JP2019019364A - Lamination molding device - Google Patents

Abstract

To provide a lamination molding device capable of shortening the time required for finishing a side face while keeping the form accuracy of an obtainable lamination molded object.SOLUTION: A lamination molding device comprises a molding table, a re-coater head that reciprocates in one horizontal direction over the molding table, and supplies a metal material powder and flattens it to form a powder layer, and a laser irradiation part that has a first laser oscillation part having a first laser source to oscillate a first laser and a second laser oscillation part having a second laser source to oscillate a second laser so that a first laser is irradiated to a laser irradiation area respectively set for each powder layer on the basis of solid data for a molded object having a desired three-dimensional shape to thereby forming a sintered layer and a second laser is irradiated to the sintered layer along a contour of the laser irradiation area where the first laser has been irradiated upon forming each sintered layer to thereby finish side faces of all the sintered layer. The second laser irradiated from the laser irradiation part is a femtosecond laser.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an additive manufacturing apparatus for manufacturing a metal additive manufacturing object.

  There is an additive manufacturing apparatus described in Patent Document 1 as an apparatus for manufacturing a metal additive manufacturing object. In this layered manufacturing apparatus, the recoater head is moved in the horizontal uniaxial direction in the modeling tank, and the metal material powder is supplied and flattened by the material storage box and blade provided in the recoater head. A layer is formed, and a laser irradiation apparatus irradiates a predetermined range of the powder layer with a laser to form a sintered layer. Then, a new powder layer is formed on the sintered layer, laser irradiation is performed, and the formation of the sintered layer is repeatedly performed to manufacture a metal layered object.

  Also, in Cited Document 2, every time a predetermined number of sintered layers are formed, the side surface of the newly formed sintered layer is corrected by a cutting device in order to obtain a layered product with higher shape accuracy. A method of forming a layered object while finishing is disclosed.

JP-T-1-502890 Japanese Patent No. 3405357

  However, generally, a layered product manufactured by layered modeling is formed by stacking thousands of sintered layers. Therefore, in the finishing processing of the side surface of the sintered layer by the cutting device described in the cited document 2, the time of the finishing processing is not so long from the driving of the cutting device to the completion of cutting, even though the time per finishing processing is not so long. The total finishing time required from the lower layer to the uppermost layer is long.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an additive manufacturing apparatus capable of shortening the time required for side finishing while maintaining the shape accuracy of the additive manufacturing object to be obtained. That is.

  An additive manufacturing apparatus according to a first aspect of the present invention includes a modeling table, a recoater head that reciprocates in the horizontal uniaxial direction on the modeling table to supply a metal material powder and flatten to form a powder layer, and a first A first laser oscillation unit including a first laser light source that oscillates a second laser and a second laser oscillation unit including a second laser light source that oscillates a second laser, and a desired tertiary When forming the sintered layer by irradiating the first laser to the laser irradiation region set for each powder layer based on the solid data of the shaped object having the original shape, and forming each sintered layer A laser irradiation unit that irradiates the sintered layer with the second laser along the contour of the laser irradiation region irradiated with the first laser, and finishes the side surfaces of all the sintered layers; And irradiated from the laser irradiation unit That the second laser is characterized in that a femtosecond laser.

  In the present invention, the second laser for finishing the side surface of the sintered layer is a femtosecond laser. Since the femtosecond laser has an extremely short pulse width, pulsed light having a high laser intensity can be irradiated in an extremely short time. As a result, before the thermal energy is transmitted to the periphery, the portion irradiated with the laser can be evaporated without melting. This so-called laser ablation process can minimize the thermal influence on the sintered layer due to thermal diffusion, so that only the portion irradiated with the second laser can be subjected to a highly accurate finishing process.

  Further, since the side surface finishing of the sintered layer is performed by laser irradiation, it is not necessary to drive the cutting device and perform the side surface finishing processing as in the prior art. Furthermore, the time required for finishing the side surface by laser irradiation is very short. Therefore, compared with the past, the time which the finishing process of the side surface of the sintered layer in the modeling process of a molded article can be shortened significantly.

