U.S. patent application number 10/678475 was filed with the patent office on 2005-04-07 for uses of support material in solid freeform fabrication systems.
Invention is credited to Collins, David C., Farr, Isaac, Nielsen, Jeffrey Allen, Oriakhi, Christopher.
Application Number | 20050072113 10/678475 |
Document ID | / |
Family ID | 34393938 |
Filed Date | 2005-04-07 |
United States Patent
Application |
20050072113 |
Kind Code |
A1 |
Collins, David C. ; et
al. |
April 7, 2005 |
Uses of support material in solid freeform fabrication systems
Abstract
The present invention is drawn to solid freeform fabrication
systems and methods for producing three-dimensional objects. The
system can include build material configured to be deposited in
layers to form a three-dimensional object; and support material
configured to be deposited adjacent to the build material for
supporting the build material during formation of the
three-dimensional object. The support material can also be
configured to form a feature that imparts a predetermined property
within the three-dimensional object.
Inventors: |
Collins, David C.;
(Philomath, OR) ; Nielsen, Jeffrey Allen;
(Corvallis, OR) ; Farr, Isaac; (Corvallis, OR)
; Oriakhi, Christopher; (Corvallis, OR) |
Correspondence
Address: |
HEWLETT PACKARD COMPANY
P O BOX 272400, 3404 E. HARMONY ROAD
INTELLECTUAL PROPERTY ADMINISTRATION
FORT COLLINS
CO
80527-2400
US
|
Family ID: |
34393938 |
Appl. No.: |
10/678475 |
Filed: |
October 3, 2003 |
Current U.S.
Class: |
52/782.1 ;
52/741.1 |
Current CPC
Class: |
B29K 2995/002 20130101;
B29C 64/40 20170801; B29C 64/188 20170801; B29C 64/112
20170801 |
Class at
Publication: |
052/782.1 ;
052/741.1 |
International
Class: |
E04B 001/00 |
Claims
What is claimed is:
1. A solid freeform fabrication system for producing a
three-dimensional object with embedded features, comprising: build
material configured to be deposited in layers to form a
three-dimensional object; and support material configured to be
deposited adjacent to the build material for supporting the build
material during formation of the three-dimensional object, said
support material also being configured to form a feature that
imparts a predetermined property within the three-dimensional
object.
2. A system as in claim 1, wherein the build material is a liquid
that is configured to be deposited in layers using an ink-jet
printhead.
3. A system as in claim 2, wherein the build material is UV
curable.
4. A system as in claim 1, wherein the feature is within a cavity
defined at least in part by the build material.
5. A system as in claim 4, wherein the cavity is a closed cavity
that is completely defined by build material.
6. A system as in claim 4, wherein the cavity is an open cavity
that is partially defined by the build material and is partially
open to a surface of the three-dimensional object.
7. A system as in claim 1, where the feature imparts color.
8. A system as in claim 1, where the feature imparts
conductance.
9. A system as in claim 7, wherein the build material is at least
partially transparent.
10. A system as in claim 8, wherein the feature also includes
additional build material.
11. A method for solid freeform fabrication of three-dimensional
objects, comprising: layering build material to form a
three-dimensional object, said three-dimensional object including a
cavity therein that is at least in part defined by the build
material; supporting overhangs formed during the layering step
using a first portion of support material; depositing a second
portion of the support material in said cavity, wherein at least
the second portion of the support material is configured to form a
feature that imparts a predetermined property within the
three-dimensional object; and removing the first portion of the
support material from the three-dimensional object.
12. A method as in claim 11, wherein the step of layering includes
step of jetting build material to form multiple layers of build
material.
13. A method as in claim 12, further comprising the step of UV
curing the build material after the jetting step.
14. A method as in claim 11, wherein the first portion and the
second portion of the support material are of the same
composition.
15. A method as in claim 11, further including the step of
depositing build material within the cavity.
16. A method as in claim 15, wherein the build material is at least
partially transparent, the support material imparts a color, and
the build material and the support material are both present within
the cavity at a 1:99 to 99:1 build material to support material
volume ratio.
17. A method as in claim 11, where the feature imparts color.
18. A method as in claim 11, where the feature imparts
conductance.
19. A method as in claim 11, further comprising the preliminary
step of predetermining the location to place cavities within the
three-dimensional object.
20. A method as in claim 19, wherein the step of predetermining is
carried out with the assistance of a computer modeling system.
