U.S. patent application number 11/867088 was filed with the patent office on 2008-04-17 for component carrier and method for making.
This patent application is currently assigned to 3M Innovative Properties Company. Invention is credited to Charlie V. Wihren.
Application Number | 20080087572 11/867088 |
Document ID | / |
Family ID | 39314349 |
Filed Date | 2008-04-17 |
United States Patent
Application |
20080087572 |
Kind Code |
A1 |
Wihren; Charlie V. |
April 17, 2008 |
COMPONENT CARRIER AND METHOD FOR MAKING
Abstract
A component carrier tape having a longitudinal flexible strip; a
plurality of pockets longitudinally positioned on the longitudinal
strip and configured for receiving a component therein, each of the
pockets separated from an adjacent pocket by a crossbar; wherein at
least one crossbar includes at least one release feature.
Inventors: |
Wihren; Charlie V.;
(Victoria, MN) |
Correspondence
Address: |
3M INNOVATIVE PROPERTIES COMPANY
PO BOX 33427
ST. PAUL
MN
55133-3427
US
|
Assignee: |
3M Innovative Properties
Company
|
Family ID: |
39314349 |
Appl. No.: |
11/867088 |
Filed: |
October 4, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60829807 |
Oct 17, 2006 |
|
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|
Current U.S.
Class: |
206/714 ;
264/554 |
Current CPC
Class: |
H05K 13/0084
20130101 |
Class at
Publication: |
206/714 ;
264/554 |
International
Class: |
B65D 85/86 20060101
B65D085/86 |
Claims
1. A component carrier tape comprising: a longitudinal flexible
strip; a plurality of pockets longitudinally positioned on the
longitudinal strip and configured for receiving a component
therein, each of the pockets separated from an adjacent pocket by a
crossbar; wherein at least one crossbar includes at least one
release feature.
2. The component carrier tape of claim 1 having multiple release
features on at least one crossbar.
3. The component carrier tape of claim 2 wherein the multiple
release features differ with respect to one or more of size, shape,
height, width, depth, and spacing.
4. The component carrier tape of claim 1 wherein the uppermost
portion of the release feature is at or below the plane of the
longitudinal flexible strip.
5. The component carrier tape of claim 1 wherein at least one
release feature is a trough.
6. The component carrier tape of claim 5 having at least two
troughs.
7. The component carrier tape of claim 3 wherein the release
features comprise at least two ridges separated by a trough.
8. The component carrier tape of claim 1 wherein the release
feature acts as a hinge as the component carrier tape is removed
from a forming tool.
9. The component carrier tape of claim 8 wherein the release
feature can flex at an angle of up to about 45 degrees.
10. A flexible carrier tape for storage and delivery of components
by an advancement mechanism, the carrier tape comprising: a
longitudinal flexible strip having a top surface and a bottom
surface opposite the top surface; a plurality of pockets for
receiving components spaced along the strip and opening through the
top surface thereof, wherein adjacent pockets are separated from
each other by a crossbar; and wherein a top surface of at least one
the crossbar has at least one release feature.
11. A method for producing an embossed carrier tape comprising:
providing a rotatable tool having an outer circumferential surface,
the outer circumferential surface including a series of projections
for forming a plurality of longitudinally spaced component
receiving pockets and at least one patterned depression between
adjacent projections for forming at least one crossbar having at
least one release feature between adjacent component receiving
pockets; introducing a polymer web onto the tool; conforming the
polymer web against the tool to emboss the web with the projections
and depressions on the circumferential surface of the tool; and
removing the embossed web from the tool.
Description
REFERENCE TO CROSS-RELATED APPLICATIONS
[0001] The present application claims priority to U.S. Provisional
Patent Application 60/829,807, filed Oct. 17, 2006.
FIELD
[0002] The present invention relates generally to carrier tapes
having a plurality of pockets spaced longitudinally on the tape for
accommodating components therein.