  Moreover, since the cutting device for finishing the side surface of the sintered layer is not required, the additive manufacturing apparatus can be reduced in size and weight. Furthermore, since it is not necessary to ensure the movement area of the cutting device in the modeling tank 1A, the space in the modeling tank 1A can be used more efficiently. Thereby, for example, although it is a small apparatus with a reduced capacity, it is possible to manufacture a shaped article having a corresponding size.

  The additive manufacturing apparatus according to a second aspect of the present invention is characterized in that, in the first aspect, the laser irradiation unit is disposed immediately above the modeling table.

  Here, when the laser irradiation unit is not disposed immediately above the modeling table, the variation in distance from the laser irradiation unit to each irradiation position when viewed from the vertical direction is increased. This greatly changes the shape of the laser irradiation spot depending on the irradiation position. More specifically, for example, when the shape of the laser irradiation spot is set to a circle, the irradiation spot has a substantially circular shape at the irradiation position close to the laser irradiation part, but the distance from the laser irradiation part. At the irradiation positions far away from each other, the shape of the irradiation spot becomes an ellipse having a long side in the linear direction connecting the laser irradiation portion and the irradiation position when viewed from the vertical direction. As a result, there may be a problem such as a positional deviation of the laser irradiation position or a decrease in irradiation energy due to a wide irradiation spot.

  In this invention, the laser irradiation part is arrange | positioned directly on the said modeling table. Accordingly, it is possible to reduce the variation in distance from the laser irradiation unit to each irradiation position when viewed from the vertical direction. Thereby, since the shape change of an irradiation spot can be suppressed, the problem mentioned above can be prevented.

  The additive manufacturing apparatus according to a third aspect of the present invention is the first or second aspect of the invention, wherein the layered manufacturing apparatus moves on the modeling table before finishing the side surface of the sintered layer and sucks at least the material powder near the side surface of the sintered layer. And a powder suction part to be removed.

  In the present invention, the powder suction unit moves on the modeling table before finishing the side surface of the sintered layer, and sucks and removes at least the material powder near the side surface of the sintered layer. Thereby, finishing can be performed in a state where the material powder is removed from the vicinity of the side surface of the sintered layer. Therefore, it is possible to prevent the second powder from being irradiated to the material powder in the vicinity of the sintered layer, and to reliably perform the finishing process of the side surface by irradiating only the desired sintered layer with the second laser.

  ADVANTAGE OF THE INVENTION According to this invention, the time required for the finishing process of a side surface can be shortened, maintaining the shape precision of the layered object to be obtained.

It is a schematic front view which shows the whole structure of this machine of the additive manufacturing apparatus which concerns on embodiment. It is a schematic side view which shows the whole structure of this machine of the additive manufacturing apparatus which concerns on embodiment. (A) is a perspective view of the laser irradiation part at the time of 1st laser irradiation, (b) is a perspective view of the laser irradiation part at the time of 2nd laser irradiation. It is a block diagram which shows control of each apparatus which comprises an additive manufacturing apparatus. (A)-(e) is a front view which shows the mode of the modeling table periphery from formation of a new powder layer to completion of the finishing process of a sintered layer. It is a top view of the sintered layer before performing a finishing process of a side surface.

  Embodiments of the present invention will be described below with reference to the drawings.

  The additive manufacturing apparatus is a sintered metal powder additive manufacturing apparatus. The additive manufacturing apparatus includes the machine 1, a CAD device 12, a CAM device 15, a numerical control device 6, and the like. In the following, the front side is defined as the front, the back side is the rear, the left side is the left, the right side is the right, the upper side is the upper side, and the lower side is the lower side. The description will be made using direction words “right”, “left”, “upper”, and “lower” as appropriate.

