U.S. patent application number 15/498111 was filed with the patent office on 2017-10-26 for custom elastomeric earmold with secondary material infusion.
The applicant listed for this patent is Russ Schreiner. Invention is credited to Russ Schreiner.
Application Number | 20170305039 15/498111 |
Document ID | / |
Family ID | 60089304 |
Filed Date | 2017-10-26 |
United States Patent
Application |
20170305039 |
Kind Code |
A1 |
Schreiner; Russ |
October 26, 2017 |
CUSTOM ELASTOMERIC EARMOLD WITH SECONDARY MATERIAL INFUSION
Abstract
A method of manufacturing a custom elastomeric earmold with a
secondary material infusion and said custom elastomeric earmold is
disclosed. The method can include establishing a representation of
a shape of the ear concha, the outer canal and the inner ear canal
cavity. The method may further include casting a custom shaped
injection mold. The injection mold may be used to cast a custom
shape of the inner and outer ear from an elastomeric material such
as silicone or urethane. An additional injection step can be
performed to infuse foam into the interior of the elastomeric
material.
Inventors: |
Schreiner; Russ; (Evanston,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Schreiner; Russ |
Evanston |
IL |
US |
|
|
Family ID: |
60089304 |
Appl. No.: |
15/498111 |
Filed: |
April 26, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62327723 |
Apr 26, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 33/3857 20130101;
B29K 2083/00 20130101; G06F 30/00 20200101; B29K 2075/00 20130101;
B29C 33/3835 20130101; G06T 17/00 20130101; H04R 25/658 20130101;
B29C 45/0055 20130101; H04R 25/652 20130101; H04R 2225/77 20130101;
B29C 2033/3871 20130101; B29C 44/181 20130101; H04R 1/1058
20130101; B29C 44/186 20130101; A61F 11/08 20130101; B33Y 80/00
20141201; B29C 33/3842 20130101 |
International
Class: |
B29C 33/38 20060101
B29C033/38; H04R 1/10 20060101 H04R001/10; B29C 45/00 20060101
B29C045/00; B29C 44/18 20060101 B29C044/18; A61F 11/08 20060101
A61F011/08 |
Claims
1. A method comprising: establishing a digital representation of a
shape of an ear concha, an outer ear canal and an inner ear canal
cavity; casting a custom-shaped injection mold from the digital
representation; casting a custom shape of the inner ear canal
cavity and outer ear canal from an elastomeric material in the
injection mold; infusing foam into an interior of the elastomeric
material.
2. The method as in claim 1 further comprising supplementing the
injection mold with a specialized sprue and controlling a flow and
placement of the foam infusion into the interior of the elastomeric
material.
3. The method as in claim 2 where infusing the foam into an
interior of the elastomeric material comprises injecting the
infused foam into an interior area of the elastomeric material to
displace the elastomeric material from the interior area.
4. A method as in claim 1 where the elastomeric material is at
least one of silicone or urethane.
5. A method as in claim 2 further comprising forming a canal area
on the order of 5 mm past a second bend of an ear.
6. A method as in claim 1 further comprising permitting an infusion
of materials such as liquids and gels into a final device.
7. A method as in claim 1 further comprising: applying a temporary
infusion of materials comprising at least one of liquids and air
into the injection mold to remove the elastomeric material and
leave an evacuated interior, and permanently filling the evacuated
interior with the secondary material comprising at least one of
liquids and gels into the mold.
8. A method of manufacturing a custom composite earmold comprising:
establishing a digital representation of a shape of an ear concha,
an outer ear canal and an inner ear canal cavity; casting a
custom-shaped injection mold from the digital representation, the
injection mold having a plurality of sprues for carrying materials
having different properties; introducing a primary material into
the injection mold through at least one of the plurality of
injection sprues, and introducing a secondary material different
from the primary material into the injection mold though a second
one of the plurality of injection spures and into an interior area
of the primary material, the primary material being around the
perimeter of the interior area.
9. The method of claim 8 where the primary material is a
biocompatible material selected from a group consisting of silicone
and urethane.
10. The method of claim 8 where the primary materials is
elastomeric.
11. The method of claim 8 where the secondary material is a
material that is softer than the primary material.
12. The method of claim 8 where the secondary material is
compressible foam.
13. The method of claim 8 where the primary material has a greater
surface tension than the secondary material and adheres to an
interior side of a wall of the mold and the secondary material has
more fluidity than the primary material, the secondary material
only displacing the primary material in the interior area.
14. The method of claim 8 further comprising controlling the flow
and placement of the secondary material into the interior of the
area, said controlling being carried out by the second one of the
plurality of injection spures.
15. The method of claim 8 where the earmold is comprised of a
composite design comprising an outer portion formed by the primary
material and an inner portion formed by the secondary material in a
predetermined area, the composite design having more softness in
the predetermined area than a conventional earmold comprised of
only the primary material.