BACKGROUND
[0003] In general, carrier tapes that are used to hold and
transport components are well known. For example, in the field of
electronics circuit assembly, a common way to provide a continuous
supply of electronic components to robotic placement equipment is
to use a carrier tape. Conventional carrier tapes generally
comprise an elongated strip that has a series of identical pockets
formed at predetermined, uniformly spaced intervals along the
length of the tape, which pockets are each designed to receive an
electronic component therein. The component manufacturer typically
loads components into the series of pockets. After components are
placed in the pockets, a cover tape is applied over the elongated
strip to retain the components in their respective pockets. The
loaded carrier tape is wound into a roll or onto a reel, and then
transported from the component manufacturer to another manufacturer
or assembler, where the roll of carrier tape may be mounted within
some type of assembly equipment. The carrier tape is typically
unwound from the roll and automatically advanced toward a robotic
pick-up location. Advancement of the carrier tape is commonly
accomplished using a series of through-holes uniformly spaced along
one or both edges of the elongated strip forming the carrier tape.
The through-holes receive the teeth of a drive sprocket that
advances the tape toward the robotic placement machine. Eventually,
the cover tape is stripped from the carrier tape, the components
are removed from the pockets, and then placed onto the circuit
board.
SUMMARY
[0004] Carrier tapes may be formed using a rotating drum. The
rotating drum has a plurality of molds disposed around its
circumference. The molds may be convex (i.e., male) or concave
(i.e., female) molds. In the production of an embossed carrier tape
using a convex rotary mold, typically a web of pliable material is
guided around the periphery of the drum. The softened material
drapes over the molds and comes into close contact with generally
the entire side surfaces of the convex molds except for those
portions of the web located between adjacent convex molds. The web
may be vacuum-drawn against the molds, or pressed against the molds
by a nip roll, to urge the web into the spaces between adjacent
molds. After the pliable web material takes on the shape of the
molds, cooling and hardening of the web material is initiated and
the shaped web material is removed from the molds. Because the
shaped web material has not completely hardened at the time it is
removed from the molds, uneven stresses applied to portions of the
shaped web material can cause desired features of the resulting
carrier tape to be skewed or misshapen.
[0005] At least one aspect of the present invention provides a
component carrier tape comprising a longitudinal flexible strip; a
plurality of pockets longitudinally positioned on the longitudinal
strip and configured for receiving a component therein, each of the
pockets separated from an adjacent pocket by a crossbar; wherein at
least one crossbar includes at least one release feature. The
component carrier tape may have multiple release features on a
single crossbar. The multiple release features may differ with
respect to one or more of size, shape, height, width, depth, and
spacing. The uppermost portion of the release feature may be at or
below the plane of the longitudinal flexible strip. A release
feature may be a trough. There may be more than one trough and the
troughs may be separated by a ridge. Alternatively, two ridges may
be separated by a trough. The release feature may act as a hinge as
the component carrier tape is removed from a forming tool. In some
embodiments, the release feature may flex at an angle of up to
about 45 degrees.
[0006] Another aspect of the present invention provides a flexible
carrier tape for storage and delivery of components by an
advancement mechanism, the carrier tape comprising a longitudinal
flexible strip having a top surface and a bottom surface opposite
the top surface; a plurality of pockets for receiving components
spaced along the strip and opening through the top surface thereof,
wherein adjacent pockets are separated from each other by a
crossbar; and wherein a top surface of at least one the crossbar
has at least one release feature.
[0007] Yet another aspect of the present invention provides a
method for producing an embossed carrier tape comprising providing
a rotatable tool having an outer circumferential surface, the outer
circumferential surface including a series of projections for
forming a plurality of longitudinally spaced component receiving
pockets and at least one patterned depression between adjacent
projections for forming at least one crossbar having at least one
release feature between adjacent component receiving pockets;
introducing a polymer web onto the tool; conforming the polymer web
against the tool to emboss the web with the projections and
depressions on the circumferential surface of the tool; and
removing the embossed web from the tool.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1A is a fragmentary perspective view of a carrier tape
according to one embodiment of the invention.
[0009] FIG. 1B is a fragmentary perspective view of a carrier tape
according to a second embodiment of the invention.
