JP2021004395A - Laminate forming apparatus - Google Patents

Abstract

To provide a laminate forming apparatus that can control the beam profile more precisely, and is high in the charge ratio of a lamination-molded body obtained and can obtain a lamination-molded body having a high electric conductivity even if using as a raw material powder a material having a characteristic less apt to be heated (melted) by an irradiation of laser light like a copper material.SOLUTION: A laminate forming apparatus comprises formed-object working means 10, laser-light emitting means 11 that emits first laser light L1, beam-profile control means 12 including a spectral unit 13 that is a diffractive optical element to diffract the first laser light into a plurality of second laser light L20, L21 and a light collection unit 14 that collects the second laser light branched at the spectral unit, and laser-light scanning means 15 that scans the plurality of second laser light collected at the light collection unit over a powder layer P and melts the powder layer, and has a stage 17 and a powder supply unit 16 that forms a powder layer by supplying a raw material powder onto the stage.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laminated modeling apparatus. More specifically, a laminated model is formed by repeatedly forming a powder layer by supplying raw material powder and locally melting and solidifying the powder layer by irradiating the powder layer with laser light. The present invention relates to a laminated molding apparatus suitable for obtaining.

As a method for forming a metal or an alloy, in addition to conventional processing methods such as casting, extrusion, cutting, and powder metallurgy, additive manufacturing methods are known. In the additive manufacturing method, raw material powder made of metal or alloy is thinly laminated on a stage on which a work piece is mounted, and a high-energy laser beam is scanned and irradiated on the raw material powder, and the irradiated part is locally irradiated. By melting and solidifying, molding for one layer is performed, the stage is lowered by the thickness of one layer, the raw material powder is laminated again, and molding is repeated layer by layer in the same manner to obtain a desired three-dimensional shape. It is to obtain a laminated model to have.

The additive manufacturing method can obtain a modeled object having a complicated shape that cannot be easily produced by a conventional processing method, and can also obtain a modeled object based on a three-dimensional shape designed on software. Because it is possible, it is possible to respond to the production of products that require tailor-made products. Further, since the powder heated by the laser / electron beam is rapidly cooled and solidified, it is possible to obtain a material having new characteristics.

As a raw material powder used in such additive manufacturing method, for example, Patent Document 1 contains a copper alloy powder containing 0.2% by mass or more and 1.3% by mass or less of aluminum, and the balance is copper and unavoidable impurities. Is described.

Further, as a layered manufacturing device used in such a layered manufacturing method, Patent Document 2 describes a device capable of changing the intensity distribution of laser light in a predetermined surface on the emission surface side of a focusing optical system for laser light. Has been done.

JP-A-2017-115220 JP-A-2018-138695

Copper material has low light absorption in the near-infrared wavelength region and high thermal conductivity, so it has the property of being difficult to heat (melt) by irradiation with laser light, and is therefore difficult to process by additive manufacturing. Is.

In a material having a property of being difficult to heat (melt) by irradiation with a laser beam, such as a copper material, it is possible to melt the material by increasing the energy density given to the material by irradiation with a laser beam. However, due to the high energy density due to the irradiation of the laser beam and the violent evaporation of the material at the processing point where the laser beam is irradiated, a deep hole called a keyhole is formed in the material, and the material at the processing point is scattered. Since it is likely to occur, there is a problem that the porosity of the laminated model is increased and the conductivity is decreased due to the increase.

In this regard, the copper alloy powder described in Patent Document 1 reduces the voids contained in the laminated model by adding aluminum to copper to increase the filling rate, thereby increasing the mechanical strength of the laminated model. Although it increases the conductivity, the conductivity of the laminated model tends to be low. Therefore, even when a material having a property of being difficult to heat (melt) by irradiation with a laser beam such as a copper material is used, the obtained laminated model has a high filling rate and high conductivity. It has been required to develop a method of laminated modeling that can obtain the above.

Further, the laminated modeling apparatus described in Patent Document 2 changes the intensity distribution of laser light by using a plurality of mirrors arranged in a matrix, but the beam profile is limited by the size and number of mirrors. Therefore, there has been a demand for a laminated molding apparatus capable of controlling the beam profile more finely.

An object of the present invention is a case where a material having a property of being able to control a beam profile more finely and having a property of being hard to be heated (melted) by irradiation with a laser beam such as a copper material is used as a raw material powder. Another object of the present invention is to provide a laminated modeling apparatus capable of obtaining a laminated model having a high filling rate and a high conductivity.

The present inventors use a diffractive optical element as a spectroscopic unit that branches the first laser light emitted from the laser light emitting means into a plurality of second laser lights that irradiate the powder layer, thereby branching at the diffractive optical element. It has been found that the beam profiles of the plurality of second laser beams thus obtained can be controlled more finely, and the filling rate and conductivity of the obtained laminated model can be increased. The present invention has been completed based on the above.