16. The method of claim 8 further comprising evacuating the
interior area by introducing a medium into the interior area before
introducing the secondary material, the medium being introduced
through one of the plurality of sprues.
17. The method of claim 16 where the medium is at least one of
compressed air and pressurized liquid.
18. A custom composite earmold comprising: an outer skin layer
comprised of a biocompatible elastomeric material; at least one
interior area comprised of a compressible foam having greater
softness than the elastomeric material, the at least one interior
area surrounded by the elastomeric material, and the earmold being
formed by: establishing a digital representation of a shape of an
ear concha, an outer ear canal and an inner ear canal cavity;
casting a custom-shaped injection mold from the digital
representation, the injection mold having a plurality of sprues for
carrying materials having different properties; introducing a
primary material into the injection mold through at least one of
the plurality of injection sprues, and introducing a secondary
material different from the primary material into the injection
mold though a second one of the plurality of injection spures and
into the at least one interior area.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of the filing date of
U.S. Provisional Application Ser. No. 62/327,723 filed Apr. 26,
2016 entitled "Custom Elastomeric Earmold with Secondary Material
Infusion" which is hereby incorporated herein by reference in its
entirety.
FIELD
[0002] Embodiments presented herein pertain generally to
customizable elastomeric earmolds used in both active sound
processing units (hearing aids, earphones) and passive devices
(earplugs, swim plugs). More particularly, embodiments presented
herein pertain to a method of manufacture for a custom composite
elastomeric earmold (and said earmold) that is comprised of an
outer soft biocompatible material infused with a secondary
compatible, compressible and/or soft material to achieve added
softness and compliance in specific areas.
BACKGROUND
[0003] Many sound producing (hearing aids and earphones) and
hearing protective (earplugs and musician plugs) devices generally
require: (1) that the device provides a good acoustic seal which is
important for device performance and sound quality, and 2) that the
device fits comfortably in the ear. There are many concepts for
achieving this through the use of a variety of materials including
elastomers and foams in a variety of shapes, sizes and
processes.
[0004] Foam has an advantage over monolithic or solid materials in
applications requiring compliance and comfort of an item in contact
with a human. Foam is commonly used to enhance comfort in products
ranging from furniture to shoes to helmets. Foam has also been used
in earplugs for decades, but generally in pre-molded form. See
Leight (U.S. Pat. No. 4,774,938 A). Foam has also been applied to
earmolds to improve comfort and also to improve performance by
providing a better acoustic seal (e.g. Staab (WO2008157557
A1)).
[0005] Foam, however, has some limitations with regard to custom
earmold applications due to problems associated with known
production methods (short working times, limitation of material
selection) and customer use associated with insertion (the foam is
too flaccid to allow insertion), cleanliness (foams allow foreign
material to become trapped in the foam cells) and strength (the
tear strength of foam limits its ability to be removed from the ear
if the mold fits too tight or is handled too roughly). Due to these
limitations, most custom soft earmoulds are made from monolithic
elastomers (silicone, PVC and urethane) rather than foam.
[0006] Various attempts have been made to provide a combination of
silicone and foam, or urethane and foam, in order to take advantage
of the beneficial properties of each (see e.g. Parkins
(US20120243701 A1), Staab, Keady (WO2010094034 A1 and WO2011163565
A1), Gebert (WO2012007193 A1) and Stonikas (US20020025055 A1)).
However, in such instances, the foam is added as a separate piece
of the mold using some assembly process. In particular, in known
examples of composite devices, the elastomeric part and the foam
part are added as separate items with the foam piece added to the
elastomer in a secondary operation such as described by Parkins.
Alternative processes involve pumping foam into an inflatable
container such as described in Staab, Keady (WO2010094034 A1 and
WO2011163565 A1), Gebert and Stonikas. In non-custom ear tip
applications, foam is used by itself or combined with other
pre-molded items to form a more complex device. See Purcell (U.S.
Pat. No. 7,984,716 B2). A multi-material concept for earplugs is
generally described by Parkins (US20110271965 A1), but in that case
there is no mention of infusion of the secondary material during
the casting operation, nor is there a description of the system for
dispersing and controlling the infused material.
[0007] Digital processes common to the manufacture of hearing aid
products are generally known and disclosed in Topholm (U.S. Pat.
No. 5,487,012), Martin (US20060239481) and Clausen (U.S. Pat. No.
8,032,337). Topholm and Clausen generally describe the advent of
digital data processing and 3D Printing (rapid prototyping) in the
custom earmold industry. Such advancements created the ability to
add sophisticated features to a custom product while maintaining a
reasonable, machine based fabrication. In Martin, for example, the
process of casting custom elastomeric molds using a single use 3D
printed mold is generally described. In particular, according to
the teachings of Martin, a 3D mold can be used as a single use
injection mold for a variety of material.
