JP2008291318A - Manufacturing method of three-dimensional shaped object - Google Patents

Abstract

[PROBLEMS] To produce a three-dimensional modeled object with high accuracy by forming a thin and uniform layer of the powder material while using a powder material with a small particle diameter in manufacturing a three-dimensional modeled object by an optical modeling method. The purpose is to manufacture.
SOLUTION: A step of applying pressure from above to a powder material supplied onto a table 20 irradiated with a light beam L to press-solidify the powders to level the entire surface of the table 20, and then the table 20 And a step B of cutting and removing the surface portion 13 having a predetermined thickness Δt of the powder material smoothed over the entire surface.
[Selection] Figure 2

Description

  The present invention relates to a method of manufacturing a three-dimensional shaped object in which a plurality of sintered layers are laminated and integrated by repeating a step of forming a sintered layer by irradiating a layer of powder material with a light beam.

  A powder layer is irradiated with a light beam (directed energy beam, for example, a laser) to form a sintered layer, and a new powder material layer is formed on the sintered layer and irradiated with the light beam. Thus, there is known a method of manufacturing a three-dimensional shaped object in which a plurality of sintered layers are laminated and integrated by repeating the step of forming a sintered layer (see, for example, Patent Document 1).

In this technique called stereolithography, by adjusting the energy density of the light beam, the powder material is solidified after being almost completely melted (that is, the sintered density is almost 100%). be able to. The surface of the three-dimensional shaped object (the surface of the sintered layer) obtained through this state becomes a very smooth surface by finishing. Therefore, the three-dimensional shaped object can be applied to a plastic mold for which a smooth surface is required. Moreover, according to the optical modeling method, a complicated three-dimensional shape can be manufactured in a short time.
Japanese Patent No. 3687667

  By the way, in order to manufacture a three-dimensional shaped object with high accuracy, it is necessary to make the layer of the powder material as thin and uniform as possible. For that purpose, it is desirable to make the particle diameter of the powder as small as possible.

  However, the smaller the particle size of the powder, the more the powder agglomerates, resulting in a decrease in the fluidity of the powder itself, which makes it difficult to form a layer of powder material. When a sintered layer is formed by irradiating the material layer with a light beam, the surface of the sintered layer irradiated with the light beam becomes a very smooth surface, and a powder with a smaller particle size on the sintered layer. There is a problem that it is difficult to form a thin layer of material.

  The present invention has been made in view of the above problems, and in manufacturing a three-dimensional shaped object by an optical modeling method, the powder material layer is made thin and uniform while using a powder material having a small particle size. It aims at manufacturing a three-dimensional shape molded article with high precision by forming.

  In order to solve the above-mentioned problem, the manufacturing method of the three-dimensional shaped object according to claim 1 sinters by irradiating a predetermined part of the layer of the powder material with a light beam and sintering the powder at the corresponding part. A layer is formed, and a new layer of powder material is coated on the sintered layer, and a predetermined portion is irradiated with a light beam to sinter the powder at that location, thereby integrating with the lower sintered layer. In forming a three-dimensional shaped object in which a plurality of sintered layers are laminated and integrated by repeating the formation of a new sintered layer, the powder material supplied on the table irradiated with the light beam A step A in which the powders are pressed and solidified by applying pressure from above to level the entire surface of the table, and then a step B in which the surface portion of the powder material that has been leveled on the entire surface of the table is removed by cutting; It is characterized by including.

  The invention described in claim 2 is characterized in that, in the method for manufacturing a three-dimensionally shaped article according to claim 1, a sharp blade or wire is used in step B.

  The invention described in claim 3 is the method for manufacturing a three-dimensionally shaped article according to claim 1 or 2, wherein the unnecessary powder material removed by cutting is recovered simultaneously with or after step B. It is characterized by.

  The method for producing a three-dimensional shaped article according to claim 4 forms a sintered layer by irradiating a predetermined portion of the powder material layer with a light beam and sintering the powder at the corresponding portion, and this sintering. A new layer of powder material is coated on the layer, and a light beam is irradiated to a predetermined location to sinter the powder at that location to form a new sintered layer that is integrated with the underlying sintered layer. When manufacturing a three-dimensional shaped object in which a plurality of sintered layers are laminated and integrated, the powder material supplied on the table irradiated with the light beam covers the entire surface of the table and the upper surface of the table. The method includes the step C of making the thickness of the powder material thin and uniform while leveling the entire surface of the table by the pressurizing body rotating substantially in parallel, and removing unnecessary powder material from the table.