That is, the gist structure of the present invention is as follows.
(1) A model processing means for forming a laminated model by repeatedly supplying raw material powder for forming a powder layer and melting and solidifying the powder layer, a laser light emitting means for emitting a first laser beam, and the first. A beam profile control means including a spectroscopic unit that is a diffraction optical element that branches one laser beam into a plurality of second laser beams, and a condensing unit that condenses the plurality of second laser beams branched by the spectroscopic unit. The plurality of second laser beams focused by the condensing unit are scanned on the powder layer formed by the raw material powder supplied to the modeled object processing means based on the three-dimensional shape data, and the powder is obtained. A powder supply unit including a laser light scanning means for melting the layer, in which the shaped object processing means supports the raw material powder from below, and supplies the raw material powder onto the stage to form the powder layer. And, a laminated molding device.
(2) When the beam profile control means considers a three-dimensional Cartesian coordinate system having three coordinate axes of x-axis, y-axis and z-axis with the optical axis of the first laser beam as the x-axis, the x-axis, The laminated molding apparatus according to (1) above, further comprising a rotation driving unit having a structure for rotating the spectroscopic unit about at least one of the y-axis and the z-axis.
(3) The laminated modeling apparatus according to (2) above, wherein the rotation drive unit has a structure for rotating the spectroscopic unit about the x-axis.
(4) The laminated modeling apparatus according to (2) above, wherein the rotation drive unit has a structure for rotating the spectroscopic unit about the y-axis.
(5) The laminated modeling apparatus according to (2) above, wherein the rotation drive unit has a structure for rotating the spectroscopic unit around the z-axis.
(6) The laminated modeling apparatus according to any one of (1) to (5) above, wherein the beam profile control means further includes a distance adjusting unit for adjusting the distance between the spectroscopic unit and the condensing unit.
(7) The plurality of second laser beams irradiated to the powder layer are composed of a main beam and a sub beam, the main beam melts the powder layer, and the sub beam melts the powder layer. The laminated molding apparatus according to any one of (1) to (6) above, which heats at 373 K or more and below the melting point of the raw material powder.
(8) The laser light scanning means has a galvano mirror, and the galvano mirror makes the main beam and the sub beam on the powder layer in a positional relationship in which the sub beam is on the front side of the main beam. The laminated molding apparatus according to (7) above.
(9) in a position to be irradiated to the raw material powder, the main beam power density _{I 1} of the ratio power density _{I 2} of sub-beams _(I 1 / _{I 2)} is 1.2 to 9.0 The laminated modeling apparatus according to (7) or (8) above, which is in the range of.

According to the present invention, it is possible to control the beam profile more finely, and even when a material having a property of being difficult to heat (melt) by irradiation with a laser beam such as a copper material is used, it can be obtained. It is possible to provide a laminated molding apparatus capable of obtaining a laminated molded product having a high filling rate and a high conductivity.

It is a front view which shows an example of the structure of the laminated modeling apparatus which concerns on embodiment of this invention. It is a schematic diagram which shows an example of the spectroscopic part (diffraction optical element) used in embodiment of this invention. It is a figure which shows an example of the shape of the main beam and the sub-beam in the embodiment of this invention. In order to explain the direction in which the spectroscopic unit is rotated by the rotation driving unit of the beam profile control means in the embodiment of the present invention, only the spectroscopic unit is extracted and shown.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments, and various modifications can be made without changing the gist of the present invention.

FIG. 1 is a front view showing an example of the configuration of the laminated modeling apparatus according to the present embodiment. The laminated molding apparatus 1 of the present embodiment includes a shaped object processing means 10 for forming a laminated shaped object M by repeatedly supplying a raw material powder forming the powder layer P and melting and solidifying the powder layer P, and a first laser beam L. _The laser light emitting means 11 that emits ₁ and the spectroscopic unit 13 that is a diffraction optical element that branches the first laser beam L ₁ into a plurality of second laser beams L ₂₀ and L ₂₁ , and a plurality of branches that are branched by the spectroscopic unit 13. a beam profile control means 12 which includes a condensing unit 14 for condensing the second laser beam _{L 20, L 21,} a plurality of second laser beam _{L 20, L 21} condensed by the condenser section 14, the three-dimensional shape A laser light scanning means 15 for melting the powder layer P by scanning on the powder layer P formed by the raw material powder supplied to the model processing means 10 based on the data is provided, and the model processing means 10 is a raw material. It has a stage 17 that supports the powder from below, and a powder supply unit 16 that supplies the raw material powder onto the stage 17 to form the powder layer P.

In laminate molding apparatus 1 according to the present embodiment, the first laser beam L ₁ emitted from the laser beam emitting unit 11, a plurality of second laser beam irradiated to the powder layer P L _20, spectroscopic unit that branches to L ₂₁ By using the diffractive optical element as 13, a plurality of second laser beams branched into at least 0th order light (second laser light L ₂₀ ) and primary light (second laser light L ₂₁ ) can be obtained by the diffractive optical element. At the same time, the beam profiles of these second laser beams L ₂₀ and L ₂₁ can be finely controlled according to a desired form. As a result, keyholes due to intense evaporation of the material and sputtering phenomenon due to scattering of the molten metal at the processing point are less likely to occur at the processing point irradiated with the laser beam, so that the obtained laminated model M is filled. The rate and conductivity can be increased.

