturing device according to the embodiment is capable of manufacturing structures with more complex shapes (for example, turbine blades with curved parts, piping, lattice-like structures, etc.).
図１及び図２に示されるように、三次元積層造形装置により造形される積層造形物１１は、ベース部１２と、このベース部１２から突出しているオーバーハング部１３とを含む。なお、ここでいうオーバーハング部とは、図１のようにベース部の一部から突出するような部分だけに限られない。積層造形物の種類によっては、ブリッジ部、横穴の天井部など、下方に空間があるために温度が力学的溶融温度よりも高い場合に自重によって形状が変形しやすい部分がある。そのような部分をオーバーハング部と称している。 As shown in Figures 1 and 2, an additive manufacturing object 11 manufactured by a 3D additive manufacturing device includes a base portion 12 and an overhang portion 13 protruding from the base portion 12. Note that the overhang portion referred to here is not limited to a portion that protrudes from a part of the base portion as shown in Figure 1. Depending on the type of additive manufacturing object, there are parts such as bridge portions and ceiling portions of horizontal holes that are prone to deformation due to their own weight when the temperature is higher than the mechanical melting temperature due to the presence of space below. Such parts are referred to as overhang portions.
積層造形物１１は、パウダベッド等に配置された金属粉末もしくは金属ワイヤなどの材料に対して照射されるレーザビーム等による熱源１４を水平方向（ｘ方向もしくはｙ方向）に走査することにより各層が形成される。熱源１４は１つであってもよいが、同時に走査する熱源１４が複数あってもよい。熱源１４の走査により、材料を溶融させて１つの層を形成した後、次にその上にも別の層を形成し、さらにその上に別の層を形成するという処理を繰り返すことにより、最終的に複数の層が積層方向（ｚ方向）に積層された積層造形物１１が造形される。ベース部１２もオーバーハング部１３も、複数の層で形成される。オーバーハング部１３のそれぞれの層は、同じ高さにある対応するベース部１２の層と共に一体として形成される。 Each layer of the additive model 11 is formed by scanning a heat source 14, such as a laser beam, horizontally (x-direction or y-direction) onto a material such as metal powder or metal wire arranged on a powder bed or the like. There may be only one heat source 14, or multiple heat sources 14 may be scanned simultaneously. The heat source 14 is scanned to melt the material to form one layer, and then another layer is formed on top of that, and the process is repeated to finally form the additive model 11 in which multiple layers are stacked in the stacking direction (z-direction). Both the base portion 12 and the overhang portion 13 are formed of multiple layers. Each layer of the overhang portion 13 is formed integrally with the corresponding layer of the base portion 12 at the same height.
積層造形物１１が造形される工程では、図２（ａ）及び（ｂ）に示されるように、熱源１４の走査により材料が溶融して形成される溶融部（溶融した材料がまだ凝固していない熱源１４近傍部分）と、熱源１４が走査された後の既造形部（溶融した材料が既に凝固している部分）１５と、熱源１４が走査される前の未造形部（材料がまだ溶融していない部分）１６とが存在する。熱源１４が走査された後の既造形部は、同一の層で熱源が既に通過した部分のほか、その下の各層の既に造形された部分も含む。 2(a) and (b), in the process of forming the additive manufacturing object 11, there are a molten portion (a portion near the heat source 14 where the molten material has not yet solidified) formed by the scanning of the heat source 14, a pre-formed portion (a portion where the molten material has already solidified) 15 after the heat source 14 is scanned, and an unformed portion (a portion where the material has not yet melted) 16 before the heat source 14 is scanned. The pre-formed portion after the heat source 14 is scanned includes not only the portion of the same layer through which the heat source has already passed, but also the already-formed portions of each layer below.
図３は、実施形態に係る三次元積層造形装置１の構成の一例を示すブロック図である。 Figure 3 is a block diagram showing an example of the configuration of a three-dimensional additive manufacturing device 1 according to an embodiment.
図３に示される三次元積層造形装置１は、例えばコンピュータを用いて実現される。当該コンピュータには、各種の機能を実現させるためのプログラムが所定の記録媒体に記録され、そのプログラムがプロセッサ５１により実行されるようになっている。プロセッサ５１が処理に使用するデータや生成したデータはメモリ５２に記憶される。 The three-dimensional additive manufacturing device 1 shown in FIG. 3 is realized, for example, by using a computer. In the computer, programs for realizing various functions are recorded on a predetermined recording medium, and the programs are executed by the processor 51. Data used for processing by the processor 51 and data generated by the processor 51 are stored in the memory 52.
図３に示される三次元積層造形装置１は、主な機能として、温度評価部２、造形条件決定部３、および熱源走査部４を備える。 The three-dimensional additive manufacturing device 1 shown in FIG. 3 has the following main functions: a temperature evaluation unit 2, a modeling condition determination unit 3, and a heat source scanning unit 4.
温度評価部２は、積層造形物１１のオーバーハング部１３が造形される工程において熱源１４の走査に応じて変化しうる少なくともオーバーハング部１３の温度場（温度分布）の時間的変化を造形条件ごとに評価するものである。 The temperature evaluation unit 2 evaluates the temporal change in the temperature field (temperature distribution) of at least the overhang portion 13, which may change in response to the scanning of the heat source 14 during the process of forming the overhang portion 13 of the layered object 11, for each forming condition.
造形条件は、予熱工程（材料を溶融させる前に予熱を行う工程）、溶融工程（材料を溶融させる工程）、後熱工程（材料を溶融させた後に後熱を行う工程）のそれぞれにおける、熱源１４の入熱量、走査速度、ビーム半径、および走査シーケンス（層ごとの熱源１４の走査パターン）を示すものである。なお、予熱工程と後熱工程は、省略することが可能である。 The modeling conditions indicate the heat input, scanning speed, beam radius, and scanning sequence (scanning pattern of the heat source 14 for each layer) of the heat source 14 in each of the preheating process (a process in which preheating is performed before melting the material), the melting process (a process in which the material is melted), and the post-heating process (a process in which post-heating is performed after melting the material). Note that the pre-heating process and the post-heating process can be omitted.
温度評価部２は、材料物性入力部２１、造形物形状入力部２２、造形条件入力部２３、および熱伝導解析部２４を含む。 The temperature evaluation unit 2 includes a material property input unit 21, a model shape input unit 22, a modeling condition input unit 23, and a heat conduction analysis unit 24.
