U.S. patent application number 15/505448 was filed with the patent office on 2017-09-21 for additive manufacturing apparatus and additive manufacturing method.
This patent application is currently assigned to Kabushiki Kaisha Toshiba. The applicant listed for this patent is Kabushiki Kaisha Toshiba. Invention is credited to Tomoko NISHINO, Naotada OKADA.
Application Number | 20170266727 15/505448 |
Document ID | / |
Family ID | 55532845 |
Filed Date | 2017-09-21 |
United States Patent
Application |
20170266727 |
Kind Code |
A1 |
NISHINO; Tomoko ; et
al. |
September 21, 2017 |
ADDITIVE MANUFACTURING APPARATUS AND ADDITIVE MANUFACTURING
METHOD
Abstract
An additive manufacturing apparatus according to one embodiment
includes a manufacturing unit, an elastic wave generation unit, an
elastic wave detection unit, and an inspection unit. The
manufacturing unit sequentially stacks a layer formed by emitting a
first energy beam to a material and solidifying the material. The
elastic wave generation unit emits a second energy beam to a
manufactured object including the layer and generates an elastic
wave propagating in the manufactured object. The elastic wave
detection unit detects the elastic wave. The inspection unit
inspects the manufactured object on the basis of a detection result
from the elastic wave detection unit.
Inventors: |
NISHINO; Tomoko; (Yokohama,
JP) ; OKADA; Naotada; (Yokohama, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kabushiki Kaisha Toshiba |
Minato-ku, Tokyo |
|
JP |
|
|
Assignee: |
Kabushiki Kaisha Toshiba
Minato-ku, Tokyo
JP
|
Family ID: |
55532845 |
Appl. No.: |
15/505448 |
Filed: |
February 23, 2015 |
PCT Filed: |
February 23, 2015 |
PCT NO: |
PCT/JP2015/055080 |
371 Date: |
February 21, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01N 21/1702 20130101;
B29C 64/386 20170801; B29C 67/00 20130101; B33Y 10/00 20141201;
G01N 2291/267 20130101; B22F 3/1055 20130101; G01B 11/2441
20130101; G01N 2291/2698 20130101; B22F 2003/1057 20130101; B29C
64/188 20170801; G01N 2021/1706 20130101; Y02P 10/295 20151101;
G01N 29/2418 20130101; Y02P 10/25 20151101; G01N 21/1717 20130101;
B33Y 50/02 20141201; B29K 2105/251 20130101; B29C 64/153 20170801;
G01N 29/043 20130101; B33Y 30/00 20141201 |
International
Class: |
B22F 3/105 20060101
B22F003/105; G01B 11/24 20060101 G01B011/24; B33Y 30/00 20060101
B33Y030/00; G01N 21/17 20060101 G01N021/17; B29C 67/00 20060101
B29C067/00; B33Y 10/00 20060101 B33Y010/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 16, 2014 |
JP |
2014-187982 |
Claims
1. An additive manufacturing apparatus comprising: a manufacturing
unit that sequentially stacks a layer formed by emitting a first
energy beam to a material and solidifying the material; an elastic
wave generation unit that emits a second energy beam to a
manufactured object including the layer and generates an elastic
wave propagating in the manufactured object; an elastic wave
detection unit that detects the elastic wave; and an inspection
unit that inspects the manufactured object on the basis of a
detection result from the elastic wave detection unit.
2. The additive manufacturing apparatus according to claim 1,
wherein the elastic wave generation unit is served as a processing
unit that processes a surface of the manufactured object by
emitting the second energy beam.
3. The additive manufacturing apparatus according to claim 2,
further comprising a measurement unit that measures a shape of the
layer, wherein the processing unit processes the surface on the
basis of a measurement result from the measurement unit.
4. The additive manufacturing apparatus according to claim 2,
wherein the elastic wave detection unit detects the elastic wave in
an area of the manufactured object having the surface processed by
the processing unit.
5. The additive manufacturing apparatus according to claim 2,
wherein the second energy beam is a first laser beam, the elastic
wave detection unit is a laser interferometer that emits a second
laser beam to the surface and receives reflected light of the
second laser beam reflected from the surface, and the first laser
beam and the second laser beam do not interfere with each
other.
6. The additive manufacturing apparatus according to claim 5,
further comprising a single lens that focuses the first laser beam
and the second laser beam.
7. The additive manufacturing apparatus according to claim 5,
further comprising: a single laser emitter that emits a third laser
beam; and a dividing unit that divides the third laser beam emitted
from the laser emitter into the first laser beam and the second
laser beam.
8. The additive manufacturing apparatus according to claim 1,
further comprising a removal unit that is capable of partially
removing the manufactured object, wherein when the inspection unit
detects abnormality in the manufactured object, the removal unit
partially removes the manufactured object from the surface of the
manufactured object to the abnormality, and the manufacturing unit
fills the material in an opening of the manufactured object formed
after removal thereof by the removal unit and solidifies the
material.
9. The additive manufacturing apparatus according to claim 8,
wherein the removal unit removes at least part of the manufactured
object protruded from the opening.
10. An additive manufacturing method comprising: emitting a first
energy beam to a material and solidifying the material to form a
layer; emitting a second energy beam to a manufactured object
including the layer, and generating an elastic wave propagating in
the manufactured object; detecting the elastic wave; and inspecting
the manufactured object on the basis of a detection result about
the elastic wave.
11. The additive manufacturing method according to claim 10,
further comprising: processing a surface of the manufactured object
by emitting the second energy beam; and generating the elastic wave
by processing the surface.
12. The additive manufacturing method according to claim 11,
further comprising: measuring a shape of the layer; and processing
the surface on the basis of a result of the measurement.
13. The additive manufacturing method according to claim 11,
wherein the detecting includes detecting the elastic wave in an
area of the manufactured object in which the surface is
processed.
