U.S. patent application number 16/986449 was filed with the patent office on 2022-02-10 for flat top metal gainer.
The applicant listed for this patent is Robert D Miller, Chunlei Wang, Dajun Zhou. Invention is credited to Robert D Miller, Chunlei Wang, Dajun Zhou.
Application Number | 20220040747 16/986449 |
Document ID | / |
Family ID | 1000005036653 |
Filed Date | 2022-02-10 |
United States Patent
Application |
20220040747 |
Kind Code |
A1 |
Zhou; Dajun ; et
al. |
February 10, 2022 |
FLAT TOP METAL GAINER
Abstract
A method of forming a metal part that includes placing a metal
blank in a stamping apparatus having a first die including a
plurality of metal gainers and a second die including a plurality
of recesses that correspond to the plurality of metal gainers, and
compressing the metal blank such that the metal gainers and the
corresponding recesses provide the metal blank with regions of
localized stretching. Each of the metal gainers and recesses
includes a flat surface such that during the compressing of the
metal blank to provide the metal blank with the regions of
localized stretching, a strain exerted on the metal blank by the
metal gainers and recesses is less than a strain exerted on the
metal blank by metal gainers and recesses that do not include the
flat surface.
Inventors: |
Zhou; Dajun; (Troy, MI)
; Wang; Chunlei; (Rochester Hills, MI) ; Miller;
Robert D; (Lake Orion, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Zhou; Dajun
Wang; Chunlei
Miller; Robert D |
Troy
Rochester Hills
Lake Orion |
MI
MI
MI |
US
US
US |
|
|
Family ID: |
1000005036653 |
Appl. No.: |
16/986449 |
Filed: |
August 6, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B21D 53/88 20130101;
B21D 19/08 20130101; B21D 35/006 20130101; B21D 22/02 20130101;
B21D 11/08 20130101 |
International
Class: |
B21D 22/02 20060101
B21D022/02; B21D 19/08 20060101 B21D019/08; B21D 35/00 20060101
B21D035/00; B21D 53/88 20060101 B21D053/88; B21D 11/08 20060101
B21D011/08 |
Claims
1. A method of forming a metal part, comprising: placing a metal
blank in a stamping apparatus having a first die including a
plurality of metal gainers and a second die including a plurality
of recesses that correspond to the plurality of metal gainers, and
forming the metal blank such that the metal gainers and the
corresponding recesses provide the metal blank with regions of
localized stretching, the regions of localized stretching being
located along a trim line of the metal blank that corresponds to a
region of the metal blank that will be trimmed from the metal
blank; after providing the metal blank with the regions of
localized stretching, trimming the metal blank along the trim line
such that portions of regions of localized stretching remain along
the trim line; and after trimming the metal blank along the trim
line, subjecting the metal blank including the regions of localized
stretching to a stretch-flanging process that forms a flange at the
trim line; wherein each of the metal gainers and recesses includes
a flat surface surrounded by a side surface such that during the
forming of the metal blank to provide the metal blank with the
regions of localized stretching, a combined strain exerted on the
metal blank by the metal gainers and recesses that include the flat
surface in combination with the stretch-flanging process is less
than a stretch limit of a material of the metal blank.
2. The method according to claim 1, wherein a surface area of the
flat surfaces of the metal gainers and the recesses ranges between
40% to 90% of a total surface area of the metal gainers and the
recesses.
3. The method according to claim 1, wherein the metal gainers and
recesses are at least one of oval-shaped, triangular-shaped,
diamond- or square-shaped, or round.
4. The method according to claim 3, wherein a shape of the flat
surface of each of the metal gainers and recesses is the same as an
overall shape of the metal gainer and recess.
5. The method according to claim 3, wherein a shape of the flat
surface of each of the metal gainers and recesses is different from
an overall shape of the metal gainer and recess.
6. The method according to claim 1, wherein the metal blank is
formed of an advanced high strength metal.