[Laser light emitting means]
The laser light emitting means 11 emits the first laser light L ₁ , and is configured to be capable of oscillating a multimode laser light having an output of, for example, several kW. The laser light emitting means 11 may be configured to include, for example, a plurality of semiconductor laser elements inside, and to oscillate a multimode laser light having an output of several kW as the total output of the plurality of semiconductor laser elements. Good. Further, as the laser light emitting means 11, various lasers such as a fiber laser, a YAG laser, and a disk laser may be used.

The wavelength of the laser light emitted from the laser light emitting means 11 is set according to the type of the raw material powder, and can be, for example, in the range of 780 nm to 1600 nm, preferably in the range of 1000 nm to 1200 nm. On the other hand, especially when the raw material powder is copper powder (copper particles) or copper alloy powder (copper alloy particles), the wavelength of the laser light may be in the range of 300 nm to 600 nm, whereby the laser light produced by the raw material powder may be used. Since the reflectance is low, the energy efficiency in laminated molding can be improved.

[Beam profile control means]
The beam profile control means 12 controls the beam profiles of the plurality of second laser beams L ₂₀ and L ₂₁ branched by the spectroscopic unit 13, and the first laser beam L ₁ is combined with the plurality of second laser beams L _20. includes a spectroscopic unit 13 is a diffractive optical element that splits the _{L 21,} a condenser 14 for condensing a plurality of second laser beam _{L 20, L 21} produced by the spectroscopic portion 13.

(Spectroscope)
The spectroscopic unit 13 is composed of a diffractive optical element, and branches the first laser light L ₁ emitted from the laser light emitting means 11 into a plurality of second laser lights L ₂₀ and L ₂₁ . The light obtained from the diffractive optical element 13 is at least the 0th-order light (second laser light L ₂₀ ) that travels straight without being diffracted by the diffractive optical element and the primary light (second laser light L) that is diffracted by the diffractive optical element. _Although it branches into ₂₁ ), light after the secondary light (not shown, for example, secondary light or tertiary light) may exist. Here, an example in which the powder layer P is irradiated with the 0th-order light (second laser light L ₂₀ ) and the first-order light (second laser light L ₂₁ ) branched from the first laser light L ₁ by the spectroscopic unit 13. Will be explained.

The diffractive optical element used as the spectroscopic unit 13 in the present embodiment may be composed of one diffractive optical element, or may be configured by combining a plurality of diffractive optical elements. For example, as shown in FIG. 2, a combination of a plurality of diffractive optical elements 131 having different lattice periods may be used, and one diffractive optical element 132 equivalent to a combination of the plurality of diffractive optical elements 131. May be good.

The laser light (second laser light L ₂₀ , L ₂₁ ) branched by the spectroscopic unit (diffractive optical element) 13 has an arbitrary beam profile according to the optical design of the diffractive optical element constituting the spectroscopic unit 13. Laser light can be obtained.

For example, the main beam 20 (for example, 0th-order light) having a high power density is used at the irradiation positions of the second laser beams L ₂₀ and L ₂₁ of the powder layer P made of the raw material powder by using the diffractive optical element constituting the spectroscopic unit 13. A plurality of second laser beams L ₂₀ and L ₂₁ are provided so as to have a second laser beam L ₂₀ ) and a secondary beam 21 having a low power density (for example, a second laser beam L ₂₁ which is a primary light). Obtainable.

The second laser beam _{L 20} is a main beam 20, along with those to melt the powder layer P, the second laser beam _{L 21} is a sub-beam 21, the powder layer P of the raw material powder than 373K melting point Tm [K ], It is preferable to heat the raw material powder to a temperature range of less than 0.5 times (0.5 Tm [K]) or more and 0.8 times (0.8 Tm [K]) or less of the melting point Tm [K] of the raw material powder. It is more preferable to heat at a temperature in the range of. As a result, the powder layer P is weakly sintered by the sub-beam 21, and the scattering of the raw material powder at the irradiated portion can be reduced. Further, the generation of keyholes due to the irradiation of the main beam 20 and the sputtering phenomenon at the irradiated portion are less likely to occur, and the raw material powder is not melted by the subbeam 21, so that the occurrence of keyholes by the subbeam 21 is also reduced. be able to. Therefore, the filling rate and the conductivity of the obtained laminated model M can be increased. In particular, sintering of the raw material powder tends to occur at 0.7 times (0.7 Tm [K]) or more of the melting point Tm [K], so the sub-beam 21 should be irradiated so as to be in a temperature range in the vicinity thereof. Is preferable.

The heating temperature by the second laser beam L ₂₁ is a sub-beam 21 is within a range that does not exceed the melting point Tm of the raw material powder, it is preferably close to the heating temperature by the main beam second laser beam L ₂₀ is 20. As a result, the temperature difference between the portion irradiated with the main beam 20 and the raw material powder irradiated with the sub-beam 21 around the main beam 20 becomes small, so that it becomes difficult for heat to escape from the portion irradiated with the main beam 20 to the surrounding raw material powder. Therefore, the flow of the melt in the portion irradiated with the main beam 20 can be promoted, and the spatter due to the bumping of the raw material powder can be reduced, so that the void ratio of the obtained laminated model M can be reduced.