14. The additive manufacturing method according to claim 11,
wherein the second energy beam is a first laser beam, the additive
manufacturing method further comprises emitting the second laser
beam to the surface and receiving reflected light of the second
laser beam reflected from the surface to detect the elastic wave,
and the first laser beam and the second laser beam do not interfere
with each other.
15. The additive manufacturing method according to claim 14,
further comprising: emitting a third laser beam; and dividing the
third laser beam into the first laser beam and the second laser
beam.
16. The additive manufacturing method according to claim 10,
further comprising when abnormality in the manufactured object is
detected, partially removing the manufactured object from the
surface of the manufactured object to the abnormality, and filling
the material in an opening of the manufactured object formed after
removal thereof and solidifying the material.
17. The additive manufacturing method according to claim 16,
wherein the partially removing includes removing at least part of
the manufactured object protruded from the opening.
Description
FIELD
[0001] Embodiments of the present invention relates to an additive
manufacturing apparatus and an additive manufacturing method.
BACKGROUND
[0002] Conventionally, there has been known an additive
manufacturing apparatus to form an additive manufactured object.
The additive manufacturing apparatus forms a layer by melting a
powder material by a laser beam, and forms the additive
manufactured object having a three-dimensional shape by stacking
the layers.
CITATION LIST
Patent Literature
[0003] Patent Literature 1: JP 2006-200030 A
[0004] Patent Literature 2: JP 2012-163406 A
SUMMARY OF THE INVENTION
Problem to be Solved by the Invention
[0005] A manufactured object which is manufactured by such an
additive manufacturing apparatus may contain an abnormal area such
as a bubble generated during manufacture. It is significant to
obtain an additive manufacturing apparatus and an additive
manufacturing method which allow detection of abnormality in such a
manufactured object.
Means for Solving Problem
[0006] An additive manufacturing apparatus according to one
embodiment includes a manufacturing unit, an elastic wave
generation unit, an elastic wave detection unit, and an inspection
unit. The manufacturing unit sequentially stacks a layer formed by
emitting a first energy beam to a material and solidifying the
material. The elastic wave generation unit emits a second energy
beam to a manufactured object including the layer and generates an
elastic wave propagating in the manufactured object. The elastic
wave detection unit detects the elastic wave. The inspection unit
inspects the manufactured object on the basis of a detection result
from the elastic wave detection unit.
BRIEF DESCRIPTION OF DRAWINGS
[0007] FIG. 1 is an exemplary schematic view of an additive
manufacturing apparatus according to a first embodiment.
[0008] FIG. 2 is an exemplary schematic cross-sectional view of
part of a nozzle according to the first embodiment.
[0009] FIG. 3 is an exemplary schematic view of an inspection
device according to the first embodiment.
[0010] FIG. 4 is an exemplary schematic view of irradiation
positions of laser beams according to the first embodiment.
[0011] FIG. 5 is an exemplary flowchart of a procedure to form an
additive manufactured object according to the first embodiment.
[0012] FIG. 6 is an exemplary explanatory view of an abnormality
detection process for an additive manufactured object according to
the first embodiment.
[0013] FIG. 7 is an exemplary explanatory view of repair processing
for an additive manufactured object according to the first
embodiment.
[0014] FIG. 8 is an exemplary schematic view of an inspection
device according to a second embodiment.
DETAILED DESCRIPTION
[0015] Embodiments will be described below with reference to the
drawings. Note that, in the following embodiments, similar elements
are included. Therefore, in the following, those similar elements
are denoted by common reference numerals/signs, and repeated
description will be omitted.
First Embodiment
[0016] An additive manufacturing apparatus 1 according to the
present embodiment, illustrated in FIG. 1, forms an additive
manufactured object according to a laser deposition method. The
additive manufacturing apparatus 1 includes a treatment tank 11, a
stage 12, a moving device 13, a nozzle device 14, an optical device
15, an inspection device 16, a control unit 17, and the like. The
additive manufacturing apparatus 1 feeds a material 121
(manufacturing material) through the nozzle device 14, and emits a
laser beam L1 to the material 121 to form a layer 110b of the
material 121 on an object 110 disposed on the stage 12, so that the
layers 110b are stacked to form an additive manufactured object
100. Here, a manufactured object 101 includes at least one layer
110b. The manufactured object 101 represents an intermediate
product provided in a manufacturing process of the additive
manufactured object 100, or the additive manufactured object 100
having been formed.
[0017] The object 110 is an object to which the material 121 is fed
through the nozzle device 14, and includes a base 110a and the
layer 110b. A plurality of the layers 110b is stacked on an upper
face of the base 110a. The material 121 includes a powdered metal
material, a powdered resin material, or the like. Alternatively,
the material 121 may be not the powdered material but a linear
material. For manufacturing, at least one material 121 can be
used.
[0018] In the treatment tank 11, a main chamber 21 and a
sub-chamber 22 are provided. The sub-chamber 22 is provided
adjacent to the main chamber 21. Between the main chamber 21 and
the sub-chamber 22, a door portion 23 is provided. When the door
portion 23 is opened, the main chamber 21 and the sub-chamber 22
communicate with each other, and when the door portion 23 is
closed, the main chamber 21 is air-tightly sealed.
[0019] In the main chamber 21, an air inlet hole 21a and an air
outlet hole 21b are provided. An inert gas such as nitrogen or
argon is supplied into the main chamber 21 through the air inlet
hole 21a by operation of an air supplying device (not illustrated).
A gas in the main chamber 21 is exhausted from the main chamber 21
through the air outlet hole 21b by operation of an air exhausting
device (not illustrated).
