JP6443300B2 - Additive manufacturing equipment - Google Patents

Description

  The present invention relates to an additive manufacturing apparatus.

  In recent years, a layered manufacturing apparatus that produces a three-dimensional layered object by irradiating a powder made of an inorganic material or an organic material with a laser beam and sintering or melting and solidifying has been attracting attention. Specifically, a process of forming a powder layer by spreading powder on a surface plate, and a process of forming a hardened layer by irradiating a predetermined region of the powder layer with a light beam and sintering or melting and solidifying it. And repeat. Thereby, many hardened layers can be laminated and integrated to produce a three-dimensional shaped object.

  A related technique is disclosed in Patent Document 1. Patent Document 1 discloses a three-dimensional shape structure that improves the quality of a shaped object by increasing the bulk density of the powder layer by applying vibration to the powder (powder layer) laminated using a vibration device. A manufacturing apparatus is disclosed.

JP 2000-336403 A

The inventors have found the following problems.
In the configuration disclosed in Patent Document 1, when vibration is applied to the powder layer in the layered manufacturing process, the amount of powder supplied (that is, the amount of one layer to be stacked) varies due to the influence of the vibration. There is a fear. Further, the light path of the laser beam may fluctuate due to vibration of the light guide component such as a mirror or a lens. As a result, there has been a problem that the accuracy of forming a shaped object is lowered.

  The present invention has been made in view of the above, and by imparting vibration only to the powder layer filled up to a predetermined height of the modeled object, it is possible to suppress a decrease in the formation accuracy of the modeled object. An object of the present invention is to provide an additive manufacturing apparatus.

  The additive manufacturing apparatus according to an aspect of the present invention includes a step of forming a powder layer by supplying powder into a modeling tank, and a predetermined region of the powder layer is irradiated with a laser beam to be sintered or melted and solidified. And a step of forming a hardened layer of a predetermined shape by a layered modeling apparatus for forming a modeled article, comprising: a vibration apparatus configured to be able to impart vibration to the powder layer, the powder Based on whether or not the height of the layer has reached a predetermined height in the modeled object, the presence or absence of vibration by the vibration exciter is controlled. As a result, vibration is applied only to the powder layer filled up to the height of the workpiece base before the additive manufacturing process, and vibration is not applied to the powder layer during the additive manufacturing process. Supply amount and the optical path of the laser beam are stabilized, and as a result, a decrease in the accuracy of forming the shaped article is suppressed.

  According to the present invention, it is possible to provide an additive manufacturing apparatus capable of suppressing a decrease in formation accuracy of a modeled object by applying vibration only to a powder layer filled up to a predetermined height of the modeled object.

It is typical sectional drawing which shows the outline | summary of the additive manufacturing apparatus which concerns on this invention. It is the figure which expanded a part of additive manufacturing apparatus shown in FIG. It is a flowchart which shows the manufacturing method of the molded article by the additive manufacturing apparatus which concerns on this invention.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiment. In addition, for clarity of explanation, the following description and drawings are simplified as appropriate.

First, the layered manufacturing apparatus according to the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view showing an outline of an additive manufacturing apparatus according to the present invention.
As shown in FIG. 1, the additive manufacturing apparatus according to the present invention includes a base 1, a surface plate 2, a modeling tank 3, a modeling tank support unit 4, a modeling tank drive unit 5, a column 6, a support unit 7, a laser scanner 8, An optical fiber 9, a laser oscillator 10, a squeegee 11, a basket 12, a powder distributor 13, a powder supply unit 14, a vibration device 15, and a height detection unit 16 are provided.

  The base 1 is a table for fixing the surface plate 2 and the column 6. The base 1 is installed on the floor so that the upper surface on which the surface plate 2 is placed is horizontal.

  The surface plate 2 is placed and fixed on the horizontal upper surface of the base 1. The upper surface of the surface plate 2 is also horizontal, and after the work base 40 is installed on the upper surface of the surface plate 2, the powder is spread and the shaped object 50 is formed. In the example of FIG. 1, the surface plate 2 is a quadrangular columnar member. As shown in FIG. 1, a flange-like convex portion 2 a that protrudes in the horizontal direction is formed on the entire periphery of the upper surface of the surface plate 2. Since the outer peripheral surface of the convex portion 2 a is in contact with the inner surface of the modeling tank 3 throughout, the laminated powder 51 can be held in the space surrounded by the upper surface of the surface plate 2 and the inner surface of the modeling tank 3. it can. Here, by providing a seal member (not shown) made of felt, for example, on the outer peripheral surface of the convex portion 2 a that is in contact with the inner side surface of the modeling tank 3, the holding power of the laminated powder 51 can be increased.