Further, the laser light (second laser light L ₂₀ , L ₂₁ ) branched by the spectroscopic unit 13 is a main beam in at least one of the directions of scanning the second laser light L ₂₀ and L ₂₁ in the irradiated portion. The shapes and positional relationships of the main beam 20 and the sub beam 21 are adjusted so that the second laser light L ₂₁ which is the sub beam 21 is irradiated in front of the position where the second laser light L _{20 which} is ₂₀ is irradiated. It is preferable to do so. As a result, the sub-beam 21 is irradiated to the powder layer P before the main beam 20 to preheat the irradiated portion, so that the irradiated portion of the sub-beam 21 in the powder layer P is weakly sintered. Therefore, it is possible to reduce the scattering of the raw material powder in the irradiated portion. Further, since the generation of keyholes due to the irradiation of the main beam 20 and the sputtering phenomenon at the irradiated portion are less likely to occur, the filling rate and the conductivity of the obtained laminated model M can be increased. In addition, since it is possible to preheat only the periphery of the laser-irradiated portion, the recyclability of the raw material powder can be improved, and the short heating time affects the oxidation of the raw material powder. It can also be reduced.

Further, the irradiation position of the second laser beam _{L 20, L 21} of the powder layer P, the power density _{I 1} of the main beam 20, the ratio power density _{I 2} sub-beam 21 _(I 1 / _{I 2)} is 1 It is preferably in the range of .2 or more and 9.0 or less. As a result, at the processing point where the second laser beams L ₂₀ and L ₂₁ are applied to the powder layer P, the generation of keyholes in the material due to the vigorous evaporation of the material and the spatter phenomenon at the processing point are less likely to occur. Therefore, the filling rate and the conductivity of the obtained laminated model M can be increased.

In the present specification, the power densities of the main beam 20 and the sub beam 21 are assumed to be the power densities in the region including the peak and having an intensity of 1 / e ² or more of the peak intensity. Further, the beam diameter of the main beam or the sub beam includes a peak and is the diameter of a region having an intensity of 1 / e ² or more of the peak intensity. Here, in the case of a non-circular beam, the length of a region having an intensity of 1 / e ² or more of the peak intensity in a direction perpendicular to both the traveling direction and the moving direction of the beam is defined as the beam diameter.

The arrangement shape of the main beam and the sub beam (when irradiated on the powder layer) is not particularly limited, but for example, in FIG. 3A, the interval d is close to some extent from the circular spot-shaped main beam 20. When the sub-beams 21 dispersed in an elliptical shape (or linear shape) are arranged (arrangement pattern A), in FIG. 3 (b), the main beam 20a is located at a certain distance d from the circular spot-shaped main beam 20a. When the sub-beams 21a dispersed in a curved line are arranged so as to surround a part of the outer periphery of the (arrangement pattern B), in FIG. 3 (c), they are brought close to the circular spot-shaped main beam 20b to form a ring shape. When the dispersed sub-beams 21b are arranged (arrangement pattern C), and in FIG. 3 (d), the sub-beams 21c dispersed in a ring shape are arranged in a ring shape at a certain close interval d from the circular spot-shaped main beam 20c. An example of the case of arrangement (arrangement pattern D) is shown. In the aspects of FIGS. 3A and 3B, when the second laser beams L ₂₀ and L ₂₁ are irradiated, the right side (the side with the secondary beam) is the scanning direction of the second laser beams L ₂₀ and L ₂₁ . It is preferable to arrange the main beam and the sub beam so as to be forward with respect to the above, and at this time, the left side (the side with the main beam) of FIGS. 3 (a) and 3 (b) is the second laser beam L ₂₀ , L. It is preferable that the scanning direction of ₂₁ is rearward.

Here, the sub-beam 21 may have a continuous linear shape, or the dots may be continuous like a dotted line. When the sub-beam 21 is a dotted line, the center spacing of the dots can be, for example, in the range of 1 μm to 500 μm. At this time, the shortest distance (interval) d between the main beam 20 and the sub beam 21 can be, for example, in the range of 1000 μm or less, and preferably in the range of 1 μm to 1000 μm. On the other hand, in the embodiment in which the annular sub-beam 21 is provided, as shown in FIG. 3C, the shortest distance d between the main beam 20b and the sub-beam 21b may be 0, and in this case, the main beam 20b and The sub-beam 21b is continuous. By setting the shortest distance d between the main beam 20 and the sub beam 21 within this range, it is possible to facilitate irradiation of the main beam 20 before the temperature of the irradiation region by the sub beam 21 drops.

In the present specification, the shortest distance d between the main beam 20 and the sub-beam 21 is 1 / e ² or more of the peak intensity of the main beam 20 and the outer edge of the region and 1 / of the peak intensity of the sub-beam 21. e The distance from the outer edge of the region where the strength is ² or more.