  According to a fifth aspect of the present invention, in the method for manufacturing a three-dimensionally shaped object according to the fourth aspect, an unnecessary powder material removed outside the table is recovered.

  According to the present invention, in manufacturing a three-dimensional shaped object by an optical modeling method, a three-dimensional shaped object is formed by forming a thin and uniform layer of the powder material while using a powder material having a small particle size. Can be manufactured with high accuracy.

(Embodiment 1)
The first embodiment will be described below with reference to the drawings. In the following description, the present invention may be described with specific examples, but the present invention is not limited to the following specific examples.

  FIG. 1 shows a three-dimensional shaped article manufacturing apparatus (hereinafter simply referred to as “manufacturing apparatus”) according to the first embodiment.

  The manufacturing apparatus supplies a powder material with a squeegee blade 21 on a table 20 that moves up and down in a space surrounded by a cylinder 15, and forms a powder material layer (powder layer) 10. 2 and a pressure member 41 provided on the base portion of the powder layer forming means 2 via an XY drive mechanism 40 (preferably a linear motion linear motor drive is preferable in terms of speeding up). And pressurizing means 3 for compressing and solidifying the powders by pressing, and a powder layer cutting means 4 for cutting and removing the surface portion 13 (see FIG. 2) of a predetermined thickness of the powder layer 10 with a sharp blade 42 Then, the light beam (laser) L output from the laser oscillator 30 is irradiated to a predetermined portion of the powder layer 10 through a scanning optical system such as a galvano mirror 31 to sinter the portion to form the sintered layer 11. You A sintered layer forming means 5, is referred to as basic structure.

  As shown in FIG. 2, the manufacturing of the three-dimensional shaped object in this product is a modeling base on the upper surface of the table 20 which is an adjusting means for adjusting the relative distance between the sintered layer forming means 5 and the sintered layer 11. The powder material is supplied to the surface 22 by the blade 21 that reciprocally moves in the horizontal direction at the same level as the upper surface of the cylinder 15 to form the powder layer 10. By applying pressure from above, the powders are pressed and solidified, and then the surface layer 13 having a predetermined thickness Δt is removed by cutting the powder layer 10 along the upper surface of the cylinder 15. The powder layer 10 is formed, and the portion of the powder layer 10 to be cured is irradiated with the light beam L to sinter the powder, thereby forming the sintered layer 11 integrated with the base 22.

  Then, the table 20 is slightly lowered and the powder material is again supplied by the blade 21 to form the powder layer 10. Next, the table 20 is slightly raised and pressure is applied to the powder layer 10 from above by the pressure body 41. Then, the powder layers are pressed and solidified, and then the powder layer 10 is cut and removed from the surface portion 13 having a predetermined thickness along the upper surface of the cylinder 15 to form a second powder layer 10. The portion 10 to be cured is irradiated with the light beam L to sinter the powder to form the sintered layer 11 integrated with the lower sintered layer 11.

  By repeating the above steps, a target three-dimensional shaped object is manufactured.

  Here, the powder material includes a fine metal powder having a particle size of 1 to 100 μm. Since the powder material contains a metal powder having a small particle size, the surface area of the powder material is increased and the absorption rate of the light beam L is increased, so that the powder material is easily sintered even under irradiation conditions with low energy density, and the molding speed is improves. Further, in order to obtain a certain degree of modeling strength, it is necessary to increase the adhesion strength between the adjacent sintered layers 11. However, in the case of a powder material, the light beam L passes through the gap between the powders, and the lower firing layer 11 The binder layer 11 is also irradiated, and the lower sintered layer 11 is heated to improve the adhesion strength.

  Specifically, the powder material is a mixed powder containing iron-based powder made of chromium molybdenum steel, nickel powder, and copper phosphorus or copper manganese powder. Chromium molybdenum steel powder is adopted from the viewpoint of hardness and strength, nickel powder is adopted from the viewpoint of strength, toughness and workability, and copper phosphorus or copper manganese powder is adopted from the viewpoint of wettability and fluidity.