材料物性入力部２１は、造形物の造形に使用する材料の材料物性を示すデータ（温度依存性を有する材料物性値）を熱伝導解析部２４に入力するものである。当該データは、外部から材料物性入力部２１を通じて熱伝導解析部２４に供給することが可能である。 The material property input unit 21 inputs data indicating the material properties of the material used to form the object (temperature-dependent material property values) to the heat conduction analysis unit 24. This data can be supplied to the heat conduction analysis unit 24 from outside via the material property input unit 21.
造形物形状入力部２２は、解析対象の層における造形物の形状（パウダベッド等の形状を含む）を示すデータを熱伝導解析部２４に入力するものである。当該データは、外部から造形物形状入力部２２を通じて熱伝導解析部２４に供給することが可能である。 The object shape input unit 22 inputs data indicating the shape of the object in the layer to be analyzed (including the shape of the powder bed, etc.) to the heat conduction analysis unit 24. This data can be supplied to the heat conduction analysis unit 24 from outside via the object shape input unit 22.
造形条件入力部２３は、予熱工程、溶融工程、後熱工程のそれぞれにおける、熱源１４の入熱量、走査速度、ビーム半径、および走査シーケンスを示す造形条件のデータを熱伝導解析部２４に入力するものである。当該データは、外部から造形条件入力部２３を通じて熱伝導解析部２４に供給することが可能である。 The modeling condition input unit 23 inputs modeling condition data indicating the heat input amount of the heat source 14, the scanning speed, the beam radius, and the scanning sequence in each of the preheating process, the melting process, and the post-heating process, to the thermal conduction analysis unit 24. This data can be supplied to the thermal conduction analysis unit 24 from outside via the modeling condition input unit 23.
熱伝導解析部２４は、材料物性入力部２１、造形物形状入力部２２、および造形条件入力部２３から供給される各種データを入力し、それらのデータを用いて、予熱工程、溶融工程、後熱工程のそれぞれについて、材料物性を示すデータおよび造形物形状を示すデータに基づき、造形条件（例えば、熱源１４の入熱量、走査速度、ビーム半径、および走査シーケンス）を変数とする熱伝導解析を行うことにより、造形条件が異なるオーバーハング部１３の温度場の時間的変化を示す複数のデータを生成する。 The heat conduction analysis unit 24 inputs various data supplied from the material property input unit 21, the object shape input unit 22, and the object shape input unit 23, and uses the data to perform heat conduction analysis with the object shape (e.g., the heat input amount of the heat source 14, the scanning speed, the beam radius, and the scanning sequence) as variables for each of the preheating process, the melting process, and the post-heating process, based on the data indicating the material properties and the data indicating the object shape, thereby generating multiple data indicating the temporal changes in the temperature field of the overhang portion 13 with different object shape conditions.
造形条件決定部３は、温度評価部２により評価された造形条件ごとの温度場の時間的変化を示す複数のデータに基づき、オーバーハング部１３が造形される工程において熱源１４により材料が溶融して形成される溶融部がその凝固過程で力学的溶融温度に達する際に、既に凝固しているオーバーハング部１３の既造形部のうちの少なくとも熱源１４から一定距離以上離れた所定の範囲内にある既造形部分の温度場が力学的溶融温度以上に保持されており、かつ、当該既造形部分と上記溶融部とが予め定めた温度差の範囲に収まる温度場を保ちながら（即ち、できるだけ均一な温度場を保ちながら）力学的溶融温度未満に冷却される造形条件を決定するものである。力学的溶融温度は、ヤング率が溶融金属程度の非常に小さい値を示す温度（降伏応力がほとんど０となる温度）であり、使用される材料に依存する材料固有の物性値である。 The modeling condition determination unit 3 determines modeling conditions based on a plurality of data showing the temporal change in the temperature field for each modeling condition evaluated by the temperature evaluation unit 2, such that when the molten part formed by melting the material by the heat source 14 in the process of modeling the overhang part 13 reaches the mechanical melting temperature during the solidification process, the temperature field of the already solidified pre-modeled part of the overhang part 13 that is within a predetermined range away from the heat source 14 is maintained at or above the mechanical melting temperature, and the pre-modeled part and the above-mentioned molten part are cooled to below the mechanical melting temperature while maintaining a temperature field that falls within a predetermined temperature difference range (i.e., while maintaining a temperature field as uniform as possible). The mechanical melting temperature is the temperature at which the Young's modulus is very small, similar to that of molten metal (the temperature at which the yield stress is almost zero), and is a physical property value specific to the material used that depends on the material used.
上記既造形部分は、上記溶融部の大きさに応じた範囲に設定されることが望ましい。また、造形条件決定部３で使用する力学的溶融温度の値には、実験的に求めた値を適用してもよい。 It is desirable that the above-mentioned pre-formed portion is set in a range according to the size of the above-mentioned molten portion. In addition, the value of the mechanical melting temperature used in the forming condition determination unit 3 may be an experimentally determined value.
要件を満たす造形条件が無い場合には、要件を満たす造形条件が得られるまで、温度評価部２に対して造形条件の修正および修正後の造形条件に基づく温度場の時間的変化の再評価を指示する（フィードバック制御を行う）ようにしてもよい。あるいは、造形条件の修正が必要である旨を外部に通知し、改めて修正後の造形条件を外部から造形条件入力部２３を通じて温度評価部２に供給するようにしてもよい。 If there are no printing conditions that satisfy the requirements, the temperature evaluation unit 2 may be instructed to modify the printing conditions and re-evaluate the temporal change in the temperature field based on the modified printing conditions (feedback control) until printing conditions that satisfy the requirements are obtained. Alternatively, the need to modify the printing conditions may be notified to the outside, and the modified printing conditions may be supplied again from the outside to the temperature evaluation unit 2 via the printing condition input unit 23.
熱源走査部４は、造形条件決定部３により決定された造形条件に基づき、熱源１４の走査を実施するものである。 The heat source scanning unit 4 scans the heat source 14 based on the printing conditions determined by the printing condition determination unit 3.
熱源走査部４は、予熱-熱源走査部４１、溶融-熱源走査部４２、および後熱-熱源走査部４３を含む。 The heat source scanning unit 4 includes a preheating-heat source scanning unit 41, a melting-heat source scanning unit 42, and a postheating-heat source scanning unit 43.