Description
FIELD OF THE INVENTION
[0001] The present invention is generally related to solid freeform
fabrication systems. More particularly, the present invention
relates to systems for forming three-dimensional objects using
ink-jet technology.
BACKGROUND OF THE INVENTION
[0002] Solid freeform fabrication (or layer manufacturing) can be
defined generally as an additive fabrication technology used to
build a three-dimensional object using layer by layer or point by
point fabrication. With this fabrication process, complex shapes
can be formed without the use of a pre-shaped die or mold.
[0003] Essentially, with such a system, an object can be designed
using a computer program, such as a Computer Aided Design (CAD)
application. Once the object has been designed three-dimensionally,
solid freeform fabrication technology enables the translation of
the computer generated model into a three-dimensional object. This
technology is useful in areas such as verifying a CAD model,
evaluating design feasibility, testing part functionality,
assessing aesthetics, checking ergonomics of design, aiding in tool
and fixture design, creating conceptual models and sales/marketing
tools, generating patterns for investment casting, reducing or
eliminating engineering changes in production, prototyping, and
providing production runs, to name a few.
[0004] Selective deposition techniques generally include the
dispensing of a binder material into a powder or slurry build
material to form the object, or alternatively, bulk-jetting build
material itself to form the object. Bulk-jetting systems can have
optional curing and/or milling systems, which can be used to harden
the build material and/or level the build material, respectively.
With bulkjetting systems, removable support material is typically
deposited during the formation of the object to support overhangs
of build material as the build material hardens.
SUMMARY OF THE INVENTION
[0005] It has been recognized that as support material is already
being used for in solid freeform fabrication systems, it would be
desirable to provide alternative uses of this material to broaden
its scope of use. As such, a solid freeform fabrication system for
producing a three-dimensional object can comprise build material
configured to be deposited in layers to form a three-dimensional
object; and support material configured to be deposited adjacent to
the build material for supporting the build material during
formation of the three-dimensional object. The support material can
also be used to form a feature that imparts a predetermined
property within the three-dimensional object.
[0006] In an alternative embodiment, a method for solid freeform
fabrication of three-dimensional objects can comprise multiple
steps. One step can include layering build material to form a
three-dimensional object, wherein the three-dimensional object
includes a cavity therein that is at least in part defined by the
build material. Additional steps can include supporting overhangs
formed during the layering process with a first portion of support
material, and depositing a second portion of the support material
in the cavity, wherein at least the second portion of the support
material is configured to form a feature that imparts a
predetermined property within the three-dimensional object. To
liberate the formed three-dimensional object, a step of removing
the first portion of the support material from the
three-dimensional object can be carried out.
[0007] Additional features and advantages of the invention will be
apparent from the detailed description and figures that follows,
which illustrates, by way of example, features of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Aspects of the invention can be better understood with
reference to the following drawings. The components in the drawings
are not necessarily to scale, emphasis instead being placed upon
clearly illustrating the principles of the present invention.
[0009] FIGS. 1a to 1h depict a solid freeform fabrication system in
accordance with embodiments of the present invention;
[0010] FIG. 2 depicts the solid freeform fabrication of a golf tee
in accordance with embodiments of the invention, exemplifying the
use of the support material to support overhangs of build material,
as well as provide a permanent predetermined property within a
cavity of the three dimensional object;
[0011] FIG. 3 depicts an alternative embodiment wherein support
material and build material is deposited within a build
material-formed cavity of a three-dimensional object; and
[0012] FIG. 4 depicts an alternative embodiment wherein a
conductive support material is formed within a cavity of a
three-dimensional object.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0013] Before the present invention is disclosed and described, it
is to be understood that this invention is not limited to the
particular process steps and materials disclosed herein because
such process steps and materials may vary somewhat. It is also to
be understood that the terminology used herein is used for the
purpose of describing particular embodiments only. The terms are
not intended to be limiting because the scope of the present
invention is intended to be limited only by the appended claims and
equivalents thereof.
[0014] It must be noted that, as used in this specification and the
appended claims, the singular forms "a," "an," and "the" include
plural referents unless the context clearly dictates otherwise.
