U.S. patent application number 17/104955 was filed with the patent office on 2021-03-18 for heat treatment to anneal residual stresses during additive manufacturing.
The applicant listed for this patent is Lawrence Livermore National Security, LLC. Invention is credited to Andrew BAYRAMIAN, James A. DEMUTH, Bassem S. EL-DASHER, Joseph C. FARMER, Kevin J. KRAMER, Alexander RUBENCHIK.
Application Number | 20210078077 17/104955 |
Document ID | / |
Family ID | 1000005241690 |
Filed Date | 2021-03-18 |
United States Patent
Application |
20210078077 |
Kind Code |
A1 |
DEMUTH; James A. ; et
al. |
March 18, 2021 |
HEAT TREATMENT TO ANNEAL RESIDUAL STRESSES DURING ADDITIVE
MANUFACTURING
Abstract
The present disclosure relates to a method of producing a
product through additive manufacturing with heat treatment. The
method involves using a fusing beam to melt powder particles
disposed on a substrate. The fused powder particles are then heat
treated with a heat treating beam. The heat treatment is thus
completed on a given layer prior to laying down additional new
layers of material. In one implementation the heat treatment is an
annealing operation. The method may further involve providing a new
layer of powdered material on top of the layer of fused powder
particles subsequent to the heat treatment, and repeating the
melting and heat treating operations in a layer-by-layer fashion
until the part is completed.
Inventors: |
DEMUTH; James A.; (Woburn,
MA) ; BAYRAMIAN; Andrew; (Marblehead, MA) ;
EL-DASHER; Bassem S.; (Livermore, CA) ; FARMER;
Joseph C.; (Tracy, CA) ; KRAMER; Kevin J.;
(Redmond, WA) ; RUBENCHIK; Alexander; (Livermore,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Lawrence Livermore National Security, LLC |
Livermore |
CA |
US |
|
|
Family ID: |
1000005241690 |
Appl. No.: |
17/104955 |
Filed: |
November 25, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16794835 |
Feb 19, 2020 |
10898954 |
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17104955 |
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|
15008989 |
Jan 28, 2016 |
10618111 |
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16794835 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22F 10/00 20210101;
Y02P 10/25 20151101; B22F 2998/10 20130101; B33Y 30/00 20141201;
B22F 3/24 20130101; B33Y 10/00 20141201; B22F 10/10 20210101; B33Y
40/00 20141201 |
International
Class: |
B22F 3/105 20060101
B22F003/105; B33Y 40/00 20060101 B33Y040/00; B22F 3/24 20060101
B22F003/24 |
Goverment Interests
STATEMENT AS TO RIGHTS TO APPLICATIONS MADE UNDER FEDERALLY
SPONSORED RESEARCH AND DEVELOPMENT
[0002] The United States Government has rights in this application
pursuant to Contract No. DE-AC52-07NA27344 between the United
States Department of Energy and Lawrence Livermore National
Security, LLC for the operation of Lawrence Livermore National
Laboratory.
Claims
1. A method of producing a product through additive manufacturing
with heat treatment, the method comprising the steps of: providing
a substrate; positioning a layer of powder particles on said
substrate producing an interface between said layer of powder
particles and said substrate; melting said powder particles with a
fusing beam, to fuse said powder particles with said substrate in a
desired shape and pattern producing fused powder particles; heat
treating said fused powder particles with a heat treating beam to
achieve heat treatment of the product, prior to laying down
additional new layers of material; wherein the heat treatment
comprises an annealing on at least one or more portions of one or
more intermediate layers of the part; providing a new layer of
powdered material on top of said layer of fused powder particles
subsequent to said heat treatment; and repeating said melting and
heat treating operations in a layer-by-layer fashion, until the
part is completed.
2. The method of claim 1, wherein heat treating said fused powder
particles comprises using a laser to perform the heat treating.
3. The method of claim 1, wherein heat treating said fused powder
particles comprises using a diode laser to perform the heat
treating.
4. The method of claim 1, wherein heat treating said fused powder
particles comprises using a source of electromagnetic radiation to
perform the heat treating.
5. The method of claim 1, wherein heat treating said fused powder
particles comprises using an electron beam to perform said heat
treating.
6. The method of claim 1, further comprising performing a laser
peening operation on said fused powder particles.
7. The method of claim 6, wherein the laser peening operation is
performed using an additional laser.
