JP2008101256A - Stack-molded die and producing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce a molded article having a three-dimensional structure of a large contour with high precision, by reducing the warp of a base plate and preventing the distortion of the contour. <P>SOLUTION: When layers 2 to be hardened are stacked on the base plate 22 to form a desirable molded article 5, the volume decreases because spaces among powders are lost while the layers 2 to be hardened are sintered, and furthermore, a contraction stress 110 is generated inside the molded article 5 by solidification shrinkage. The molded article 5 is tentatively bonded with the base plate 22 and causes the volume shrinkage, so that a reaction force 111 acts in the base plate 22 due to a tensile force. When the contraction stress 110 is larger than the reaction force 111, the base plate 22 is warped and causes distortion in the three-dimensional shape formed thereon. The production method includes forming a notch 6 on the surface which is located in the lower part of the molded article 5 and contacts with the base plate 22. Then, the notch reduces a contacting area between the base plate 22 and the molded article 5, decreases a bending moment caused by the shrinkage, makes a balance between the contraction stress 110 and the reaction force 111 advantageous to the base plate 22, suppresses the warp of the base plate 22, and accurately forms the molded three-dimensional shape. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a three-dimensional shaped object, and more specifically, a three-dimensional shaped object of a three-dimensional shaped object obtained by laminating metal powders in layers using a light beam and continuously curing the powder. It relates to the manufacturing method.

  As a conventional technique for forming a three-dimensional shaped object by irradiating an inorganic powder (metal powder) with a light beam (directional energy beam, for example, a laser beam) and curing it, and laminating a cured layer, for example, Patent Document There was the method shown in 1. 3A to 3D are cross-sectional views schematically showing a method for manufacturing a three-dimensional shaped object described in Patent Document 1. FIG.

  As shown in FIG. 3A, the bottom surface 12 of the supply unit 10 and the bottom surface 24 of the modeling unit 20 can be raised and lowered. A plate-like base plate 22 is disposed on the bottom surface 24, and a hardened layer 2 formed by sintering the powder material 1 is sequentially stacked on the base plate 22 to manufacture the model 5. The transfer blade 30 has a plate shape longer than the inner width of the supply unit 10 and the modeling unit 20, and moves horizontally from the outside of the supply unit 10 to the outside of the modeling unit 20 through the supply unit 10 and the modeling unit 20. To do. In the modeling unit 20, the upper surface of the hardened layer 2 formed and stacked in advance is slightly lowered from the upper end of the modeling unit 20. Further, in the supply unit 10, the powder material 1 is disposed up to a position slightly higher than the upper end of the supply unit 10.

  In this state, the transfer blade 30 is moved horizontally from the supply unit 10 to the modeling unit 20. As shown in FIG. 3B, a portion of the powder material 1 higher than the upper end of the supply unit 10 is pushed by the transfer blade 30 and transferred to the modeling unit 20. The powder material 1 leveled at the lower end of the transfer blade 30 is deposited in a thin layer in the space 4. The transfer blade 30 that has finished supplying the powder material 1 to the modeling unit 20 moves to the outside of the modeling unit 20.

  As shown in FIG. 3C, the powder material 1 is cured by irradiating the upper surface of the modeling unit 20 with the light beam 3 in a predetermined pattern, thereby forming a new cured layer 2 ′. The transfer blade 30 is prepared at a standby position outside the supply unit 10 during or after the light irradiation process.

  In the supply part 10, the bottom surface 12 is raised and the powder material 1 to be supplied to the modeling part 20 next time is prepared, and the bottom surface 24 of the modeling part 20 is lowered as shown in FIG. A space 4 in which the powder material 1 is supplied is provided. By repeating the steps as described above, a plurality of hardened layers 2 are stacked on the base plate 22 of the modeling unit 20, and a modeled object 5 having a desired three-dimensional shape is obtained.

Since the three-dimensional layered object manufactured by this method can be manufactured by data directly converted from CAD data, it can be processed faster than the case of manufacturing by normal machining. For this reason, it is more suitable when it is used for a mold having a complicated shape.
JP 2001-150557 A

  However, in the conventional configuration, when the hardened layer 2 that forms the shaped object is sintered, the space between the powders generated in the powder state is lost during melting, the volume is reduced, and the solidification shrinks. Thus, once the volume of the base plate 22 is contracted with the base plate 22, the base plate 22 is warped by receiving a pulling force, and the three-dimensional shape formed thereon is distorted. In particular, the amount of warpage has a strong correlation with the contact area between the modeled object and the base plate 22 and the length of the contact part, and in the case of manufacturing a modeled object whose outer shape exceeds 100 mm, the base plate 22 is used. If a sufficient thickness is not taken, a warp of 0.01 mm or more is generated, leading to an error in the dimension of the modeled object, and there is a problem in manufacturing a precise mold part.