(Condensing part)
The condensing unit 14 condenses a plurality of second laser beams L ₂₀ and L ₂₁ branched by the spectroscopic unit 13, and can be configured by a condensing lens or the like. At this time, the branched second laser beams L ₂₀ and L ₂₁ are irradiated to different irradiation positions on the surface of the powder layer P. Here, from the viewpoint of easily controlling the beam profiles of the plurality of second laser beams L ₂₀ and L ₂₁ irradiated on the powder layer P, the condensing unit 14 transmits the plurality of second laser beams L ₂₀ and L ₂₁ . The branched beam profile state can be maintained and the light can be focused on the model processing means 15. FIG. 1 shows a case where a single lens is used as the condensing unit 14 for the sake of simplicity, but the present invention is not limited to this, and may be configured by a combination of a plurality of optical elements, for example. It may include an optical element having an action other than focusing, such as a collimating lens, or a combination thereof.

(Rotation drive unit)
The beam profile control means 12, as shown in FIG. 4, the optical axis of the first laser beam L ₁ as the x-axis, x-axis, three-dimensional orthogonal coordinate system having three axes of y-axis and z-axis When considered, it is preferable to include a rotation drive unit (not shown) having a structure for rotating the diffractive optical element of the spectroscopic unit 13 around at least one of the x-axis, y-axis, and z-axis.

More specifically, the rotation driving unit preferably has a structure for rotating the diffractive optical element of the spectroscopic unit 13 around the x-axis which is the optical axis of the first laser beam L _1. At this time, the diffractive optical element Can rotate in the rotation direction α of FIG. As a result, even if the direction in which the second laser light L ₂₀ and L ₂₁ are scanned is changed by the laser light scanning means 15 described later, the second laser light L 20 which is the main beam ₂₀ and the secondary laser light L ₂₀ are subordinate to each other according to the scanning direction. by changing the positional relationship between the second laser beam L ₂₁ is a beam 21, since it is possible for the scan direction to maintain the same beam profile, regardless the main beam 20 in the scan direction and the symmetry of the sub-beams 21, It is possible to obtain the effect of increasing the filling rate and the conductivity of the laminated model M by preheating using the sub-beam 21.

Further, it is also preferable that the rotation drive unit has a structure in which the diffraction optical element of the spectroscopic unit 13 is rotated around the y-axis or the z-axis, which is an axis perpendicular to the optical axis of the first laser beam. The optical element can rotate in the rotation direction β and the rotation direction γ in FIG. As a result, the beam shapes of the second laser beams L ₂₀ and L ₂₁ irradiated to the powder layer P can be adjusted, so that the material of the raw material powder and the filling rate required for the obtained laminated model M can be obtained. Therefore, since the beam profile of the powder layer P in the thickness direction can be adjusted, it is possible to easily obtain the laminated model M having desired characteristics. In addition, it is possible to a second laser beam L _20, L ₂₁ when such smoke is generated when irradiating a powder layer P, and reduce the scattering of the second laser beam L _20, L ₂₁ Smoke.

The rotation drive unit may have a structure for rotating the diffractive optical element of the spectroscopic unit 13 around two axes, the y-axis and the z-axis, which are axes perpendicular to the optical axis of the first laser beam. , The x-axis, the y-axis, and the z-axis may be centered on the structure of rotating the diffractive optical element of the spectroscopic unit 13.

On the other hand, it is also preferable that the beam profile control means 12 includes a distance adjusting unit (not shown) that adjusts the distance f between the spectroscopic unit 13 and the condensing unit 14. As a result, the beam profile in the thickness direction of the powder layer P can be adjusted according to the material of the raw material powder and the filling rate required for the obtained laminated model M, and thus the desired characteristics. It is possible to easily obtain the laminated model M having the above.

Here, when the raw material powder is copper powder (copper particles) or copper alloy powder (copper alloy particles), the offset value from the focal distance of the condensing unit 14 is set to 0.1 mm or more by using the distance adjusting unit. It is preferable to adjust the thickness to 1 mm. In particular, when the filling rate required for the obtained laminated model M is 98% or more, it is preferable to adjust the offset value to 0.2 mm to 0.4 mm by using a distance adjusting unit. ..

[Laser light scanning means]
The laser light scanning means 15 irradiates the powder layer P formed by the raw material powder supplied to the model processing means 10 with the plurality of second laser beams L ₂₀ and L ₂₁ focused by the light condensing unit 14. It is configured to scan on the surface of the powder layer P, and scans the second laser beams L ₂₀ and L ₂₁ irradiated on the powder layer P based on the three-dimensional shape data. By allowing the powder layer P to melt.

The laser light scanning means 15 has at least a mirror, and it is preferable to have a galvano mirror among them. Within the range in which the second laser beams L ₂₀ and L ₂₁ are irradiated on the powder layer P, the angle of incidence θ of the laser light on the mirror is changed by using the laser beam scanning means 15 on the powder layer P. , The position where the second laser beam L ₂₀ which is the main beam and the second laser beam L ₂₁ which is the secondary beam are focused can be scanned. As a result, the scanning of the condensing position based on the three-dimensional shape data can be smoothly performed, so that the laminated model M can be efficiently produced.