[0020] Furthermore, in the main chamber 21, a transfer device (not
illustrated) is provided. Furthermore, a conveying device 24 is
provided from the main chamber 21 to the sub-chamber 22. The
transfer device transfers the additive manufactured object 100
treated in the main chamber 21 to the conveying device 24. The
conveying device 24 conveys the additive manufactured object 100
transferred from the transfer device, into the sub-chamber 22. That
is, the sub-chamber 22 stores therein the additive manufactured
object 100 treated in the main chamber 21. After the additive
manufactured object 100 is stored in the sub-chamber 22, the door
portion 23 is closed, and the sub-chamber 22 and the main chamber
21 are isolated from each other.
[0021] In the main chamber 21, the stage 12, the moving device 13,
part of the nozzle device 14, the inspection device 16, and the
like are provided.
[0022] The stage 12 supports the object 110. The moving device 13
can move the stage 12 in orthogonal triaxial directions.
[0023] The nozzle device 14 feeds the powdered (or linear) material
121 to the object 110 positioned on the stage 12. Furthermore, the
nozzle device 14 has a nozzle 33 emitting the laser beam L1 to the
object 110 positioned on the stage 12. Furthermore, the nozzle 33
emits the laser beam L1 while feeding the material 121. The nozzle
device 14 emits the laser beam L1 to the material 121 to melt the
material 121, and forms the layer 110b. The nozzle device 14
repeatedly forms the layer 110b, and sequentially stacks the layers
110b. The nozzle device 14 constitutes a manufacturing unit 18
together with the optical device 15. The laser beam L1 is an
example of a first energy beam. Note that, the energy beam
preferably melts or sinters the material 121, and may be, for
example, an electron beam or an electromagnetic wave ranging from
microwaves to ultraviolet.
[0024] The nozzle device 14 has a feeding device 31 (manufacturing
material feeding device), the nozzle 33, a feed tube 34, and the
like. The material is fed from the feeding device 31 to the nozzle
33, through the feed tube 34.
[0025] The feeding device 31 includes a tank 31a and a feed unit
31b. The tank 31a stores therein the powder material 121. The feed
unit 31b feeds a predetermined amount of the material 121 in the
tank 31a, to the nozzle 33. When the material 121 is the powdered
material, the feed unit 31b feeds a carrier gas (gas) containing
the material 121 to the nozzle 33. The carrier gas is, for example,
an inert gas such as nitrogen or argon.
[0026] The nozzle 33 has a casing 71. The casing 71 is configured
to have a vertically elongated tubular shape. As illustrated in
FIG. 2, in the casing 71, a plurality of passages 71a and a single
passage 71b are provided.
[0027] The passage 71b is positioned coaxially with an axis Ax of
the casing 71. That is, the passage 71b extends vertically. In the
passage 71b, the laser beam L1 is introduced from the optical
device 15. In the passage 71b, an optical system is provided which
includes a conversion lens for converting the laser beam L1 to
parallel light, and a lens for focusing the laser beam L1 converted
to the parallel light. The laser beam L1 is focused under the
casing 71 by the lens. The laser beam L1 has a focal point
(convergence point) positioned on the axis Ax.
[0028] Each of the passages 71a is connected to the feeding device
31 through the feed tube 34. When the material 121 is the powdered
material, the material 121 is fed to each passage 71a from the
feeding device 31, together with the carrier gas. The passage 71a
has a lower portion inclined with respect to the axis Ax of the
casing 71 to be closer to the axis Ax toward the lower side.
[0029] When the material 121 is the powdered material, the nozzle
33 jets (injects) the material 121 below the casing 71 (passage
71a), from a lower end (an opening) of the passage 71a.
Alternatively, when the material 121 is the linear material, the
nozzle 33 extrudes (injects) the material 121 below the casing 71
(passage 71a), from the lower end (the opening) of the passage 71a.
The jetted or extruded material 121 reaches the convergence point
of the laser beam L1. The material 121 fed by the nozzle 33 is
melted by the laser beam L1 to form a mass of the molten material
121. Note that, the material 121 may be sintered by the laser beam
L1.
[0030] As illustrated in FIG. 1, the optical device 15 includes a
laser emitter 41 and a cable 210. The laser emitter 41 has an
oscillator (not illustrated), and emits the laser beam L1 by
oscillation of the oscillator. The laser emitter 41 can change a
power density of the laser beam L1 to be emitted. The laser emitter
41 is connected to the nozzle 33 through the cable 210. The laser
beam L1 emitted from the laser emitter 41 is guided to the nozzle
33.
[0031] As illustrated in FIG. 3, the inspection device 16
(apparatus) has a measurement unit 51, a processing unit 52, a
laser interferometer 53, and an inspection unit 54 (abnormality
detection unit). The measurement unit 51 measures a shape of the
manufactured object 101. The processing unit 52 emits a laser beam
L2 to the manufactured object 101 to partially remove a surface
101a of the manufactured object 101, and generates an elastic wave
propagating in the manufactured object 101, upon impact of emission
of the laser beam L2. Furthermore, the processing unit 52 processes
the surface 101a of the manufactured object 101 on the basis of a
measurement result from the measurement unit 51, and irregularities
on the surface 101a of the manufactured object 101 can be reduced,
that is, can be leveled. The laser interferometer 53 detects the
elastic wave. The inspection unit 54 inspects the manufactured
object 101 on the basis of a detection result of the elastic
wave.
[0032] The measurement unit 51 has an illuminating device 55
(illuminating apparatus), a camera 56 (imaging unit), and an image
processing device (not illustrated). The measurement unit 51
measures a shape of a surface of an object to be measured (layer
110b or manufactured object 101), for example, using a light
section method. In this measurement, the illuminating device 55
emits linear light to the surface of the object to be measured
(layer 110b or manufactured object 101). The camera 56 captures an
image including the linear light. The image processing device
measures irregularities in the surface shape on the basis of a
position of the linear light (deviation from reference line). The
measurement unit 51 transmits the measured shape (measurement
result) to the control unit 17 (see FIG. 1). Note that, the
measurement unit 51 may measure the shape of the object to be
measured using a method (e.g., interference method or the like)
other than the light section method.