8. The method of claim 1, wherein the fusing beam comprises a two
dimensional pattern to selectively fuse only specific portions of
the layer of powder particles.
9. The method of claim 1, wherein the heat treating beam comprises
a two dimensional pattern to selectively heat treat only specific
portions of the layer of fused powder particles.
10. A method of producing a product through additive manufacturing
with heat treatment, the method comprising the steps of: providing
a substrate; positioning a layer of powder particles on said
substrate producing an interface between said layer of powder
particles and said substrate; using a laser to melt said powder
particles with a laser beam impressed with a two dimensional
pattern containing image information from a first layer to be
printed in making the product, to fuse said powder particles with
said substrate in a desired shape and pattern producing fused
powder particles; heat treating said fused powder particles with an
additional laser beam to achieve heat treatment of the product,
prior to laying down additional new layers of material; and wherein
the heat treatment comprises an annealing operation.
11. The method of claim 10, further comprising providing a new
layer of powdered material on top of said layer of fused powder
particles subsequent to said heat treatment.
12. The method of claim 11, further comprising repeating said
melting and heat treating operations in a layer-by-layer fashion,
until the part is completed.
13. The method of claim 10, wherein using a laser comprises using a
diode laser.
14. The method of claim 10, wherein heat treating said fused powder
particles comprises using a diode laser to perform the heat
treating using a 2D pattern.
15. The method of claim 10, wherein heat treating said fused powder
particles comprises using a source of electromagnetic radiation to
perform the heat treating.
16. The method of claim 10, wherein heat treating said fused powder
particles comprises using an electron beam to perform the heat
treating.
17. The method of claim 10, further comprising performing a laser
peening operation on said fused powder particles.
18. A method of producing a product through additive manufacturing
with heat treatment, the method comprising the steps of: providing
a substrate; positioning a layer of powder particles on said
substrate producing an interface between said layer of powder
particles and said substrate; melting said powder particles with a
first laser beam to fuse said powder particles with said substrate,
and thus producing fused powder particles; performing an annealing
operation with a second laser beam impressed with a two dimensional
pattern containing image information, to achieve heat treatment of
at least a portion of the first layer of the product in accordance
with the two dimensional pattern, prior to laying down additional
new layers of material; providing a new layer of powdered material
on top of the first layer of fused powder particles subsequent to
the heat treatment; and repeating said melting and annealing in a
layer-by-layer fashion, until the part is completed.
19. The method of claim 18, wherein performing an annealing
operation with a second laser beam comprises using at least one of:
a diode laser; a source of electromagnetic radiation; or an
electron beam.
20. The method of claim 18, wherein the first laser beam impresses
the fusing beam with a two dimensional pattern for selectively
fusing only selection portions of the powder particles.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of and claims priority to
U.S. patent application Ser. No. 16/794,835, filed on Feb. 19,
2020, which is a divisional and claims priority to U.S. patent
application Ser. No. 15/008,989, filed on Jan. 28, 2016 (now U.S.
Pat. No. 10,618,111). The entire disclosures of each of the above
applications are incorporated herein by reference.
FIELD OF ENDEAVOR
[0003] The present application relates to additive manufacturing
and more particularly to heat treatment to anneal residual stresses
during additive manufacturing.
BACKGROUND
[0004] This section provides background information related to the
present disclosure which is not necessarily prior art.
[0005] U.S. Pat. No. 4,944,817 for multiple material systems for
selective beam sintering issued Jul. 31, 1990 to David L. Bourell
et al and assigned to Board of Regents, The University of Texas
System provides the state of technology information reproduced
below.
[0006] A method and apparatus for selectively sintering a layer of
powder to produce a part comprising a plurality of sintered layers.
The apparatus includes a computer controlling a laser to direct the
laser energy onto the powder to produce a sintered mass. The
computer either determines or is programmed with the boundaries of
the desired cross-sectional regions of the part. For each
cross-section, the aim of the laser beam is scanned over a layer of
powder and the beam is switched on to sinter only the powder within
the boundaries of the cross-section. Powder is applied and
successive layers sintered until a completed part is formed.
[0007] U.S. Pat. No. 5,155,324 for a method for selective laser
sintering with layer-wise cross-scanning issued Oct. 12, 1992 to
Carl R, Deckard et al, University of Texas at Austin, provides the
state of technology information reproduced below.