[0008] Thus, there is a need in the art for an improved method for
combining foam and silicone in a custom application by using
casting techniques provided by 3D printing. There is further a need
in the art for an improved composite sound processing
device/product (and method of manufacturing same) that can be
formed from a variety of materials to enhance the properties,
performance and appearance of the resulting earmold. There is
further a need in the art for a composite sound processing device
that can incorporate a secondary casting operation which can infuse
foam (or other soft, compressible material) into the interior of an
outer elastomeric casting to achieve softness and compliance in
specific areas. There is also generally a need in the art for a
composite earmold that can demonstrate excellent retention in the
ear due to the outer ear customization, improved compliance to move
as the ear canal moves, improved comfort, increased flexibility,
excellent acoustic seal and a deeper seal resulting in reduced
occlusion in the ear canal.
SUMMARY OF THE INVENTION
[0009] Embodiments of the subject invention represent an
advancement beyond known processes in that they can incorporate a
secondary casting operation which can infuse the foam into the
interior of the elastomeric casting. In particular, in addition to
injecting a primary elastomer, an additional process step can be
performed to add a secondary interior material that can be fully
contained within the primary elastomer. The process can take
advantage of the surface tension effect of the primary material to
stay adhered to the interior side of the walls of the mold. This
can allow the secondary material to occupy the interior without
displacing the base elastomer from the exterior.
[0010] An elastomeric composite system according to embodiments
presented herein is unique in that the foam can be an integral part
of casting process. Thus, embodiments presented herein move beyond
known technologies and processes by enabling the creation of an
earmold having a specialized exterior shape and also a specialized
interior made from compatible foam. Such innovations represent and
incorporate new design elements and fabrication methods in custom
earmold and hearing aid shell design and fabrication.
[0011] The result is an earmold with localized softness and
compliancy that surpasses previous art by achieving higher degrees
of comfort, improved acoustic seal, and by allowing a deeper fit in
the ear canal can prevent occlusion effects. Specifically, the
combination of the material and novel design concepts disclosed
herein can provide numerous benefits, including for example: (1)
creating a product with excellent retention in the ear due to the
outer ear customization; (2) creating a product with improved
compliance to move as the ear canal moves, improved comfort,
increased flexibility, excellent acoustic seal and a deeper seal
resulting in reduced occlusion in the ear canal. Such improvement
can be attributable to the foam infused areas that are softer, more
compressible, but springier than a solid elastomeric material and,
therefore, enabling the design to become more accommodating to the
dynamics of the canal when compared to full custom molds. The light
spring force of the foam material can provide an improved acoustic
seal without discomfort; (3) creating a comfortable product with
improved and deeper acoustic seal over a full custom product as the
silicone/silicone foam combination provides a compliant seal that
does not break when the wearer moves his head or jaw. Thus, the
innovation presented herein can greatly improve the performance of
any in-ear product including, but not exclusive to: 1) hearing
aids, 2) hearing protection, and 3) custom earphones.
[0012] Embodiments set forth herein can consist of a custom mold
for the ear where the custom portion is confined to the outer ear
and entry to the canal only. Specifically, the mold can be made
from injecting an elastomeric material into a one use injection
made in a 3D printing process (Martin). Any portion of the mold can
be enhanced through the infusion of a secondary material which
displaces the original material from only the interior of the mold
due to the surface tension characteristics of the primary
elastomeric material which keep the primary material adhered to the
injection mold surface. Accordingly, embodiments of the subject
invention can make use of the surface tension involved in the
elastomer casting process. For example, when an elastomer is
injected into a 3D printed one-shot injection mold, the surface
tension of the original, or primary, material can cause the
elastomer to adhere to the surface of the mold. When any secondary
material (such as another elastomer, air, water, other liquids,
pastes or foam) possessing the characteristic of fluidity is
injected into the mold it cannot displace the original material
from the surface of the mold; it can only displace it from the
interior of the mold. This means that the original elastomer will
remain along the outside surface of the mold and can form the outer
"skin" or "layer" of the final device; while the secondary material
will form the interior of the device.
[0013] There is a variety of process controls available that can
provide for control of both the location and amount of the residual
primary material and the secondary infused material. A few examples
are: [0014] 1. The timing of the primary material curing and the
secondary material infusion. If the curing of the primary material
is time dependent, then the thickness of the outer layer of primary
material can be controlled by time. Since the curing of the primary
material, if it is a two-part catalyst curing system, is a function
of time. The same can be accomplished by heat exposure with a heat
dependent primary material. [0015] 2. The use of specialized sprues
and vents in the injection molding process. Placement and shape of
sprues and vents can control the injection process and can
determine the location and volume of each material during
injection. [0016] 3. The evacuation of the primary material before
the infusion of the secondary material. In this case, the primary
material is removed by using pressurized air or liquid, such as
water, that acts as a temporary displacement of the primary
material prior to the infusion of the final secondary material.