[0010] FIG. 1C is a cross-sectional view of the embodiment of FIG.
1B.
[0011] FIG. 2 is a schematic illustration of an exemplary process
for producing a carrier tape according to an embodiment of the
invention.
[0012] FIG. 3 is a photograph of a carrier tape according to one
embodiment of the invention.
[0013] FIG. 4 is a photograph of a cross-section of a carrier tape
according to one embodiment of the invention.
[0014] In the following detailed description of the preferred
embodiments, reference is made to the accompanying drawings, which
form a part hereof, and in which is shown by way of illustration
specific embodiments in which the invention may be practiced. It is
to be understood that other embodiments may be utilized and
structural or logical changes may be made without departing from
the scope of the present invention. The following detailed
description, therefore, is not to be taken in a limiting sense, and
the scope of the present invention is defined by the appended
claims.
DETAILED DESCRIPTION
[0015] At least one aspect of the present invention provides a
longitudinal component carrier tape having a plurality of pockets
for storing, transporting, and otherwise handling electronic or
other components separated by crossbars on which are located one or
more release features. Although illustrative embodiments of
component carriers are described below with reference to carrier
tapes for use with electronic components, it is understood that the
component carriers may be adapted for use with materials or
substances of any type.
[0016] Referring now to the drawings, one embodiment of a carrier
tape according to the invention is shown in FIG. 1A. A unitary
flexible carrier tape 100 has a strip portion 101 defining a top
surface 102 and a bottom surface 103 opposite the top surface 102.
Strip portion 101 includes longitudinal edge surfaces 104 and 106,
and a row of aligned advancement holes 108 and 110 formed in and
extending along one, and preferably both, edge surfaces.
Advancement holes 108 and 110 provide a means for receiving an
advancement mechanism such as the teeth of a sprocket drive (not
shown) for advancing carrier tape 100 toward a predetermined
location.
[0017] A series of pockets 112 is formed in and spaced along strip
portion 101, the pockets opening through the top surface 102 of the
strip portion. Within a given carrier tape, each pocket 112 is
usually practically identical to the other pockets. Typically, the
pockets 112 are aligned with each other and equally spaced apart.
In the illustrated embodiment, each pocket 112 includes four
sidewalls 114, each at generally right angles with respect to each
adjacent wall. Sidewalls 114 adjoin and extend downwardly from the
top surface 102 of the strip portion and adjoin bottom wall 116 to
form pocket 112. Although not specifically illustrated, the pockets
may have more or less sidewalls than the four that are shown in the
preferred embodiment. The pockets 112 may be circular, oval,
triangular, pentagonal, or have other shapes in outline. Bottom
wall 116 is generally planar and parallel to the plane of strip
portion 101. The transverse sidewalls 114 of adjacent
longitudinally positioned pockets 112 define crossbars 117 that
separate adjacent pockets 112. Crossbars 117 include release
features 119. Release features 119 are two ridges separated by a
trough. FIGS. 1B and 1C illustrate an alternate embodiment in which
release features 119 are two troughs. The uppermost portions of the
troughs are at or below the plane of strip portion 101.
[0018] Although a single column of pockets 112 is illustrated in
the drawings, two or more columns of aligned pockets could also be
formed along the length of the strip portion 101 to facilitate the
simultaneous delivery of multiple components.
[0019] The web forming strip portion 101 may have any thickness, so
long as the web has sufficient flexibility to permit it to be wound
about the hub of a storage reel. Strip portion 101 may be optically
clear, pigmented or modified to be electrically dissipative or
conductive. Electrically conductive material allows an electric
charge to dissipate throughout the carrier tape and preferably to
the ground. This feature may prevent damage to components contained
within the carrier tape due to an accumulated static electric
charge.
[0020] Carrier tape 100 may optionally include an elongate cover
tape 120. Cover tape 120 is applied over the pockets 112 of the
carrier tape 100 to retain the components therein. An exemplary
component 118 is schematically illustrated in FIG. 1A. Cover tape
120 can also protect the components from dirt and other
contaminants that could invade the pockets. As best shown in FIG.