[0033] The processing unit 52 has a laser emitter 60 (light
source), a beam splitter 61, and a lens 62 (condensing lens).
[0034] The laser emitter 60 has the oscillator (not illustrated),
and emits the laser beam L2 by oscillation of the oscillator. The
laser beam L2 is, for example, a pulse laser beam. The laser
emitter 60 emits the laser beam L2 having intensity large enough to
vaporize a solidified material 121 of the manufactured object 101.
The laser beam L2 emitted from the laser emitter 60 is made
incident to the beam splitter 61.
[0035] The beam splitter 61 is positioned on a side of the laser
emitter 60, from which the laser beam L2 is emitted. The beam
splitter 61 reflects part of the incident laser beam L2. Note that,
in FIG. 3 and the like, illustration of the laser beam L2 emitted
from the laser emitter 60 and passing through the beam splitter 61
is omitted. The laser beam L2 reflected from the beam splitter 61
is made incident to the lens 62.
[0036] The laser beam L2 from the beam splitter 61 is focused by
the lens 62, and is emitted to the surface 101a of the manufactured
object 101 (layer 110b). Specifically, the laser beam L2 is emitted
to, for example, an end face 101b of the manufactured object 101 in
a stacking direction of the plurality of layers 110b. At this time,
the laser beam L2 is emitted to the end face 101b (surface 101a) of
the manufactured object 101, substantially along a normal direction
(stacking direction of the layers 110b) of the end face 101b
(surface 101a).
[0037] The processing unit 52 vaporizes part of the material of the
manufactured object 101 and removes part of the manufactured object
101 with the laser beam L2 emitted to the manufactured object 101
through the above-described optical system (first optical system).
At this time, the processing unit 52 can change an amount of
manufactured object 101 to be removed according to a measurement
result from the measurement unit 51 to reduce the irregularities on
the surface 101a (end face 101b), that is, to level the end face
101b (surface 101a). The processing unit 52 can change an amount of
end face 101b (surface 101a) to be removed by, for example,
changing the intensity of the laser beam L2. In this case, the
intensity of the laser beam L2 is set larger with increasing height
of the surface 101a. The processing unit 52 processes the end face
101b to have a flat face parallel with a movement direction
(direction orthogonal to the stacking direction) of the stage.
[0038] Furthermore, the processing unit 52 generates the elastic
wave (density wave) in the manufactured object 101, upon impact of
irradiation of the end face 101b (surface 101a) with the laser beam
L2. In the manufactured object 101, the elastic wave radially
propagates from a processing position processed by the laser beam
L2 on the end face 101b (surface 101a). The processing unit 52 is
an example of an elastic wave generation unit and a removal unit.
That is, the elastic wave generation unit serves as the processing
unit 52 and the removal unit. In other words, the processing unit
52 serves as the elastic wave generation unit and the removal unit.
Furthermore, the laser beam L2 is an example of a second energy
beam and a first laser beam.
[0039] Furthermore, an optical filter 63 is provided between the
beam splitter 61 and the lens 62. The optical filter 63 is
configured to transmit the laser beam L2 reflected from the beam
splitter 61 to the lens 62, and not to transmit the reflected light
of the laser beam L2 emitted from the lens 62 to the manufactured
object 101 and reflected from the manufactured object 101.
Furthermore, an optical filter (not illustrated) can be provided on
the opposite side of the beam splitter 61 relative to the laser
emitter 60. The optical filter does not transmit the laser beam L2
emitted from the laser emitter 60 and passing through the beam
splitter 61.
[0040] The laser interferometer 53 has a laser emitter 65, a beam
splitter 66, the beam splitter 61, the lens 62, a mirror 67, and a
detector 64. The laser interferometer 53 detects the elastic wave
propagating in the manufactured object 101. The laser
interferometer 53 is an example of an elastic wave detection
unit.
[0041] The laser emitter 65 has the oscillator (not illustrated),
and emits a laser beam L3 oscillated by the oscillator. The laser
beam L3 is, for example, a continuous laser beam (CW laser beam) or
a pulse laser beam. The laser beam L3 emitted from the laser
emitter 65 is made incident to the beam splitter 66.
[0042] The beam splitter 66 is positioned on a side of the laser
emitter 65, from which the laser beam L3 is emitted. The beam
splitter 66 partially reflects the incident laser beam L3. The
laser beam L3 reflected from the beam splitter 61 is made incident
to the lens 62. Note that, in FIG. 3 and the like, the laser beam
L3 emitted from the laser emitter 65 and passing through the beam
splitter 66 is not illustrated.
[0043] The laser beam L3 from the beam splitter 66 is focused by
the lens 62, and is emitted to the end face 101b (surface 101a) of
the manufactured object 101 (layer 110b). At this time, the laser
beam L3 is emitted to the end face 101b (surface 101a) of the
manufactured object 101 substantially along a normal direction of
the end face 101b (surface 101a). The laser beam L3 emitted to the
end face 101b is reflected from the end face 101b, and is made
incident to the detector 64 as detected light through the lens 62,
the beam splitter 61, and the beam splitter 66. The end face 101b
of the manufactured object 101 is oscillated by a reflected wave
(elastic wave) of the elastic wave reflected in the manufactured
object 101. The laser interferometer 53 detects displacement of the
end face 101b on the basis of reflected light from the end face
101b. Note that, the laser emitter 65 emits the laser beam L3
having intensity at which the material 121 does not melt on the end
face 101b.
[0044] While, part of the laser beam L3 emitted from the laser
emitter 65 and made incident to the beam splitter 61 through the
beam splitter 66 is reflected from the beam splitter 61 and made
incident to the mirror 67.
[0045] The mirror 67 reflects the incident laser beam L3. Part of
the laser beam L3 reflected from the mirror 67 is made incident to
the detector 64 as reference light through the beam splitter 61 and
the beam splitter 66.