[0017] Utilizing the abilities of application specific software and
3D printing, an earmold is now a sophisticated composite structure
combining a variety of materials to enhance the properties,
performance and appearance of the resulting earmold. Again
utilizing the abilities of application specific software and 3D
printing, interior features are no longer limited to a set
arrangement of interior spaces.
[0018] Embodiments disclosed herein can additionally provide an
improved method for combining foam and silicone in a custom
application by using the casting techniques provided by 3D
printing. As discussed in Martin, a 3D mold can be used as a single
use injection mold for a variety of material. The subject invention
can incorporate the same concept of the one shot mold, but can
additionally rely on the concept of a secondary infusion of
material to create a composite mold of both the primary material
injected in the mold and the secondary material injected in the
mold. The process can also utilize the chemical characteristic of
surface tension to maintain the primary material as the "outer"
skin or layer of the final device, while limiting the secondary
material to the interior of the device. In this way, the outer
layer can maintain the advantages of the primary material while the
interior can maintain the advantages of the secondary material.
[0019] The combination of materials can be unlimited as long as
they are chemically compatible and can be injected into a 3D
printed mold. Examples of some combinations can include, for
instance [0020] Primary: silicone Secondary: silicone foam [0021]
Primary: silicone of hardness A, Secondary: silicone of a different
hardness [0022] Primary: silicone, Secondary: silicone gel [0023]
Primary: silicone, Secondary: silicone of another color [0024]
Primary: urethane Secondary: urethane foam [0025] Primary: urethane
of hardness A, Secondary: urethane of a different hardness [0026]
Primary: urethane, Secondary: urethane gel [0027] Primary:
urethane, Secondary: urethane of another color [0028] Primary:
urethane or urethane and urethane foam [0029] Primary: silicone,
secondary: air [0030] Primary: silicone, secondary: a compatible
liquid
[0031] A composite mold has the advantage of combining the
desirable properties of both materials. For example, the silicone
(primary) and silicone foam (secondary) composite has the advantage
of the softness and compliance of the foam, but has the stiffness,
strength and chemical stability of silicone. This results in an
earmold of superior performance since it is very comfortable due to
the foam, can go deep in the ear because of this comfort, will
provide a better acoustic seal due to the compliance of the foam,
but due to the stiffness of the silicone outer layer the earmold
can be inserted easily, provides a biologically compatible surface,
is easily cleaned and provides durable performance regarding tear
strength and chemical resistance.
[0032] The composite earmold described herein can accomplish
numerous benefits, including for example: 1) achieving a better
acoustic seal than a tight-fitting, full custom canal due to the
improved compliance (softness) and shape changing abilities of
foam; 2) improving the comfort of the device for the same reasons
of improved compliance and shape changing while forgiving
incomplete ear impressions; 3) extending deeper into the canal due
to the improved softness and flexibility which has the advantages
of reducing the occlusion effect; 4) achieving lower noise levels
associated with jaw movement and leaks associated with the
continual loss and regain of an acoustic seal experienced using a
tight fitting, monolithic material.
[0033] Another advantage of the molding process that entraps the
secondary material on the interior of the mold is the allowance of
liquids or gels as the secondary material. This can allow the use
of superior acoustic dampening caused by a variety of material
choices (see e.g. Parkins US20110271965 A1).
[0034] The custom injection mold and casting can be performed using
processes common to the hearing aid industry. Custom injection mold
and casting processes as well as 3D printing process used to make
injection molds are generally well-known and common to the hearing
aid industry. In addition, processes used to prepare molds, fill
molds with soft biocompatible material such as silicone, or remove
the silicone from the molds are also generally known. See e.g.
Martin (US20060239481), Mcleod (WO2011044903).
[0035] In this case, the shape of a person's ear can be acquired
through the injection of silicone into the ear and ear canal, or
the outer ear and canal entry areas can be scanned with a laser or
white light scanner. The scanned image can be used to fashion, or
sculpt, the final shape of the product, and to add predesigned
features to the mold that are merged into the digital image of the
mold. A digital file of the final product design can then be output
to a 3D Rapid Prototyping/Manufacturing machine. In this process,
the object that is made on the 3D printer can be an injection mold
which is then filled with silicone (Martin). Once the silicone
cures, the outer "shell" of the mold can be cracked open and
removed to reveal the silicone mold on the inside.
[0036] The capture of the image of a person's ear and the use of
software to design an earmold are generally known. However,
embodiments described herein can incorporate novel objects used
within the software to add complexity to the injection mold and
earmold design. As described herein, one unique/novel object that
can be added to the earmold design can be the injection mold sprue
system: 1) a pre-designed shape which is chosen and located to
optimize the amount and position of the secondary material, this is
usually in the canal area but can also be in the outer ear area
where the ear moves or is pressed upon when the wearer rests one
side of the head against a surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] FIG. 1A is a perspective view of a posterior section of an
ear impression captured with digital 3D scanning according to an
exemplary embodiment.