[0008] Selective laser sintering is a relatively new method for
producing parts and other freeform solid articles in a
layer-by-layer fashion. This method forms such articles by the
mechanism of sintering, which refers to a process by which
particulates are made to form a solid mass through the application
of external energy. According to selective laser sintering, the
external energy is focused and controlled by controlling the laser
to sinter selected locations of a heat-fusible powder. By
performing this process in layer-by-layer fashion, complex parts
and freeform solid articles which cannot be fabricated easily (if
at all) by subtractive methods such as machining can be quickly and
accurately fabricated. Accordingly, this method is particularly
beneficial in the production of prototype parts, and is
particularly useful in the customized manufacture of such parts and
articles in a unified manner directly from computer-aided-design
(CAD) or computer-aided-manufacturing (CAM) data bases.
[0009] Selective laser sintering is performed by depositing a layer
of a heat-fusible powder onto a target surface; examples of the
types of powders include metal powders, polymer powders such as wax
that can be subsequently used in investment casting, ceramic
powders, and plastics such as ABS plastic, polyvinyl chloride
(PVC), polycarbonate and other polymers. Portions of the layer of
powder corresponding to a cross-sectional layer of the part to be
produced are exposed to a focused and directionally controlled
energy beam, such as generated by a laser having its direction
controlled by mirrors, under the control of a computer. The
portions of the powder exposed to the laser energy are sintered
into a solid mass in the manner described hereinabove. After the
selected portions of the layer have been so sintered or bonded,
another layer of powder is placed over the layer previously
selectively sintered, and the energy beam is directed to sinter
portions of the new layer according to the next cross-sectional
layer of the part to be produced. The sintering of each layer not
only forms a solid mass within the layer, but also sinters each
layer to previously sintered powder underlying the newly sintered
portion. In this manner, the selective laser sintering method
builds a part in layer-wise fashion, with flexibility, accuracy,
and speed of fabrication superior to conventional machining
methods.
SUMMARY
[0010] This section provides a general summary of the disclosure,
and is not a comprehensive disclosure of its full scope or all of
its features.
[0011] In one aspect the present disclosure relates to a method of
producing a product through additive manufacturing with heat
treatment. The method may comprise the steps of providing a
substrate, positioning a layer of powder particles on the substrate
producing an interface between the layer of powder particles and
the substrate, and melting the powder particles with a fusing beam.
The fusing beam may be impressed with a two dimensional pattern
containing image information from a first layer to be printed. The
fusing beam fuses the powder particles with the substrate in a
desired shape and pattern producing fused powder particles. The
method may further include heat treating the fused powder particles
with a beam impressed with an additional two dimensional pattern.
The additional two dimensional pattern may contain image
information from the first layer to be printed to achieve heat
treatment of the product. The heat treating may be completed prior
to laying down additional new layers of material. The heat
treatment may comprise an annealing operation implemented using the
additional two dimensional pattern on at least one or more portions
of one or more intermediate layers of the part. The method may
further include providing a new layer of powdered material on top
of said layer of fused powder particles subsequent to said heat
treatment, and repeating the melting and heat treating operations
in a layer-by-layer fashion using the two dimensional pattern and
the additional two dimensional pattern, until the part is
completed.
[0012] In another aspect the present disclosure relates to a method
of producing a product through additive manufacturing with heat
treatment. The method may comprise the steps of providing a
substrate, positioning a layer of powder particles on the substrate
producing an interface between said layer of powder particles and
the substrate, and using a laser to melt the powder particles with
a laser beam. The laser beam may be impressed with a two
dimensional pattern containing image information from a first layer
to be printed in making the product. The laser beam may be used to
fuse the powder particles with the substrate in a desired shape and
pattern producing fused powder particles. The method may further
include heat treating the fused powder particles with an additional
laser beam impressed with an additional two dimensional pattern
containing additional image information to achieve heat treatment
of the product, prior to laying down additional new layers of
material. The heat treatment may comprise an annealing operation
implemented using the additional two dimensional pattern.