In FIG. 1, the laser light scanning means 15 is provided on the downstream side of the spectroscopic unit 13 (the side of the model processing means 10), but the present invention is not limited to this mode. For example, it may be provided on the upstream side (the side of the laser light emitting means 11) of the spectroscopic unit 13, or may be provided on both the upstream side and the downstream side. In particular, when a plurality of laser light scanning means 15 are provided, the scanning range of the irradiation positions of the second laser beams L ₂₀ and L ₂₁ can be widened, and it can also contribute to the miniaturization of the laminated modeling apparatus 1.

[Model processing means]
Molded object processing unit 10 in the present embodiment, by repeating the supply of the raw material powder to form a powder layer P, and the melting of the powder layer P by irradiation of the second laser beam L ₂₀ described above, and a solidification by cooling, It forms a laminated model M. More specifically, it has at least a stage 17 that supports the raw material powder from below, and a powder supply unit 16 that supplies the raw material powder onto the stage 17 to form the powder layer P.

Of these, the stage 17 serves as a base material on which the laminated model M is formed, and supports the powder layer P from below together with the side wall 18 that supports the powder layer P from the side. It supports the laminated model M to be formed from below. Further, the stage 17 also adjusts the height position h of the raw material powder (the position of the surface of the laminated model M in the laminating direction) by moving up and down. Here, if the surface on the upper side of the stage 17 is flat, the irradiation surface of the powder layer P can be easily flattened. After modeling the laminated model M, the laminated model M can be obtained by separating the laminated model M from the stage 17. By providing such a stage 17, the distance between the above-mentioned beam profile control means 12 and the surface of the powder layer P can be kept constant, so that the modeling by laminating the layered processed regions can be made more stable. It can be carried out.

The material of the stage 17 is preferably the same material as the raw material powder in order to suppress an adverse effect on the physical properties of the obtained laminated model M.

The powder supply unit 16 includes means (not shown) for supplying the raw material powder onto the stage 17. Further, the powder supply unit 16 preferably includes means for flattening the surface of the raw material powder in the height direction (the direction of the y-axis in FIG. 1). By supplying the raw material powder using the powder supply unit 16, the powder layer P is laminated, and the surfaces thereof are irradiated with the second laser beams L ₂₀ and L ₂₁ to perform the laminated modeling. Here, for example, a recorder can be used as the powder supply unit 16.

As the material of the raw material powder that is the basis of the laminated model M, a material that can absorb the second laser beams L ₂₀ and L ₂₁ can be widely used. In particular, in the laminated modeling apparatus 1 of the present embodiment, even when a copper material such as copper powder (copper particles) or copper alloy powder (copper alloy particles) is used as the raw material powder, the laminated model M obtained can be obtained. It is possible to obtain a laminated model M having a high filling rate and a high conductivity. Here, as the copper alloy, for example, chromium (Cr) is 0.01% by mass to 1.0% by mass, tin (Sn) is 0.01 to 1.0% by mass, and nickel (Ni) is 0.01% by mass. % To 1.0% by mass, the total content of the impurity elements oxygen (O), phosphorus (P), iron (Fe), and silver (Ag) is 0.5% by mass or less, and the balance is copper. A copper alloy made of (Cu) can be mentioned.

[Laminate modeling method using a laminate modeling device]
In the laminated modeling method using the laminated modeling device 1 of the present embodiment, for example, the raw material powder is supplied from the powder supply unit 16 to form the powder layer P, and then the first laser emitted from the laser light emitting means 11 is emitted. The light L ₁ is separated into a plurality of second laser beams L ₂₀ and L ₂₁ by using the spectroscopic unit 13 which is a diffraction optical element in the beam profile control means 12, and these are condensed by the condensing unit 14 and the laser. The powder layer P is preheated and melted by irradiating the powder layer P with the second laser beams L ₂₀ and L ₂₁ while scanning the condensing position using the optical scanning means 15, so that the powder layer P has a desired shape. A one-layer processing region can be obtained. Then, when the processing region for one layer is obtained, the raw material powder is supplied from the powder supply unit 16 by the thickness of one layer, and the stage 17 is lowered by the thickness of one layer in the same manner. By repeating the above, it is possible to obtain a laminated model M having a desired three-dimensional shape.

Next, examples of the present invention will be described, but the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.