[0038] FIG. 1B is a perspective view of an anterior section of the
ear impression of FIG. 1A.
[0039] FIG. 2A is a perspective view of a first pre-designed sprue
according to an exemplary embodiment.
[0040] FIG. 2B is a perspective view of a second pre-designed sprue
according to an exemplary embodiment.
[0041] FIG. 3A is a first perspective view of an injection mold for
creation of a composite mold according to an exemplary
embodiment.
[0042] FIG. 3B is a second perspective view of the injection mold
of FIG. 3A.
[0043] FIG. 3C is a second perspective view of the injection mold
of FIG. 3A.
[0044] FIG. 4 is a partial cross section view of an injection mold
according to an exemplary embodiment.
[0045] FIG. 5 is a partial cross section view of the injection mold
showing an earmold according to an exemplary embodiment.
[0046] FIG. 6A is a first perspective view of a composite device
according to an exemplary embodiment.
[0047] FIG. 6B is a second perspective view of the composite device
of FIG. 6A.
[0048] FIG. 7A is a perspective view of the inferior side of a
composite device according to an exemplary embodiment.
[0049] FIG. 7B is a partial cross section view through the anterior
portion of the composite device of FIG. 7A.
[0050] FIG. 8A is a perspective view of a composite device
according to an exemplary embodiment.
[0051] FIG. 8B is a partial cross section view of the composite
device of FIG. 8A.
[0052] FIG. 9 is a detail cross section view through the canal
portion of the composite device of FIGS. 8A and 8B.
[0053] FIG. 10A is a perspective view of a single use injection
mold according to an exemplary embodiment.
[0054] FIG. 10B is a perspective partial cutaway view of the single
use injection mold of FIG. 10A.
[0055] FIG. 11 is a perspective partial cutaway view of a single
use injection mold filled with a primary material according to an
exemplary embodiment.
[0056] FIG. 12 is a perspective partial cutaway view of a single
use injection mold showing a hollow interior area of the primary
material displaced with air or water according to an exemplary
embodiment.
[0057] FIG. 13 is a perspective partial cutaway view of a single
use injection mold showing the secondary material filling the
hollow interior area of the primary material according to an
exemplary embodiment.
[0058] FIG. 14 is a graphical flowchart of a process according to
an exemplary embodiment.
[0059] FIG. 15 is a graphical flowchart of a process according to
an exemplary embodiment.
DETAILED DESCRIPTION
[0060] While the subject invention is susceptible of embodiment in
many different forms, there are shown in the drawings, and will be
described herein in specific detail, embodiments thereof with the
understanding that the present disclosure is to be considered as an
exemplification of the principles of the invention and is not
intended to limit the invention to the specific embodiments
illustrated.
[0061] Embodiments presented herein are directed to a new process
for custom elastomeric earmolds used in both active sound
processing units (hearing aids, earphones) and passive devices
(earplugs, swim plugs) which can create a product that is made from
soft, biocompatible material such as silicone or urethane that can
be infused with compatible, compressible foam, or other soft
materials, in order to achieve softness and compliance in specific
areas on the earmold. The result is an earmold with localized
softness and compliancy that surpasses previous art by achieving
higher degrees of comfort, improved acoustic seal, and by allowing
a deeper fit in the ear canal can prevent occlusion effects.
[0062] The combination of the material and novel design concepts
can provide numerous benefits, including for example: (1) creating
a product with excellent retention in the ear due to the outer ear
customization; (2) creating a product with improved compliance to
move as the ear canal moves, improved comfort, increased
flexibility, excellent acoustic seal and a deeper seal resulting in
reduced occlusion in the ear canal. This improvement can be
attributable to the foam infused areas that are softer, more
compressible, but springier than a solid elastomeric material and,
therefore, enabling the design to become more accommodating to the
dynamics of the canal when compared to full custom molds. The light
spring force of the foam material can provide an improved acoustic
seal without discomfort; (3) creating a comfortable product with
improved and deeper acoustic seal over a full custom product as the
silicone/silicone foam combination provides a compliant seal that
does not break when the wearer moves his head or jaw.
[0063] Embodiments described herein can be created using digital
processes common to the manufacture of hearing aid products. Such
processes can be used to make a one-time mold for casting silicone
or urethane elastomers, but in addition to injecting the primary
elastomer, an additional process step can be performed to add a
secondary interior material that can be fully contained within the
primary elastomer. The process can take advantage of the surface
tension effect of the primary material to stay adhered to the
exterior walls of the mold. This can allow the secondary material
to occupy the interior without displacing the base elastomer from
the exterior.
[0064] It has been observed that embodiments disclosed herein can
improve the performance of any in-ear product including, but not
exclusive to: 1) hearing aids, 2) hearing protection, and 3) custom
earphones.