1A, cover tape 120 is flexible, overlies part or all of pockets
112, and is disposed between the rows of advancement holes 108 and
110 along the length of strip portion 101. Cover tape 120 is
releasably secured to the top surface of strip portion 101 so that
it can be subsequently removed to access the stored components. As
illustrated, cover tape 120 includes parallel longitudinal bonding
portions 122 and 124 that are bonded to longitudinal edge surfaces
104 and 106, respectively, of strip portion 101. For example, a
pressure sensitive adhesive such as an acrylate material, or a
heat-activated adhesive such as an ethylene vinyl acetate
copolymer, may be used to adhere the cover to edge surfaces 104 and
106. Alternatively, cover tape 120 could be secured to strip
portion 101 by other means. Cover tape 120 could also be omitted,
and components retained in the pockets 112 by an adhesive, for
example.
[0021] In one exemplary embodiment, the carrier tapes according to
the present invention are made by shaping the pockets 112 in a
sheet of polymeric material and winding the carrier tape onto a
reel to form a roll. FIG. 2 schematically shows an apparatus and
manufacturing process used in the production of a component carrier
tape according to one embodiment of the present invention. A
rotatable tool 200 has a structured outer circumferential surface
202. The surface 202 includes projections 204 extending therefrom
and depressions (not shown) that correspond to the various features
to be formed in a component carrier tape 100, e.g., component
pockets 112, crossbars 117, release features 119, alignment
features within the pockets, bosses for sprocket or alignment
holes, etc. For purposes of illustration, projections 204 have been
greatly enlarged in the schematic representation of FIG. 2.
[0022] In the process illustrated in FIG. 2, a melt-processable
polymer is delivered from an extruder 220 to a slot die apparatus
222. The melt-processable polymer is delivered to the slot die
apparatus 222 at or above its melting temperature (i.e., the
temperature at which it can be formed or molded). A web 230 of
polymer is discharged from the die apparatus 222 into the nip 240
between the rotatable tool 200 and the nip roll 210 or drop cast
onto the rotatable tool 200 just before the nip 240 formed with the
nip roll 210. The conformable outer surface 212 of the nip roll 210
deforms as the polymer web 230 is pressed between the rotatable
tool 200 and the nip roll 210 and is embossed with the features of
the rotatable tool 200. The circumferential surface 212 of the nip
roll 210 is preferably covered with an elastomeric material.
Suitable elastomeric materials include, but are not limited to,
rubbers, silicones, ethylene propylene diene monomers (EPDM),
urethanes, TEFLON, nitrites, neoprenes, and fluoroelastomers. In
some embodiments, the conformable outer surface 212 of the nip roll
210 has a Shore A hardness in the range of 30 to 100, preferably in
the range of 50 to 90, depending upon the material being formed.
The pressure applied to the web 230 by the conformable nip roll 210
is sufficient to force molten resin of web 230 into small crevices
between projections 204 (forming features of the carrier tape 100
such as pocket crossbars 117 and release features 119) of the
rotatable tool 200, and to provided backside feature definition to
the web 230 (i.e., features are defined on bottom surface 103 of
strip portion 101).
[0023] As an alternative to using a nip roll, the web may be
vacuum-drawn against the molds to urge the web into the spaces
between adjacent molds. Rotary molds used in vacuum forming a
carrier tape are generally constructed by stacking a plurality of
drum sections as described in U.S. Pat. No. 5,800,772. When a
plurality of drum sections are assembled together, a suitable
rotatable tool is created. The space between the drum sections
enables the use of vacuum to draw down the web to form pocket
features.
[0024] Additionally, as an alternative to extruding a
melt-processable polymer onto the die apparatus, a pre-formed
polymer sheet, which has been heated and softened, may be placed
onto the rotatable tool. The pre-formed polymer sheet may be in the
form of a continuous roll that is incrementally heated and fed onto
the rotatable tool.
