Note: Descriptions are shown in the official language in which they were submitted.
200552'
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FABRICATION OF COMPONENTS BY hAYERED DEPOSITION
BACKGROUND OF THE INVENTION
This invention relates to the fabrication of
components, and, more particularly, to fabrication by
controlled deposition of layers of the constituents.
Improvements in manufacturing technology and
materials are the keys to increased performance and
reduced cost for many articles. As an example,
continuing and often interrelated improvements in
processes and materials have resulted in major increases
in the performance of aircraft gas turbine engines.
An aircraft gas turbine or jet engine draws in
and compresses air with an axial flow compressor, mixes
the compressed air with fuel, burns the mixture, and
expels the combustion product through an axial flow
turbine that powers the compressor. The compressor
includes a disk with blades projecting from its
periphery. The disk turns rapidly on a shaft, and the
curved blades draw in and compress air in somewhat the
same manner as an electric fan.
In current manufacturing practice, the
compressor is made by forging the compressor disk as a
single piece with slots at the periphery. The
compressor blades are individually cast or forged to
shape with a root section termed a "dovetail" that fits
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into the slots in the disk. Assembly is completed by
sliding the dovetail sections of the blades into the
slots in--the disk. If a blade does not fit properly,
fails or is damaged during service, it may be readily
replaced by reversing the assembly procedure to remove
the blade, and providing a new blade.
More recently, it has been proposed to form
the blades integrally with the disk, in a combination
termed a "blisk". The blisk approach to manufacturing
offers the potential for increased performance through
reduced weight. Such an article can be cast or forged
as a large disk with an excess of metal at the
periphery. The blades are then machined from the excess
metal, integrally attached to the disk. The final
product -is expensive to produce, as it requires
extensive high-precision machining operations. An error
in machining even one of the blades may result in
rejection and scrapping of the entire blisk.
Replacement or repair of a damaged blade
portion of the blisk presents a difficult problem with
this manufacturing approach. If all or a portion of a
blade breaks off due to ingested foreign objects during
operation, for example, the blisk becomes unbalanced.
There is no method presently known to repair the damaged
blade in a manner that does not result in reduced
performance, and there is a need for such an approach.
Desirably, such an approach would be utilized in
manufacturing the blisk to reduce its cost. The present
invention fulfills this need, and further provides
related advantages.
SUMMARY OF THE INVENTION
The present invention provides a process for
fabricating and repairing articles and portions of
articles -such as the blades of blisks. The process
200552'7
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produces an article comparable in properties with cast
or forged articles, but with the additional benefit of
being integrally formed with another component. When
the process is used to repair a damaged article that was
previously manufactured by the same process, the
repaired article is virtually indistinguishable from the
original. The process permits excellent control over
shape and configuration of simple and complex shapes,
and also permits gradation in composition throughout the
article. The composition variation control in turn
provides designers with the opportunity to design an
article with specific properties suited to the
performance requirements of different regions.
In accordance with the invention, a process
for fabricating an article comprises the steps of
depositing a first bead of a material in a pattern and
width of a first cross section of the article;
depositing a second bead of a material overlying the
first bead of material, in a pattern, position, and
width relative to the first bead, of a second cross
section of the article, the second cross section being
taken at a location spaced from the first cross section
by the thickness of the first bead; and repeating the
step of depositing a second bead in a plurality of
deposition steps, -each successive bead being deposited
in a pattern, position, and width relative to the
previously deposited bead, of the next cross section of
the article taken at a location spaced from the prior
cross section by the thickness of the previously
deposited bead; until the entire-article is complete.
Alternatively stated and in another
embodiment, a process for fabricating an article
comprises the steps of characterizing the article as a
plurality of parallel sections, each section having a
pattern and position, and each section being displaced
200552'7
i
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from adjacent sections by the thickness of a bead of a
material; and depositing a succession of beads of the
material overlying each other, each bead having a
pattern and position corresponding to that of the
respective section determined in the step of
characterizing.
In accordance with a preferred specific
application of the invention, a process for fabricating
a compressor blade that is integral with a compressor
disk comprises the steps of furnishing a compressor disk
having a substrate surface at its periphery; depositing
a first bead of a material onto the substrate surface,
the bead having the pattern and position of the
compressor blade adjacent the compressor disk; and
depositing a succession of beads of a material, each
bead overlying the previously deposited bead, and each
bead having the pattern and position of the
corresponding portion of the compressor blade. If the
section of the blade is thicker than a single bead, two
or more side-by-side beads may be deposited to make a
single layer, and then additional sets of beads
deposited overlying that layer to form subsequent
layers.