[0065] According to an exemplary embodiment, a secondary casting
operation can infuse a foam substance into the interior of the
elastomeric casting. Thus, in addition to injecting a primary
elastomer, an additional process step can be performed to add a
secondary interior material that can be fully contained within the
primary elastomer. The process can take advantage of the surface
tension effect of the primary material to stay adhered to the
exterior walls of the mold. This can allow the secondary material
to occupy the interior without displacing the base elastomer from
the exterior.
[0066] Embodiments set forth herein can consist of a custom mold
for the ear where the custom portion is confined to the outer ear
and entry to the canal only. Specifically, the mold can be made
from injecting an elastomeric material into a one use injection
made in a 3D printing process. Any portion of the mold can be
enhanced through the infusion of a secondary material which
displaces the original material from only the interior of the mold
due to the surface tension characteristics of the primary
elastomeric material which keep the primary material adhered to the
injection mold surface. Accordingly, embodiments of the subject
invention can make use of the surface tension involved in the
elastomer casting process. For example, when an elastomer is
injected into a 3D printed one-shot injection mold, the surface
tension of the original, or primary, material can cause the
elastomer to adhere to the surface of the mold. When any secondary
material (such as another elastomer, air, water, other liquids,
pastes or foam) possessing the characteristic of fluidity is
injected into the mold it cannot displace the original material
from the surface of the mold; it can only displace it from the
interior of the mold. This means that the original elastomer will
remain along the outside surface of the mold and can form the outer
"skin" or "layer" of the final device; while the secondary material
will form the interior of the device.
[0067] There is a variety of process controls available that can
provide for control of both the location and amount of the residual
primary material and the secondary infused material. A few examples
are: [0068] 1. The timing of the primary material curing and the
secondary material infusion. If the curing of the primary material
is time dependent, then the thickness of the outer layer of primary
material can be controlled by time. Since the curing of the primary
material, if it is a two-part catalyst curing system, is a function
of time. The same can be accomplished by heat exposure with a heat
dependent primary material. [0069] 2. The use of specialized sprues
and vents in the injection molding process. Placement and shape of
sprues and vents can control the injection process and can
determine the location and volume of each material during
injection. [0070] 3. The evacuation of the primary material before
the infusion of the secondary material. In this case, the primary
material is removed by using pressurized air or liquid, such as
water, that acts as a temporary displacement of the primary
material prior to the infusion of the final secondary material.
[0071] Utilizing the abilities of application specific software and
3D printing, an earmold is now a sophisticated composite structure
combining a variety of materials to enhance the properties,
performance and appearance of the resulting earmold. Again
utilizing the abilities of application specific software and 3D
printing, interior features are no longer limited to a set
arrangement of interior spaces.
[0072] Embodiments disclosed herein can additionally provide an
improved method for combining foam and silicone in a custom
application by using the casting techniques provided by 3D
printing. For example, embodiments disclosed herein can incorporate
the known concept of a one-shot mold, but can additionally rely on
the concept of a secondary infusion of material to create a
composite mold of both the primary material injected in the mold
and the secondary material injected in the mold. The process can
also utilize the chemical characteristic of surface tension to
maintain the primary material as the "outer" skin or layer of the
final device, while limiting the secondary material to the interior
of the device. In this way, the outer layer can maintain the
advantages of the primary material while the interior can maintain
the advantages of the secondary material.
[0073] The combination of materials can be unlimited as long as
they are chemically compatible and can be injected into a 3D
printed mold. Examples of some combinations can include, for
instance [0074] Primary: silicone Secondary: silicone foam [0075]
Primary: silicone of hardness A, Secondary: silicone of a different
hardness [0076] Primary: silicone, Secondary: silicone gel [0077]
Primary: silicone, Secondary: silicone of another color [0078]
Primary: urethane Secondary: urethane foam [0079] Primary: urethane
of hardness A, Secondary: urethane of a different hardness [0080]
Primary: urethane, Secondary: urethane gel [0081] Primary:
urethane, Secondary: urethane of another color [0082] Primary:
urethane or urethane and urethane foam [0083] Primary: silicone,
secondary: air [0084] Primary: silicone, secondary: a compatible
liquid
[0085] A composite mold has the advantage of combining the
desirable properties of both materials. For example, the silicone
(primary) and silicone foam (secondary) composite has the advantage
of the softness and compliance of the foam, but has the stiffness,
strength and chemical stability of silicone. This results in an
earmold of superior performance since it is very comfortable due to
the foam, can go deep in the ear because of this comfort, will
provide a better acoustic seal due to the compliance of the foam,
but due to the stiffness of the silicone outer layer the earmold
can be inserted easily, provides a biologically compatible surface,
is easily cleaned and provides durable performance regarding tear
strength and chemical resistance.
[0086] The composite earmold described herein can accomplish
numerous benefits, including for example: 1) achieving a better
acoustic seal than a tight-fitting, full custom canal due to the
improved compliance (softness) and shape changing abilities of
foam; 2) improving the comfort of the device for the same reasons
of improved compliance and shape changing while forgiving
incomplete ear impressions; 3) extending deeper into the canal due
to the improved softness and flexibility which has the advantages
of reducing the occlusion effect; 4) achieving lower noise levels
associated with jaw movement and leaks associated with the
continual loss and regain of an acoustic seal experienced using a
tight fitting, monolithic material.