予熱-熱源走査部４１は、予熱工程において、造形条件決定部３により決定された予熱工程に対応する造形条件に基づく熱源走査を外部の図示しない熱源走査装置に指示するものである。 The preheating-heat source scanning unit 41 instructs an external heat source scanning device (not shown) to perform heat source scanning based on the modeling conditions corresponding to the preheating process determined by the modeling condition determination unit 3 during the preheating process.
この予熱-熱源走査部４１は、例えば、予熱工程において、オーバーハング部１３もしくはその周辺を選択的に繰り返し予熱し、オーバーハング部１３もしくはその周辺の温度を溶融温度以下および力学的溶融温度以上の温度範囲内に収まるように調整する。予熱を行うタイミングは、溶融工程の直前であってもよいし、溶融工程の途中であってもよい。 This preheating-heat source scanning unit 41 selectively and repeatedly preheats the overhang portion 13 or its surroundings in the preheating process, for example, and adjusts the temperature of the overhang portion 13 or its surroundings to fall within a temperature range below the melting temperature and above the mechanical melting temperature. The timing of preheating may be immediately before the melting process or during the melting process.
溶融-熱源走査部４２は、溶融工程において、造形条件決定部３により決定された溶融工程に対応する造形条件に基づく熱源走査を外部の図示しない熱源走査装置に指示するものである。 The melting-heat source scanning unit 42 instructs an external heat source scanning device (not shown) to perform heat source scanning based on the molding conditions corresponding to the melting process determined by the molding condition determination unit 3 during the melting process.
この溶融-熱源走査部４２は、例えば、溶融工程において、オーバーハング部１３にて熱源１４を走査する方向を水平面のうちオーバーハング部１３が積層造形物１１のベース部１２から突出する方向（ｘ方向）に垂直な方向（ｙ方向もしくはその反対方向）とし、走査する熱源１４を定期的に当該熱源の幅よりも小さいピッチで上記突出する方向（ｘ方向）へ移動させてから走査方向の向きを反対方向にする折り返しを繰り返しながら熱源１４の走査を行う。 For example, in the melting process, this melting-heat source scanning unit 42 scans the heat source 14 at the overhanging portion 13 in a direction perpendicular to the direction in which the overhanging portion 13 protrudes from the base portion 12 of the layered object 11 in a horizontal plane (the y direction or the opposite direction), and periodically moves the heat source 14 to be scanned in the protruding direction (x direction) at a pitch smaller than the width of the heat source, and then repeatedly turns around to reverse the scanning direction to scan the heat source 14.
走査面における熱源１４の面積の大きさ（熱源サイズ）は、熱源１４の入熱量および走査速度に応じて設定されてもよい。走査方向は熱源サイズに応じて変えなくてもよいが、折返しピッチ（ｙ方向のピッチ）は、熱源サイズに応じて変わりうる。例えば、熱源サイズが比較的小さい場合は、図４（ａ）に示されるように、折返しピッチは熱源サイズに応じて小さく設定され、複数の熱源１４で分担して走査が行われるようにしてもよい。一方、熱源サイズが比較的大きい場合は、図４（ｂ）に示されるように、折返しピッチは熱源サイズに応じて大きく設定され、１つの熱源１４のみで走査が行われるようにしてもよい。 The size of the area of the heat source 14 on the scanning plane (heat source size) may be set according to the heat input and scanning speed of the heat source 14. The scanning direction does not need to be changed according to the heat source size, but the folding pitch (pitch in the y direction) can be changed according to the heat source size. For example, when the heat source size is relatively small, as shown in FIG. 4(a), the folding pitch may be set small according to the heat source size, and scanning may be shared among multiple heat sources 14. On the other hand, when the heat source size is relatively large, as shown in FIG. 4(b), the folding pitch may be set large according to the heat source size, and scanning may be performed by only one heat source 14.
後熱-熱走査部４３は、後熱工程において、造形条件決定部３により決定された後熱工程に対応する造形条件に基づく熱源走査を外部の図示しない熱源走査装置に指示するものである。 The post-heating-thermal scanning unit 43 instructs an external heat source scanning device (not shown) to perform heat source scanning based on the modeling conditions corresponding to the post-heating process determined by the modeling condition determination unit 3 during the post-heating process.
この後熱-熱走査部４３は、例えば、後熱工程において、オーバーハング部１３もしくはその周辺を選択的に繰り返し後熱し、オーバーハング部１３もしくはその周辺の温度を溶融温度以下および力学的溶融温度以上の温度範囲内に収まるように調整する（オーバーハング部１３やその周辺の温度ができるだけ均一になるようにする）。その際の熱源１４の走査シーケンスは、図４（ａ）及び（ｂ）で説明したような条件に限定されるものではない。 The post-heat-thermal scanning unit 43 selectively and repeatedly post-heats the overhang portion 13 or its periphery in the post-heating process, for example, and adjusts the temperature of the overhang portion 13 or its periphery to fall within a temperature range below the melting temperature and above the mechanical melting temperature (so that the temperature of the overhang portion 13 and its periphery is as uniform as possible). The scanning sequence of the heat source 14 at this time is not limited to the conditions described in Figures 4(a) and (b).
次に、図５乃至図８を参照して、温度評価部２により評価される温度場の時間的変化に基づいて造形条件の良し悪しを判定する手法の例、及び、要件を満たさない造形条件を適切に修正する手法の例について説明する。 Next, with reference to Figures 5 to 8, we will explain an example of a method for determining whether the printing conditions are good or bad based on the temporal changes in the temperature field evaluated by the temperature evaluation unit 2, and an example of a method for appropriately correcting printing conditions that do not satisfy the requirements.
図５は、オーバーハング部１３の温度場の評価の説明に使用する簡易なモデルの例を示す図である。 Figure 5 shows an example of a simple model used to explain the evaluation of the temperature field in the overhang portion 13.
図５に示されるように、オーバーハング部１３に、既凝固点Ａ、既凝固点Ｂ、評価点Ｖを設ける。 As shown in FIG. 5, the overhang portion 13 is provided with a solidified point A, a solidified point B, and an evaluation point V.
