U.S. patent application number 16/372749 was filed with the patent office on 2019-10-03 for wire fabricator.
The applicant listed for this patent is The Charles Stark Draper Laboratory, Inc.. Invention is credited to David J. Carter, Amy Duwel, Ernest Soonho Kim, Peter Houghton Lewis, Vinh Quang Nguyen, Kasey Joe Russell.
Application Number | 20190301091 16/372749 |
Document ID | / |
Family ID | 68056859 |
Filed Date | 2019-10-03 |
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United States Patent
Application |
20190301091 |
Kind Code |
A1 |
Russell; Kasey Joe ; et
al. |
October 3, 2019 |
WIRE FABRICATOR
Abstract
A wire fabrication apparatus includes a number of fluid
channels, each fluid channel configured to receive a first portion
of a corresponding wire of a number of wires and including a fluid
flowing in a first direction therein. A twisting mechanism is
configured for attachment to second portions of the number of
wires, the twisting mechanism being configured to draw the number
of wires from the number of fluid channels in a second direction
opposite to the first direction and to twist the number of drawn
wires. A controller controls twisting mechanism to form a twisted
wire, including controlling the twisting mechanism to draw the
number of wires from the number of fluid channels in the second
direction and to twist the drawn wire.
Inventors: |
Russell; Kasey Joe;
(Cambridge, MA) ; Carter; David J.; (Concord,
MA) ; Duwel; Amy; (Cambridge, MA) ; Lewis;
Peter Houghton; (Cambridge, MA) ; Kim; Ernest
Soonho; (Cambridge, MA) ; Nguyen; Vinh Quang;
(Cambridge, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Charles Stark Draper Laboratory, Inc. |
Cambridge |
MA |
US |
|
|
Family ID: |
68056859 |
Appl. No.: |
16/372749 |
Filed: |
April 2, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62651381 |
Apr 2, 2018 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D07B 2401/40 20130101;
D07B 2207/409 20130101; D07B 3/00 20130101; D07B 2207/20 20130101;
D07B 3/08 20130101; D07B 2207/4031 20130101 |
International
Class: |
D07B 3/08 20060101
D07B003/08 |
Claims
1. A wire fabrication apparatus comprising: a plurality of fluid
channels, each fluid channel configured to receive a first portion
of a corresponding wire of a plurality of wires and comprising a
fluid flowing in a first direction therein; a twisting mechanism
configured for attachment to second portions of the plurality of
wires, the twisting mechanism being configured to draw the
plurality of wires from the plurality of fluid channels in a second
direction opposite to the first direction and to twist the
plurality of drawn wires; and a controller for controlling the
twisting mechanism to form a twisted wire, including controlling
the twisting mechanism to draw the plurality of wires from the
plurality of fluid channels in the second direction and to twist
the drawn wire.
2. The wire fabrication apparatus of claim 1 wherein the twisting
mechanism comprises: a motor including a rotatable attachment head
for attachment to second portions of the plurality of wires; and a
separator for changing a distance between the plurality of fluid
channels and the motor; wherein controlling the twisting mechanism
to form the twisted wire further comprises, controlling the
separator to increase the distance between the motor and the
plurality of fluid channels to draw the plurality of wires from the
plurality of fluid channels in the second direction, and
controlling motor to twist the plurality of wires by rotating the
attachment head.
3. The wire fabrication apparatus of claim 1 wherein the controller
is further configured to control flow properties of the fluid
flowing through the plurality of fluid channels to adjust a drag
force acting on the plurality of wires in the plurality of fluid
channels.
4. The wire fabrication apparatus of claim 3 wherein the flow
properties of the fluid are controlled by adjusting one or more
parameters including velocity of the fluid in the fluid channels
and a viscosity of the fluid in the channels.
5. The wire fabrication apparatus of claim 4 wherein the controller
is configured to adjust a velocity of the fluid in the fluid
channels relative to a velocity of the wires in the fluid
channels.
6. The wire fabrication apparatus of claim 1 further comprising a
propulsion mechanism for causing the fluid to flow in the plurality
of fluid channels.