  The modeling tank 3 is a cylindrical member that holds the powder spread on the upper surface of the surface plate 2 from the side surface. In the example of FIG. 1, since the surface plate 2 has a quadrangular prism shape, the modeling tank 3 is a square pipe having a flange portion 3a at the upper end. The modeling tank 3 is made of, for example, a stainless steel plate having a thickness of about 1 to 6 mm (preferably about 3 to 5 mm) and is lightweight. A powder layer is formed on the upper opening end 3b of the modeling tank 3, and a hardened layer is formed by irradiating the powder layer with a laser beam LB. The shape of the upper opening end 3b is, for example, 600 mm × 600 mm.

  The modeling tank 3 is installed so as to be movable in the vertical direction (z-axis direction). As will be described in detail later, each time a hardened layer is formed, the modeling tank 3 is raised by a certain amount with respect to the surface plate 2 to form a modeled object 50. Here, in the additive manufacturing apparatus according to the first embodiment, only the constant-weight and lightweight modeling tank 3 may be raised. Therefore, the powder layer can be formed with high accuracy every time. As a result, the molded article 50 can be formed with high accuracy.

The modeling tank support part 4 is a support member that supports the lower surface of the flange part 3a at three points so that the upper surface of the flange part 3a of the modeling tank 3 is horizontal.
The modeling tank support part 4 is connected to a connecting part 5c of a modeling tank drive unit 5 that moves the modeling tank 3 in the vertical direction (z-axis direction).

  The modeling tank drive unit 5 is a drive mechanism for moving the modeling tank 3 in the vertical direction (z-axis direction). The modeling tank driving unit 5 includes a motor 5a, a ball screw 5b, and a connecting portion 5c. When the motor 5a is driven, the ball screw 5b extending in the z-axis direction rotates. When the ball screw 5b rotates, the connecting portion 5c moves in the vertical direction (z-axis direction) along the ball screw 5b. Since the modeling tank support part 4 which supports the modeling tank 3 is connected with the connection part 5c as above-mentioned, the modeling tank 3 becomes movable by the modeling tank drive part 5 to an up-down direction (z-axis direction). The drive source of the modeling tank drive unit 5 is not limited to a motor, and a hydraulic cylinder or the like may be used.

  Here, the modeling tank drive unit 5 is fixed to an upper portion of a support column 6 that is erected substantially vertically (that is, in a vertical direction) from the base 1. As described above, in the additive manufacturing apparatus according to the present embodiment, the modeling tank driving unit 5 is installed outside the modeling tank 3, and thus has excellent maintainability.

The laser scanner 8 irradiates the powder layer formed on the upper opening end 3 b of the modeling tank 3 with the laser beam LB. The laser scanner 8 has a lens and a mirror (not shown). Therefore, as shown in FIG. 1, the laser scanner 8 can focus the laser beam LB on the powder layer regardless of the position on the horizontal plane (xy plane) in the powder layer.
Here, the laser beam LB is generated in the laser oscillator 10 and introduced into the laser scanner 8 via the optical fiber 9.

  The laser scanner 8 is fixed to the flange portion 3 a of the modeling tank 3 through the support portion 7. Therefore, the distance between the laser scanner 8 and the powder layer that is the irradiation target of the laser beam LB can be kept constant. Therefore, the additive manufacturing apparatus according to the first embodiment can manufacture the modeled object 50 with high accuracy.

  The squeegee 11 includes a first squeegee 11a and a second squeegee 11b. Both the first squeegee 11a and the second squeegee 11b extend in the y-axis direction. Further, the squeegee 11 can slide in the x-axis direction from one flange portion 3 a to the opposing flange portion 3 a through the upper opening end 3 b of the modeling tank 3.