  As shown in FIGS. 1 and 2, the machine 1 includes a powder layer forming device 2 and a recoater head 3 provided in the modeling tank 1A, and a laser irradiation device 5 and the like provided above the modeling tank 1A. Have. An inert gas is supplied into the modeling tank 1A from an inert gas supply device (not shown). Thereby, the inside of modeling tank 1A is comprised so that oxygen concentration may become as low as possible.

  The powder layer forming apparatus 2 includes a modeling table 2A, a support mechanism 2B that supports the modeling table 2A and moves up and down, a transmission mechanism 2C that transmits an operation to the support mechanism 2B, and a drive device that includes a motor that drives the support mechanism 2B. have. After forming each sintered layer, the modeling table 2A is lowered by an amount corresponding to the thickness of the powder layer newly formed thereon.

  The recoater head 3 reciprocates on the modeling table 2A along the guide rail 21 extending in the left-right direction based on a scanning command from a servo motor control device 19 described later. More specifically, the recoater head 3 reciprocates between an initial position on the left side of the modeling table 2A and a standby position on the right side of the modeling table 2A.

  The recoater head 3 has a powder layer forming part 3A for forming a powder layer and a powder suction part 3B for sucking material powder. When viewed from the front of the machine 1, the powder layer forming part 3A is arranged on the left side, and the powder suction part 3B is arranged on the right side. When the recoater head 3 moves from the initial position to the standby position, the powder layer forming unit 3A opens the powder supply port provided in the material storage box to supply the material powder onto the modeling table 2A and By flattening, a powder layer is formed on the modeling table 2A. After the recoater head 3 moves to the standby position, the powder supply port is closed. When the recoater head 3 moves from the standby position to the initial position, the powder suction unit 3B sucks and removes the upper layer portion of the material powder spread on the modeling table 2A.

  The laser irradiation apparatus 5 forms a sintered layer by irradiating the irradiation region set for each powder layer with the first laser L1, and irradiates the second laser L2 with the second laser L2 on the side surface. Finishing processing is performed. The laser irradiation device 5 is disposed immediately above the center of the modeling table 2A.

  As shown in FIGS. 3A and 3B, the laser irradiation apparatus 5 includes a first laser oscillator 5A that oscillates the first laser L1 and a second laser oscillator 5B that oscillates the second laser L2. And mirrors 5C1 and 5C2 for changing the irradiation directions of the first laser L1 and the second laser L2, and a focus lens 5D for converging the first laser L1 and the second laser L2.

  The first laser oscillator 5A has a first laser light source. The first laser oscillator 5A oscillates by adjusting the first laser L1 oscillated from the first laser light source to a desired spot diameter and laser intensity. The first laser L1 is, for example, a fiber laser, a YAG laser, or the like.

  The second laser oscillator 5B has a second laser light source. The second laser oscillator 5B converts the second laser L2 oscillated from the second laser light source into a femtosecond laser, and oscillates by adjusting to a desired spot diameter and laser intensity.

  The first laser L1 and the second laser L2 reach the mirrors 5C1 and 5C2 via the laser transmission member. The mirrors 5C1 and 5C2 are tilted to a desired angle by driving an electric actuator (not shown) based on a scanning command of a laser control device 20 described later. Each laser reflected by the mirrors 5C1 and 5C2 is converged by the focus lens 5C and passes through a transmission lens 1a provided in a through hole formed in the top plate of the modeling tank 1A.

  As shown in FIGS. 1 and 2, the top plate of the modeling tank 1A is provided with a fume diffusing portion 8 that covers the transmission lens 1a. An inert gas supply space 8 b connected to an inert gas supply device (not shown) is provided on the outer periphery of the fume diffusing unit 8. At the boundary between the inert gas supply space 8b and the inner clean space 8a, a partition portion 8c in which a large number of micro holes 8c1 are formed is provided, and from the inert gas supply space 8b via the micro holes 8c1. A clean inert gas is supplied to the normal space 8a. The inert gas filled in the clean space 8a is ejected into the modeling tank 1A through the opening 1b. By removing the fumes from the laser irradiation path by this inert gas, contamination of the transmission lens 1a is prevented.