[0046] The detector 64 is positioned on the opposite side of the
beam splitter 66 relative to the beam splitter 61. The detector 64
receives reflected light (detected light) of the laser beam L3
reflected from the end face 101b of the manufactured object 101,
and reflected light (reference light) of the laser beam L3
reflected from the mirror 67. The detector 64 can detect
displacement of the end face 101b (temporal change in height of the
end face 101b) on the basis of interference between the detected
light and the reference light. That is, the detector 64 detects the
elastic wave (reflected wave) on the end face 101b of the
manufactured object 101.
[0047] The inspection unit 54 detects (determines) an abnormality
101c in the manufactured object 101 on the basis of a detection
result from the detector 64. Here, when a portion of the
manufactured object 101 having no abnormality 101c therein is
inspected, the elastic wave generated on the end face 101b reaches
a bottom face of the manufactured object 101, is reflected from the
bottom face, and returns to the end face 101b. In contrast, when a
portion of the manufactured object 101 having the abnormality 101c
therein is inspected, the elastic wave generated on the end face
101b is reflected from the abnormality 101c and returns to the end
face 101b. That is, an elapsed time is longer with increasing depth
of the abnormality 101c, and the elapsed time is shorter with
decreasing depth of the abnormality 101c. Therefore, the inspection
unit 54 can detect the depth (position) of the abnormality 101c on
the basis of the elapsed time from emission of the laser beam to
detection of the displacement of the end face 101b, or on the basis
of a parameter changing according to the elapsed time.
[0048] Furthermore, when the abnormality 101c is a void, the
reflected wave has a smaller intensity with decreasing size of the
abnormality 101c and with increasing density of the inspected
portion, and the reflected wave has a larger intensity with
increasing size of the abnormality 101c and with decreasing density
of the inspected portion. Therefore, the inspection unit 54 can
detect a size of the abnormality 101c or a density of an inspected
portion, on the basis of the intensity (amplitude) of the reflected
wave or the parameter changing according to the intensity of the
reflected wave.
[0049] As described above, the inspection unit 54 can detect the
presence or absence, the depth (position), the density, or the like
of the abnormality 101c in the manufactured object 101, on the
basis of a detection result (elastic wave, elastic wave signal)
from the detector 64. Note that, the inspection unit 54 can detect
a position of the abnormality 101c on a plane orthogonal to the
stacking direction, on the basis of information obtained from the
control unit 17 and representing an irradiation position of the
laser beam L3 from the laser emitter 65. Furthermore, the
inspection unit 54 has, for example, a control unit and a storage
unit. The control unit has a central processing unit (CPU), a
controller, or the like. The storage unit has a read only memory
(ROM), a random access memory (RAM), and the like. The control unit
can execute various calculation processing relating to the
abnormality detection according to a loaded program (e.g., an
operating system (OS), an application, or a web application).
[0050] Here, in the present embodiment, a single lens 62 focuses
the laser beam L2 and the laser beam L3, as illustrated in FIG. 3.
However, as illustrated in FIG. 4, a focal position (converging
position) of the laser beam L2 focused by the lens 62 is different
in location from a focal position (converging position) of the
laser beam L3 focused by the lens 62. Specifically, in a relative
movement direction of the laser beams L2 and L3, that is, the
relative movement direction of the inspection device 16 relative to
the manufactured object 101 (direction indicated by an arrow A in
FIG. 3), an irradiation position P3 of the laser beam L3 is
positioned in back (on the upstream side) of an irradiation
position P2 of the laser beam L2. Therefore, the laser beam L3 is
emitted to a position of the end face 101b which has the
irregularities reduced or leveled by the laser beam L2, and
displacement is then detected on the basis of the reflected wave
(elastic wave) from the position. Thus, according to the present
embodiment, displacement can be detected with high accuracy,
compare with, for example, detection of the displacement based on a
reflected wave (elastic wave) from a position which has
irregularities not reduced by the laser beam L2 and to which the
laser beam L3 is emitted. Note that, an arrow B in FIG. 3
represents the movement direction of the stage 12 (manufactured
object 101) moved by driving the moving device 13.
[0051] Furthermore, in the present embodiment, the laser beam L2
(first laser beam) and the laser beam L3 (second laser beam) may
have different wavelengths so that the laser beams do not interfere
with each other. Specifically, for example, the wavelength of the
laser beam L2 may be shorter than the wavelength of the laser beam
L3. Furthermore, the laser beam L2 and the laser beam L3 may be
different in polarization direction (polarization plane) so that
the laser beams do not interference with each other. Specifically,
for example, one of the laser beam L2 and the laser beam L3 may be
P polarized light, and the other thereof may be S polarized
light.
[0052] Furthermore, when the laser beam L2 has a smaller pulse
width, the elastic wave has a higher frequency and resolution is
increased, whereby detection of a smaller abnormality 101c is
facilitated. However, when the laser beam L2 has the smaller pulse
width, that is, the elastic wave has a higher frequency, the
elastic wave is more absorbed in the manufactured object 101 and
detection of the elastic wave is made more difficult. Accordingly,
the pulse width of the laser beam L2 is set according to the size
of the abnormality 101c to be detected. For example, for the
abnormality 101c having a size not less than several micrometers,
the pulse width of the laser beam L2 can be set to 1 fs to 1
ns.
[0053] As an example, the control unit 17 has a central processing
unit (CPU) and a storage unit. The storage unit has a read only
memory (ROM), a random access memory (RAM), and the like. The
control unit 17 is electrically connected to the moving device 13,
the optical device 15, the conveying device 24, the feeding device
31, and the inspection device 16, through a signal line 220. The
control unit 17 (CPU) controls the moving device 13, the optical
device 15, the conveying device 24, the feeding device 31, and the
inspection device 16, according to a loaded program (e.g., an
operating system (OS), an application, or a web application). The
additive manufacturing apparatus 1 forms the additive manufactured
object 100 on the basis of control (program) of the control unit
17.