  As shown in FIG. 1, the powder is supplied between the first squeegee 11a and the second squeegee 11b on the flange 3a on the negative side of the x-axis. Here, the powder for forming the powder layer for 2 times is supplied. That is, the squeegee 11 slides from the x-axis minus side flange portion 3 a to the x-axis plus side flange portion 3 a, so that one powder layer is formed at the upper opening end 3 b of the modeling tank 3. As indicated by a broken line in FIG. 1, while the powder layer is irradiated with the laser beam LB and the hardened layer is formed, the squeegee 11 stands by on the flange 3a on the x-axis plus side. Then, the squeegee 11 slides from the x-axis plus side flange portion 3 a to the x-axis minus side flange portion 3 a, whereby another powder layer is formed on the upper opening end 3 b of the modeling tank 3.

  For example, when the formation region of the hardened layer is narrow, the hardened layer formation region is covered without sliding the squeegee 11 from the x-axis minus side flange portion 3a to the x-axis plus side flange portion 3a as much as possible. Above, you may stop the slide in the middle. The amount of powder for forming the powder layer can be saved and the time can be shortened.

The basket 12 and the powder distributor 13 are for uniformly distributing the powder dropped from the powder supply unit 14 in the longitudinal direction of the squeegee 11.
An opening having a length (y-axis direction) that is narrower than the distance (x-axis direction) between the first squeegee 11 a and the second squeegee 11 b (x-axis direction) and is approximately the same as the powder injection region of the squeegee 11 is formed on the lower surface of the flange 12. Is formed. However, the powder is dropped from the powder supply unit 14 to the end of the ridge 12 where no opening is formed.

  The powder distributor 13 is a plate-like member having the same shape as the cross-sectional shape of the groove of the ridge 12. The powder distributor 13 can be slid in the y-axis direction between both ends of the basket 12 by a driving mechanism (not shown). Here, in FIG. 1, the powder distributor 13 is drawn away from the basket 12 for easy understanding. However, in practice, the powder distributor 13 slides in contact with both sides of the groove of the ridge 12 without any gap. When the powder distributor 13 slides from one end to the other end where the powder is dropped in the basket 12, the powder is uniformly distributed in the longitudinal direction of the squeegee 11 through the opening of the basket 12.

  For example, when the formation area of the hardened layer is narrow, the powder distributor 13 is not slid from one end to the other end of the basket 12 as much as possible. May be. The amount of powder for forming the powder layer can be saved and the time can be shortened.

  The powder supply unit 14 is a small tank in which powder is stored, and drops (supplies) the stored powder to the basket 12. The powder is made of an inorganic material (metal or ceramic) or an organic material (plastic). Preferably, iron powder having an average particle size of about 20 μm is used.

  The vibration device 15 is built in the surface plate 2 and configured to be able to impart vibration to the powder layer formed in the modeling tank 3.

  The height detection unit 16 is a linear member provided on the side surface of the modeling tank 3 along the z-axis direction, and detects the height of the powder layer formed in the modeling tank 3 from the upper surface of the surface plate 2. To do. Instead of the height detector 16, a camera for photographing the inside of the modeling tank 3 may be installed, and the height of the powder layer may be detected by analyzing a photographed image of the camera.

FIG. 2 is an enlarged view of the periphery in the modeling tank 3 of the additive manufacturing apparatus shown in FIG.
As shown in FIG. 2, in the modeling tank 3, a work base 40 is first installed on the upper surface of the surface plate 2 as a base for the modeled object 50. The upper surface of the work base 40 is horizontal as is the upper surface of the surface plate 2. Then, the powder layer 51a is formed by supplying powder to the same height as the work base 40. Thereafter, by further irradiating a predetermined region of each of the powder layers 51b and 51c formed by supplying the powder with a laser beam LB and sintering or melting and solidifying, the hardened layers 50b and 50c having desired shapes are formed into workpieces. Sequentially formed on the base 40.

Then, with reference to FIGS. 1-3, the manufacturing method of the molded article 50 is demonstrated in detail.
FIG. 3 is a flowchart showing a method for manufacturing a modeled object 50 by the additive manufacturing apparatus according to the present invention. In addition, in the flowchart of FIG. 3, the vibration process before an additive manufacturing process is demonstrated in detail.

  First, the height information of the workpiece base 40 installed on the upper surface of the surface plate 2 is acquired from information input in advance or CAD / CAM information (step S201).