  As shown in FIG. 4, the CAD device 12 is for creating solid data of a modeled object modeled by the machine 1. The CAD device 12 includes a calculation unit 13 that creates solid data of a model and a storage unit 14 that stores the solid data created by the calculation unit 13. The solid data is three-dimensional data indicating the shape and dimensions of a predetermined modeled object.

  The CAM device 15 is for generating a modeling program from the solid data created by the CAD device 12. The CAM device 15 stores a calculation unit 16 that generates a modeling program from the solid data generated by the CAD device 12, a solid data generated by the CAD device 12, and a storage program that is generated by the calculation unit 16. A portion 17 is provided. The modeling program indicates an operation procedure of each apparatus constituting the machine 1 when modeling a predetermined modeled object. The modeling program includes, for example, data on the irradiation region of the first laser L1. The data of the irradiation region of the first laser L1 is used to define the irradiation range of the first laser L1 irradiated from the laser irradiation device 5 for each powder layer.

  The numerical control device 6 includes a storage unit 7 and a calculation unit 8. The storage unit 7 is a hard disk that stores a modeling program for the layered object generated by the CAM device 15. The calculation unit 8 servos a command from the command unit 10, a decoding unit 9 that decodes the modeling program stored in the storage unit 7, a command unit 10 that outputs a command based on the modeling program decoded by the decoding unit 9. A distribution output unit 11 that distributes and outputs the motor control device 19 and the laser control device 20 is provided.

  The servo motor control device 19 receives a movement command from the command unit 10 of the calculation unit 8 as a signal or data. The servo motor that drives the recoater head 3 reciprocates the recoater head 3 in the left-right direction based on a scanning command from the servo motor control device 19.

  The laser control device 20 includes an actuator control device and a drive current supply device (not shown). The actuator control device outputs a scanning command from the command unit 10 of the calculation unit 8 to the electric actuator as a signal or data. The electric actuator receives the drive current supplied from the drive current supply device, tilts the mirrors 5C1 and 5C2, and irradiates the first laser L1 and the second laser L2 in desired directions.

  Next, the operation of the machine 1 from the formation of the new powder layer 51 to the completion of the finishing process of the sintered layer 52 will be described in detail with reference to FIGS. 5 (a) to 5 (e) and FIG. . 5A shows a state around the modeling table 2A before the new powder layer 51 is formed. At this time, the recoater head 3 is disposed at the initial position. Moreover, the powder supply port provided in the material storage box of the powder layer forming unit 3A is closed, and the powder suction unit 3B is stopped.

  As shown in FIG. 5B, with the powder supply port opened and the powder suction unit 3B stopped, the recoater head 3 is moved from the initial position to the standby position, and the powder layer forming unit 3A A new powder layer 51 is formed on the modeling table 2A by flattening the material powder with a blade while supplying the material powder from the powder supply port provided in the material storage box. After the recoater head 3 moves to the standby position, the powder supply port is closed.

  The laser irradiation device 5 tilts the mirrors 5C1 and 5C2 based on the command from the laser control device 20 described above, and irradiates the irradiation region R of the powder layer 51 with the first laser L1. Thereby, as shown in FIG.5 (c), the new sintered layer 52 is formed on the molded object 50 which has been modeled.

  Here, on the side of the sintered layer obtained by laser sintering, an excessively sintered portion that protrudes outward is formed on the side surface of the sintered layer due to the characteristics of modeling by melting. In this embodiment, every time a single layer of the sintered layer is formed, a surplus sintered portion generated in the sintered layer is removed by a femtosecond laser, thereby finishing the side surface of the sintered layer.

  As shown in FIG. 5 (d), before finishing the side surface of the sintered layer 52, the recoater head 3 is moved from the standby position to the initial position while the powder suction unit 3B is in operation. The material powder is sucked and removed so that the side surfaces of the sintered layer 52 buried in the material powder are all exposed. After the recoater head 3 moves to the initial position, the powder suction unit 3B is stopped again.