Many articles may be analyzed as being an
assembly of sections or slices parallel to each other.
The article is then uniquely defined by specifying the
pattern of each section, that is, its shape and size,
and the position of each section, that is, its
relationship to the adjacent sections. The pattern of
each section may be amenable to formation by a bead of
deposited material, where a bead is an elongated deposit
typically formed by moving the substrate relative to the
heat source. Where such is the case, the article may be
formed by depositing a bead (or several side-by-side
beads, if necessary) in the shape of the pattern of a
2005~2'~
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section, and then incrementing the deposition apparatus
upwardly by the bead height, thereafter depositing
another bead having the pattern of the next section and
the required position in relation to the previously
deposited bead. The process is repeated as many times
as necessary to form the article.
For example, certain compressor blades are
relatively thin in width, on the order of 1/8 inch, a
readily deposited bead width for a laser welding
apparatus. Each section is deposited in a single pass
of the laser welding apparatus. Upon completion of the
pass, the weld head is incremented upwardly by the
height of the bead, typicallyabout .015 inch, and the
next section is deposited in a single laser welding
pass. During each pass, the laser welding deposition
unit melts the upper portion of the previously deposited
bead (or substrate, in the first pass), and adds more
material through its powder feed to form the overlying
bead. The newly added material of the overlying bead
and the melted portion of the previously deposited bead
partially intermix and solidify together, ensuring a
continuous, strong structure through the beads.
A wide variety of shapes and sectional
configurations can be made by this approach. Solid
figures are made by laying down beads one above the
other. Increased thickness is achieved by laying down
several beads in a side-by-side fashion in each layer,
and then adding more beads above that layer. Parts of
varying thickness are made by changing the number of
beads in a layer. Hollow airfoil or other hollow shapes
are made by depositing the bead in the shape of the
outer wall, and then depositing additional beads one on
top of the other. Hollow sections with internal
structure, such as cooling passages, are made by adding
internal ribs and the like to each section, in addition
200552'
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to the outer walls. Virtually any shape can be defined
as a collection of beads, and the present approach has
the versatility to make such a wide variety of shapes.
Typical aircraft engine applications include compressor
blades, turbine blades, fan blades, tubes, and boxes,
with the later being square, rectangular, or of
irregular cross section.
The preferred pieces made utilizing the
invention, compressor blades, are typically a complex
airfoil shape, involving a two-dimensional curvature.
One dimension of curvature is readily introduced into
the article by moving the part relative to the weld
deposition bead in a curved path during each pass, with
movement achieved by moving the part, the weld
deposition head, or both. The other dimension of
curvature is introduced by displacing each section
laterally by a small amount from the preceding section.
The control of the deposition is accomplished
by numerically characterizing the shape of the article
such as a blade from drawings or a part prepared by more
conventional methods such as machining. Once the shape
of the part is numerically characterized, the movement
of the part (or equivalently, the deposition head) is
programmed using available numerical control computer
programs to create a pattern of instructions as to the
movement of the part during each pass, and its lateral
displacement between passes. The resulting article
reproduces the shape of the numerical characterization
quite accurately, including complex curvatures of an
airfoil or the like.
The laser welding technique melts powders in a
feed and projects the molten material onto a surface.
The approach is controllable and yields reproducible,
precise results. In fabricating an article by the
present approach, the composition of the powder feed may
200552
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be maintained constant throughout the entire article.
Alternatively, the composition of the powder feed may be
intentionally varied within any bead or as between
successive beads, to produce controllable composition
variations throughout the article. For example, in a
compressor blade a strong, tough alloy composition may
be used near the base and a hard, wear resistant or
abrasive alloy near the tip.
For the repair of articles, it is necessary
only to repeat a portion of the deposition sequence from
the previously developed characterization. For example,
if a compressor blade breaks near the midpoint, it is
necessary only to grind a flat surface onto the blade
corresponding to the closest remaining undamaged
section, and then to repeat the computer controlled
deposition of the remainder of the blade. The repaired
blade is virtually indistinguishable from the originally
fabricated blade, as it is accomplished by the same
apparatus and with the same shape-controlling pattern.