  The present invention is directed to solving the above-described problems of the prior art, and is a three-dimensional layered structure manufactured by continuously curing a metal powder in a layer shape using a light beam. An object of the present invention is to provide an additive manufacturing mold and a method for manufacturing the same, which can manufacture a molded article having a size exceeding 100 mm with less warping of the base plate and less distortion of the shape.

  In order to achieve the above object, the additive manufacturing mold according to claim 1 according to the present invention is an additive manufacturing mold comprising an additive manufacturing object obtained by curing metal powder deposited on a base plate, Between the modeled object and the base plate, a surface other than the contact surface with the base plate has a space surrounded by the layered object, and this space is formed in the layered object.

  The additive manufacturing mold described in claims 2 to 3 is the additive manufacturing mold according to claim 1, wherein the first area in an arbitrary first cross section parallel to the base plate of the space is parallel to the first cross section, and It is larger than the second area in any second cross section separated from the first cross section in the stacking direction, and the length of the contact surface with the base plate in the space is 2 mm or more and 15 mm or less, and from the contact surface with the base plate The height is 15 mm or less, and there are a plurality of spaces between the layered object and the base plate.

  The manufacturing method of the additive manufacturing mold according to claim 5 is a manufacturing method of the additive manufacturing mold made of the additive manufacturing object obtained by curing the metal powder deposited on the base plate. Forming a space on which the surface other than the contact surface is surrounded by the layered object, and manufacturing the layered object on the base plate.

  Moreover, the manufacturing method of the additive manufacturing mold described in claims 6 and 7 is the manufacturing method of the additive manufacturing mold of claim 5, wherein the first area in an arbitrary first cross section parallel to the base plate of the space is A space is formed that is larger than the second area in any second cross section that is parallel to the first cross section and separated from the first cross section in the stacking direction, and a plurality of spaces are formed between the layered object and the base plate. It is characterized by that.

  According to the above-described configuration, a three-dimensional layered structure manufactured by continuously curing a metal powder in a layer shape using a light beam, and a shaped object having an outer shape exceeding 100 mm is warped of the base plate. By reducing the amount of distortion, it is possible to reduce the distortion of the shape and to manufacture with an accurate shape.

  According to the present invention, a three-dimensional layered object manufactured by continuously curing a metal powder in a layer shape using a light beam, and the object whose outer shape exceeds 100 mm is warped of the base plate. As a result, the distortion of the shape is reduced, and an accurate shape can be produced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a layered object according to Embodiment 1 of the present invention, in which (a) and (b) are schematic cross-sectional views, and (c) is a simplified perspective view. Here, components having the same functions corresponding to the components described in FIGS. 3A to 3D showing the conventional example are denoted by the same reference numerals, and the same applies to the following drawings. To do.

  As shown in FIG. 1A, a plurality of hardened layers 2 are stacked on a base plate 22 to obtain a shaped article 5 having a desired three-dimensional shape. When the layer 2) is sintered, the space between the powders generated in the powder state is lost during melting, the volume is reduced, and the solidification and shrinkage are further caused, so that a shrinkage stress 110 is generated in the interior of the model 5. Will occur. Furthermore, the volume 5 shrinks once the shaped article 5 is connected to the base plate 22, so that the base plate 22 receives a pulling force and a reaction force 111 acts, but the shrinkage stress 110> the reaction force 111. In this case, the base plate 22 is warped, and the three-dimensional shape formed thereon is distorted. For this reason, as shown in FIG.1 (b), the notch 6 used as space is provided in the contact surface with the base plate 22 in the lower part of the molded article 5. FIG.

  As a result, the contact area between the divided individual base plate 22 and the modeled object 5 is reduced, the magnitude of the bending moment generated on the base plate 22 due to the contraction of the modeled object 5 is reduced, and the modeled object 5 itself is notched. Since the shape 6 is added, the balance between the shrinkage stress 110 of the model 5 and the reaction force 111 of the base plate 22 is advantageous to the base plate 22, and the warpage of the base plate 22 can be suppressed. For this reason, the three-dimensional shape modeled on it can be formed correctly.