[0054] The control unit 17 controls the moving device 13 to move
the stage 12 in the triaxial directions. The control unit 17
controls the conveying device 24 to convey the additive
manufactured object 100 having been formed to the sub-chamber 22.
The control unit 17 controls the feeding device 31 to adjust
feeding or non-feeding of the material 121 and an amount of the
material 121 to be fed. The control unit 17 controls the laser
emitter 41 to adjust the intensity (power density) of the laser
beams L1, L2, and L3 emitted from the laser emitters 41, 60, and
65. Furthermore, the control unit 17 controls a moving device (not
illustrated) to control the movement of the nozzle 33. Furthermore,
the control unit 17 controls a moving device (not illustrated) to
control the movement of the inspection device 16.
[0055] The storage unit of the control unit 17 stores therein data
or the like representing a shape (reference shape) of the additive
manufactured object 100 to be formed. This shape data includes data
about the shape (reference shape) of each layer 110b.
[0056] The control unit 17 has a function of determining the shape
of the layer 110b or the additive manufactured object 100. The
control unit 17 compares the shape of the layer 110b or the
additive manufactured object 100 measured by the measurement unit
51 with the reference shape stored in the storage unit, and
determines whether a portion without a predetermined shape is
formed.
[0057] Furthermore, the control unit 17 has a function of trimming
the shape of the layer 110b or the additive manufactured object 100
into a predetermined shape. The control unit 17 controls the laser
emitter 60 of the processing unit 52 so that the laser beam L2 has
intensity strong enough to vaporize a portion (portion to be
removed) of the layer 110b or the additive manufactured object 100
having a shape other than the predetermined shape. Next, the
control unit 17 controls the processing unit 52 and the moving
device 13 so that the laser beam L2 is emitted to the portion.
Therefore, the portion is vaporized.
[0058] Next, an example of a procedure of forming the additive
manufactured object 100 by the additive manufacturing apparatus 1
(i.e., a method for producing the additive manufactured object 100)
will be described with reference to a flowchart of FIG. 5.
[0059] First of all, the control unit 17 controls the moving device
13, the nozzle device 14, and the optical device 15 to form the
layer 110b (S1). At S1, the material 121 is fed and the laser beam
L1 is emitted on the basis of the data (reference data) about the
layer 110b stored in the storage unit. At this time, the control
unit 17 controls the moving device 13, the feeding device 31, and
the like to feed the material 121 from the nozzle 33 to a
predetermined range, and controls the laser emitter 41 to melt the
fed material 121 by the laser beam L1. Therefore, a predetermined
amount of the molten material 121 is fed to a range in which the
layer 110b is formed on the base 110a. At this time, in the present
embodiment, the material 121 is fed so that the layer 110b to be
formed has a height larger than the height in the data about the
layer 110b stored in the storage unit. After the material 121 is
jetted or extruded on the base 110a or the layer 110b, a mass of
the material 121, such as a layer or a thin film, is formed. At
this time, the material 121 is cooled by the carrier gas carrying
the material 121 or solidified by being cooled due to heat transfer
to the mass of the material 121, and then the layer 110b is formed.
The control unit 17 may perform annealing. In the annealing, the
control unit 17 controls the laser emitter 41 so that the laser
beam L1 is emitted to the layer 110b onto the base 110a. Therefore,
after the material 121 in the layer 110b is melted again, the
material 121 is solidified again. Note that, annealing may be
performed outside the additive manufacturing apparatus 1, using an
annealing apparatus (not illustrated).
[0060] Next, the control unit 17 controls the inspection device 16
and the moving device 13 to inspect inside the manufactured object
101 (S2: abnormality detection process (inspection process)). As
illustrated in FIG. 6, at S2, shape measurement, trimming, and
inspection are performed. First of all, the control unit 17
controls the measurement unit 51 and the moving device 13 to
measure the shape (surface shape, three-dimensional shape) of the
surface 101a of the layer 110b of the manufactured object 101. The
control unit 17 obtains measured shape data representing the shape
of the layer 110b from the measurement unit 51. Then, the control
unit 17 controls the processing unit 52 and the moving device 13 to
trim the end face 101b of the manufactured object 101 (surface
101a). At this time, the control unit 17 controls the processing
unit 52 and the moving device 13 so that the height of the layer
110b is substantially the same as the height indicated in the data
about the layer 110b stored in the storage unit (e.g., a certain
height). At this time, the control unit 17 changes the amount of
end face 101b to be removed according to a measured height of the
end face 101b of the layer 110b (irregularities) so that the height
of the end face 101b of the layer 110b (thickness of the layer
110b) is substantially constant. Specifically, the control unit 17
controls the processing unit 52 so that the laser beam L2 has
intensity according to the amount of end face 101b to be removed.
Therefore, for example, a next layer 110b can be effectively formed
flat, or accuracy in inspection of the elastic wave is effectively
increased. Trimming is performed with emission of the laser beam L2
by the processing unit 52. Then, the laser interferometer 53
detects, using the laser beam L3, the elastic wave generated by
emission of the laser beam L2, and the inspection unit 54 detects
(determines) the presence or absence of an abnormality 101c in the
manufactured object 101 on the basis of a detection result from the
laser interferometer 53. The detection of the presence or absence
of the abnormality 101c is performed whenever the laser beam L2 is
emitted. In the present embodiment, detection of the presence or
absence of the abnormality 101c is performed for whole area of the
end face 101b. Furthermore, when comparison, which is performed
between reference shape data about the layer 110b stored in the
storage unit and the measured shape data as a measurement result
from the measurement unit 51, shows that the manufacturing is
performed in a portion (area) where the manufacturing should not be
performed, the control unit 17 removes the portion at the trimming.