[0013] In still another aspect the present disclosure relates to a
method of producing a product through additive manufacturing with
heat treatment. The method may include providing a substrate,
positioning a layer of powder particles on the substrate producing
an interface between said layer of powder particles and the
substrate, and melting the powder particles. Melting of the powder
particles may be accomplished with a first laser beam impressed
with a two dimensional pattern containing image information from a
first layer to be printed, to fuse the powder particles with the
substrate and produce fused powder particles. The method may
further include performing an annealing operation with a second
laser beam impressed with an additional two dimensional pattern
containing additional image information to achieve heat treatment
of at least a portion of the first layer of the product, prior to
laying down additional new layers of material. The method may
further include performing a laser peening operation on at least a
portion of the first layer of the product, then providing a new
layer of powdered material on top of the first layer of fused
powder particles subsequent to the heat treatment, and then
repeating the melting, annealing and laser peening operations in a
layer-by-layer fashion using the two dimensional pattern and the
additional two dimensional pattern, until the part is
completed.
[0014] Further areas of applicability will become apparent from the
description provided herein. The description and specific examples
in this summary are intended for purposes of illustration only and
are not intended to limit the scope of the present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The accompanying drawings, which are incorporated into and
constitute a part of the specification, illustrate specific
embodiments of the apparatus, systems, and methods and, together
with the general description given above, and the detailed
description of the specific embodiments, serve to explain the
principles of the apparatus, systems, and methods.
[0016] An embodiment of the inventor's apparatus, systems, and
methods is illustrated in the single FIGURE of drawings.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0017] Referring to the drawings, to the following detailed
description, and to incorporated materials, detailed information
about the apparatus, systems, and methods is provided including the
description of specific embodiments. The detailed description
serves to explain the principles of the apparatus, systems, and
methods. The apparatus, systems, and methods are susceptible to
modifications and alternative forms. The application is not limited
to the particular forms disclosed. The application covers all
modifications, equivalents, and alternatives falling within the
spirit and scope of the apparatus, systems, and methods as defined
by the claims.
[0018] Additive manufacturing, or 3D printing, is the process of
turning digital designs into three-dimensional objects. It is a
convenient and affordable way to make prototypes as well as
finished products, making it popular with businesses, hobbyists and
inventors. One of the technologies used by today's 3D printers is
called selective laser sintering (SLS). SLS is a manufacturing
technology that was created in the 1980s at The University of Texas
at Austin. During SLS, tiny particles of plastic, ceramic or glass
are fused together by heat from a high-power laser to form a solid,
three-dimensional object. Another technology used by today's 3D
printers is called selective laser melting (SLM). SLM is similar to
SLS except that metal powder is used to form a three-dimensional
product.
[0019] Like all methods of 3D printing, an object printed with an
SLS or SLM machine starts as a computer-aided design (CAD) file.
CAD files are converted to .STL format, which can be understood by
a 3D printing apparatus. Objects printed with SLS or SLM are made
with powder materials, most commonly plastics such as nylon in SLS,
and metal powders in SLM, which are dispersed in a thin layer on
top of the build platform inside an SLS or SLM machine. A laser,
which is controlled by a computer that tells it what object to
"print," is incident on the platform, tracing a cross-section of
the object onto the powder.
[0020] Initially a 3D model of the desired product is designed by
any suitable method, e.g., by bit mapping or by computer aided
design (CAD) software at a PC/controller. The CAD model of the
desired product is electronically sliced into series of
2-dimensional data files, i.e., 2D layers, each defining a planar
cross section through the model of the desired product. The
2-dimensional data files are stored in a computer and provide a
digital image of the final product.
[0021] The digital images are used in the additive manufacturing
system to produce the final product. Solidified powder particles
are applied to a substrate in a layer by layer process to produce
the final product. The digital image of the first 2D layer is used
to produce the first layer of the desired product.
[0022] A first embodiment of the inventor's apparatus, systems, and
methods is illustrated in the drawing. This embodiment is
designated generally by the reference numeral 100. A delivery
system directs metal powder particles from a material build supply
onto a substrate 102. A fusing light source 110 directs a projected
beam 114 onto the layer of metal powder particles 104 that have
been deposited on the substrate 102. The digital image of the first
2D layer is used to produce the first layer of the desired product.
Relative movement between the projected beam 114 and the substrate
102 is indicated by the arrow 118.
[0023] The projected beam 114 containing the digital image of the
first 2D layer is projected from the fusing light source 110 onto
the layer of metal powder particles 104 that has been deposited on
the substrate 102. The projected beam 114 solidifies the metal
powder particles according to the digital image of the first 2D
layer information producing the sintered layer 106.