7. The wire fabrication apparatus of claim 1 wherein at least a
portion of each wire of the plurality of wires has a diameter less
than or equal to 10 .mu.m.
8. The wire fabrication apparatus of claim 1 wherein controlling
the twisting mechanism to draw the plurality of wires from the
plurality of fluid channels in the second direction and to twist
the drawn wire includes controlling a linear velocity of the motor
in the second direction and a rotational velocity of the motor.
9. A wire fabrication method comprising: positioning, for each wire
of a plurality of wires, a first portion of the wire in a
corresponding fluid channel of a plurality of fluid channels, each
fluid channel comprising a fluid flowing in a first direction
therein; drawing the plurality of wires from the plurality of fluid
channels in a second direction opposite to the first direction; and
twisting the plurality of drawn wires using a twisting mechanism to
form a twisted wire.
10. The wire fabrication method of claim 9 wherein twisting the
plurality of drawn wires includes: rotating an attachment head of a
motor, the attachment head being attached to the plurality of
wires; and changing a distance between the plurality of fluid
channels and the motor.
11. The wire fabrication method of claim 10 wherein controlling the
twisting mechanism to draw the plurality of wires from the
plurality of fluid channels in the second direction and to twist
the drawn wire includes controlling a linear velocity of the motor
in the second direction and a rotational velocity of the motor.
12. The wire fabrication method of claim 9 further comprising
controlling flow properties of the fluid flowing through the
plurality of fluid channels to adjust a drag force acting on the
plurality of wires in the plurality of fluid channels.
13. The wire fabrication method of claim 12 wherein the flow
properties of the fluid are controlled by adjusting one or more
parameters including velocity of the fluid in the fluid channels
and a viscosity of the fluid in the channels.
14. The wire fabrication method of claim 9 further comprising
adjusting a velocity of the fluid in the fluid channels relative to
a velocity of the wires in the fluid channels.
15. The wire fabrication method of claim 9 further comprising
causing the fluid to flow in the plurality of fluid channels using
a propulsion mechanism.
16. The wire fabrication method of claim 9 wherein at least a
portion of each wire of the plurality of wires has a diameter less
than or equal to 10 .mu.m.
17. The wire fabrication method of claim 9 further comprising
preparing the plurality of wires including, for each wire of the
plurality of wires: attaching the wire to a substrate using a
soluble adhesive; and attaching one end of the wire to an
attachment member using a permanent adhesive.
18. The wire fabrication method of claim 17 wherein a dimension of
the attachment member is greater than a diameter of the wire.
19. The wire fabrication method of claim 18 wherein the dimension
of the attachment member is one or more orders of magnitude greater
than the diameter of the wire.
20. The wire fabrication method of claim 17 wherein the soluble
adhesive is water-soluble.
21. The wire fabrication method of claim 17 wherein the attachment
member includes a ferromagnetic disk dimensioned such that it is
incapable of passing through a fluid channel of the plurality of
fluid channels.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 62/651,381 filed Apr. 2, 2018, the entire contents
of which incorporated herein by reference.
BACKGROUND
[0002] This invention relates to fabrication of wires.
[0003] Wires and fibers (sometimes collectively referred to as
"wires" for simplicity) are commonly arranged in bundles containing
multiple wires or fibers. Often these bundles are designed to
achieve specific characteristics (such as electrical or mechanical
characteristics) that depend upon both the properties of the
individual wires or fibers as well as the order in which the
individual wires or fibers are arranged within the bundle.
[0004] An example of such a bundle is Litz wire, which is a bundle
of insulated, conducting wires that are arranged in a hierarchical
twist of twists. The characteristics of the individual wires are
chosen primarily to mitigate resistive losses due to skin effect
for a given frequency range, the number of individual wires is
chosen based on the power requirements of the application, and the
arrangement of wires within the bundle is designed primarily to
mitigate resistive losses due to proximity effect.