The repaired portion has no macroscopically detectable
bond line after finishing or discontinuity to the base
portion of the blade, because the two are welded
together in the same manner employed when the blade was
manufactured.
A wide variety of materials may be deposited
using the approach of the invention. For example,
titanium alloys, nickel alloys, cobalt alloys, iron
alloys, ceramics, and plastics may be deposited.
The present invention provides an important
advance in the art of fabrication. Complex pieces may
be fabricated integrally to another part, with no
macroscopically detectable bond line after machining, or
use of fasteners. There is great versatility as to both
shape and local composition of the article. Repair is
facilitated by using the same procedure as in initial
200SS2'7
- 8 - 13DV-9145
fabrication, with computer controlled deposition. Other
features and advantages of the present invention will be
apparent from the following more detailed description of
the preferred embodiment, taken in conjunction with the
accompanying drawings, which illustrate, by way of
example, the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective drawing of an
integral compressor disk and blades, or blisk;
Figure 2 is an enlarged perspective view of
the blade portion of Figure 1;
Figure 3 is an elevational view of the blade
of Figure 2;
Figure 4 is an end plan view of the blade of
Figure 2;
Figure 5 isa diagrammatic representation of
the patterns of four representative beads A, B, C, and D
as indicated in Figure 3; and
Figure 6 is an elevational view of a laser
welding apparatus for practicing the process of the
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention is preferably embodied
in a process for fabricating or repairing a compressor
blade integral with a compressor disk, although the
invention is not so limited. Referring to Figure 1, an
integral combination of a compressor disk 10 and a
plurality of compressor blades 12 constitutes an
integral blade/disk unit or blisk 14. The disk portion
10 is of a generally cylindrical, wheel shaped
configuration having a rim 16 at the periphery. The
plurality of blades 12 are joined to the disk portion 10
at the rim 16, in the correct position and orientation
200552'7
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to catch and compress air as the blisk 14 turns. (In
Figure 1, only a few blades 12 are illustrated around
the periphery of the disk portion, for clarity of
illustration. Normally, many more closely spaced blades
are present).
Figure 2 illustrates a blade portion 12 in
greater detail. The blade portion 12 is joined to the
rim 16 integrally. That is, the blade is not formed as
a separate piece and then joined to the rim and the
disk. The blade is structurally integral with the rim
16, with a continuous structure progressing from the rim
16 to the blade 12.
The blade 12 is normally of a complex airfoil
shape determined by detailed calculations of the optimal
approach for compressing the air. The axial compressor
of the engine normally includes numerous stages of
compressors, and the precise shape and size of each
blade portion varies from stage to stage. Generally,
however, the blade portion 12 is curved in two
directions. That is, if a perpendicular coordinate
geometry is defined by a radius 18 of the disk 10 and a
circumferential tangent 20 to the rim 16, at least some
portions of the blade 12 will be curved with respect to
each of the radius 18 and the tangent 20. Moreover, the
chord length and curvature are not constant throughout
the blade, with the curvature usually varying across the
span of the airfoil and along its length, and the chord
varying along the length. The fabrication of such
complex curved shapes by conventional machining,
forging, or casting procedures requires careful
attention and is costly.
The structure of the blade portion 12 may be
characterized with section lines taken through the blade
12 normal to the radial direction 18. Four exemplary
sections A, B, C, and D are indicated in Figure 3 at
i~~~JJI~r~
- 10 - 13DV-9145
increasing radial distances. The complex curvature of
the blade 12 can also be seen in the end view of Figure
4.
Figure 5 illustrates the pattern and relative
position of the section lines A, B, C, and D in an
abstract sense,- apart from their relationship to the
blade 12. The shape of the blade at section A is as
indicated by the pattern of A, the shape of the blade at
section B is as indicated by the pattern of B, and so
forth. In the present approach, the blade 12 is
fabricated by depositing a first bead of metal along the
pattern of A, a second bead of metal overlying the first
bead, but following the pattern of B, and so forth. The
thickness of the blade at section A is usually greater
than the thickness of the blade at-section B, because a
filet of increased width is normally formed near the
bottom or root of the blade. Thus, for example,
adjacent the substrate the blade may be made 4 beads
wide, the next layer up may be 3 beads wide, the next
layer 2 beads wide, and succeeding layers 1 bead wide.
The thickness of the blade at different layers or
sections may be controllably varied by changing the
number of beads in each layer.