7. A method of forming a metal part, comprising: placing a metal
blank in a stamping apparatus having a first die including a
plurality of metal gainers and a second die including a plurality
of recesses that correspond to the plurality of metal gainers, and
forming the metal blank such that the metal gainers and the
corresponding recesses provide the metal blank with regions of
localized stretching, the regions of localized stretching being
located along a trim line of the metal blank that corresponds to a
region of the metal blank that will be trimmed from the metal
blank; after providing the metal blank with the regions of
localized stretching, trimming the metal blank along the trim line
such that portions of regions of localized stretching remain along
the trim line; and after trimming the metal blank along the trim
line, subjecting the metal blank including the regions of localized
stretching to a stretch-flanging process that forms a flange at the
trim line; wherein each of the metal gainers and recesses includes
a flat surface surrounded by a side surface such that during the
forming of the metal blank to provide the metal blank with the
regions of localized stretching.
8.-9. (canceled)
10. The method according to claim 7, wherein a surface area of the
flat surfaces of the metal gainers and the recesses ranges between
40% to 90% of a total surface area of the metal gainers and the
recesses.
11. The method according to claim 7, wherein the metal gainers and
recesses are at least one of oval-shaped, triangular-shaped,
diamond- or square-shaped, or round.
12. The method according to claim 11, wherein a shape of the flat
surface of each of the metal gainers and recesses is the same as an
overall shape of the metal gainer and recess.
13. The method according to claim 11, wherein a shape of the flat
surface of each of the metal gainers and recesses is different from
an overall shape of the metal gainer and recess.
14. The method according to claim 7, wherein the metal blank is
formed of an advanced high strength metal.
15. A stamping press comprising: a first die including a plurality
of protrusions; and a second die including a plurality of recesses
that correspond to the plurality of protrusions, wherein the
plurality of protrusions in combination with the plurality of
protrusions are configured to provide a metal blank with regions of
localized stretching when the metal blank is formed between the
plurality of protrusions and the plurality of recesses, and wherein
each of the protrusions and each of the recesses includes a flat
surface surrounded by a side surface such that during the forming
of the metal blank to provide the metal blank with the regions of
localized stretching; and wherein a shape of the flat surface of
each of the protrusions and recesses is the same as an overall
shape of the protrusions and recesses.
16. The stamping press according to claim 15, wherein a surface
area of the flat surfaces of the protrusions and the recesses
ranges between 40% to 90% of a total surface area of the
protrusions and the recesses.
17. The stamping press according to claim 15, wherein the
protrusions and recesses are at least one of oval-shaped,
triangular-shaped, diamond-or square-shaped, or round.
18.-19. (canceled)
Description
FIELD
[0001] The present disclosure relates to a stamping method and
system that uses a metal gainer having a flat top for providing
additional material before a flanging operation is conducted.
BACKGROUND
[0002] Many manufacturing processes are available to form sheet
metal blanks into parts in a wide variety of industries. For
example, drawing and deep drawing of sheet metal blanks is a
process in which the metal blank is drawn between an upper die and
a lower die to take a shape that initially resembles the shape of
the finished part. Additional manufacturing process might also take
place after the drawings. For example, flanging can bend an end
region of the metal blank to form a flange. When these flanges are
formed, however, there may be residual stress in regions of the
flange that can distort the final shape of the part due to the
stretching and bending of the metal to form the flange.
[0003] In addition, when the metal blank is formed from an advanced
high strength metal such as an ultra-high strength steel or a 7000
series aluminum alloy, the metal blank may have poor ductility
and/or formability. The reduced formability of these newer
materials may result in cracks, necking, or other imperfections
during the flanging process. Any of these imperfections may
compromise the integrity of the finished part, and are simply not
acceptable in commercial products, including automotive
applications.