[0005] Some conventional strategies for fabricating bundled wires
work well when using metal wires that have diameters of
approximately 25 .mu.m and larger, where the tensile strength of
the wires is above about 0.1 N. Such wires can support many grams
of mass, and gravity is the strongest ambient force per unit length
on the wire. These conventional wires can be stored on spools and
are pulled off the spools during wire fabrication. Twisting of the
wires is accomplished by moving the spools around each other while
tension is mechanically controlled (e.g., by passing the wires
under weighted pulleys).
SUMMARY
[0006] In one general aspect, a method enables the manipulation of
individual wires and fibers of diameter less than approximately 10
.mu.m. The manipulation of the individual wires achieves a
combination of two or more wires with a specific arrangement that
provides a bundle of wires with specific electrical, mechanical, or
other properties.
[0007] In another general aspect, a wire fabrication apparatus
includes a number of fluid channels, each fluid channel configured
to receive a first portion of a corresponding wire of a number of
wires and including a fluid flowing in a first direction therein. A
twisting mechanism is configured for attachment to second portions
of the number of wires, the twisting mechanism being configured to
draw the number of wires from the number of fluid channels in a
second direction opposite to the first direction and to twist the
number of drawn wires. A controller controls twisting mechanism to
form a twisted wire, including controlling the twisting mechanism
to draw the number of wires from the number of fluid channels in
the second direction and to twist the drawn wire.
[0008] Aspects may have one or more of the following features.
[0009] The twisting mechanism may include a motor including a
rotatable attachment head for attachment to second portions of the
number of wires and a separator for changing a distance between the
number of fluid channels and the motor. Controlling the twisting
mechanism to form the twisted wire may include controlling the
separator to increase the distance between the motor and the number
of fluid channels to draw the number of wires from the number of
fluid channels in the second direction and controlling motor to
twist the number of wires by rotating the attachment head.
[0010] The controller may be configured to control flow properties
of the fluid flowing through the number of fluid channels to adjust
a drag force acting on the number of wires in the number of fluid
channels. The flow properties of the fluid may be controlled by
adjusting one or more parameters including velocity of the fluid in
the fluid channels and a viscosity of the fluid in the channels.
The controller may be configured to adjust a velocity of the fluid
in the fluid channels relative to a velocity of the wires in the
fluid channels.
[0011] The wire fabrication apparatus may include a propulsion
mechanism for causing the fluid to flow in the fluid channels. At
least a portion of each of the wires may have a diameter less than
or equal to 10 .mu.m.
[0012] Controlling the twisting mechanism to draw the wires from
the fluid channels in the second direction and to twist the drawn
wire includes controlling a linear velocity of the motor in the
second direction and a rotational velocity of the motor.
[0013] In another general aspect, a wire fabrication method
includes positioning, for each wire of a number of wires, a first
portion of the wire in a corresponding fluid channel of a number of
fluid channels, each fluid channel including a fluid flowing in a
first direction therein, drawing the wires from the fluid channels
in a second direction opposite to the first direction, and twisting
the drawn wires using a twisting mechanism to form a twisted
wire.
[0014] Aspects may include one or more of the following
features.
[0015] Twisting of the drawn wires may include rotating an
attachment head of a motor, the attachment head being attached to
the wires, and changing a distance between the fluid channels and
the motor. Controlling the twisting mechanism to draw the wires
from the fluid channels in the second direction and to twist the
drawn wire may include controlling a linear velocity of the motor
in the second direction and a rotational velocity of the motor.
[0016] The method may include controlling flow properties of the
fluid flowing through the fluid channels to adjust a drag force
acting on the wires in the fluid channels. The flow properties of
the fluid may be controlled by adjusting one or more parameters
including velocity of the fluid in the fluid channels and a
viscosity of the fluid in the channels. The method may include
adjusting a velocity of the fluid in the fluid channels relative to
a velocity of the wires in the fluid channels. The method may
include causing the fluid to flow in the fluid channels using a
propulsion mechanism.
[0017] At least a portion of each of the wires may have a diameter
less than or equal to 10 .mu.m.