熱源１４が走査された後のオーバーハング部１３の既造形部のうち、走査中の熱源１４がある層よりも下方に位置する層の任意の点を既凝固点Ａとし、走査中の熱源１４がある層と同じ層の任意の点を既凝固点Ｂとする。熱源１４がこれから走査されるオーバーハング部１３の未造形部の任意の点を評価点Ｖとする。 After the heat source 14 is scanned, any point in the already-formed part of the overhanging part 13 that is located below the layer where the heat source 14 is currently being scanned is defined as already-solidified point A, and any point in the same layer as the layer where the heat source 14 is currently being scanned is defined as already-solidified point B. Any point in the unformed part of the overhanging part 13 that will be scanned by the heat source 14 is defined as evaluation point V.
図６（ａ）及び（ｂ）に、温度評価部２による評価結果の例（その１）を示す。
図６（ａ）は要件を満たさない造形条件による温度場の時間的変化の例を示すものであり、図６（ｂ）は要件を満たす造形条件による温度場の時間的変化の例を示すものである。
6A and 6B show an example (part 1) of the evaluation result by the temperature evaluation unit 2. FIG.
FIG. 6( a ) shows an example of a change in temperature field over time under modeling conditions that do not satisfy the requirements, and FIG. 6 ( b ) shows an example of a change in temperature field over time under modeling conditions that satisfy the requirements.
図６（ａ）の例では、走査中の熱源１４が評価点Ｖに達してその場所の溶融が開始されると、実線の曲線に示されるように、評価点Ｖの温度が急上昇する。その後、評価点Ｖの温度は低下していき、時刻ｔ＊において一定の温度領域幅を有する力学的溶融温度Ｔｍｅｌｔに達する。このとき、既凝固点Ａ，Ｂの温度ＴＡ（ｔ＊），ＴＢ（ｔ＊）は、すでに力学的溶融温度Ｔｍｅｌｔを下回っており、評価点Ｖの温度からかけ離れた状態にある。このような場合、オーバーハング部１３の凝固時の温度分布に偏りが生じ、面外変形が発生しやすい。 In the example of Fig. 6(a), when the heat source 14 reaches the evaluation point V during scanning and melting of that location begins, the temperature of the evaluation point V rises sharply as shown by the solid curve. Thereafter, the temperature of the evaluation point V decreases, and at time t * , it reaches the mechanical melting temperature T melt , which has a certain temperature range width. At this time, the temperatures TA (t * ) and TB (t * ) of the already-solidified points A and B are already below the mechanical melting temperature T melt and are far from the temperature of the evaluation point V. In such a case, the temperature distribution during solidification of the overhang portion 13 becomes uneven, and out-of-plane deformation is likely to occur.
図６（ａ）のような評価結果に対しては、例えば「熱源の走査速度」を適切に変えることよって造形条件を修正すれば、要件を満たす造形条件を実現することができる。 For evaluation results such as those shown in Figure 6(a), by modifying the printing conditions, for example by appropriately changing the "heat source scanning speed", it is possible to realize printing conditions that satisfy the requirements.
図６（ｂ）の例では、図６（ａ）の場合よりも「熱源の走査速度」が高く設定されている。走査中の熱源１４が早く評価点Ｖに達することから、図６（ａ）の場合よりも早く評価点Ｖの溶融が開始され、実線の曲線に示されるように、評価点Ｖの温度が急上昇し、その後に低下し、前述した時刻ｔ＊よりも早い時刻ｔ＊＊に力学的溶融温度Ｔｍｅｌｔに達する。このとき、既凝固点Ａ，Ｂの温度ＴＡ（ｔ＊＊），ＴＢ（ｔ＊＊）は、まだ力学的溶融温度Ｔｍｅｌｔの下限値以上を保持しており、評価点Ｖの温度と同様に力学的溶融温度Ｔｍｅｌｔの温度領域内にある。そのため、既凝固点Ａ，Ｂがある既造形部分と評価点Ｖがある溶融部とは、共に、予め定めた温度差の範囲に収まる温度場を保ちながら（ほぼ均一な温度場を保ちながら）力学的溶融温度未満に冷却される。このような場合、オーバーハング部１３の凝固時の温度分布はほぼ均一となり、面外変形が発生しにくい。 In the example of FIG. 6(b), the "scanning speed of the heat source" is set higher than in the case of FIG. 6(a). Since the heat source 14 during scanning reaches the evaluation point V earlier, melting of the evaluation point V starts earlier than in the case of FIG. 6(a). As shown by the solid curve, the temperature of the evaluation point V rises sharply, then falls, and reaches the mechanical melting temperature T melt at time t **, which is earlier than the above-mentioned time t * . At this time, the temperatures T A (t ** ) and T B (t ** ) of the already solidified points A and B are still equal to or higher than the lower limit of the mechanical melting temperature T melt , and are within the temperature range of the mechanical melting temperature T melt , as is the temperature of the evaluation point V. Therefore, both the already-shaped part with the already-solidified points A and B and the molten part with the evaluation point V are cooled below the mechanical melting temperature while maintaining a temperature field within a predetermined temperature difference range (while maintaining an almost uniform temperature field). In such a case, the temperature distribution during solidification of the overhanging part 13 becomes almost uniform, and out-of-plane deformation is unlikely to occur.
図７（ａ）及び（ｂ）に、温度評価部２による評価結果の例（その２）を示す。
図７（ａ）は要件を満たさない造形条件による温度場の時間的変化の例を示すものであり、図７（ｂ）は要件を満たす造形条件による温度場の時間的変化の例を示すものである。
7A and 7B show an example (part 2) of the evaluation result by the temperature evaluation unit 2. FIG.
FIG. 7( a ) shows an example of a change in temperature field over time under modeling conditions that do not satisfy the requirements, and FIG. 7 ( b ) shows an example of a change in temperature field over time under modeling conditions that satisfy the requirements.
図７（ａ）は、前述した図６（ａ）と同じものであり、その説明については省略する。 Figure 7(a) is the same as Figure 6(a) described above, and its description will be omitted.
図７（ａ）のような評価結果に対しては、例えば「予熱」の処理を適切に加えることよって造形条件を修正すれば、要件を満たす造形条件を実現することができる。 For evaluation results such as those shown in Figure 7(a), by modifying the printing conditions, for example by appropriately adding a "preheating" process, it is possible to realize printing conditions that meet the requirements.