For example, when manufacturing is performed in a portion (area)
where manufacturing should not be performed in a direction
orthogonal to the stacking direction, the control unit 17 removes
the portion.
[0061] S2 may be performed whenever one layer 110b is formed, or
may be performed whenever a plurality of layers 110b is formed. S2
is performed after the layer 110b is formed. Note that, the shape
measurement and the trimming may be performed whenever one layer
110b is formed, and detection of the elastic wave may be performed
whenever a plurality of layers 110b is formed.
[0062] Then, as illustrated in FIG. 5, when the inspection device
16 (the inspection unit 54) detects an abnormality 101c in the
manufactured object 101 ("Yes" at S3), the control unit 17 repairs
(removes) the abnormality 101c (S4: repairing processing). When the
abnormality 101c is a void, at S4, formation of an opening,
manufacturing (filling), and removal of a protruding portion are
performed, as illustrated in FIG. 7. First of all, the control unit
17 controls the processing unit 52 and the moving device 13 to
remove a portion of the manufactured object 101 between the end
face 101b (surface 101a) and the abnormality 101c, that is, a
portion of the manufactured object 101 on a side of the end face
101b relative to the abnormality 101c. Therefore, an opening 101d
is formed in the manufactured object 101 to have the abnormality
101c at the bottom. Next, the control unit 17 controls the
manufacturing unit 18 so that the opening 101d is filled with the
material 121 and the material 121 is solidified. At this time, the
manufacturing unit 18 performs manufacturing, for example, until
the material 121 protrudes from the opening 101d. Then, the control
unit 17 controls the processing unit 52 to remove at least part of
the manufactured object 101 protruded from the opening 101d, that
is, all or part of a portion of the manufactured object 101
protruding from the opening 101d. More specifically, the control
unit 17 controls the laser emitter 60 of the processing unit 52 to
vaporize the protruding portion (material 121) protruded from the
opening 101d. Since the protruding portion is removed as described
above, a filled portion is further readily leveled. Note that, S4
may be performed whenever a plurality of layers 110b is formed.
[0063] In contrast, when the inspection device 16 does not detect
the abnormality 101c in the manufactured object 101 ("No" at S3),
S4 is not performed.
[0064] Next, as illustrated in FIG. 5, when not all layers 110b are
formed ("No" at S5), the processing returns to S1, and a new layer
110b is formed on the layer 110b having been formed. The control
unit 17 repeatedly performs processing of S1 to S5 to stack the
plurality of layers 110b. When all layer 110b are formed ("Yes" at
S5), a series of processing is finished.
[0065] As described above, in the present embodiment, the
manufacturing unit 18 sequentially stacks the layer 110b formed by
emitting the laser beam L1 (first energy beam) to the powdered (or
linear) material 121 and solidifying the material 121; the
processing unit 52 (elastic wave generation unit) generates the
elastic wave propagating in the manufactured object 101 including
at least one layer 110b; the laser interferometer 53 detects the
elastic wave; and the inspection unit 54 inspects the manufactured
object 101 on the basis of a detection result from the laser
interferometer 53. Thus, the abnormality 101c in the manufactured
object 101 can be detected.
[0066] Furthermore, in the present embodiment, the processing unit
52 emits the laser beam L2 (second energy beam) to process the
surface 101a of the manufactured object 101. The processing unit 52
emits the laser beam 12 to the surface 101a to generate the elastic
wave. That is, since the processing unit 52 functions as the
elastic wave generation unit, the additive manufacturing apparatus
1 can have a simple configuration in comparison with a
configuration in which the elastic wave generation unit is provided
separately from the processing unit 52.
[0067] Furthermore, in the present embodiment, the laser beam L2
(first laser beam) and the laser beam L3 (second laser beam) do not
interfere with each other. Thus, the abnormality 101c in the
manufactured object 101 can be detected with high accuracy.
[0068] Furthermore, in the present embodiment, a single lens 62
focuses the laser beam L2 and the laser beam L3. Thus, the additive
manufacturing apparatus 1 can have a simple configuration in
comparison with a configuration in which the laser beam L2 and the
laser beam L3 are focused by different lenses.
[0069] Furthermore, in the present embodiment, the processing unit
52 (removal unit) can partially remove the manufactured object 101.
When the inspection unit 54 detects the abnormality 101c in the
manufactured object 101, the processing unit 52 partially removes
the manufactured object 101 from the surface 101a of the
manufactured object 101 to the abnormality 101c, and then the
manufacturing unit 18 fills the material 121 in the opening 101d of
the manufactured object 101 formed after removal thereof by the
processing unit 52, so that the material 121 is solidified. Thus,
the manufactured object 101 repaired after removing the abnormality
101c can be obtained.
Second Embodiment
[0070] An additive manufacturing apparatus 1A according to the
present embodiment includes a configuration similar to that of the
additive manufacturing apparatus 1 according to the first
embodiment. However, in the present embodiment, an inspection
device 16A is different from the inspection device 16 according to
the first embodiment, as illustrated in FIG. 8.
[0071] The inspection device 16A has the measurement unit 51, a
processing unit 52A, a laser interferometer 53A, and the inspection
unit 54.
[0072] In the present embodiment, a laser emitter 201 (light
source), the beam splitter 61, the beam splitter 66, a beam
splitter 202, the mirror 67, a mirror 203, the lens 62 (condensing
lens), a wavelength converter 204, a light intensity adjusting
member 205, and the detector 64 are provided as members
constituting the processing unit 52A and the laser interferometer
53A. The processing unit 52A has the laser emitter 201, the beam
splitters 61 and 202, the mirror 203, and the lens 62. In contrast,
the laser interferometer 53A has the laser emitter 201, the beam
splitters 61, 66, and 202, the lens 62, the mirror 67, the
wavelength converter 204, the light intensity adjusting member 205,
and the detector 64. The processing unit 52A is an example of the
elastic wave generation unit and the removal unit.