[0018] The method may include preparing the wires including, for
each wire, attaching the wire to a substrate using a soluble
adhesive, and attaching one end of the wire to an attachment member
using a permanent adhesive. A dimension of the attachment member
may be greater than a diameter of the wire. The dimension of the
attachment member may be one or more orders of magnitude greater
than the diameter of the wire. The soluble adhesive may be
water-soluble. The attachment member may include a ferromagnetic
disk dimensioned such that it is incapable of passing through a
fluid channel of the number of fluid channels.
[0019] Aspects may have one or more of the following
advantages.
[0020] In contrast to conventional mechanical wire manipulation
approaches, aspects described herein are able to create
arrangements of wires or fibers having the requisite diameter to
yield desired bundle properties, even when using small-diameter
wires or fibers with low tensile strength, which are prone to
breakage. For example, a copper wire of diameter 1 .mu.m would have
a tensile strength of less than 200 .mu.N. Conventional wire
tensioners, even those specifically designed for very fine wire,
typically apply a minimum of 1 centinewton of force--this is 100
times too large. Aspects described herein are advantageously able
to apply forces appropriate for working with very fine wire or
fiber.
[0021] Aspects are able to manipulate wires and fibers with
diameters less than 10 .mu.m into bundles. Aspects advantageously
leverage technology developed for microfluidic devices. Some
aspects are able to manipulate wires and fibers with a diameter of
approximately 1 .mu.m, where gravity is several orders of magnitude
weaker than other ambient forces such as static electricity and
fluid drag from air disturbances, and tensile strength of the wire
or fiber is less than 300 .mu.N. Some aspects reduce the influence
of uncontrolled ambient forces by twisting and bundling wires while
they are submerged in fluid. Tensile force on the wires is
controlled hydrodynamically rather than mechanically. Hydrodynamic
control of tensile forces is accomplished by placing the wires
inside of fluid flow channels. In some aspects, the wires are
stored and inserted into the wire fabrication apparatus in straight
individual sections (rather than being stored on spools). In some
aspects, the rotational motion responsible for twisting the wires
is generated by an electric motor at a single common attachment
point for the wires (rather than by movement of separate
spools).
[0022] Aspects are advantageously able to manipulate very thin
wires or fibers without being adversely affected by forces arising
from static electricity and air currents which can lead to
unpredictable and/or uncontrollable behavior of the wires or
fibers. Aspects are capable of applying the requisite force to
manipulate wires or fibers while simultaneously mitigating common
environmental factors such as static electricity and air
currents.
[0023] Aspects advantageously leverage microfluidic technology such
that many fluid channels can be arranged on a single substrate or
within a single system to increase the number of wires/fibers that
can be processed simultaneously. Aspects are capable of working
with wires/fibers with centimeters of length or more; the fluid
channels can be arbitrarily long to accommodate longer
wires/fibers.
[0024] Other features and advantages of the invention are apparent
from the following description, and from the claims.
DESCRIPTION OF DRAWINGS
[0025] FIG. 1 is a wire fabrication system.
[0026] FIG. 2 shows the wire fabrication system of FIG. 1 with a
partially fabricated wire.
[0027] FIG. 3 shows a wire prepared for attachment to the wire
fabrication system of FIG. 1.
[0028] FIG. 4 shows the prepared wires of FIG. 3 attached to the
wire fabrication system of FIG. 1.
[0029] FIG. 5 shows another wire prepared for attachment to a wire
fabrication system.
[0030] FIG. 6 shows the prepared wires of FIG. 5 inserted into the
fluid channels of another wire fabrication system.
[0031] FIG. 7 shows the prepared wires of FIG. 6 with the substrate
removed from the fluid channels of the wire fabrication system.
[0032] FIG. 8 shows the prepared wires of FIG. 7 attached to the
wire fabrication system.
DESCRIPTION
[0033] Referring to FIGS. 1 and 2, a wire fabrication system 100 is
configured to manipulate individual wires and fibers (sometimes
collectively referred to as "wires") to form bundles of multiple
wires or fibers.
[0034] The wire fabrication system 100 includes a motor 102 (e.g.,
a rotary electric motor) positioned above a fluid chamber 104. The
motor 102 includes a rotatable spindle 103 (sometimes referred to
as an attachment member or attachment point) and is movable along
an axis 105 such that a distance between the motor 102 and the
fluid chamber 104 can be increased or decreased.