  The laser irradiation device 5 tilts the mirrors 5C1 and 5C2 based on a command from the laser control device 20, and the irradiation region R irradiated with the first laser L1 when forming the sintered layer 52 indicated by the oblique lines in FIG. As shown in FIG. 5D, the second laser L2 that is a femtosecond laser is irradiated to the sintered layer 52 along the contour of FIG. 5, and the surplus of the sintered layer 52 formed outside the contour. The sintered part 52a is removed. Note that the laser intensity of the second laser L2 at this time is set to such an extent that processing can be performed up to a depth corresponding to the thickness of the sintered layer 52 to be finished. The diameter of the irradiation spot of the second laser L2 is set to a very small size compared to the diameter of the irradiation spot of the first laser L1. As described above, as shown in FIG. 5E, the side surface of the sintered layer 52 is finished so that the actual shaped object that is the laminate of the sintered layers substantially matches the solid data created by the CAD device 12. be able to.

(Action / Effect)
In the present embodiment, the second laser L2 that performs the finishing process on the side surface of the sintered layer is a femtosecond laser. Since the femtosecond laser has an extremely short pulse width, pulsed light having a high laser intensity can be irradiated in an extremely short time. As a result, before the thermal energy is transmitted to the periphery, the portion irradiated with the laser can be evaporated without melting. This so-called laser ablation process can minimize the thermal effect on the sintered layer due to thermal diffusion, so that only the portion irradiated with the second laser L2 can be finished with high accuracy. .

  The laser intensity of the second laser L2 is set to such an extent that processing can be performed up to a depth corresponding to the thickness of the sintered layer 52 to be finished. The diameter of the irradiation spot of the second laser L2 is It is set to a very small size compared to the diameter of the irradiation spot of one laser L1. Thereby, it is possible to perform the finishing process by irradiating only the desired sintered layer with the second laser L2 without affecting the already shaped object.

  Further, since the side surface finishing of the sintered layer is performed by laser irradiation, it is not necessary to drive the cutting device and perform the side surface finishing processing as in the prior art. Furthermore, the time required for finishing the side surface by laser irradiation is very short. Therefore, compared with the past, the time which the finishing process of the side surface of the sintered layer in the modeling process of a molded article can be shortened significantly.

  Further, since a cutting device for finishing the side surface of the sintered layer is not required, the machine 1 can be reduced in size and weight. Furthermore, since it is not necessary to ensure the movement area of the cutting device in the modeling tank 1A, the space in the modeling tank 1A can be used more efficiently. Thereby, although it is a small apparatus which suppressed capacity | capacitance, the molded article of a suitable magnitude | size can be manufactured.

  Further, the laser irradiation device 5 is disposed immediately above the center of the modeling table 2A. Therefore, variation in distance from the laser irradiation device 5 to each irradiation position when viewed from the vertical direction can be reduced. Thereby, since the change in the shape of the irradiation spot can be suppressed, it is possible to prevent problems such as a displacement of the laser irradiation position or a decrease in irradiation energy due to the widening of the irradiation spot.

  Further, before finishing the side surface of the sintered layer, the recoater head 3 is moved from the standby position to the initial position while the powder suction unit 3B is in operation, and the sintered layer buried in the material powder is moved. The material powder is removed by suction so that all sides are exposed. Thereby, finishing can be performed in a state in which the material powder is removed from the vicinity of the side surface of the sintered layer to be finished. Accordingly, it is possible to prevent the material powder in the vicinity of the sintered layer from being irradiated with the second laser L2, and to reliably irradiate only the desired sintered layer with the second laser L2 to perform side finishing. it can.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments and examples, and various design changes can be made as long as they are described in the claims. is there.

  In the present embodiment, the powder supply port provided in the material storage box is described as opening when the recoater head 3 moves from the initial position to the standby position, and closed before moving from the standby position to the initial position. In addition, a configuration in which the powder supply port is opened and closed without providing a mechanism for opening and closing the powder supply port may be used. In this case, when the recoater head 3 moves from the standby position to the initial position, the powder suction unit 3B sucks the material powder including the material powder supplied from the material storage box of the powder layer forming unit 3A.