  Thereafter, when the operation signal of the powder supply unit 14 is switched from inactive (NO in step S202) to active (YES in step S202), powder supply is started (step S203).

  Specifically, the modeling tank 3 is moved upward until the upper surface of the workpiece base 40 and the upper surface of the flange portion 3a of the modeling tank 3 become flat. Thereafter, the squeegee 11 to which the powder is supplied by the powder supply unit 14 is slid from the x-axis minus side flange portion 3a to the x-axis plus side flange portion 3a (outward path). Thereby, powder is supplied to the space enclosed by the upper surface of the surface plate 2 and the inner surface of the modeling tank 3 (step S203).

  When the height of the powder layer 51a formed by stacking the powder does not reach the same height as the workpiece base 40 (NO in step S204), the powder is continuously supplied (step S203).

  Specifically, the squeegee 11 is slid from the x-axis plus side flange portion 3a to the x-axis minus side flange portion 3a (return path). Thereby, powder is further supplied to the space enclosed by the upper surface of the surface plate 2 and the inner surface of the modeling tank 3 (step S203).

  Such an operation is repeated until the height of the powder layer 51a reaches the same height as the workpiece base 40.

  After that, when the height detection unit 16 detects that the height of the powder layer 51a has reached the same height as the workpiece base 40 (YES in step S204), the operation signal of the powder supply unit 14 changes from active to inactive. Thus, the powder supply is completed (step S205).

  The powder may be supplied directly by the operator instead of being supplied via the squeegee 11 by the powder supply unit 14. In this case, for example, when a button indicating the start of powder supply is pressed by the operator (YES in step S202), powder supply is enabled and powder is supplied (step S203), indicating that powder supply is complete. When the button is pressed by the operator, the state where the powder can be supplied is canceled and the supply of the powder is completed (step S205).

  Thereafter, with the powder supply stopped, the vibration device 15 vibrates the powder layer 51a (step S206). Thereby, the bulk density of the powder layer 51a increases. This leads to an improvement in the quality of the shaped object 50 formed in the subsequent additive manufacturing process. However, as a result, the height of the powder layer 51a decreases. Therefore, additional powder is supplied to the powder layer 51a.

  Specifically, first, the height detector 16 detects whether or not the height of the powder layer 51a after vibration has reached the same height as the workpiece base 40 (step S207).

  When the height of the powder layer 51a after vibration does not reach the same height as that of the workpiece base 40 (NO in step S207), for example, the height of the powder layer 51a after vibration and the height of the workpiece base 40 After the amount of powder to be added is calculated based on the difference (step S208), the calculated amount of powder is supplied again (step S203). Thereafter, the same operation is repeated from step S204 to S207.

  Thereafter, when the height detection unit 16 detects that the height of the powder layer 51a after vibration has reached the same height as the workpiece base 40 (YES in step S207), the modeling is performed on the workpiece base 40. The process proceeds to the additive manufacturing process for forming an object (step S209).

  In the additive manufacturing process, for example, the powder is supplied to the powder input region of the squeegee 11 in a state where the squeegee 11 is installed on the flange 3a on the minus side of the x axis. Here, the powder for forming the powder layer for 2 times at a time is supplied.

  Then, only the modeling tank 3 is moved upward by, for example, 30 μm from the state in which the upper surface of the powder layer 51a after vibration (the upper surface of the workpiece base 40) and the upper surface of the flange portion 3a of the modeling tank 3 are completely flat. . Thereafter, the squeegee 11 is slid from the x-axis minus side flange portion 3a to the x-axis plus side flange portion 3a (outward path). Thereby, powder is supplied to the space surrounded by the upper surface of the powder layer 51a after vibration, the work base 40, and the inner surface of the modeling tank 3, and a powder layer 51b having a thickness of 30 μm is formed.

  Thereafter, a predetermined region of the powder layer 51b is irradiated with a laser beam LB, and sintered or melted and solidified to form a hardened layer 50b having a desired shape on the workpiece base 40. During this time, the squeegee 11 stands by on the flange portion 3a on the x-axis plus side.

  Further, when a predetermined region of the powder layer 51b is irradiated with the laser beam LB and sintered or melted and solidified, fumes are generated. However, in the additive manufacturing apparatus of the present invention, an inert gas such as nitrogen gas or argon gas is allowed to flow in the y-axis direction 30 to 50 mm above the entire powder layer (the z-axis direction plus side). Therefore, the generated fumes can be quickly removed without blowing gas toward the powder layer.