[0035] The fluid chamber 104 is filled with a fluid 106 (e.g.,
water or oil) and includes a number of fluid channels 108. The
fluid 106 in the fluid channels 108 flows in a direction away from
the motor 102, as is indicated by the arrows directed away from the
motor 102 in FIGS. 1 and 2. In some examples, the flow of fluid
through the fluid channels 108 is caused by one or more pumps or
propellers (not shown).
[0036] A number of wire assemblies 110 extend from the spindle 103
of the motor 102 and into the fluid channels 108 in the fluid
chamber 104. Each wire assembly 110 includes an attachment wire 112
at a first end 114 of the wire assembly 110 and a wire 116 affixed
to the attachment wire 112. The wire 116 extends from the
attachment wire 112 to a second end 118 of the wire assembly
110.
[0037] When the wire assemblies 110 are placed in the wire
fabrication system 100, the attachment wire 112 at the first end
114 of each wire assembly 110 is affixed to the spindle 103 of the
motor 102 and at least a portion of the wire 116 the wire assembly
110 is disposed in one of the fluid channels 108 (as is shown in
FIGS. 1 and 2).
[0038] The fluid moving through the fluid channels 108 subjects the
wires 116 in the fluid channels 108 to an axial drag force that
pulls the wires 116 in a direction away from the motor 102. Very
generally, the axial drag force is hydrodynamically controlled to
maintain tension on the wires 116 without breaking the wires
116.
[0039] In general, the hydrodynamic control of the axial drag force
on a given wire 116 is accomplished by varying either the relative
velocity between the fluid in the fluid channel 108 and the wire
116, the viscosity of the fluid in the fluid channel 108, or both.
The relative velocity between the fluid in the fluid channel 108
and the wire 116 is adjustable by varying the fluid flow rate
within the channel or by varying the wire velocity within the
channel, or both. The viscosity of the fluid in the fluid channel
108 is adjustable by, for example, varying the type of fluid used,
varying a ratio of fluids with different viscosities used in a
mixture of fluids, varying a temperature of the fluid, applying an
electric field to the fluid, or applying a magnetic field to the
fluid.
[0040] Referring to FIG. 2, in operation, the motor 102 rotates the
spindle 103 about the axis 105 while the motor 102 is moved along
the axis 105 in a direction away from the fluid chamber 104. As the
motor 102 moves away from the fluid chamber 104, the wires 116 are
pulled through the fluid channels 108 while still under tension,
and the rotation of the spindle 103 twists the taut wires 116 to
form a twisted (or bundled) section of wire 218. A pitch of the
twist in the twisted wire is determined by the ratio of the linear
velocity of the motor in the direction away from the fluid chamber
104 and the rotational velocity of the motor 102 (provided that the
tension applied to the wires is sufficient to provide the necessary
bending force for a desired bend radius).
[0041] The force required for twisting the wires 116 is estimated
by modeling the wires using the electrostatics of bending a slender
rod. For an approximately 1 .mu.m diameter copper wire, twisting
with a pitch of approximately 50 .mu.m requires .mu.N or smaller
forces, depending on the point of application of the force. The
force on the wires from axial fluid drag can be estimated as Stokes
drag using the equation
F.apprxeq.4.pi..mu.lu/ln(l/a)
where .mu. is the dynamic viscosity of the fluid, u is the velocity
of the fluid relative to the wire, l is the wire length over which
the drag force is operating, and a is the wire radius.
[0042] For example, if the fluid 106 in the fluid chamber 104 is
water, the wires can be twisted to a pitch of approximately 50
.mu.m using a fluid velocity of approximately 1 m/min, which is
estimated to generate less than 50 nN of force per millimeter of
wire. If necessary, larger drag forces can be generated by
increasing the flow rate of the fluid, decreasing a cross-sectional
area of the fluid channels 108, or using a fluid with a higher
viscosity.