SUMMARY
[0004] The present disclosure provides a method of forming a metal
part that includes placing a metal blank in a stamping apparatus
having a first die including a plurality of metal gainers and a
second die including a plurality of recesses that correspond to the
plurality of metal gainers, and stretching the metal blank such
that the metal gainers and the corresponding recesses provide the
metal blank with regions of localized stretching; and subjecting
the metal blank including the regions of localized stretching to a
stretch-flanging process; wherein each of the metal gainers and
recesses includes a flat surface surrounded by a side surface such
that during the stretching of the metal blank to provide the metal
blank with the regions of localized stretching, a combined strain
exerted on the metal blank by the metal gainers and recesses that
include the flat surface in combination with the stretch-flanging
process is less than a combined strain exerted on the metal blank
by traditional metal gainers and recesses that do not include the
flat surface in combination with the stretch-flanging process.
[0005] The present disclosure also provides a method of forming a
metal part that includes placing a metal blank in a stamping
apparatus having a first die including a plurality of metal gainers
and a second die including a plurality of recesses that correspond
to the plurality of metal gainers, and stretching the metal blank
such that the metal gainers and the corresponding recesses provide
the metal blank with regions of localized stretching; and
subjecting the metal blank including the regions of localized
stretching to a stretch-flanging process; wherein each of the metal
gainers and recesses includes a flat surface surrounded by a side
surface such that during the stretching of the metal blank to
provide the metal blank with the regions of localized stretching, a
curve that graphically represents the strains exerted on the metal
blank at the regions of localized stretching exhibits a pair of
peaks at different locations rather than a single peak when the
metal blank is stretched between metal gainers and recesses that do
not have the flat surface.
[0006] Lastly, the present disclosure provides a stamping press
that includes a first die including a plurality of protrusions; and
a second die including a plurality of recesses that correspond to
the plurality of protrusions, wherein the plurality of protrusions
in combination with the plurality of protrusions are configured to
provide a metal blank with regions of localized stretching when the
metal blank is stretched between the plurality of protrusions and
the plurality of recesses, and wherein each of the protrusions and
each of the recesses includes a flat surface surrounded by a side
surface such that during the stretching of the metal blank to
provide the metal blank with the regions of localized stretching, a
curve that graphically represents the strains exerted on the metal
blank at the regions of localized stretching exhibits a pair of
peaks at different locations rather than a single peak when the
metal blank is compressed between metal gainers and recesses that
do not have the flat surface.
[0007] Further areas of applicability of the teachings of the
present disclosure will become apparent from the detailed
description, claims and the drawings provided hereinafter, wherein
like reference numerals refer to like features throughout the
several views of the drawings. It should be understood that the
detailed description, including disclosed embodiments and drawings
referenced therein, are merely exemplary in nature intended for
purposes of illustration only and are not intended to limit the
scope of the present disclosure, its application or uses. Thus,
variations that do not depart from the gist of the present
disclosure are intended to be within the scope of the present
disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a perspective view of a body panel or fender
manufactured using the teachings of the present disclosure;
[0009] FIG. 2 is a cross-sectional view of the body panel or fender
illustrated in FIG. 1 along line 2-2 of FIG. 1;
[0010] FIG. 3 is a perspective view of a metal blank used to form
the body panel or fender illustrated in FIG. 1;
[0011] FIG. 4 is a perspective view of the metal blank illustrated
in FIG. 3 after being subjected to a metal-gaining (bubble) process
to form regions of localized stretching in the metal blank;
[0012] FIG. 5 is a perspective view of the metal blank illustrated
in FIG. 4, after undergoing a material removal process
(trimming);
[0013] FIG. 6 is a perspective view of the metal blank illustrated
in FIG. 5, after undergoing a flanging process;
[0014] FIG. 7 is a cross-sectional view of a stamping press
including metal gainers according to a principle of the present
disclosure;
[0015] FIGS. 8a to 8c are graphic representations of the strain
distribution exerted on the metal blank during the metal-gaining
process (FIG. 8a) using a metal gainer that does not include a flat
surface, the strain exerted on the metal blank during a
stretch-flanging process (FIG. 8b), and the combined (overlapped)
total strain exerted on the metal blank during the metal-gaining
process and the stretch-flanging process (FIG. 8c);
[0016] FIGS. 9a to 9c are graphic representations of the strain
exerted on the metal blank during the metal-gaining process (FIG.