(1) Preparation of Laminated Model Using Laminated Modeling Equipment As raw materials, chromium (Cr) is 0.01% by mass to 1.0% by mass, tin (Sn) is 0.01 to 1.0% by mass, and nickel ( Ni) is contained in an amount of 0.01% by mass to 1.0% by mass, and the total content of the impurity elements oxygen (O), phosphorus (P), iron (Fe), and silver (Ag) is 0.5% by mass. A copper alloy (melting point: about 1354K) having a balance of copper (Cu) was used as described below, and the weighed components were put into a melting furnace and melted to prepare a copper alloy (ingot). The produced copper alloy (ingot) is mechanically crushed to dissolve the crushed crushed copper alloy, and then 85% by volume of nitrogen gas (N ₂ ) and 15% by volume of hydrogen gas (H) are used using a gas atomizing device. The mixture gas with ₂ ) was sprayed to obtain copper alloy particles (particle size: 20 to 50 μm) as a raw material powder. The obtained raw material powder was supplied by using a recorder so that a powder layer P having a thickness of 50 μm was formed on the stage of a laminated modeling apparatus having a stage as a model processing means.

A fiber laser (wavelength: 1070 nm) having the output shown in Table 1 is used as the first laser light L ₁ , and in Examples 1 to 11 of the present invention, an arrangement pattern A shown in FIG. 3A is used by using a diffractive optical element. The light was dispersed into a plurality of second laser beams L ₂₀ and L ₂₁ . At this time, the shortest distance (interval) d between the second laser beam L ₂₀ which is the main beam and the second laser beam L ₂₁ which is the secondary beam was 100 μm. Further, in at least one of the directions in which the second laser beams L ₂₀ and L ₂₁ are scanned, the second laser which is the secondary beam is in front of the position where the second laser beam L ₂₀ which is the main beam is irradiated. A diffractive optical element is provided so that the light L ₂₁ is irradiated, and the angle of incidence θ on the galvanometer mirror that reflects the second laser beams L ₂₀ and L ₂₁ is changed, whereby the powder layer P is irradiated with the second laser beam P. By scanning the condensing positions of the laser beams L ₂₀ and L ₂₁ at a scanning speed of 200 mm / s, the raw material powder was preheated and melt-solidified to obtain a single molding layer.

On the other hand, Comparative Examples 1 to 3, without performing spectroscopy using diffractive optical elements, the incident angle of the galvanometer mirror by focusing the laser beam is irradiated to the powder layer P, and reflecting the first laser beam L ₁ varying the theta, thereby the focusing position of the first laser light L ₁ irradiated to the powder layer P performs vitrification of the raw material powder by scanning at a scan rate of 200 mm / s, a shaped layer of one layer Obtained.

In the example of the present invention, the main beam heats the powder layer above the melting point of the raw material powder which is a copper alloy. At the irradiation position of the second laser beam _{L 20, L 21,} shown main beam power density _{I 1} of the ratio power density _{I 2} of sub-beams _(I 1 / _{I 2)} in Table 1. Moreover, when the temperature of the raw material powder heated by the secondary beam was measured by using thermography, it was as shown in Table 1.

Further, the present invention examples 2-11, a rotating mechanism for rotating the diffractive optical element a first laser beam L ₁ of the optical axis (x-axis) as the center axis is provided, by rotating the diffractive optical element about the x-axis Therefore, even if the scanning direction is changed, the beam profile is maintained so that the second laser beam L ₂₁ which is the secondary beam is irradiated in front of the position where the second laser beam L ₂₀ which is the main beam is irradiated. .. On the other hand, in Examples 1 of the present invention and Comparative Examples 1 to 3, the modeling layer was produced in a state where the diffractive optical elements were oriented in the same direction without providing a rotation mechanism for rotating the diffractive optical elements. Of these, Example 1 of the present invention is an example in which the diffractive optical elements are oriented in the same direction, and the second laser beams L ₂₀ and L ₂₁ are scanned so that the condensing positions reciprocate. This is an example in which the second laser beam L ₂₁ is irradiated in front of the irradiation position of the second laser beam L ₂₀ only in the direction.

Further, the present invention example 3,5～11 is provided with a rotating mechanism for rotating the diffractive optical element as the center axis y-axis or z-axis, 5 ° tilted diffractive optical element from the first laser light L ₁ of the optical axis The modeling layer was produced in a state where the incident angle was 5 °. On the other hand, in Examples 1, 2 and 4 of the present invention and Comparative Examples 1 to 3, the modeling layer was produced without tilting the diffractive optical element.

Further, in Examples 4 to 11 of the present invention, the offset value for the distance between the spectroscopic unit 13 and the condensing unit 14 was adjusted to be 0.3 mm shorter than the focal length of the condensing unit 14. On the other hand, in Examples 1 to 3 of the present invention and Comparative Examples 1 to 3, the offset value of the distance between the spectroscopic unit 13 and the condensing unit 14 from the focal length of the condensing unit 14 was set to 0 mm.

After obtaining the modeling layer, in the same manner, one layer of raw material powder is supplied onto the stage from the powder supply unit, the stage is lowered by the thickness of one layer, and the laser is similarly irradiated to the modeling layer. By repeating the operation of obtaining the above, a block-shaped laminated model having a length of 10 mm, a width of 10 mm, and a thickness of 10 mm was obtained.