[0087] Another advantage of the molding process that entraps the
secondary material on the interior of the mold is the allowance of
liquids or gels as the secondary material. This can allow the use
of superior acoustic dampening caused by a variety of material
choices (see e.g. Parkins US20110271965 A1).
[0088] The custom injection mold and casting can be performed using
processes common to the hearing aid industry. Custom injection mold
and casting processes as well as 3D printing process used to make
injection molds are generally well-known and common to the hearing
aid industry. In addition, processes used to prepare molds, fill
molds with soft biocompatible material such as silicone, or remove
the silicone from the molds are also generally known.
[0089] In this case, the shape of a person's ear can be acquired
through the injection of silicone into the ear and ear canal, or
the outer ear and canal entry areas can be scanned with a laser or
white light scanner. The scanned image can be used to fashion, or
sculpt, the final shape of the product, and to add predesigned
features to the mold that are merged into the digital image of the
mold. A digital file of the final product design can then be output
to a 3D Rapid Prototyping/Manufacturing machine. In this process,
the object that is made on the 3D printer can be an injection mold
which is then filled with silicone (Martin). Once the silicone
cures, the outer "shell" of the mold can be cracked open and
removed to reveal the silicone mold on the inside.
[0090] The capture of the image of a person's ear and the use of
software to design an earmold are generally known. However,
embodiments described herein can incorporate novel objects used
within the software to add complexity to the injection mold and
earmold design. As described herein, one unique/novel object that
can be added to the earmold design can be the injection mold sprue
system: 1) a pre-designed shape which is chosen and located to
optimize the amount and position of the secondary material, this is
usually in the canal area but can also be in the outer ear area
where the ear moves or is pressed upon when the wearer rests one
side of the head against a surface.
[0091] With reference now to the figures, FIGS. 1A and 1B show an
exemplary ear impression 1 captured with digital 3D scanning. FIG.
1A shows a posterior section of the impression 1 and FIG. 1B shows
an anterior section of the impression 1. Such an impression 1 can
be a starting point image for creating custom earphone devices
according to embodiments set forth herein. The impression 1 can
then loaded into software specifically designed for creating custom
earmold products from digitally scanned images--this process is
generally known as eSculpting. eSculpting can alter the shape of
the original image to adapt it to the shape of a final product (see
e.g. FIGS. 6A and 6B, ref. no. 5). eSculpting can also be used to
include CAD objects that can produce sprues for injecting primary
and secondary materials into the mold.
[0092] FIGS. 2A and 2B show pre-designed sprues 2, 3 that can be
used to inject materials into the mold to create composite custom
earmold products according to exemplary embodiments. According to
an exemplary embodiment as shown schematically, spure 2 shown in
FIG. 2A can be used to inject the primary elastomeric material into
the mold and spure 3 shown in FIG. 2B can be used to inject the
secondary material into the mold.
[0093] FIGS. 3A through 3C and FIG. 4 show an exemplary hearing
protection single use injection mold 4 according to embodiments of
the subject invention. As shown schematically, the mold 4 can have
at least two injection ports (shown as sprues 2, 3) to allow the
creation of a composite earmold from two different materials such
as soft and hard, or different color materials. For example,
according to embodiments disclosed herein, injection sprue 2 can be
used to inject a primary material into the single use injection
mold and sprue 3 can be used to inject a secondary material into
the single use injection mold.
[0094] FIG. 5 shows a silicone earmold 5 shown inside of the single
use injection mold 4 according to an exemplary embodiment.
According to an exemplary embodiment, FIG. 5 shows earmold 5 during
the "demolding" step where the silicone earmold 5 can be removed
from the mold 4. For example, once the earmold 5 cures, the outer
"shell" of the mold 4 can be cracked open and removed to reveal the
silicone earmold 5 on the inside.
[0095] FIGS. 6A-6B, 7A-7B and 8A-8B show a final earmold device 5
according to exemplary embodiments. According to exemplary
embodiments, earmold device 5 can be made from a primary material
of either silicone or silicone elastomer that is infused with an
interior of a secondary material 6 such as foam, gel, or a
elastomer of a different hardness or characteristic from the
primary material.
[0096] FIGS. 7B, 8B and 9 show the location of the primary and
secondary materials 6, 7 within earmold 5. As shown schematically
in FIGS. 7B, 8B and 9, the primary material 6 can remains in areas
where it was in contact with the injection mold wall, but is
displaced in specific areas by the secondary material 7.
[0097] FIGS. 10A and 10B show the single use injection mold 4
according to an exemplary embodiment with a sections cutaway to
show the interior area of the mold 4 where earmold 5 can be formed.