[0025] The temperature of the polymer web is preferably lowered to
below the melt processing temperature at some point after it
conforms to the shape of the rotatable tool 200 to retain the
structures formed in the polymer web 230 and provide mechanical
stability to the web. To aid in temperature control of the web 230,
the rotatable tool 200 and/or the nip roll 210, if used, may be
heated or cooled, as necessary. The result of the processing
depicted in FIG. 2 is an embossed web 250 that can be used to form
the carrier tapes 100 according to the present invention.
[0026] Any suitable cooling means may be employed to cool the web
and sufficiently harden the material such that it may be removed
from the rotatable tool 200. Cooling can be accomplished, for
example, by convective air cooling, direct impingement of air jets
by high-pressure blowers, a water bath or spray, or a cooling oven
until the thermoplastic polymer sufficiently solidifies.
[0027] Suitable resin compositions for component carrier tapes of
this invention are dimensionally stable, durable, and readily
formable into the desired configuration. Suitable materials
include, but are not limited to, polyesters (e.g., glycol-modified
polyethylene terephthalate, or polybutylene terephthalate),
polycarbonate, polypropylene, polystyrene, polyvinyl chloride,
acrylonitrile-butadiene-styrene, amorphous polyethylene
terephthalate, polyamide, polyolefins (e.g. polyethylene,
polybutene, or polyisobutene), modified poly (phenylene ether),
polyurethane, polydimethylsiloxane, acrylonitrile-butadiene-styrene
resins, and polyolefin copolymers. In some embodiments, the
material has a melt temperature in the range of 400.degree. to
630.degree. F. The material may be modified to be electrically
dissipative or conductive. In the latter case, the material may
include an electrically conductive material, such as carbon black
or vanadium pentoxide, that is either interspersed within the
polymeric material or is subsequently coated onto the web. These
materials may also include dyes, colorants, pigments, UV
stabilizers, or other additives.
[0028] Although the tool 200 is depicted and described herein as a
roll, the tool 200 may alternatively be provided as any other
rotatable structure amenable to continuous web-form processing,
such as a continuous belt. In general, the rotatable tool 200 may
be comprised of any substrate suitable for forming by direct
machining. Suitable substrates machine cleanly with minimal or no
burr formation, exhibit low ductility and low graininess, and
maintain dimensional accuracy after machining. A variety of
machinable metals or plastics may be utilized. Suitable metals
include aluminum, steel, brass, copper electroless nickel, and
alloys thereof. Suitable plastics comprise thermoplastic or
thermoset materials such as acrylics or other materials. In some
embodiments, the material forming rotatable tool 200 may comprise a
porous material, such that a vacuum can be applied through the
material of rotatable tool 200, in combination with, or instead of,
nip roll 210.
[0029] The rotatable tool 200 is preferably formed as a unitary
sleeve having projections 204 and optionally depressions (not
shown) for all of the desired carrier tape 100 features on the
unitary sleeve. The sleeve may include projections for forming the
pockets, alignment features, release features, and protuberances
for skiving to form sprocket holes, for example. The sleeve may
also include depressions for forming cross bars and release
features. Whether a release feature is formed using a projection or
depression will depend on the desired attributes of the release
feature.
[0030] Projections and depression on the outer circumference 202 of
the rotatable tool 200 are preferably cut directly onto the sleeve
using either a carbide or diamond tooling machine that is capable
of shaping each projection with fine precision. Moore Special Tool
Company, Bridgeport, Conn.; Precitech, Keen, N.H.; and Aerotech
Inc., Pittsburgh Pa., manufacture suitable machines for such
purposes. Such machines typically include a laser
interferometer-positioning device, a suitable example of which is
available from Zygo Corporation, Middlefield Conn. The diamond
tools suitable for use are those such as can be purchased from
K&Y Diamond, Mooers, N.Y., or Chardon Tool, Chardon, Ohio.