  Further, in the present embodiment, in order to prevent the size of the modeled object from being reduced by finishing, the diameter of the irradiation spot of the second laser L2 is set to be extremely small, and the sintered layer 52 indicated by the oblique lines in FIG. The case where the second laser L2 that is a femtosecond laser is irradiated onto the sintered layer 52 along the contour of the irradiation region R irradiated with the first laser L1 when forming the laser beam is described. The diameter of the irradiation spot of the laser L2 and the locus of irradiating the second laser L2 when finishing the side surface of the sintered layer are not limited to this. For example, an average value of the amount of protrusion of the surplus sintered portion from the outline of the irradiation region set for each powder layer is experimentally calculated, and the average value is set as the radius of the irradiation spot of the second laser L2. When forming the sintered layer for performing the finishing process, the finishing process is performed such that the center of the irradiation spot passes outside the outline of the irradiation area irradiated with the first laser L1 by the radius of the irradiation spot. The locus of the second laser L2 may be set.

  Moreover, in this embodiment, although described about the case where the modeling object which has a taper-shaped side surface in which the width | variety of a sintered layer becomes small as it progresses to an upper layer, for example, it progressed to the upper layer, The same finishing process may also be performed when modeling a shaped article having an overhang-shaped side surface with an increased width, or a shaped article having both a tapered shape and an overhang-shaped side surface.

  Moreover, in this embodiment, although described about the case where it finishes only to the outer peripheral surface of a sintered layer, for example, when modeling the modeling thing which has internal space, it is in said internal space to a predetermined sintered layer. Corresponding holes are formed. In this case, in addition to the outer peripheral surface of the sintered layer, the same finishing process may be performed on the inner wall of the hole.

  Moreover, in this embodiment, it described about the case where a side surface finishing process is performed whenever it forms a sintered layer, but, for example, if it is in the range in which the shape accuracy of the obtained molded article is maintained, a plurality of The same finishing process may be performed for each sintered layer. In this case, the irradiation position of the second laser is set to, for example, the contour position of the irradiation region of the first laser L1 when forming the sintered layer located at the center in the thickness direction of the plurality of sintered layers. . The laser intensity of the second laser L2 is set to such an extent that processing can be performed up to a depth of the thickness of the plurality of sintered layers to be finished.

DESCRIPTION OF SYMBOLS 1 Layered modeling apparatus 2A Modeling table 3 Recoater head 3A Powder layer formation part 3B Material powder suction part 5 Laser irradiation apparatus 6 Numerical control apparatus 20 Laser control apparatus 50 Modeling object 51 Powder layer 52 Sintered layer 52a Surplus sintering part L1 1st 1 laser L2 2nd laser R irradiation area

Claims (3)

A modeling table,
A recoater head that reciprocates in the horizontal uniaxial direction on the modeling table to supply a metal material powder and flatten to form a powder layer;
A first laser oscillation unit including a first laser light source that oscillates a first laser, and a second laser oscillation unit including a second laser light source that oscillates a second laser; The laser irradiation region set for each powder layer is irradiated with the first laser based on the solid data of the three-dimensional shaped object to form the sintered layers, and the sintered layers are formed. A laser irradiation unit that irradiates the sintered layer with the second laser along the contour of the laser irradiation region irradiated with the first laser and finishes the side surfaces of all the sintered layers; ,
With
The layered manufacturing apparatus, wherein the second laser irradiated from the laser irradiation unit is a femtosecond laser.   The additive manufacturing apparatus according to claim 1, wherein the laser irradiation unit is disposed immediately above the modeling table.   The powder suction part which moves on the modeling table before finishing the side surface of the sintered layer and sucks and removes at least the material powder in the vicinity of the side surface of the sintered layer is further provided. The additive manufacturing apparatus according to 1 or 2.

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