  Note that it is difficult to produce a high-density three-dimensional shaped object by irradiating only the iron-based powder with the light beam L. This is because, when only iron-based powder is used, it is difficult to integrate the next sintered layer 11 into the previously formed sintered layer 11 without creating a gap. Even if the chromium molybdenum steel itself has high hardness and excellent mechanical strength, the modeling density of the three-dimensional shaped object obtained by irradiating only the chromium molybdenum steel powder with the light beam L is low and the modeling strength is also low.

  Further, when the iron-based powder is an alloy containing a large amount of nickel component, the above-described problem becomes serious because a strong oxide film formed on the surface of the iron-based powder inhibits fusion integration between the iron-based powders. Including a nickel component in an iron-based metal has the advantage of improving the toughness, strength, and corrosion resistance of the iron-based metal, but when manufacturing a three-dimensional shaped object by irradiation with a light beam L, The advantage cannot be demonstrated at all.

  If the irradiation energy of the light beam L is increased, even the chromium-molybdenum steel itself or the iron-based powder containing the nickel component may be sufficiently fused and integrated, but in that case, the irradiation device of the light beam L is large. In addition to the disadvantages of excessive power consumption and high manufacturing costs, the scanning speed of the light beam L cannot be increased, and the manufacturing efficiency also decreases. In addition, a three-dimensional shaped object created with an excessive amount of irradiation energy tends to warp or deform due to thermal stress.

  The powder material irradiated with the light beam L is partially melted or partially melted and then cooled and solidified to form a sintered layer 11. If the wettability at the time of melting is large, the adjacent sintered material is sintered. If the bonding area with the layer 11 is large and the fluidity is large, the bulge on the upper surface is small, and a new powder layer 10 is easily formed there. It is.

  Here, the copper has good fluidity when melted, good wettability with the iron-based material in the molten state, and hardly deteriorates in characteristics even when alloyed with the iron-based material. When the light beam L is irradiated to the mixed powder composed of iron-based powder and copper alloy powder, the copper alloy powder is melted first and fills the gaps between the iron-based powders. Turn into. When the irradiation energy of the light beam L is high, all iron-based powder and copper alloy powder forming the mixed powder are melted to form an alloy. Moreover, the fluidity of the molten metal is better as the difference between the melting temperature and the melting point is larger, and the melting point is lower in the copper phosphorus alloy and the copper manganese alloy than in pure copper, so the light beam L was irradiated with the same energy. In this case, the fluidity of the copper phosphorus alloy or the copper manganese alloy is better than that of pure copper.

  As described above, when the iron-based powder is an alloy containing a nickel component, fusion integration between the powders is hindered by a strong oxide film formed on the powder surface. When the nickel powder is mixed with the copper alloy powder as a separate powder, the fusion integration of these powders is performed well. And the sintered layer 11 which consists of this mixed powder has the high sintered density, As a result, it becomes a thing with high toughness and intensity | strength.

  Particularly preferable results are obtained when the mixing ratio of chromium-molybdenum steel powder is 60 to 90% by weight, the mixing ratio of nickel powder is 5 to 35% by weight, and the mixing ratio of copper manganese alloy powder is 5 to 15% by weight. be able to. The mixed powder has an average particle diameter of 1 to 100 μm and a substantially spherical shape.

  For example, a pressure roller is used as the pressure body 41.

  And in this embodiment, in order to cut and remove the surface part 13 of the predetermined thickness of the powder layer 10, the sharp blade 42 is used, but it is not limited to this, and using a wire (piano wire or thread). Also good. In addition, the thickness of the powder layer 10 from which the surface portion 13 is cut and removed is 0.2 to 0.01 mm. When the surface portion 13 is cut and removed using the blade 42 or the wire, a force is applied in the lateral direction rather than the downward direction, so the blade 21 is used in which the downward force is greater than that of the blade 42 or the wire. The desired powder layer 10 can be reliably formed as compared with the case where the surface portion 13 is removed by cutting.

  As the light beam L, a carbon dioxide laser is used. The irradiation path of the light beam L is created in advance from three-dimensional CAD data. That is, contour shape data of each cross section obtained by slicing STL data generated from a three-dimensional CAD model at an equal pitch is used.

Therefore, when manufacturing a three-dimensional shaped object by an optical modeling method, a three-dimensional shaped object is manufactured with high accuracy by forming the powder layer 10 thinly and uniformly while using a powder material having a small particle size. can do.
(Embodiment 2)
FIG. 3 shows the manufacturing apparatus according to the second embodiment, and FIG. 4 shows the operation of the manufacturing apparatus. This embodiment is different from the first embodiment in that a collecting unit 6 that collects the unnecessary powder material that has been cut and removed is provided, and the other points are the same.