[0024] The sintered layer 104 is heat treated to remove residual
stress in the first and subsequent layers to improve the quality of
the final product. Residual stresses are common in additive
manufacturing due to localized heat deposition into the powder bed,
and the cooling process that follows. Residual stresses can weaken
the part being formed and cause changes in dimension while being
formed, or afterwards. These stresses can cause internal cracking
or yielding and present a serious problem in additive manufacturing
technology.
[0025] The inventor's apparatus, systems, and methods utilize a
secondary energy source 112 to peen or anneal residual stresses
developed during the additive manufacturing process. A beam 116 is
projected from the secondary energy source 112 onto the sintered
layer 104 to remove residual stress in the sintered layer and
produce the final layer 108. Relative movement between the beam 116
and the substrate 102 is indicated by the arrow 118.
[0026] Once the first layer 108 is completed, production of the
second layer of the product is started. A second layer of metal
powder particles is applied on top of the competed first layer 108.
This procedure is continued by repeating the steps and building the
final product in a layer by layer process. The inventor's
apparatus, systems, and methods remove residual stresses in each
layer as it is formed and/or through post processing though peening
or annealing through the use of lasers, diodes, other forms of
electromagnetic radiation, or other heat sources.
[0027] The inventor's apparatus, systems, and methods uses laser
peening and thermal annealing technology in situ with the additive
manufacturing process to anneal residual stresses and harden the
structure of parts as they are being created. For Direct Metal
Laser Sintering (DMLS) or Diode Additive Manufacturing (DiAM),
these processes would be used intermediately between layer
development (or in a post processing step) to ensure that the
residual stresses in that layer(s) were eliminated. Through
peening, layer hardening and uniform compressive stresses could be
added internally to the part instead of just on the skin depth
which is traditionally up to a couple millimeters. Upon part
completion, peening and other thermal processes can be used to
polish and smooth the rough and sometime "stair-stepped" edges that
result from the layer by layer additive manufacturing process.
[0028] Although the description above contains many details and
specifics, these should not be construed as limiting the scope of
the application but as merely providing illustrations of some of
the presently preferred embodiments of the apparatus, systems, and
methods. Other implementations, enhancements and variations can be
made based on what is described and illustrated in this patent
document. The features of the embodiments described herein may be
combined in all possible combinations of methods, apparatus,
modules, systems, and computer program products. Certain features
that are described in this patent document in the context of
separate embodiments can also be implemented in combination in a
single embodiment. Conversely, various features that are described
in the context of a single embodiment can also be implemented in
multiple embodiments separately or in any suitable subcombination.
Moreover, although features may be described above as acting in
certain combinations and even initially claimed as such, one or
more features from a claimed combination can in some cases be
excised from the combination, and the claimed combination may be
directed to a subcombination or variation of a subcombination.
Similarly, while operations are depicted in the drawings in a
particular order, this should not be understood as requiring that
such operations be performed in the particular order shown or in
sequential order, or that all illustrated operations be performed,
to achieve desirable results. Moreover, the separation of various
system components in the embodiments described above should not be
understood as requiring such separation in all embodiments.
[0029] Therefore, it will be appreciated that the scope of the
present application fully encompasses other embodiments which may
become obvious to those skilled in the art. In the claims,
reference to an element in the singular is not intended to mean
"one and only one" unless explicitly so stated, but rather "one or
more." All structural and functional equivalents to the elements of
the above-described preferred embodiment that are known to those of
ordinary skill in the art are expressly incorporated herein by
reference and are intended to be encompassed by the present claims.
Moreover, it is not necessary for a device to address each and
every problem sought to be solved by the present apparatus,
systems, and methods, for it to be encompassed by the present
claims. Furthermore, no element or component in the present
disclosure is intended to be dedicated to the public regardless of
whether the element or component is explicitly recited in the
claims. No claim element herein is to be construed under the
provisions of 35 U.S.C. 112, sixth paragraph, unless the element is
expressly recited using the phrase "means for."
[0030] While the apparatus, systems, and methods may be susceptible
to various modifications and alternative forms, specific
embodiments have been shown by way of example in the drawings and
have been described in detail herein. However, it should be
understood that the application is not intended to be limited to
the particular forms disclosed. Rather, the application is to cover
all modifications, equivalents, and alternatives falling within the
spirit and scope of the application as defined by the following
appended claims.
* * * * *