[0073] The laser emitter 201 has the oscillator (not illustrated),
and emits a laser beam L4 oscillated by the oscillator. The laser
beam L4 is, for example a pulse laser beam. The laser beam L4 is an
example of a third laser beam.
[0074] The laser beam L2 emitted from the laser emitter 201 is made
incident to the beam splitter 202, and is divided into the laser
beam L2 and the laser beam L3 by the beam splitter 202. The beam
splitter 202 is an example of a dividing unit.
[0075] The laser beam L2 is reflected from the mirror 203 and is
made incident to the beam splitter 61. The laser beam L2 is
partially reflected from the beam splitter 61, is focused by the
lens 62, and is emitted to the end face 101b of the manufactured
object 101.
[0076] The laser beam L3 is made incident to the wavelength
converter 204 and the light intensity adjusting member 205 in
sequence, is converted in wavelength by the wavelength converter
204, and is reduced in light intensity by the light intensity
adjusting member 205. The laser beam L3 emitted from the light
intensity adjusting member 205 is made incident to the beam
splitter 66. The laser beam L3 is partially reflected by the beam
splitter 66, and is made incident to the beam splitter 61. The
laser beam L3 incident to the beam splitter 61 is divided into
light incident to the lens 62 and light incident to the mirror 67,
similarly to the first embodiment. The laser beam L3 incident to
the lens 62 is focused by the lens 62, and is emitted to the end
face 101b of the manufactured object 101. The laser beam L3 emitted
to the end face 101b of the manufactured object 101 is reflected
from the end face 101b, and is made incident to the detector 64
through the lens 62, the beam splitter 61, and the beam splitter
66. In contrast, the laser beam L3 reflected from the mirror 67 is
made incident to the detector 64 through the beam splitter 61 and
the beam splitter 66. Note that, the laser beam L3 is adjusted by
the light intensity adjusting member 205 in light intensity to have
intensity small enough to prevent melting of the material 121 on
the end face 101b.
[0077] Furthermore, also in the present embodiment, a single lens
62 focuses the laser beam L2 and the laser beam L3, similarly to
the first embodiment. Furthermore, the focal position (converging
position) of the laser beam L2 focused by the lens 62 is different
in location from the focal position (converging position) of the
laser beam L3 focused by the lens 62. Specifically, in a relative
movement direction of the laser beams L2 and L3, that is, a
relative movement direction of the inspection device 16A relative
to the manufactured object 101 (e.g., direction indicated by an
arrow A), an irradiation position P3 of the laser beam L3 is
positioned in back (on the upstream side) of an irradiation
position P2 of the laser beam L2.
[0078] Furthermore, in the present embodiment, since the wavelength
of the laser beam L3 of the laser beam L2 is converted by the
wavelength converter 204, the laser beam L3 and the laser beam L2
do not interference with each other even if the laser beam L3 and
the laser beam L2 overlap each other.
[0079] As described above, in the present embodiment, a single
laser emitter 201 emits the laser beam L4 (third laser beam), and
the beam splitter 202 (dividing unit) divides the laser beam L4
emitted from the laser emitter 201 into the laser beam L2 (first
laser beam) and the laser beam L3 (second laser beam). Thus, the
number of laser emitters 201 can be reduced in comparison with a
configuration in which laser emitters are provided for the laser
beams L2 and L3 emitted from the laser emitter 201.
[0080] Note that, each of the above-described embodiments may be
configured, for example, so that the feeding device 31 supplies a
plurality of materials 121 of different kinds to the nozzle 33 and
the plurality of different materials 121 is selectively supplied
from the nozzle 33 so as to adjust (change) the percentages of the
materials 121. Therefore, a gradient material (functional gradient
material), in which the proportions of the materials 121 change
(gradually reduce or gradually increase) according to the position
(location) in the additive manufactured object 100, can be
manufactured. Specifically, for example, upon forming the layer
110b, the control unit 17 can control the feeding device 31 to have
the proportions of the materials 121 set (stored) corresponding to
each position of three-dimensional coordinates of the additive
manufactured object 100, so that the additive manufactured object
100 can be formed as the gradient material (functional gradient
material) in which the proportions of the materials 121 are
arbitrarily changed in a three-dimensional direction. An amount of
change (rate of change) in percentage of the material 121 per unit
length can be also variously set.
[0081] As described above, according to each of the above-described
embodiments, the additive manufacturing apparatuses 1 and 1A and
the additive manufacturing method can be obtained by which the
abnormality 101c in the manufactured object 101 can be detected,
for example.
[0082] Certain embodiments have been described, but these
embodiments have been presented by way of example only, and are not
intended to limit the scope of the inventions. The novel
embodiments may be embodied in a variety of other forms, and
furthermore, various omissions, substitutions and changes may be
made without departing from the spirit of the inventions. The
accompanying claims and their equivalents are intended to cover
such embodiments or modifications as would fall within the scope
and spirit of the inventions.
[0083] For example, the additive manufacturing apparatus may have a
configuration (powder bed process) or the like, in which a step of
feeding powder material by a material feed unit to form a material
layer and a step of emitting the first energy beam such as laser
beam to the material layer by an irradiation device to solidify a
material are repeatedly performed to stack individualized layers
(layers) for manufacturing. In this configuration, the material 121
protruded from the opening 101d may be removed as required. For
example, when the material 121 protruded from the opening 101d has
a height smaller than the height of the material layer, the
material 121 may not be removed.
[0084] Furthermore, in each of the above-described embodiments, the
elastic wave is generated in an ablation mode using the laser beam
L2 emitted from the processing unit 52, but a configuration for
emitting the laser beam may be provided separately from the
processing unit 52 to generate the elastic wave in a thermal stress
mode using the laser beam.
* * * * *