(2) Evaluation of packing rate of laminated model The apparent density of the obtained laminated model was measured by the Archimedes method, and the filling rate (%) was calculated using the following formula (A) based on the difference from the true density. Was calculated. Here, as the electronic balance, QUINTIX5100-1SJP manufactured by Sartorius was used.
Filling rate (%) = 100- (true density-apparent density) ÷ true density x 100 ... (A)
The results were evaluated according to the following criteria. The results are shown in Table 1.
⊚: Filling rate is 98% or more 〇: Filling rate is 95% or more and less than 98% ×: Filling rate is less than 95%

(3) Evaluation of Conductivity of Laminated Model The obtained laminated model was used in a constant temperature bath controlled at 20 ° C (± 1 ° C) using the four-terminal method according to JIS H0505-1975. Two test pieces were measured, and the average value (% IACS) was calculated. In this evaluation, the measurement was performed with the distance between terminals in the four-terminal method as 100 mm. The results were evaluated according to the following criteria. The results are shown in Table 1.
〇: Conductivity is 70% IACS or more ×: Conductivity is less than 70% IACS

As is clear from Table 1, a laminated model (Examples 1 to 11 of the present invention) produced by using a layered modeling device that disperses the second laser beams L ₂₀ and L ₂₁ using a diffractive optical element. In), both the evaluation result regarding the filling rate of the laminated model and the evaluation result regarding the conductivity of the laminated model were equal to or higher than the “○” evaluation, and thus it was found that both the filling rate and the conductivity were good. ..

On the other hand, in the laminated shaped products of Comparative Examples 1 to 3 in which the powder layer P is irradiated with a single laser beam without using a diffractive optical element, the evaluation result regarding the filling rate of the laminated molded product and the laminated molding The evaluation results regarding the conductivity of the objects were all "x", which were inferior in both the filling rate and the conductivity.

Based on the above results, a laminated model (Examples 1 to 11 of the present invention) produced by using a laminated modeling device that disperses the second laser beams L ₂₀ and L ₂₁ using a spectroscopic unit that is a diffractive optical element. ), It was found that both the filling rate and the conductivity were better than those of the laminated shaped products of Comparative Examples 1 to 3.

1 Laminated modeling device 10 Modeled object processing means 11 Laser light emitting means 12 Beam profile control means 13 Spectroscopy (or diffractive optical element)
14 Condensing unit 15 Laser light scanning means 16 Powder supply unit 17 Stage 18 Side wall 20, 20a, 20b, 20c Main beam 21, 21a, 21b, 21c Secondary beam 131, 132 Diffractive optical element L ₁ First laser light L _20th 2 Laser light L ₂₁ Second laser light M Laminated model P Powder layer θ Incident angle h Height position of raw material powder

Claims (9)

A model processing means for forming a laminated model by repeatedly supplying the raw material powder for forming the powder layer and melting and solidifying the powder layer.
Laser light emitting means for emitting the first laser light and
A beam profile control means including a spectroscopic unit that is a diffraction optical element that branches the first laser beam into a plurality of second laser beams, and a condensing unit that collects the plurality of second laser beams branched by the spectroscopic unit. When,
The plurality of second laser beams focused by the condensing unit are scanned on the powder layer formed by the raw material powder supplied to the modeled object processing means based on the three-dimensional shape data, and the powder is obtained. Equipped with a laser beam scanning means for melting the layer,
The modeled object processing means
A stage that supports the raw material powder from below,
A powder supply unit that supplies the raw material powder onto the stage to form the powder layer,
Laminated modeling equipment. When the beam profile control means considers a three-dimensional Cartesian coordinate system having three coordinate axes of x-axis, y-axis and z-axis with the optical axis of the first laser beam as the x-axis, the x-axis and the y-axis The laminated modeling apparatus according to claim 1, further comprising a rotation driving unit having a structure for rotating the spectroscopic unit about at least one of the z-axis. The laminated modeling apparatus according to claim 2, wherein the rotation driving unit has a structure for rotating the spectroscopic unit about the x-axis. The laminated modeling apparatus according to claim 2, wherein the rotation driving unit has a structure for rotating the spectroscopic unit about the y-axis. The laminated modeling apparatus according to claim 2, wherein the rotation driving unit has a structure for rotating the spectroscopic unit about the z-axis. The laminated modeling device according to any one of claims 1 to 5, wherein the beam profile control means further includes a distance adjusting unit for adjusting the distance between the spectroscopic unit and the condensing unit. The plurality of second laser beams irradiated to the powder layer are composed of a main beam and a sub beam.
The main beam melts the powder layer and
The laminated modeling apparatus according to any one of claims 1 to 6, wherein the sub-beam heats the powder layer at 373 K or more and below the melting point of the raw material powder. The laser light scanning means has a galvanometer mirror.
The laminated modeling apparatus according to claim 7, wherein the galvanometer mirror scans the main beam and the sub beam on the powder layer in a positional relationship in which the sub beam is on the front side of the main beam. In the position to be irradiated to the raw material powder, the power density _{I 1} of the main beam, the ratio power density _{I 2} of sub-beams _(I 1 / _{I 2)} is in the range of 1.2 to 9.0 The laminated modeling apparatus according to claim 7 or 8.

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