[0015] The term "solid three-dimensional object" or
"three-dimensional object" refers to objects that are formed by one
of the printing methods of the present invention. Solid
three-dimensional objects can be sufficiently firm so as to
maintain a fixed volume and shape to an extent which is appropriate
for use in solid freeform fabrication. In some embodiments, such
three-dimensional objects need not be strictly rigid, such as in
cases where the object formed is self supporting at minimum, or
alternatively, flexible.
[0016] "Hardening," "curing," "solidifying," or the like, refers to
a change that occurs when the build material and/or the support
material are chemically or physically modified from a more liquid
state to a more solid state. The process of hardening, curing, or
solidifying can occur as a result of electromagnetically
irradiating liquid build material to cause curing, e.g., UV curing,
by overprinting or underprinting a reactive chemical with a liquid
build material, e.g., epoxy build material jetted with an amine, or
by cooling or freezing the liquid material after jetting, for
example.
[0017] "Build material" includes substances that can be used to
form the bulk of the solid three-dimensional object. These build
materials typically include groups that can be cured or hardened as
a result of exposure to electromagnetic irradiation, such as UV
radiation, or as a result of a chemical reaction with a curing
agent. Build materials can include a liquid modifier(s) admixed
therewith when it is desired to alter color and/or jettability
properties, such as with respect to viscosity, surface tension, and
the like. Temperature adjustment can also be used to alter the
jettability properties as well.
[0018] "Support material" includes substances that are deposited,
such as by ink-jet architecture, for the purpose of supporting
overhangs of a solid three-dimensional object during the build
process. This material is typically configured such that it can be
relatively easily removed after the build process is complete.
Materials that can be used include the use of wax, patterned
hardening composition, water swellable gel, readily meltable
material, readily soluble material, or another material that can
carry the solid three-dimensional object being built, as well as be
configured to be readily removed. Removal can be by heating,
chemical reaction, power washing, dissolution, or other similar
methods. However, in accordance with embodiments of the present
invention, depending on the location of support material
deposition, the build material can be deposited in a position such
that the support material will remain with the three-dimensional
object as a more permanent feature.
[0019] A "build platform" is typically the rigid substrate that is
used to support the solid three-dimensional object being formed
(including build material and support material).
[0020] The term "substrate" can include the build platform,
previously deposited support material, and/or previously deposited
build material, depending on the context. For example, in one
embodiment, support material can be applied to a build platform to
enable easy removal of the solid three-dimensional object from the
build platform. In this case, the build platform is the substrate
for the support material. Alternatively, previously deposited build
material and/or support material can be a substrate for
subsequently applied build material and/or support material. To
illustrate, when laying down an initial layer of a build material
and/or support material, the initial layer will typically be
carried by a build platform or a removable material on the build
platform. However, subsequent layers of build material and/or
support material can be deposited onto the previously deposited
layer substrate.
[0021] The term "at least partially transparent" refers to
materials that can be viewed into and/or viewed through. For
example, materials that are from completely transparent to
translucent to nearly opaque would be considered at least partially
transparent. At least partially transparent build material can be
used in any embodiment of the present invention, but is
particularly useful in embodiments wherein a colored support
material is present within a cavity of the build material, and
thus, can be viewed through a wall formed by the build
material.
[0022] The terms "jetting," "ink-jetting," "bulk-jetting," or the
like, refer to a process of jetting liquid build material or
support material from jetting architecture, such as an ink-jetting
architecture. After jetting, the jetted material can be hardened or
solidified to become part of a three-dimensional object formed by
solid freeform fabrication in accordance with embodiments of the
present invention.
[0023] The term "cavity" refers to an opening defined by build
material. The cavity can be completely defined by build material,
e.g., a closed cavity, or partially defined by build material,
e.g., an open cavity.
[0024] As used herein, "liquid modifier" refers to any composition
that can be prepared for jetting with a build material or a support
material, and which, in combination, can be jetted from a
dispensing architecture, such as an ink-jet architecture.
Optionally, the liquid modifier can be a colorant to be jetted with
the build or support material. A wide variety of other liquid
modifiers can be used with the systems and methods of the present
invention. For example, such liquid modifiers that can be used
include water, surfactants, organic solvents and co-solvents,
buffers, biocides, sequestering agents, viscosity modifiers, as
well as soluble low molecular weight monomers, oligomers, and
polymers, etc.