The shape of the blade (as distinct from its
thickness) is varied by changing the shape and pattern
of the bead. The bead along pattern B has a shape
different from the bead along pattern A, as is apparent
from the different curvature of patterns A and B of
Figure 5. Curvature may also be controllably varied by
displacing a bead from the underlying, previously
deposited bead. For example, pattern B is laterally
displaced from pattern A by a displacement 22, which
varies with location along the bead. That is, pattern B
not only has a different shape or pattern, but also a
different position in space in respect to pattern A.
2~OS52'~
- 11 - 13DV-9145
The bead following pattern B is therefore not directly
overlying the bead following pattern A, but is slightly
displaced to a different position. The displacement may
also be along the length of the pattern, creating a
sweeping shape to the blade. Although the illustrated
displacement may appear to be rather large, it will be
recalled that illustrative patterns A and B in the
drawings are taken at well-separated sections for
purposes of illustration. In reality, the displacements
H between two adjacent beads is small, typically about
.015 inch, and well within the limits of maintaining
continuity of the blade 12.
To fabricate the blade 12, the shape of the
blade is first characterized in a section by section
manner. That is, the pattern and position of each
section is carefully recorded, either from a drawing, a
calculation, or a previously prepared part. For each
section, the necessary information can be obtained in
one of two ways. In a relative positioning method, it
is necessary to know (1) the pattern of -the section,
that is, the coordinates of each point along the pattern
line (such as B) and (2) the relativeposition of the
section in respect to the previous section (such as the
displacement 22 between pattern B and pattern A, on a
point by point basis. Alternatively, in an absolute
positioning method, it is-necessary to know the position
of each point of deposition of bead material in respect
to some external frame of reference. In either case,
the numerical information which, in total, defines the
shape of the blade in three dimensions is readily
determined and stored in the manner used for numerically
controlled metalworking machinery.
After the detailed shape of the blade or other
article is defined, metal beads are deposited in an
overlying fashion to reproduce the stored numerical
2~~552'7
- 12 - 13DV-9145
form. It is necessary to utilize apparatus which
produces a well defined bead, and is also controllable
to follora the required numerical form. A laser welding
apparatus has been developed to meet these requirements,
and will be described in detail below. The present
invention does not, however, encompass the apparatus
itself, but instead relates to a method of use.
More specifically, a first bead 24 is
deposited along the pattern A, upon the rim 16 as a
substrate. Enough heat is transferred into the rim 16
to cause some surface melting of the substrate material,
and the material of the~bead 24 is predominantly molten
when it reaches the substrate. The molten materials
intermix and quickly solidify. The first bead 24 is
thereby fused into the rim 16 to form an integral bond
therewith. No bond line or lamination is
macroscopically visible or detectable. After final
machining and finishing, for all practical purposes, the
first bead 24 is fully integral with the rim 16. If the
compositions of the material of the rim 16 and the first
bead 24 are different, there will be some intermixing of
the compositions in the melted zone.
After completion of the pass that forms the
first bead 24, the deposition apparatus performs a
second pass to deposit a second bead 26. In the second
pass, the part follows the pattern of the next section
up from section A, which generally will have a slightly
different pattern (curvature), position, and length, and
may be laterally displaced, which parameters had been
3o previously determined and stored. The distance between
each section in characterizing the shape of the blade 12
is usually taken to be about the height H of the bead
that is deposited by the deposition apparatus, which is
dependent upon the type of apparatus, the material being
deposited, the travel rate, and other factors, but for
- 13 - 2005527 13DV-9145
laser welding is typically about 0.015 inch. The first bead 24 is locally
partially melted as the second bead 26 is deposited thereover. The second
bead 26 is thus fused into the underlying first bead 24 in the same manner
described above for the fusing of the first bead 24 with the substrate, again
resulting in a fully integral structure.
This procedure of depositing an overlying bead is repeated
until the entire height of the blade 12 has been formed. By depositing the
beads following the patterns previously determined, the blade is accurately
reproduced. Any roughness on the surface of the blade due to imperfect
registry of successive blades can be ground and polished away, completing
the manufacture of the integral blade.
The present approach offers important advantages in addition
to the versatility and integral construction indicated previously. The
material feed into the deposition apparatus can be varied along the length of
. any one bead, or between successive beads, to vary the composition of the
article between different regions thereof. Because the composition of the
deposited material, like the shape, may be numerically controlled, it is
possible to form fields of particular composition to achieve particular
purposes. For example, the portions near the base of the blade 12 (i.e.,
section A) may be made strong and ductile, while the portions near the tip
of the blade 12 (i.e., section D) may be made hard and wear resistant or
abrasive. Portions most subject to aerothermal heating can be given a
particular composition. Moreover, the microstructure of the blade is unlike
that of a blade produced by any other method, having a successively
remelted structure.