  As shown in FIG. 1C, when the total length of the shaped object 5 is L and the strain amount at the point A shown in FIG. 1B is y, the contraction stress 110 is simply approximated by an upward equal weight w. Applying the formula of a cantilever beam that receives an equal load starting from point B, the Young's modulus is E and the secondary moment of moment is I. (Equation 1)

により、近似的に表すことができる。例えば、造形物５が点Ｃで完全に分割された場合、点Ｃを起点とした均等加重を受ける片持ち梁の式を当てはめると、（数２）

Can be expressed approximately. For example, when the shaped object 5 is completely divided at the point C, when a cantilever beam formula that receives an equal load from the point C is applied, (Equation 2)

となり、歪量は１６分の１に低減できることになるが、実際には造形物５は、金型部品の３次元形状部であり、製品の３次元形状の大きさから全長Ｌが決まっているため、点Ｃで完全に分割することはできない。ところが、切り欠き６があるので、造形物５とベースプレート２２との接触面に空間を有し、かつ造形物５は空間の上部でつながっている形状を有している。このように、上部で結合されている影響で点Ｃの左右で各々の造形形状が相互作用を生じさせるため、その相互作用の係数をＤとすると、（数３）

Thus, the amount of distortion can be reduced to 1/16, but in actuality, the molded object 5 is a three-dimensional shape part of a mold part, and the total length L is determined from the size of the three-dimensional shape of the product. Therefore, it cannot be completely divided at the point C. However, since there is the notch 6, there is a space on the contact surface between the modeled object 5 and the base plate 22, and the modeled object 5 has a shape connected at the upper part of the space. Thus, since each modeling shape produces an interaction on the left and right of the point C due to the effect of being coupled at the upper part, assuming that the coefficient of the interaction is D, (Equation 3)

で示されることになる。相互作用の係数がＤ＜１６の状態で、切り欠き６を追加した場合の歪量ｙが、切り欠き６のない場合に比べて小さいことになるが、造形物５の形状に着目すると、切り欠き６が存在することにより反力１１１に対する抵抗力は確実に弱まるため、相互作用の係数Ｄ＜１６となることは容易に予想できる。

Will be shown. When the notch 6 is added in the state where the coefficient of interaction is D <16, the distortion amount y is smaller than when the notch 6 is not provided. Since the resistance against the reaction force 111 is surely weakened by the presence of the notch 6, it can be easily predicted that the interaction coefficient D <16.

  In the first embodiment, the base plate 22 is a rectangular parallelepiped, and the secondary moment I of the cross section is represented by (Equation 4) where the width of the base plate 22 is b and the thickness is h as shown in FIG.

となる。効果を確認するために、全長Ｌを８５ｍｍとして、厚み４０ｍｍで直方体形状の造形物５を切り欠き６のあるものとないものの２つを、幅ｂが１００ｍｍ、厚さｈが１５ｍｍのベースプレート２２を使用して製作した。その結果、切り欠きなしの単純な直方体で造形した場合の歪量ｙ＝０．１８６ｍｍ、切り欠きありの場合ｙ＝０．１５ｍｍとなり、切り欠きの追加で歪量ｙが小さくなり、その結果ベースプレート２２上に形成される造形物５の歪量も小さくなり、所望の３次元形状を有する造形物５を得られることが確認できた。この場合の相互作用の係数Ｄは約１２．９７である。

It becomes. In order to confirm the effect, the base plate 22 having a total length L of 85 mm, a cuboid-shaped shaped article 5 having a thickness of 40 mm and a notch 6 and a base plate 22 having a width b of 100 mm and a thickness h of 15 mm is used. Made using. As a result, the distortion amount y = 0.186 mm when modeling with a simple rectangular parallelepiped without cutout, and y = 0.15 mm with cutout, the distortion amount y is reduced by adding the cutout, and as a result, the base plate It was confirmed that the amount of distortion of the shaped object 5 formed on the surface 22 was reduced, and the shaped object 5 having a desired three-dimensional shape was obtained. In this case, the coefficient of interaction D is about 12.97.

  For reference, the value of the strain amount y in the case where there is a notch corresponds to the actual measurement value in the case where the stacking thickness of the model 5 is reduced from 40 mm to 20 mm. Further, if the width of the cross-sectional shape of the notch 6 is not at least 2 mm or more, the effect of providing the notch 6 is not obtained, the width of the cross-sectional shape of the notch 6 exceeds 15 mm, or the height is formed. If it exceeds 1/3 of the thickness of the article 5, the strength of the shaped article 5 is lowered, which impedes practical use as a mold part. Actually, since the thickness of the modeled object 5 varies depending on the shape of the mold, the effect is enhanced by setting the height of the notch to 15 mm or less.

  In Embodiment 1, the space provided on the contact surface between the base plate 22 and the modeled object 5 has a triangular cross-sectional shape as the notch 6, but the space of the notch 6 is the same as that of the base plate 22. As long as the contact surface side is wide and narrow in the stacking direction of the shaped object 5, it may be trapezoidal, pentagonal, semicircular or elliptical, and is not necessarily exposed.