図７（ｂ）の例では、図７（ａ）の場合において行われなかった「予熱」が行われるように設定されている。「予熱」は、オーバーハング部１３の凝固時の温度分布に不均一な部分が生じないように、材料の溶融を行う前に要所に対して行われる。この「予熱」により、評価点Ｖの溶融が開始される前に、すでに力学的溶融温度Ｔｍｅｌｔを下回っていた既凝固点Ａ，Ｂの温度が上昇して力学的溶融温度Ｔｍｅｌｔを上回る。そして、評価点Ｖの溶融が開始され、評価点Ｖの温度が急上昇し、その後に低下し、時刻ｔ＊に力学的溶融温度Ｔｍｅｌｔに達する。このとき、既凝固点Ａ，Ｂの温度ＴＡ（ｔ＊），ＴＢ（ｔ＊）は、まだ力学的溶融温度Ｔｍｅｌｔの下限値以上を保持しており、評価点Ｖの温度と同様に力学的溶融温度Ｔｍｅｌｔの温度領域内にある。そのため、既凝固点Ａ，Ｂがある既造形部分と評価点Ｖがある溶融部とは、共に、予め定めた温度差の範囲に収まる温度場を保ちながら（ほぼ均一な温度場を保ちながら）力学的溶融温度未満に冷却される。このような場合、オーバーハング部１３の凝固時の温度分布はほぼ均一となり、面外変形が発生しにくい。 In the example of Fig. 7(b), "preheating" is set to be performed, which was not performed in the case of Fig. 7(a). "Preheating" is performed on key points before melting the material so that the temperature distribution during solidification of the overhanging portion 13 does not become uneven. This "preheating" causes the temperatures of the solidified points A and B, which were already below the mechanical melting temperature T melt , to rise and exceed the mechanical melting temperature T melt before melting of the evaluation point V begins. Then, melting of the evaluation point V begins, and the temperature of the evaluation point V rises sharply, then drops, and reaches the mechanical melting temperature T melt at time t * . At this time, the temperatures T A (t * ) and T B (t * ) of the solidified points A and B are still above the lower limit of the mechanical melting temperature T melt , and are within the temperature range of the mechanical melting temperature T melt , just like the temperature of the evaluation point V. Therefore, both the already-shaped portion having the already-solidified points A and B and the molten portion having the evaluation point V are cooled below the mechanical melting temperature while maintaining a temperature field within a predetermined temperature difference range (while maintaining a substantially uniform temperature field). In such a case, the temperature distribution during solidification of the overhang portion 13 becomes substantially uniform, and out-of-plane deformation is unlikely to occur.
図８（ａ）及び（ｂ）に、温度評価部２による評価結果の例（その３）を示す。
図８（ａ）は要件を満たさない造形条件による温度場の時間的変化の例を示すものであり、図８（ｂ）は要件を満たす造形条件による温度場の時間的変化の例を示すものである。
8A and 8B show an example (part 3) of the evaluation result by the temperature evaluation unit 2. FIG.
FIG. 8( a ) shows an example of a change in temperature field over time under modeling conditions that do not satisfy the requirements, and FIG. 8 ( b ) shows an example of a change in temperature field over time under modeling conditions that satisfy the requirements.
図８（ａ）は、前述した図６（ａ）や図７（ａ）と同じものであり、その説明については省略する。 Figure 8(a) is the same as Figure 6(a) and Figure 7(a) described above, and its description will be omitted.
図８（ａ）のような評価結果に対しては、例えば「後熱」の処理を適切に加えることよって造形条件を修正すれば、要件を満たす造形条件を実現することができる。 For evaluation results such as those shown in Figure 8(a), by modifying the printing conditions, for example by appropriately adding "post-heat" processing, it is possible to realize printing conditions that satisfy the requirements.
図８（ｂ）の例では、図８（ａ）の場合において行われなかった「後熱」が行われるように設定されている。「後熱」は、オーバーハング部１３の凝固時の温度分布に不均一な部分が生じないように、材料の溶融を行った後に要所に対して行われる。走査中の熱源１４が評価点Ｖに達してその場所の溶融が開始されると、実線の曲線に示されるように、評価点Ｖの温度が急上昇し、その後、評価点Ｖの温度は低下していく。そして、「後熱」により、評価点Ｖの温度が再び上昇するとともに、すでに力学的溶融温度Ｔｍｅｌｔを下回っていた既凝固点Ａ，Ｂの温度が上昇して力学的溶融温度Ｔｍｅｌｔを上回る。評価点Ｖの温度と既凝固点Ａ，Ｂの温度とは共に低下し、時刻ｔ＊＊＊に力学的溶融温度Ｔｍｅｌｔに達する。このとき、既凝固点Ａ，Ｂの温度ＴＡ（ｔ＊＊＊），ＴＢ（ｔ＊＊＊）は、まだ力学的溶融温度Ｔｍｅｌｔの下限値以上を保持しており、評価点Ｖの温度と同様に力学的溶融温度Ｔｍｅｌｔの温度領域内にある。そのため、既凝固点Ａ，Ｂがある既造形部分と評価点Ｖがある溶融部とは、共に、予め定めた温度差の範囲に収まる温度場を保ちながら（ほぼ均一な温度場を保ちながら）力学的溶融温度未満に冷却される。このような場合、オーバーハング部１３の凝固時の温度分布はほぼ均一となり、面外変形が発生しにくい。 In the example of FIG. 8(b), "post-heating" is set to be performed, which was not performed in the case of FIG. 8(a). "Post-heating" is performed on key points after melting the material so that the temperature distribution during solidification of the overhanging portion 13 does not become uneven. When the heat source 14 reaches the evaluation point V during scanning and starts melting the location, the temperature of the evaluation point V rises sharply as shown by the solid curve, and then the temperature of the evaluation point V drops. Then, due to "post-heating", the temperature of the evaluation point V rises again, and the temperatures of the solidified points A and B, which were already below the mechanical melting temperature T melt , rise and exceed the mechanical melting temperature T melt . The temperatures of the evaluation point V and the solidified points A and B both drop, and reach the mechanical melting temperature T melt at time t *** . At this time, the temperatures TA (t *** ) and TB (t *** ) of the already-solidified points A and B are still above the lower limit of the mechanical melting temperature T melt , and are within the temperature range of the mechanical melting temperature T melt , like the temperature of evaluation point V. Therefore, both the already-shaped part having the already-solidified points A and B and the molten part having evaluation point V are cooled below the mechanical melting temperature while maintaining a temperature field within a predetermined temperature difference range (while maintaining an almost uniform temperature field). In such a case, the temperature distribution during solidification of the overhanging part 13 becomes almost uniform, and out-of-plane deformation is unlikely to occur.