[0025] Though liquid modifiers are described herein in some detail,
it is not always required that a liquid modifier be used. In some
embodiments, the build material or the support material can be
configured to be jetted from an ink-jet architecture without the
use of a liquid modifier. For example, a wax can be heated to a
jettable temperature and cooled upon application to form a
solidified build material object or support material. However, if
such liquid modifiers are used, they are typically present in small
amounts. An example where a liquid modifier can be added is with
respect to embodiments wherein it is desired to alter the
viscosity, surface tension, or the like, of the build material
and/or the support material. This being stated, modification of
jettable compositions with a liquid modifier is not required, and
in some cases, can be undesirable.
[0026] With these definitions in mind, a solid freeform fabrication
system for producing a three-dimensional object is provided. The
system can comprise build material configured to be deposited in
layers to form a three-dimensional object; and support material
configured to be deposited adjacent to the build material for
supporting the build material during formation of the
three-dimensional object. The support material can also be
configured to form a feature that imparts a predetermined property
within the three-dimensional object, such as a color or
conductivity, for example.
[0027] Alternatively, a method for solid freeform fabrication of
three-dimensional objects can comprise various steps, including
layering build material to form a three-dimensional object, wherein
the three-dimensional object includes a cavity therein that is at
least in part defined by the build material. Method steps can also
include supporting overhangs formed during the layering process
with a first portion of support material, and depositing a second
portion of the support material in the cavity, wherein at least the
second portion of the support material is configured to form a
feature that imparts a predetermined property within the
three-dimensional object. Additionally, a step of removing the
first portion of the support material from the three-dimensional
object can be carried out. In one embodiment, the first portion and
second portion of the support material are of the same
composition.
[0028] Reference will now be made to the exemplary embodiments
illustrated in the drawings, and specific language will be used
herein to describe the same. It will nevertheless be understood
that no limitation of the scope of the invention is thereby
intended. Alterations and further modifications of the inventive
features illustrated herein, and additional applications of the
principles of the invention as illustrated herein, which would
occur to one skilled in the relevant art and having possession of
this disclosure, are to be considered within the scope of the
invention.
[0029] Referring now to FIGS. 1a to 1h, a system in accordance with
an embodiment of the present invention is shown, wherein sequential
application of build material, indicated generally at 14a to 14g,
and support material, indicated generally at 16a to 16e, are
applied to a build platform 12. In a typical embodiment, a layer of
build material and/or support material is applied, and the build
platform is lowered (or the printing architecture is raised) in
preparation for applying a subsequent layer. Specifically, FIG. 1a
exemplifies a build platform which provides a substrate for
application of support material 16a. FIG. 1b depicts the same build
platform at a later point in time, wherein build material 14a has
been applied to support material 16a. FIG. 1c depicts the build
platform at a later point in time, wherein additional build
material 14b and additional support material 16b has been applied.
FIG. 1d and 1e illustrates the fabrication at respective later
points in time, wherein additional build material 14c, 14d, and
additional support material 16c, 16d are applied. FIG. 1f depicts
an additional build material layer 14e after application, which
acts to enclose a support material mass or feature 16e within a
cavity 20. If the build material is at least partially transparent,
then the build material will be viewable through three-dimensional
object walls formed by the collective layers of build material.
FIG. 1g depicts the application of more build material 14f and more
support material 16e. Support material 16e is used to support an
overhang 22 of build material 14g, as shown in FIG. 1h.
[0030] The application of the layers shown in FIGS. 1a to 1h can be
by known methods, such as by jetting build material and support
material from ink-jet architecture. These selective liquid-ejection
systems can have a planing and/or milling process between the
applications of each layer, which can be implemented to compensate
for variations in drop volume or directionality that can
subsequently result in variations in layer thickness. For example,
to compensate, layers can be intentionally printed overly thick and
then planed down to a known controlled height using a planing or
milling process, e.g., using a heated roller. Additionally, upon
application of each layer, a curing process can be used, such as a
UV curing process (using a UV lamp) or chemical curing process
(using a separately jetted curing agent). In either embodiment, the
support material can be applied within cavities to form features
within the build material, in accordance with embodiments of the
present invention.
[0031] The following examples depict a few three-dimensional
printing models that can be used in accordance with embodiments of
the present invention. It should be noted that this list of
embodiments is not considered to be exhaustive, but rather
exemplary. While all of the examples describe the dispensing and
layering of build material and support material together at the
first layer, this is not required. For example, it may be desirable
to dispense support material along the entire first layer in order
to provide a layer that can be easily removed to separate the build
material from the build platform.