9a) using a metal gainer that includes a flat surface, the strain
exerted on the metal blank during the stretch-flanging process
(FIG. 9b), and the combined (overlapped) total strain exerted on
the metal blank during the metal-gaining process and the
stretch-flanging process (FIG. 9c); and
[0017] FIGS. 10a to 10e are perspective views of example metal
gainers having engineered shapes that result in optimized strain
distributions when forming regions of localized stretching in a
metal blank according to a principle of the present disclosure.
DETAILED DESCRIPTION
[0018] A stamped metal part may become dimensionally unstable or
undesirable for later use in a vehicle assembly due to stresses
that can be a byproduct of the metal stamping process. Depending on
the function of the metal part and its location in the vehicle, the
dimensional defect can cause vehicle build issues and can be
visibly undesirable to the driver or customer. This undesirability
may occur in a flange of a stamped part. Stretch-flanging is an
operation in which a part of the metal part, such as an edge of the
metal part, is bent with respect to the body. Some example regions
of the vehicle body with a flanged edge include a fender door line,
a roof line, a fender wheel opening, a cowling, and a liftgate
outer roof line.
[0019] FIG. 1 illustrates an example body panel or fender 10 that
is formed from a metal blank. In the illustrated example, fender 10
includes a main body 12 that includes a wheel opening 14. At wheel
opening 14, as best shown in FIG. 2, an edge 16 of wheel opening 14
is bent using the aforementioned stretch-flanging operation to form
a flange 18. Although flange 18 is illustrated as being oriented at
about ninety degrees relative to main body 12, it should be
understood that flange 18 can be oriented at other angles greater
or lesser than ninety degrees without departing from the scope of
the present disclosure. Regardless, during formation of flange 18,
the material of fender 10 can be formed during the flanging
process. When fender 10 is formed of an advanced high strength
metal such as an ultra-high strength steel or a 7000 series
aluminum alloy, which generally have poor ductility and/or
formability, the flange 18 may crack during the stretch-flanging
process due to the stretching of the metal material. The cracking
or splitting of flange 18 is typically a result of the material of
the metal blank not being able to stretch enough during the
stretch-flanging process (poor edge formability).
[0020] In order to suppress cracking or splitting of the metal
blank during formation of flange 18, a metal blank 20 is subjected
to a stamping process where the metal material of the metal blank
20 is stretched before conducting the flanging process. FIG. 3
illustrates metal blank 20 before it has been subjected to trimming
to form wheel opening 14. In this regard, the broken line 22
represents the location where wheel opening 14 will be cut during a
trimming process of metal blank 20. It should be understood that
metal blank 20 may have already been subjected to a drawing or deep
drawing process to impart a designed contour to metal blank 20 that
will correspond to that of fender 10.
[0021] Now referring to FIG. 4, it can be seen that prior to
trimming of metal blank 20 to form wheel opening 14, metal blank 20
has been subjected to a stretching process. Specifically, metal
blank 20 has been stamped to impart regions or bubbles 24 of
localized stretching (areas of increased material) of metal blank
20 at locations along line 22 in order to reserve some additional
material for a later-conducted stretch-flanging process, or to make
the to-be-stretched edge line longer after trimming. Bubbles 24 are
formed along line 22 because after trimming metal blank 20 to form
wheel opening 14, edge 16 of wheel opening 14 will be bent to form
flange 18 during the stretch-flanging process. Due to the localized
stretching of metal blank 20 at bubbles 24, the material of metal
blank 20 is less prone during stretch-flanging to stretch to an
extent that causes the material of metal blank 20 to crack or
split.