次に、図９を参照して、図３に示される三次元積層造形装置１による動作の一例を説明する。 Next, an example of the operation of the three-dimensional additive manufacturing device 1 shown in FIG. 3 will be described with reference to FIG. 9.
最初に、温度評価部２において、少なくともオーバーハング部１３の温度場（温度分布）の時間的変化が造形条件ごとに評価される（ステップＳ１）。 First, in the temperature evaluation unit 2, the change over time in the temperature field (temperature distribution) of at least the overhang portion 13 is evaluated for each molding condition (step S1).
具体的には、材料物性入力部２１により、造形物の造形に使用する材料の材料物性を示すデータ（温度依存性を有する材料物性値）が熱伝導解析部２４に入力され、造形物形状入力部２２により、解析対象の層における造形物の形状（パウダベッド等の形状を含む）を示すデータが熱伝導解析部２４に入力され、造形条件入力部２３により、予熱工程、溶融工程、後熱工程のそれぞれにおける、熱源１４の入熱量、走査速度、ビーム半径、および走査シーケンスを示す造形条件のデータが熱伝導解析部２４に入力される。 Specifically, the material property input unit 21 inputs data indicating the material properties of the material used to form the object (temperature-dependent material property values) to the heat conduction analysis unit 24, the object shape input unit 22 inputs data indicating the shape of the object in the layer to be analyzed (including the shape of the powder bed, etc.) to the heat conduction analysis unit 24, and the modeling condition input unit 23 inputs modeling condition data indicating the heat input amount, scanning speed, beam radius, and scanning sequence of the heat source 14 in each of the preheating process, melting process, and post-heating process to the heat conduction analysis unit 24.
また、熱伝導解析部２４により、材料物性入力部２１、造形物形状入力部２２、および造形条件入力部２３から供給される各種データを入力し、それらのデータを用いて、予熱工程、溶融工程、後熱工程のそれぞれについて、材料物性を示すデータおよび造形物形状を示すデータに基づき、造形条件（例えば、熱源１４の入熱量、走査速度、ビーム半径、および走査シーケンス）を変数とする熱伝導解析を行うことにより、造形条件が異なるオーバーハング部１３の温度場の時間的変化を示す複数のデータを生成する処理が行われる。 The heat conduction analysis unit 24 also inputs various data supplied from the material properties input unit 21, the object shape input unit 22, and the object shape input unit 23, and uses the data to perform heat conduction analysis with the object shape (e.g., the heat input of the heat source 14, the scanning speed, the beam radius, and the scanning sequence) as variables for each of the preheating process, the melting process, and the post-heating process, based on the data indicating the material properties and the data indicating the object shape, thereby generating multiple data showing the temporal changes in the temperature field of the overhang portion 13 with different object shape conditions.
次に、造形条件決定部３において、温度評価部２により評価された造形条件ごとの温度場の時間的変化に基づき、オーバーハング部１３が造形される工程において熱源１４により材料が溶融して形成される溶融部がその凝固過程で力学的溶融温度に達する際に、既に凝固しているオーバーハング部１３の既造形部のうちの少なくとも熱源１４から一定距離以上離れた所定の範囲内にある既造形部分の温度場が力学的溶融温度以上に保持されており、かつ、当該既造形部分と上記溶融部とが予め定めた温度差の範囲に収まる温度場を保ちながら（即ち、できるだけ均一な温度場を保ちながら）力学的溶融温度未満に冷却される造形条件を決定する処理が行われる（ステップＳ２）。 Next, in the modeling condition determination unit 3, based on the temporal change in the temperature field for each modeling condition evaluated by the temperature evaluation unit 2, when the molten part formed by melting the material by the heat source 14 in the process of modeling the overhang portion 13 reaches the mechanical melting temperature during its solidification process, the temperature field of the already solidified pre-modeled part of the overhang portion 13 that is within a predetermined range away from the heat source 14 is maintained at or above the mechanical melting temperature, and the pre-modeled part and the above-mentioned molten part are cooled to below the mechanical melting temperature while maintaining a temperature field that falls within a predetermined temperature difference range (i.e., while maintaining a temperature field as uniform as possible) (step S2).
要件を満たす造形条件が無い場合には、要件を満たす造形条件が得られるまで、温度評価部２に対して造形条件の修正および修正後の造形条件に基づく温度場の時間的変化の再評価を指示する（フィードバック制御を行う）処理が行われる。 If there are no printing conditions that satisfy the requirements, a process is performed in which the temperature evaluation unit 2 is instructed to modify the printing conditions and to reevaluate the temporal changes in the temperature field based on the modified printing conditions (feedback control is performed) until printing conditions that satisfy the requirements are obtained.
最後に、熱源走査部４において、造形条件決定部３により決定された造形条件に基づき、熱源１４の走査を実施する処理が行われる（ステップＳ３）。 Finally, the heat source scanning unit 4 performs a process of scanning the heat source 14 based on the printing conditions determined by the printing condition determination unit 3 (step S3).
具体的には、予熱-熱源走査部４１により、予熱工程において、造形条件決定部３により決定された予熱工程に対応する造形条件に基づく熱源走査を外部の図示しない熱源走査装置に指示する処理が行われる。 Specifically, in the preheating process, the preheating-heat source scanning unit 41 performs a process of instructing an external heat source scanning device (not shown) to perform heat source scanning based on the modeling conditions corresponding to the preheating process determined by the modeling condition determination unit 3.
また、溶融-熱源走査部４２により、溶融工程において、造形条件決定部３により決定された溶融工程に対応する造形条件に基づく熱源走査を外部の図示しない熱源走査装置に指示する処理が行われる。 In addition, the melting-heat source scanning unit 42 performs a process of instructing an external heat source scanning device (not shown) to perform heat source scanning based on the modeling conditions corresponding to the melting process determined by the modeling condition determination unit 3 during the melting process.