[0031] The sleeve can be machined using techniques and methods
known in the art to form the desired projections 204 and
depressions thereon. For example, the projection surfaces
corresponding to the component pockets 112 and release features
illustrated in FIGS. 1B and 1C can be formed by turning the sleeve
in a typical lathe operation in which the sleeve is turned and the
cutter is in a fixed position. The depressed surfaces corresponding
to the component pocket crossbars 117 and release features 119
illustrated in FIG. 1A can be formed by holding the sleeve
stationary and cutting slots or other features in the sleeve.
Additional projections, such as those for forming posts for
skiving, can be formed in a manner similar to the formation of the
projections used to shape the pockets. Beneficially, projections
204 on the sleeve can be formed to simultaneously produce a
plurality of carrier tapes. Specifically, pockets and other
features for a plurality of carrier tapes can be produced on a
single sleeve, and the web 250 slit after forming to isolate the
individual carrier tapes.
[0032] When the formed carrier tape 120 is removed from the
rotatable tool 200, it can be difficult to separate the web
material from the rotatable tool 200. Release features 119 on
crossbars 117 aid in the release of the web material from the
rotatable tool. The release features 119 contribute to a reduction
in stress placed on the shaped web material when it is removed from
the rotatable tool. Preferably, the release features 119 provide
one or more additional hinge points that allow the incremental
release of the shaped web material. Preferably, the release
features can flex at an angle of up to 45 degrees. Typically a
lesser angle of flex will be sufficient to reduce the stress placed
on the shaped web material when it is removed from the rotatable
tool. This reduction in stress prevents the carrier tape features
from becoming skewed or misshaped due to a difficult release from
the rotatable tool. The release features do not affect the
functionality of the carrier tape and because the release features
are located in the crossbars between the pockets, the pocket
features do not need to be altered with the addition of the release
features. The release features may be any size or shape that allows
for easier release of the carrier tape from the rotatable tool. For
example, the features may be linear, curved, or a combination of
both; continuous or discontinuous; discrete or connected,
projections or depressions, etc. They may extend from one edge of
the crossbar to the other edge, may extend from one edge to the
interior of the cross-bar, or may be located only in the interior
of the cross bar. If there is more than one release feature, they
may be separated from each other by any suitable distance (which
need not be constant between all release features) and may be any
suitable number of features. The one or more release features may
have any suitable diameter or shape, radii, heights, etc.
[0033] FIG. 3 is a digital image of a carrier tape having a first
crossbar 310 with an example of release features of the present
invention and a second crossbar 312 without a release feature of
the present invention. The first crossbars shows multiple ridge and
trough release features.
[0034] FIG. 4 is a photograph of a cross-sectional view of a
carrier tape having a first crossbar 310 with a first example of
release features of the present invention, a second crossbar 312
without a release feature of the present invention, and a third
crossbar 314 with a second example of release features of the
present invention. As can be seen from FIG. 4, the crossbars with
the release features are skewed much less than the crossbar with no
release feature. Skewing occurs as the carrier tape is removed from
the rotatable tool. As can also be seen from FIG. 4, the radii of
the ridges and troughs of the first exemplary release features are
different from the radii of the ridges and troughs of the second
exemplary release features.
[0035] Once the pockets 112 of the carrier tape 100 have been
prepared, the advancement holes 108, 110 are subsequently formed in
a separate operation such as by punching the strip portion 101, or
by skiving off protuberances formed on one or both of longitudinal
edge surfaces 104 and 106 as described, for example, in U.S. Pat.
No. 5,738,816. The carrier tape 100 is then wound (either
concentric or level windings) about a reel 260 to form a supply
roll for storage until the carrier tape is loaded with
components.
[0036] Although specific embodiments have been illustrated and
described herein for purposes of description of the preferred
embodiment, it will be appreciated by those of ordinary skill in
the art that a wide variety of alternate and/or equivalent
implementations calculated to achieve the same purposes may be
substituted for the specific embodiments shown and described
without departing from the scope of the present invention. Those
with skill in the art will readily appreciate that the present
invention may be implemented in a very wide variety of embodiments.
This application is intended to cover any adaptations or variations
of the preferred embodiments discussed herein. Therefore, it is
manifestly intended that this invention be limited only by the
claims and the equivalents thereof.
* * * * *