  When the light beam 3 is irradiated in a predetermined pattern in order to form the hardened layer 2 to be the conventional shaped article 5 shown in FIG. 3C, the light beam 3 is selectively not irradiated as the notch 6. A portion where the hardened layer 2 is not formed is formed, and the area of the notch 6 is formed so that the second layer is smaller than the first layer, and this is repeated to cut between the base plate 22 and the modeled object 5. A space to be a notch 6 is formed. In this case, since the portion where the hardened layer 2 is not selectively formed remains in a powder form, the space that becomes the notch 6 is physically formed by removing after the formation 5 is formed. Even if it does not contribute, it does not contribute to the structural strength of the shaped article 5 and thus has the same function as the notch 6.

  The space of the notch 6 includes a first area in an arbitrary first cross section parallel to the base plate 22 and a second area in an arbitrary second cross section parallel to the first cross section and separated from the first cross section in the stacking direction. When compared, a space is formed between the shaped article 5 and the base plate 22 such that the first area is larger than the second area. That is, a space surrounded by the modeled object 5 is formed except for the contact surface with the base plate 22. Thereby, the laminate 5 with less distortion can be manufactured on the base plate 22.

  In the first embodiment, only one notch 6 is provided at one place, but the notch 6 may be provided at two or more places, and the notch 6 does not have to be a straight line, and may be a curve. A plurality of notches 6 may intersect or touch each other.

(Embodiment 2)
FIG. 2 is a simplified perspective view of the layered object according to Embodiment 2 of the present invention. In FIG. 2, the model 5 has a cylindrical outer shape in order to mold a rotating body such as a fan. In the second embodiment, the shape is divided into four parts, and it is not desirable that the amount of distortion of each shape varies. Therefore, four notches 6 are provided at the boundary of the four shapes. As a result, the amount of distortion of the base plate 22 is reduced, but the reduction of the amount of distortion is also brought equally to the four shapes. Although the four cutouts 6 are provided, two cutouts 6 that intersect in a cross shape at the joint surface with the base plate 22 may be used.

  The shape and number of the notches 6 are preferably set to a desired shape and number in accordance with the shape of the modeled article 5 after lamination.

  The additive manufacturing mold and the manufacturing method thereof according to the present invention is a three-dimensional additive manufacturing object manufactured by continuously curing a metal powder in a layer shape using a light beam, and the outer shape exceeds 100 mm. Can be manufactured with an accurate shape by reducing warping of the base plate, and is useful as a three-dimensional shaped object and a manufacturing method thereof. .

BRIEF DESCRIPTION OF THE DRAWINGS It is a laminate-molded article in Embodiment 1 of this invention, (a), (b) is typical sectional drawing, (c) is a figure which shows the simplified perspective view. Simplified perspective view of the layered object in Embodiment 2 of the present invention It is the manufacturing method of the conventional three-dimensional shape molded article, (a)-(d) is sectional drawing which shows typically

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Powder material 2, 2 'Hardened layer 3 Light beam 4 Space 5 Modeling object 6 Notch 10 Supply part 12, 24 Bottom face 20 Modeling part 22 Base plate 30 Transfer blade 110 Contraction stress 111 Reaction force

Claims (7)

It is an additive manufacturing mold made of an additive manufacturing product obtained by curing metal powder deposited on a base plate,
Between the layered object and the base plate, a surface other than the contact surface with the base plate has a space surrounded by the layered object, and the space is formed in the layered object. Additive manufacturing mold.   A first area in an arbitrary first cross section parallel to the base plate in the space is larger than a second area in an arbitrary second cross section parallel to the first cross section and separated from the first cross section in the stacking direction. The additive manufacturing mold according to claim 1.   3. The additive manufacturing metal according to claim 1, wherein a length of a contact surface with the base plate in the space is 2 mm or more and 15 mm or less, and a height from the contact surface with the base plate is 15 mm or less. Type.   The additive manufacturing mold according to any one of claims 1 to 3, wherein there are a plurality of the spaces between the additive manufacturing object and the base plate. A method for manufacturing a layered mold comprising a layered product obtained by curing metal powder deposited on a base plate,
The additive manufacturing object characterized in that the additive manufacturing object is formed on the base plate by forming a space in which the surface other than the contact surface with the base plate is surrounded by the additive object. Mold manufacturing method.   A first area of an arbitrary first cross section parallel to the base plate of the space is larger than a second area of an arbitrary second cross section parallel to the first cross section and separated from the first cross section in the stacking direction; 6. The method for manufacturing an additive manufacturing mold according to claim 5, wherein the space is formed.   7. The method for manufacturing an additive manufacturing mold according to claim 5, wherein a plurality of the spaces are formed between the additive manufacturing object and the base plate.

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