また、後熱-熱走査部４３により、後熱工程において、造形条件決定部３により決定された後熱工程に対応する造形条件に基づく熱源走査を外部の図示しない熱源走査装置に指示する処理が行われる。 In addition, the post-heating-thermal scanning unit 43 performs a process of instructing an external heat source scanning device (not shown) to perform heat source scanning based on the modeling conditions corresponding to the post-heating process determined by the modeling condition determination unit 3 during the post-heating process.
以上詳述したように、実施形態によれば、積層造形物のオーバーハング部を造形する際の面外変形の発生を抑制することができる。さらに、オーバーハング部についてサポート配置を不要とする造形が可能になり、加工などの後工程の工数を低減することもできる。 As described above in detail, according to the embodiment, it is possible to suppress the occurrence of out-of-plane deformation when forming an overhanging portion of a layered object. Furthermore, it is possible to form the overhanging portion without the need for support placement, which can reduce the man-hours required for post-processing such as machining.
本発明のいくつかの実施形態を説明したが、これらの実施形態は、例として提示したものであり、発明の範囲を限定することは意図していない。これら新規な実施形態は、その他の様々な形態で実施されることが可能であり、発明の要旨を逸脱しない範囲で、種々の省略、置き換え、変更を行うことができる。これら実施形態やその変形は、発明の範囲や要旨に含まれるとともに、特許請求の範囲に記載された発明とその均等の範囲に含まれる。 Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.
１…三次元積層造形装置、２…温度評価部、３…造形条件決定部、４…熱源走査部、１１…積層造形物、１２…ベース部、１３…オーバーハング部、１４…熱源、１５…既造形部、１６…未造形部、２１…材料物性入力部、２２…造形物形状入力部、２３…造形条件入力部、２４…熱伝導解析部、４１…予熱-熱源走査部、４２…溶融-熱源走査部、４３…後熱-熱源走査部、５１…プロセッサ、５２…メモリ。 1...3D additive manufacturing device, 2...temperature evaluation section, 3...modeling condition determination section, 4...heat source scanning section, 11...additive model, 12...base section, 13...overhang section, 14...heat source, 15...pre-modeled section, 16...unmodeled section, 21...material property input section, 22...modeled object shape input section, 23...modeling condition input section, 24...thermal conduction analysis section, 41...pre-heating-heat source scanning section, 42...melting-heat source scanning section, 43...post-heating-heat source scanning section, 51...processor, 52...memory.
Claims (8)
前記積層造形物の下方に空間がある部分であるオーバーハング部が造形される工程において前記熱源の走査に応じて変化しうる少なくとも前記オーバーハング部の温度場の時間的変化を造形条件ごとに評価する温度評価手段と、
前記温度評価手段により評価された造形条件ごとの温度場の時間的変化に基づき、前記オーバーハング部が造形される工程において前記熱源により材料が溶融して形成される溶融部がその凝固過程で力学的溶融温度に達する際に、既に凝固している前記オーバーハング部の既造形部のうちの少なくとも温度場が力学的溶融温度以上に保持されている既造形部分と前記溶融部とが力学的溶融温度の温度領域内に収まる温度場を保ちながら力学的溶融温度未満に冷却される造形条件を決定する造形条件決定手段と、
前記造形条件決定手段により決定された造形条件に基づき、前記熱源の走査を実施する熱源走査手段と、
を具備する、積層造形装置。 1. An additive manufacturing apparatus for manufacturing an additive object by scanning a heat source with respect to a material,
a temperature evaluation means for evaluating, for each modeling condition, a temporal change in a temperature field of at least the overhang portion, which may change in response to the scanning of the heat source, in a process of modeling an overhang portion, which is a portion having a space below the layered model; and
a molding condition determination means for determining, based on the temporal change in the temperature field for each molding condition evaluated by the temperature evaluation means, a molding condition under which, when the molten portion formed by melting the material by the heat source in the process of molding the overhang portion reaches the mechanical melting temperature during its solidification process, at least a pre-molded portion of the already solidified overhang portion, whose temperature field is maintained at or above the mechanical melting temperature, and the molten portion are cooled to below the mechanical melting temperature while maintaining a temperature field within the temperature range of the mechanical melting temperature ;
a heat source scanning means for scanning the heat source based on the modeling conditions determined by the modeling condition determining means;
An additive manufacturing apparatus comprising:
材料物性を示すデータおよび造形物形状を示すデータに基づき、造形条件を変数とする熱伝導解析を行うことにより、造形条件が異なる前記オーバーハング部の温度場の時間的変化を示す複数のデータを生成する、
請求項１に記載の積層造形装置。 The temperature evaluation means includes:
generating a plurality of data showing temporal changes in the temperature field of the overhang portion under different printing conditions by performing a heat conduction analysis using the printing conditions as variables based on the data showing the material properties and the data showing the shape of the object;
The additive manufacturing apparatus according to claim 1 .
要件を満たす造形条件が無い場合には、要件を満たす造形条件が得られるまで、前記温度評価手段に対して造形条件の修正および修正後の造形条件に基づく温度場の時間的変化の再評価を指示する、
請求項１又は２に記載の積層造形装置。 The molding condition determination means includes:
if there are no printing conditions that satisfy the requirements, instructing the temperature evaluation means to modify the printing conditions and re-evaluate the temporal change in the temperature field based on the modified printing conditions until printing conditions that satisfy the requirements are obtained;
The additive manufacturing apparatus according to claim 1 or 2.
前記材料を溶融させる前の予熱工程において、前記オーバーハング部を選択的に繰り返し予熱し、前記オーバーハング部の温度を溶融温度以下および力学的溶融温度以上の温度範囲内に収まるように調整する、
請求項１乃至３のいずれか１項に記載の積層造形装置。 The heat source scanning means is
In a preheating step before melting the material, the overhang portion is selectively and repeatedly preheated to adjust the temperature of the overhang portion to fall within a temperature range below the melting temperature and above the mechanical melting temperature.
The layered manufacturing apparatus according to claim 1 .