[0022] Now referring to FIG. 5, after metal blank 20 has been
imparted with bubbles 24, metal blank 20 has been subjected to a
trimming process where metal blank 20 is trimmed by stamping or
subjected to laser cutting to remove portions of metal blank 20 to
form wheel opening 14. As can be seen in FIG. 5, portions 26 of
bubbles 24 remain along edge 16 of wheel opening 14. Thereafter, as
shown in FIG. 6, metal blank 20 is subjected to stretch-flanging to
form flange 18 along edge 16 of wheel opening 14. As can be seen in
FIG. 6, the stretch-flanging process also flattens bubbles 24 such
that fender 10 is formed.
[0023] The regions or bubbles 24 of localized stretching of metal
blank 20 are provided by placing metal blank 20 in a stamping
apparatus or stamping press die 28. An example stamping press die
28 is illustrated in FIG. 7. Stamping press die 28 includes an
upper die 30 and a lower die 32. Lower die 32 includes a plurality
of protrusions or metal gainers 34 formed therein. Upper 30
includes a plurality of recesses 36 that are shaped for receipt of
metal gainers 34 therein. After blank 20 is placed between upper
and lower dies 30, 32, blank 20 is pressed to form bubbles 24.
Blank 20 is then free to be removed from stamping press 28 by an
operator or robot and placed in an apparatus (not shown) configured
to form wheel opening 14. Alternatively, formation of wheel opening
14 may occur at the same time as formation of bubbles 24. After
formation of wheel opening 14 by trimming, the blank 20 can be
placed in another apparatus (not shown) by an operator or robot to
form flange 18 to complete formation of fender 10.
[0024] As noted above, due to the localized stretching of metal
blank 20 at bubbles 24 that are formed by metal gainers 34, the
material of metal blank 20 is less prone during stretch-flanging to
stretch to an extent that causes the material of metal blank 20 to
crack or split. As shown in FIG. 7, metal gainers 34 include a
first flat surface 38 and recesses 36 include a corresponding
second flat surface 40. The first and second flat surfaces 38 and
40 are important when stretching the material of metal blank 20
before conducting the stretch-flanging process of forming flange
18, especially when the material of metal blank 20 is an advanced
high strength metal such as an ultra-high strength steel or an
aluminum alloy.
[0025] More specifically, FIG. 8a graphically illustrates the
strain that is exerted on metal blank during formation of the
regions or bubbles 24 of localized stretching using a metal gainer
34 and recess 36 that do not have first flat surface 38 and second
flat surface 40, respectively. FIG. 8b graphically illustrates the
strain that is exerted on metal blank 20 during formation of the
flange 18 itself. FIG. 8c graphically illustrates the combined
(total) strain distribution from forming bubbles 24 using metal
gainers 34 and recesses 36 that do not have first flat surface 38
and second flat surface 40, respectively, and the strain exerted on
metal blank 20 during the formation of flange 18.
[0026] As can be seen in FIG. 8c, because the peaks (strains) of
each process overlap, the combined final or total strain
(amplitude) exerted on metal blank 20 is much greater in comparison
to the strains exerted on metal blank 20 by either the metal gainer
stretching process (FIG. 8a) or flanging process (FIG. 8b) alone.
The combined strain exerted on metal blank 20, especially when
metal blank 20 is formed of an advanced high strength metal,
therefore, may be too great for metal blank 20 (i.e., beyond the
edge stretch limit of the material), which may result in the
material cracking or splitting during the stretch-flanging
process.
[0027] FIG. 9a illustrates the strain that is exerted on metal
blank 20 during formation of the regions or bubbles 24 of localized
stretching using a metal gainer 34 and recess 36 having the first
flat surface 38 and second flat surface 40, respectively, according
to the present disclosure. As can be seen in FIG. 9a, when the
metal gainers 34 and recesses include the first flat surface 38 and
second flat surface 40, respectively, the strain exerted on metal
blank 20 exhibits a curve having a pair of peaks separated by a
valley. The pair of peaks result from the strain being exerted on
metal blank 20 by side surfaces 42 of metal gainers 34 being
greater than the strain exerted on metal blank 20 by first flat
surface 38 and second flat surface 40, which are represented by the
valley. FIG. 9b graphically illustrates the strain that is exerted
on metal blank 20 during formation of flange 18 itself. FIG. 9b is
the same as FIG. 8b because the strains exerted on metal blank 20
are the same during the stretch-flanging process. FIG. 9c
graphically illustrates the combined final or total strain from
forming bubbles 24 using metal gainers 34 and recesses 36 that have
first flat surface 38 and second flat surface 40, respectively, and
the strain exerted on metal blank 20 during the formation of flange
18.