[0043] Referring to FIG. 3, in some examples the wire assemblies
110 are prepared prior to being placed in the wire fabrication
system. To prepare a wire assembly, a wire 116 is provided with a
predetermined length. The wire 116 is then affixed to a carrier
substrate 224 (e.g., a 25 mm.times.5 mm.times.1 mm glass substrate)
using a soluble adhesive 226 (e.g., a water-soluble adhesive if the
fluid 106 includes water). An attachment wire 112 having a greater
diameter (e.g., a 100 .mu.m diameter) than the wire 116 is then
affixed to first end 220 of the wire 116 using a permanent adhesive
222.
[0044] Referring to FIG. 4, to place the prepared wire assemblies
110 into the wire fabrication system 100, the substrates 224 with
the wires 116 affixed thereto are placed into the fluid channels
108. The attachment wires 112 are attached to the spindle 103 of
the motor 102. In the presence of the fluid 106 in the fluid
channels 108, the soluble adhesive 226 dissolves and the wires 116
are no longer affixed to the substrate 224 (i.e., the wires 116 are
freely floating in the fluid channels 108).
[0045] In some examples, the substrates 224 are removed from the
fluid channels 108 once the soluble adhesive 226 is dissolved (see
FIG. 1). In other examples, the substrates 224 remain in the fluid
channels 108 during operation of the wire fabrication system
100.
[0046] Referring to FIGS. 5-7, in another example, rather than
attaching an attachment wire to the wire 116, a small (e.g., 2-10
mm diameter.times.about 100 .mu.m thick) mu-metal (or other
ferromagnetic metal) disk 521 is attached to the end of the wire
116. In operation, the mu-metal disks are attached to the spindle
103 of the motor 102 by magnetic force.
[0047] Referring now to FIG. 5, in some examples the wire
assemblies 510 are prepared prior to being placed in a wire
fabrication system 500. To prepare a wire assembly 510, a mu-metal
disk 521 is affixed to a carrier substrate 524 using a soluble
adhesive (not shown). A wire 116 is provided with a predetermined
length. The wire 116 is affixed to the carrier substrate 524 (e.g.,
a 25 mm.times.5 mm.times.1 mm glass substrate) using a soluble
adhesive 526 (e.g., a water-soluble adhesive if the fluid 506
includes water). A first end 520 of wire 116 is affixed to the
mu-metal disk 521 using a permanent adhesive 522.
[0048] Referring to FIGS. 6 and 7, to place the prepared wire
assemblies 510 into the wire fabrication system 500, the substrates
524 with the wires 116 affixed thereto are placed into the fluid
channels 508. In the presence of the fluid 506 in the fluid
channels 508, the soluble adhesive 526 attaching the wires 116 and
the mu-metal disks 521 to the carrier substrates 524 dissolves such
that both the mu-metal disks 521 and the wires 116 are no longer
affixed to the substrate 524 (i.e., the mu-metal disks 521 and the
wires 116 are freely floating in the fluid channels 508). The
mu-metal disks 521 are dimensioned such that they are too large to
move into or through the fluid channels 508.
[0049] Referring to FIG. 8, with the wire assemblies 510 in the
fluid channels, the motor 502 is positioned in proximity to the
mu-metal disks 521 and the spindle 503 of the motor is magnetized
(e.g., by inserting a magnet into the spindle or turning on an
electromagnet). The magnetized spindle 503 attracts the mu-metal
disks 521, attaching the mu-metal disks to the spindle 503. The
wire fabrication system 500 then proceeds to draw the wires 116
through the fluid channels 508 while rotating the spindle 503 (as
was described in the examples above) to form the twisted wire.
[0050] In some examples, upon completion of wire fabrication, the
spindle 503 is demagnetized (e.g., by removing the magnet or
turning off the electromagnet) such that the mu-metal disks 521 can
be easily removed from the spindle 503. In some examples, the
polarity of the electromagnet is reversed to force the mu-metal
disks 521 away from the spindle 503, making removal of the mu-metal
disks 503 even easier.
[0051] It is to be understood that the foregoing description is
intended to illustrate and not to limit the scope of the invention,
which is defined by the scope of the appended claims. Other
embodiments are within the scope of the following claims.
* * * * *