[0032] Referring specifically to FIG. 2, a side cross-sectional
view of a system in accordance with embodiments of the present
invention is exemplified. A blow up of a section of the
cross-sectional view is also provided to depict the layering system
more fully. This depiction is not necessarily to scale, but is
shown primarily for exemplary purposes. In this embodiment, a build
platform 12 is shown for supporting the solid three-dimensional
object being formed, which in this case, can be a monogrammed or
personalized golf tee. The object is formed by applying layers of
both build material 14 and support material 16a, 16b. A first
portion of the support material 16a can be used to support
overhangs of the build material used to form the three-dimensional
object. A second portion of the support material 16b can be formed
within a cavity 20 within the build material to form a feature 18
that imparts a property, such as a symbol having a certain color or
colors. In this embodiment, the support material 16b can be formed
in the shape of a personalized monogram, trademark, slogan, symbol,
or the like. The only limitation as to what can be present is
related to the boundaries of the build material, and the thickness
of the individual layers 24 of material. For example, a line cannot
be thinner than that which is capable of being printed by the
ink-jet printing system used to lay down the individual layers. In
this embodiment, the build material can be of an at least partially
transparent material, which can range in opacity from transparent
to translucent to nearly opaque. Colored or other see through
materials can also be used. In other words, as long as the colored
symbol (which in this case is a diamond) can be seen through the
build material, it is within the scope of the present
embodiment.
[0033] In one embodiment, colored parts and/or regions can be
created by intentionally embedding colored support material in
enclosed internal cavities. Based on the ratio of build to support
material within the build material, and the depth of this internal
cavity below the surface, a desired degree of color can be
generated. Such a system and method can enable a cheap multi-color
solution to existing single color deposition methods.
[0034] In an alternative embodiment, the colored support material
can be formed to be exposed at a surface of the three-dimensional
object so that it can be seen having a predetermined shape at the
surface. In such an embodiment, when removing the supporting
support material from the build material, care should be taken to
not remove the support material that is configured to remain to
provide a decorative or other permanent feature. When the feature
formed by the support material is on the surface, the build
material can be at least partially transparent as describe
previously, or can be opaque. If the build material is opaque, the
support material-formed feature will not be visible through the
build material, but will be visible from the surface of the
three-dimensional object. In this embodiment, the support material
itself can be either opaque, or at least partially transparent.
[0035] With respect to embodiments where the support material is
exposed to a surface of the three-dimensional object, a section
facing a top horizontal plane of the three-dimensional object will
not actually be used to support build material per se, as no build
material will be applied atop the support material. However,
support material could still be included at such a surface to
provide the function of imparting an alternative property to the
three-dimensional object, such as color or conductivity, etc. In
these embodiments, it may be desirable to modify software used to
designate the placement of the support material such that in
locations where the support material does not actually support
build material, it can still be so placed. If, on the other hand, a
section of the cavity that is open on a surface is still used to
support build material, e.g., vertical surface, angled surface, or
bottom surface, then the open section can be filled with support
material for its supporting function, as well as its alternative
property imparting function.
[0036] In another embodiment, voids or cavities can be formed
within a three-dimensional object using software. In this sense,
objects can be formed using but one build material, and variations
in the appearance of the build material can be provided by
placement of support material in strategic locations within the
object. This can be planned using computer modeling. For example, a
single material (the build material) that can be made to have the
appearance or the function of having multiple materials by creating
voids within the three-dimensional object that are automatically
filled with support material. In this embodiment, voids can be
formed in a CAD model prior to printing.
[0037] In another alternative embodiment, a cavity formed by the
build material can be filled with a network of both support
material and build material, as exemplified in FIG. 3.
Specifically, FIG. 3 depicts an embodiment wherein both support
material 16b and build material 14b are both within a common cavity
20. In this embodiment, collectively, the build material 14b and
support material 16b form the feature 18. Again, a build platform
12 is used to support the object as it is being fabricated, and
support material 16a and build material 14a are used as previously
described, and as is known in the art. In such an embodiment, both
support material 16b and build material 14b can be dispensed in a
half-tone density, ranging from 1:99 to 99:1 of build material to
support material by volume. To illustrate, in one embodiment, 5% by
volume for 20 layers of support material can be dispensed with 95%
by volume of build material to form a half-tone density of 95%. As
long as the half-tone patterns are appropriately shifted from layer
to layer, the overall result can be designed to be relatively
strong and uniformly colored region. Alternatively, by changing the
ratio of support material 16b to build material 14b within the
cavity (as shown in FIG. 3), the saturation of the colored portion
of the part could be modified and variable, with the limitation of
color and saturation being dependent on the base color of the build
and support material selected for use. In still another embodiment,
by changing the depth of the cavity below the surface of the
object, the hue of the part could be modified and variable. For
example, in the case of a yellow-translucent build material and a
cyan support material, the apparent hue of the support material of
the feature inside the part could range from near cyan (at points
of the cavity nearer the surface) to near green (at points of the
cavity embedded under more and more yellow build material).