Repair of the blade 12, as after undergoing
20~552'7
- 14 - 13DV-9145
damage in use, is also facilitated by the present
approach. If, for example, the tip of the blade 12 were
broken off along a gagged line indicated at numeral 28
in Figure 3, repair is accomplished by grinding the
blade 12 back to a section at which it is determined
that there has been no damage. Such a section might be
section C. Deposition of a new tip overlying section C
would then be performed, in exactly the same manner as
if the blade were first being manufactured using this
method. The numerical characterization of the blade
having been retained for such possibility, the new tip
can be deposited as identical to the original damaged
tip. Any improved characteristics, such as a new,
improved airfoil shape or a different material
composition, could be incorporated, if such modification
would not alter the performance of the blisk 14 because
the other blades were not given the same modification.
In any event,--because of the melting and fusion of
succeeding beads, the repaired blade would remain fully
integral along its length and have no plane of
significant weakness.
Many different techniques araknown to deposit
beads of metal and other substances. Some produce a
diffuse spray, and such techniques are generally not
applicable to the practice of the present invention. A
particularly satisfactory apparatus for practicing the
present invention has been found to be a laser welding
apparatus, in which a laser beam melts a pool on the
surface at which it is directed, and a finely divided
feed material is fed to the melted region to add a new
deposit of material, termed a "bead". By moving the
part along a controlled path, a carefully defined and
shaped bead is formed.
An apparatus 38 for performing controlled
laser welding deposition of beads, and useful in
20055''.'7
- 15 - 13DV-9145
practicing the present invention, is illustrated in
Figure 6. This apparatus is described in greater detail
in U.S. Patent 4,730,093, issued March 8, 1988, Mehta
et al.
The apparatus 38 includes an enclosed powder
reservoir shown generally at 40, heated by heating coils
42 for the purpose of controlling the moisture content
at a low level in the powder. Also included is a gas
inlet port 44 through which a preferably dry inert gas
such as argon, represented by arrow 46, is introduced to
maintain powder 48 in reservoir 40 under pressure and to
assist in powder transport. Associated with the powder
reservoir is a mechanical, volumetric powder feed
mechanism such as powder feed wheel 50 of a type
commercially available. For example, the type used in
one form of the apparatus of the present invention was a
modified Metco powder feed "L" type wheel.
Downstream of wheel 50 is a vibrator such as
air actuated vibrator 52 associated with conduit 54 to
inhibit powder particles moving in conduit 54 from
adhering one to the other or to walls of the conduit 54.
Conduit 54 terminates in a water-cooled powder delivery
noz2le 56 which directs the powder, assisted by the
pressurized inert gas, in a consistent flow, such as
toward a substrate or previously deposited bead on a
blade 12. It has been found that reflection from the
laser beam can result in clogging of powder passing
through nozzle 56. Therefore, such a nozzle, preferably
having at least a tip portion made of a material, such
as copper or aluminum, which is highly reflective to the
wavelength of the laser used, is fluid cooled, as by
water, to avoid such problem and to assist in a
consistent flow of powder. Such consistent flow of
powder resultsfrom the combination of use of powder
~oassz~
i
- 16 - 13DV-9145
maintained in a low moisture condition, under a positive
inert gas pressure, being fed by a mechanical volumetric
powder feed mechanism along with a powder vibrator, and
a cooled nozzle through which the powder passes toward
the article surface in the laser beam spot.
It is contemplated that there may be
additional conduits 54 of similar configuration spaced
around the delivery point of the powder, should that be
desired. The powder streams delivered by the several
conduits 54 would be positioned so that there was
convergence at the surface of the workpiece.
The apparatus 38 includes a laser 58 emitting
a beam 60 having a beam axis 62. The laser 58 has a
power output sufficient to accomplish its melting
functions. An operable embodiment of the invention has
used a 5 kilowatt (kW) carbon dioxide laser to
manufacture compressor blades, but larger or smaller
lasers may be used as necessary. The beam 60 has a
focal plane 64 beneath the surface 66 upon which the
bead is to be deposited, to provide at the surface a
beam spot 68 of a size typically in the range 0.005-0.2
inches, although again these dimensions are illustrative
and not restrictive. The laser energy is ordinarily
applied with a power density of from about 103 to about
106 watts per square centimeter to melt a pool of
material coincident with the beam spot 68.