FIG. 11 illustrates the mold 4 filled with the primary material 6
which can form the outer layer of the earmold. FIG. 12 shows mold 4
filled with primary material 6 and a hollow interior area 8.
According to embodiments presented herein, an interior portion of
the primary material 6 within mold 4 can be displaced with air or
water to create the hollow interior area 8. FIG. 13 shows injection
mold 4 filled with the evacuated primary material 6 forming a thin
wall against the interior side of the mold 4 with the evacuated
interior filled with secondary material 7 to form a compliant
interior.
[0098] FIG. 14 illustrates a graphical flowchart illustrating an
exemplary process of manufacturing a custom composite earmold
device according to an exemplary embodiment where a secondary
material is infused to displace a primary material. According to
the process shown schematically in FIG. 14, a digital scan of an
ear can be taken. This can be acquired through either a direct
material cast of the ear cavity and shape which is then placed in a
digital scanner, or the scanned image of the ear can be acquired by
a direct scan of the ear by a hand held digital scanner.
[0099] The impression of the ear can then loaded into software
specifically designed for creating custom earmold products from
digitally scanned images via eSculpting. The eSculpting process can
also use CAD software to sculpt a digital scan. A CAD module of the
product silicone mold can then be created which includes the
specialized sprue features for injecting primary and secondary
materials into the mold.
[0100] The eSculpting process can ultimately create earmold 5 (see
e.g. FIGS. 6A and 6B) which is a digital representation of the
final ear mold. The software can also use the digital
representation of the final earmold 5 to create the single use
injection mold 4 by creating an offset of the final product object
5 that can make a hollow mold with the interior having the shape of
the desired final product. It is during this process that the
predesigned features of the injection sprues 2, 3 (see FIGS. 2A-2B,
3A-3B and 4) for both the primary and secondary materials can be
created as well.
[0101] The digital files of the injection mold 4 (see FIGS. 3A and
4) can then be loaded into 3D printing software and prepared for
the 3D printing process. The 3D printing process can be performed
by any of a variety of 3D printers on the market today using a
variety of materials. After printing, the mold 4 can be prepared
for the injection molding process. According to exemplary
embodiments, it is preferred that the mold material be chemically
compatible with the elastomer used to make the ear mold 5. The
primary material 6 can be injected into the mold 4 until the entire
interior surface is covered (see e.g. FIG. 11). The amount of time
allowed between the primary and the secondary injections can alter
the material surface thickness of the primary material 6 if the
primary material 6 curing reaction is time or temperature
dependent.
[0102] According to the exemplary process illustrated in FIG. 14, a
secondary material 7 can be injected into the injection mold 4
using only the sprues 3 intended for the secondary material 7. This
can place the secondary material 7 in the specific locations chosen
to optimize the performance of the mold and help to balance the
flow of the material into specific areas of the single use
injection mold 4 (see e.g. FIGS. 7B, 8B and 9). Time and injection
pressure can also be used to affect the injection results. The
materials 6, 7 can be allowed to reach a cured state after being
injected into the mold.
[0103] FIG. 15 illustrates a graphical flowchart illustrating an
second exemplary process of manufacturing a custom composite
earmold device according to an exemplary embodiment where an
alternate medium is used to displace the primary material before a
secondary material is added or injected/infused. According to the
process shown schematically in FIG. 15, an alternate medium such as
compressed air or pressurized liquid can be used to evacuate the
interior of the primary material 6--the secondary material 7 can be
then injected into the injection mold through the sprues and can
fill the evacuated interior 8 (see e.g. FIGS. 12-13). This
alternative process can achieve more displacement of the primary
material 6 allowing for more of the secondary material 7 in the
final device interior 8. Time and injection pressure can also be
used to affect the injection results. The materials 6, 7 can be
allowed to reach a cured state after being injected into the
mold.
[0104] According to the processes illustrated in FIGS. 14 and 15,
the 3D printed mold 4 filled with cured primary and secondary
material 6, 7 can then be fractured and removed in order to release
the final elastomeric earmold 5 (see FIG. 5). Final treatments can
be completed to the earmold 5 to make the final product. According
to exemplary embodiments, the final product can consist of the
primary material 6 which can maintain its position on the outside
of the earmold 5, with the secondary material 7 encased within the
primary material 6 (see FIGS. 7B, 8B and 9).
[0105] From the foregoing, it will be observed that numerous
variations and modifications may be effected without departing from
the spirit and scope of the invention. It is to be understood that
no limitation with respect to the specific apparatus illustrated
herein is intended or should be inferred. It is, of course,
intended to cover by the appended claims all such modifications as
fall within the scope of the claims.
[0106] Further, logic flows depicted in the figures do not require
the particular order shown, or sequential order, to achieve
desirable results. Other steps may be provided, or steps may be
eliminated, from the described flows, and other components may be
add to, or removed from the described embodiments.
* * * * *