  Here, the recovery means 6 includes an air pump 50 and a suction nozzle 51 connected to the air pump 50, and the suction nozzle 51 is provided in the XY drive mechanism 40 so as to be freely movable.

  In the second embodiment, the wire 43 is used to cut and remove the surface portion 13 having a predetermined thickness of the powder layer 10. In the powder layer 10, the powders are pressed and solidified by the pressure applied previously. However, by using the wire 43 for cutting and removing the powder layer 10, unnecessary powder material that has been cut and removed is powdered. This is because it becomes easy to separate and recover.

  Further, the unnecessary powder material that has been removed by cutting may be collected simultaneously with the removal of unnecessary powder material by cutting.

Therefore, unnecessary powder material can be reused.
(Embodiment 3)
FIG. 5 is a schematic perspective view of a main part of the manufacturing apparatus according to the third embodiment.

  The pressure body 41 that covers the table 20 and the entire surface of the table 20 has a substantially cylindrical shape, and the pressure body 41 applies pressure from above to the powder material on the table 20 while rotating substantially parallel to the upper surface of the table 20. To do. As a result, the powder material is smoothed over the entire surface of the table to form a thin and uniform powder layer 10, and unnecessary powder material is pushed out of the table 20 by the rotation of the pressure body 41. This unnecessary powder material can be removed.

  If the unnecessary powder material pushed out of the table 20 is collected, the powder material can be reused. For collecting the unnecessary powder material, the collecting means 6 including the air pump 50 and the suction nozzle 51 connected to the air pump 50 as described in the second embodiment can be used.

  Therefore, when manufacturing a three-dimensional shaped object by stereolithography, a powder material with a small particle size is used, but a three-dimensional shaped object is formed with high accuracy by forming a thin layer of the powder material uniformly. Can be manufactured.

  Note that items described in each embodiment can be appropriately selected and combined.

2 is a schematic perspective view according to an example of Embodiment 1. FIG. It is operation | movement explanatory drawing same as the above. 10 is a schematic perspective view according to an example of Embodiment 2. FIG. It is operation | movement explanatory drawing same as the above. 10 is a schematic perspective view of main parts according to an example of Embodiment 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Pressurization means 4 Powder layer cutting means 6 Collection | recovery means 10 Powder layer 11 Sintered layer 13 Surface part 41 Pressurizing body 42 Sharp blade 43 Wire rod L Light beam

Claims (5)

A predetermined layer of the powder material layer is irradiated with a light beam to sinter the powder at the corresponding portion to form a sintered layer, and a new layer of the powder material is coated on the sintered layer to cover the predetermined portion. A plurality of sintered layers are laminated and integrated by repeating the formation of a new sintered layer that is integrated with the underlying sintered layer by irradiating the light beam onto In manufacturing a three-dimensional shaped object
A step A in which the powder material supplied onto the table irradiated with the light beam is pressed and solidified by applying pressure from above to level the entire surface of the table;
Thereafter, a step B of cutting and removing the surface portion of the predetermined thickness of the powder material leveled on the entire surface of the table;
The manufacturing method of the three-dimensional shape molded article characterized by including.   The method for manufacturing a three-dimensional shaped object according to claim 1, wherein a sharp blade or a wire is used in step B.   The method for producing a three-dimensional shaped article according to claim 1 or 2, wherein unnecessary powder material that has been cut and removed is recovered simultaneously with or after the process B. A predetermined layer of the powder material layer is irradiated with a light beam to sinter the powder at the corresponding portion to form a sintered layer, and a new layer of the powder material is coated on the sintered layer to cover the predetermined portion. A plurality of sintered layers are laminated and integrated by repeating the formation of a new sintered layer that is integrated with the underlying sintered layer by irradiating the light beam onto In manufacturing a three-dimensional shaped object
The powder material supplied on the table to which the light beam is irradiated is covered with the pressure material that covers the entire surface of the table and rotates approximately parallel to the upper surface of the table. And a process C for removing unnecessary powder material out of the table.   The method for producing a three-dimensional shaped object according to claim 4, wherein unnecessary powder material removed outside the table is collected.

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