The bead of deposited material is deposited by
feeding powder through the conduit 54 into the molten
pool at the beam spot 68. The powder is fed from nozzle
56 at an angle preferably in the range of about 35-60
degrees from the article surface, and most preferably in
the range of about 40-55 degrees. An angle of greater
than about 60 degrees makes it difficult for the nozzle
and powder to avoid premature interaction with the laser
beam, and less than about 35 degrees makes it difficult
200552'7
- 17 - 13DV-9145
to deliver the powder concurrently with the laser beam
at the spot desired on the article surface. As relative
lateral movement is provided between the laser beam spot
and the article carrying its superimposed powder,
progressive melting, cooling and solidification of the
molten interaction zone occurs, producing a bead.
The blisk 14, of which the blade 12 and the
rim 16 are a part, is supported on a movable support 80,
which moves the blade 12 in two directions, the x
direction 70 (and the -x direction) and the y direction
71 (out of the plane of the illustration of Figure 6,
and the -y direction into the plane of the illustration
of Figure 6, as illustrated by the dot at numeral 71).
By controlling the combination of x and y direction
movement of the support 80, while maintaining the
conduit 54 and laser 58 at constant height, a
well-defined bead is deposited having the pattern
required for that particular section of the blade 12.
The conduit 54 and laser 58 are rigidly
supported on an apparatus support 82. The support 82 is
movable in the z direction 84 (and the -z direction), to
raise or lower the conduit 54 and the laser 58. Through
the supports 80 and 82, the laser 58 and conduit 54 may
be moved relative to the blade 12 in all three
dimensions. By controlling the combination of x and y
direction movement of the support 80, while maintaining
the conduit 54 and laser 58 at constant z height, a
well-defined bead is deposited having the pattern
required for that particular section of the blade 12.
(Equivalently, the combination of relative x, y, and z
movement could be supplied by moving the support 82 in
the x and y directions, and the support 80 in the z
direction, or any other similar combination of
movements).
20055 '~
- 18 - 13DV-9145
At the completion of a bead (for example, the
first bead 24), the apparatus 38 is incremented upwardly
to raise the conduit 54 and the laser 58 by an amount
typically chosen to be the height or thickness of the
bead H, so that another bead (for example, the second
bead 26) may be deposited overlying the first bead 24.
Figure 6 illustrates the deposition process at a stage
whereat the first bead 24 has been completed, and the
second bead 26 is partially deposited. As the second
bead 26 is deposited, the upper portion of the first
bead 24 is remelted, ensuring the mixing and structural
continuity of the two beads 24 and 26.
The following examples are presented to
illustrated aspects of the invention, and should not be
taken as limiting of the invention in any respect.
Examule 1
The apparatus previously described was
utilized to form a compressor blade integral with a
substrate. The beam of a 3 kW carbon dioxide laser was
focused to a spot diameter of .356 centimeters, and thus
a power density of 30 kW per square centimeter. A
doubly curved compressor blade having the general
configuration illustrated in Figures 1-5 was deposited.
The length of the blade was about 3 inches. The height
of each bead was about .015 inch. A total of 200 passes
was required to fabricate the blade, at a linear
traverse rate -of the substrate relative to the laser
beam of 50 inches per minute as the powder was
deposited. The deposited alloy was Ti-6A1-4V, furnished
to the conduit as -35/+230 mesh powder, at a feed rate
of about 10 grams per minute, and the substrate was
Ti-6A1-4V. The blade and surrounding area were within
an atmosphere of argon during deposition.
~ooss~~
- 19 - 13DV-9145
Egamule 2
Example 1 was repeated, except that the
deposited alloy was Inconel 718TM alloy, the substrate
was Inconel 718 alloy, and the traverse rate was 8o
inches per minute.
Eaamole 3
Example 2 was repeated, except that the
substrate was Rene 95TM alloy.
The present invention thus provides a highly
l0 versatile tool for fabricating and repairing articles.
Although the present invention has been described in
connection with specific examples and embodiments, it
will be understood by those skilled in the arts involved
that the present invention is capable of modification
without departing from its spirit and scope as
represented by the appended claims.