[0028] As can be seen in FIG. 9c, because the peaks (strains) of
each process (bubble making and flanging) do not overlap, the
combined final or total strain (amplitude) exerted on metal blank
20 is much less in comparison to the combined strain illustrated in
FIG. 8c, and is safely less than the edge stretch limit of the
material. The combined strain exerted on metal blank 20, especially
when metal blank 20 is formed of an advanced high strength metal,
therefore, can be reduced when using metal gainers 34 and recesses
36 having first flat surface 38 and second flat surface 40,
respectively, which prevents or at least substantially minimizes
the risk of material cracking or tearing during the flanging
process. In other words, the use of flat surfaces 38 and 40 allows
for engineering the strain peak locations to avoid overlap with the
strain peak that results during the stretch-flanging process such
that the combined final or total strain exerted on metal blank 20
during the metal gaining and stretch-flanging processes is much
less in comparison to instances when traditional metal gainers 34
and recesses 36 do not include flat surfaces 38 and 40,
respectively.
[0029] Metal gainers 34 do not necessarily need to be oval-shaped,
as shown in FIGS. 4 and 10a. In contrast, metal gainers 34 can have
any shape desired by one skilled in the art provided that metal
gainers 34 includes a first flat surface 38, and the
correspondingly shaped recesses 36 have a second flat surface 40.
The shape of metal gainers 34 and recesses 36 can be engineered
using a numerical forming simulation tool. For example, as shown in
FIGS. 10b to 10d, metal gainers 34 and recesses 36 may be
triangular-shaped (FIG. 10b), diamond- or square-shaped (FIG. 10c),
or round (FIG. 10d) without departing from the scope of the present
disclosure. Moreover, it should be understood that metal gainers 34
do not need to be oriented as shown in FIG. 4. In contrast, metal
gainers 34 may be slightly rotated to the left or right, especially
when metal gainers 34 are formed to have the shapes illustrated in
FIG. 4, FIG. 10a, and FIG. 10b.
[0030] Regardless of the shape of metal gainer 34, the important
aspect of the present disclosure is to provide metal gainer 34 and
recesses 36 with first flat surface 38 and second flat surface 40.
First and second flat surfaces 38 and 40 may have a similar shape
as that of metal gainer 34 and recess 36 as shown in FIGS. 10a to
10d, or a flat surface having a shape that is different from that
of metal gainer 34 and recess 36. For example, if metal gainer 34
and recess 36 are oval-shaped, first and second flat surfaces 38
and 40 may be round, square (FIG. 10e), or triangular if
desired.
[0031] The surface area of first and second flat surfaces 38 and 40
may also be variable. For example, the surface area of flat
surfaces 38 and 40 of metal gainers 34 and recesses 36 can range
between 40% to 90% of the surface area of metal gainers 34 and
recesses 36, more preferably between 50% to 75% of the surface
area, and most preferably 60% to 70% of the surface area.
[0032] Lastly, first and second flat surfaces 38 and 40 are not
necessarily planar surfaces. In contrast, as noted above, the
important aspect to keep in mind is that first and second flat
surfaces 38 and 40 can be designed or engineered such that metal
gainers 34 and recesses 36 allow for management of the locations of
the strain peaks that indicate the locations of the strains exerted
on metal blank 20 in the manner shown in FIG. 9a where a pair of
peaks of strain are exhibited rather than the curve illustrated in
FIG. 8a. Thus, the first and second "flat surfaces" 38 and 40 may
be slightly curved or slightly hemispherical so long as the
management of the location of the strain peaks is similar to that
shown in FIG. 9a.
* * * * *