[0038] There are several advantages that can be realized by the
system and method exemplified in FIGS. 2 and 3. For example, such a
system and method allows for the adding of alternative material
properties to bulk-jetting solid freeform fabrication systems
without any machine cost penalty or any fabrication time penalty.
More specifically, such a system and method allows for adding color
to bulk-jetting solid freeform fabrication techniques without any
machine cost penalty, without any fabrication time penalty, and
without affecting the surface finish or dimensional accuracy of the
final part (unless used in an embodiment where surface support
material is included to provide a surface detail). Additionally,
these systems and methods allows for using spot colors within an
object for feature differentiation, labeling, revision control, and
the like, without any machine cost penalty and without any
fabrication time penalty.
[0039] Referring now to FIG. 4, an alternative property (other than
color) can be imparted by support material in a solid freeform
fabrication-produced object. Specifically, FIG. 4 exemplifies an
embodiment that uses support material to form a conductive feature
that passes through the three-dimensional object. More
specifically, a build platform 12, support material 16a and build
material 14 are used as previously described, and as known
generally in the art. However, if the support material is
conductive, then channels of support material 16b that pass through
the build material can be used to provide conductive paths within
or through the three-dimensional object. More specifically, in this
example, enclosed internal channels or cavities 20 can be prepared
using a computer model of the object, and the object can be formed
such that these channels would be filled with the conductive
support material during the fabrication process. In one embodiment,
these channels can be patterned to form functional features 18,
such as RF antennas or circuits to route electrical signals through
or inside of the three dimensional object. This type of function is
does not require that the build material be transparent or at least
partially transparent, and additionally, such a system and method
allows for adding conductive material to bulk-jetting solid
three-dimensional objects without any machine cost penalty and
without any fabrication time penalty.
[0040] In each of the embodiments described above, the support
material that is used to form a feature, such as a conductive
and/or color feature, will remain as part of the three-dimensional
object. However, the support material that is used to merely
support the build material during fabrication will typically be
removed by one of a number of known processes, including power
washing, melting, chemical removal, dissolution, and the like.
[0041] With respect to embodiments wherein the dispensing system is
an ink-jet or bulk-jetting printing system, various techniques can
be used to modify the viscosity or other jetting properties of the
build material and/or support material. For example, heat can be
used to liquefy material such that it becomes ink-jettable. The
selection of an appropriate heat range is generally composition
specific, but can range from 25.degree. C. to 170.degree. C. In one
embodiment, if the build material is stearyl acrylate, and no
liquid modifier is added, then a temperature range that can be used
is from 50.degree. C. to 170.degree. C.
[0042] Alternatively, liquid modifier components can be added to
liquid build material and/or support material to modify properties,
or colorant can be added to impart color to the finished
three-dimensional object. Exemplary colorants that can be used
include dyes and/or pigments. Examples of liquid modifier
components that can be used, in small amounts if at all, include
water, surfactants, organic solvents and co-solvents, buffers,
biocides, sequestering agents, viscosity modifiers, as well as
soluble low molecular weight monomers, oligomers, and polymers,
etc. As mentioned, liquid modifiers are typically not added to
carry the build material and/or the support material, but can
optionally be added to modify jetting characteristics, such as
color viscosity, surface tension, or other properties.
[0043] It is to be understood that the above-referenced
arrangements are illustrative of the application for the principles
of the present invention. Numerous modifications and alternative
arrangements can be devised without departing from the spirit and
scope of the present invention while the present invention has been
shown in the drawings and described above in connection with the
exemplary embodiments(s) of the invention. It will be apparent to
those of ordinary skill in the art that numerous modifications can
be made without departing from the principles and concepts of the
invention as set forth in the claims.
* * * * *