前記材料を溶融させる溶融工程において、前記オーバーハング部にて前記熱源を走査する方向を水平面のうち前記オーバーハング部が前記積層造形物のベース部から突出する方向に垂直な方向とし、走査する前記熱源を定期的に当該熱源の幅よりも小さいピッチで前記突出する方向へ移動させてから走査方向の向きを反対方向にする折り返しを繰り返しながら前記熱源の走査を行う、
請求項１乃至４のいずれか１項に記載の積層造形装置。 The heat source scanning means is
In a melting step of melting the material, a direction in which the heat source is scanned at the overhang portion is set to a direction perpendicular to a direction in which the overhang portion protrudes from a base portion of the layered object in a horizontal plane, and the heat source is periodically moved in the protruding direction at a pitch smaller than a width of the heat source, and then the scanning direction is reversed while repeatedly being turned around to scan the heat source.
The layered manufacturing apparatus according to claim 1 .
前記材料を溶融させた後の後熱工程において、前記オーバーハング部を選択的に繰り返し後熱し、前記オーバーハング部の温度を溶融温度以下および力学的溶融温度以上の温度範囲内に収まるように調整する、
請求項１乃至５のいずれか１項に記載の積層造形装置。 The heat source scanning means is
In a post-heating step after melting the material, the overhang portion is selectively and repeatedly post-heated to adjust the temperature of the overhang portion to fall within a temperature range below the melting temperature and above the mechanical melting temperature.
The layered manufacturing apparatus according to claim 1 .
温度評価手段により、前記積層造形物の下方に空間がある部分であるオーバーハング部が造形される工程において前記熱源の走査に応じて変化しうる少なくとも前記オーバーハング部の温度場の時間的変化を造形条件ごとに評価する温度評価ステップと、
造形条件決定手段により、前記温度評価ステップにおいて評価された造形条件ごとの温度場の時間的変化に基づき、前記オーバーハング部が造形される工程において前記熱源により材料が溶融して形成される溶融部がその凝固過程で力学的溶融温度に達する際に、既に凝固している前記オーバーハング部の既造形部のうちの少なくとも温度場が力学的溶融温度以上に保持されている既造形部分と前記溶融部とが力学的溶融温度の温度領域内に収まる温度場を保ちながら力学的溶融温度未満に冷却される造形条件を決定する造形条件決定ステップと、
熱源走査手段により、前記造形条件決定ステップにおいて決定された造形条件に基づき、前記熱源の走査を実施する熱源走査ステップと、
を含む、積層造形方法。 1. An additive manufacturing method applied to an additive manufacturing apparatus that manufactures an additive object by scanning a heat source with respect to a material, comprising:
a temperature evaluation step in which a temperature evaluation means evaluates, for each modeling condition, a temporal change in a temperature field of at least the overhang portion, which may change in response to the scanning of the heat source, in a process in which an overhang portion, which is a portion having a space below the layered object, is modeled;
a modeling condition determination step in which, based on the temporal change in the temperature field for each modeling condition evaluated in the temperature evaluation step, a modeling condition determination means determines modeling conditions under which, when the molten portion formed by melting the material by the heat source in the process of modeling the overhang portion reaches the mechanical melting temperature during its solidification process, at least the pre-modeled portion of the overhang portion that has already solidified, whose temperature field is maintained at or above the mechanical melting temperature, and the molten portion are cooled to below the mechanical melting temperature while maintaining a temperature field within the temperature range of the mechanical melting temperature ;
a heat source scanning step of scanning the heat source by a heat source scanning means based on the modeling conditions determined in the modeling condition determining step;
An additive manufacturing method comprising:
コンピュータを、
前記積層造形物の下方に空間がある部分であるオーバーハング部が造形される工程において前記熱源の走査に応じて変化しうる少なくとも前記オーバーハング部の温度場の時間的変化を造形条件ごとに評価する温度評価手段、
前記温度評価手段により評価された造形条件ごとの温度場の時間的変化に基づき、前記オーバーハング部が造形される工程において前記熱源により材料が溶融して形成される溶融部がその凝固過程で力学的溶融温度に達する際に、既に凝固している前記オーバーハング部の既造形部のうちの少なくとも温度場が力学的溶融温度以上に保持されている既造形部分と前記溶融部とが力学的溶融温度の温度領域内に収まる温度場を保ちながら力学的溶融温度未満に冷却される造形条件を決定する造形条件決定手段、
前記造形条件決定手段により決定された造形条件に基づき、前記熱源の走査を実施する熱源走査手段、
として機能させるためのプログラム。 A computer program applied to an additive manufacturing apparatus that manufactures an additive object by scanning a heat source with respect to a material, comprising:
Computer,
a temperature evaluation means for evaluating, for each modeling condition, a temporal change in a temperature field of at least the overhang portion, which may change in response to the scanning of the heat source, in a process of modeling an overhang portion, which is a portion having a space below the layered model;
a molding condition determination means for determining, based on the temporal change in the temperature field for each molding condition evaluated by the temperature evaluation means, a molding condition under which, when a molten portion formed by melting a material by the heat source in a process of molding the overhang portion reaches a mechanical melting temperature during its solidification process, at least a pre- molded portion of the overhang portion that has already solidified, whose temperature field is maintained at or above the mechanical melting temperature, and the molten portion are cooled to below the mechanical melting temperature while maintaining a temperature field within a temperature range of the mechanical melting temperature ;
a heat source scanning means for scanning the heat source based on the modeling conditions determined by the modeling condition determining means;
A program to function as a
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| JP2017179517A (en) | 2016-03-31 | 2017-10-05 | 株式会社東芝 | Residual stress reduction system for laminated molding, residual stress reduction method for the same, and residual stress reduction program for the same |
| JP2018184623A (en) | 2017-04-24 | 2018-11-22 | 株式会社東芝 | Inherent strain calculation device for laminated molding, inherent strain calculation method therefor, inherent strain calculation program therefor, analysis device therefor, analysis method therefor, and lamination molding device |
| WO2019049981A1 (en) | 2017-09-08 | 2019-03-14 | 公立大学法人大阪府立大学 | Method and device for analyzing lamination-shaped article, and method and device for manufacturing lamination-shaped article |
| JP2020097193A (en) | 2018-12-19 | 2020-06-25 | 株式会社神戸製鋼所 | Excess amount setting method, excess amount setting device, manufacturing method of molded object, and program |
| JP2021094698A (en) | 2019-12-13 | 2021-06-24 | 株式会社東芝 | Molding data creation device and molding data creation program |
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