Thereafter, only the modeling tank 3 is again moved upward by, for example, 30 μm.
Thereafter, the squeegee 11 is slid from the flange portion 3a on the plus side of the x axis to the flange portion 3a on the minus side of the x axis (return path). Thereby, powder is supplied to the space surrounded by the powder layer 51b and the hardened layer 50b and the inner surface of the modeling tank 3, and a powder layer 51c having a thickness of 30 μm is formed.

  Thereafter, a predetermined region of the powder layer 51c is irradiated with a laser beam LB, and sintered or melted and solidified to integrally form a cured layer 50c having a desired shape on the cured layer 50b.

  Then, with the squeegee 11 installed on the flange 3a on the minus side of the x axis, the powder is supplied again to the powder input region of the squeegee 11.

  In the layered modeling process, the powder is supplied to the squeegee 11, moved upward in the modeling tank 3, the powder layer (for example, the powder layer 51b) is formed by the slide of the squeegee 11 (outward path), and the cured layer (for example, the cured layer 50b) is formed. The formation, the upward movement of the modeling tank 3, the formation of the powder layer (for example, the powder layer 51c) by the slide of the squeegee 11 (return path), and the formation of the cured layer (for example, the cured layer 50c) are repeated. As a result, a three-dimensional shaped object 50 in which a large number of hardened layers are laminated and integrated is obtained. The laminated powder 51 remaining in the modeling tank 3 is collected and reused.

  As described above, in the additive manufacturing apparatus according to the present invention, vibration is applied to the powder layer 51a filled up to the height of the workpiece base 40 before the additive manufacturing process, and the powder layers 51b and 51c are applied during the additive manufacturing process. Therefore, the amount of powder supplied by the powder supply unit 14 and the optical path of the laser beam LB are stabilized during the additive manufacturing process. As a result, a decrease in the formation accuracy of the model 50 is suppressed.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

  For example, in the workpiece base 40, when there is a portion (or a portion) that is difficult to fill with the powder material, such as an uneven shape or a hole (particularly, an inclined hole or a tapered hole), the height of the powder layer is the height of the workpiece base 40. Instead of detecting whether or not the height of the powder layer has reached the height of the shape part (or part) based on the shape data of the modeled object (or workpiece base). Thus, vibration control can also be performed.

  In addition, in order to prevent sudden or large “bulk density” changes in the layered manufacturing process, it may be possible to add a process / work of vibration + material replenishment after temporarily stopping the stacking. Even in such a case, the vibration device is detected by detecting the height of a part (or part) that is likely to cause a change in "bulk density", such as an uneven shape of a modeled object based on the model data of the modeled object, an inclined hole or a tapered hole. Vibration control can be performed.

DESCRIPTION OF SYMBOLS 1 Base 2 Surface plate 2a Convex part 3 Modeling tank 3a Flange part 3b Upper opening end 4 Modeling tank support part 5 Modeling tank drive part 5a Motor 5c Connection part 6 Support | pillar 7 Support part 8 Laser scanner 9 Optical fiber 10 Laser oscillator 11 Squeegee 11a First squeegee 11b Second squeegee 12 １３ 13 Powder distributor 14 Powder supply unit 15 Excitation device 16 Height detection unit 40 Work base 50 Modeling object 50b Cured layer 50c Cured layer 51 Laminated powder 51a Powder layer 51b Powder layer 51c Powder layer LB Laser beam

Claims (1)

A step of forming a powder layer by supplying powder into the modeling tank; a step of forming a hardened layer of a predetermined shape by irradiating a predetermined region of the powder layer with a laser beam and sintering or melting and solidifying; Is a layered modeling apparatus that forms a modeled object by repeating
Of the powder layer formed on the shaping vessel, a structure has been vibrating device so that only applying vibration to the powder layer which is filled up to the height of the base of the shaped object,
The vibratory apparatus waits for the powder to be supplied to the height of the foundation until the height of the powder layer after vibration is maintained at the same height as the foundation of the modeled object, and An additive manufacturing apparatus configured to repeatedly perform a step of applying vibration to the powder layer formed at the same height as a base .

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