U.S. patent application number 14/847301 was filed with the patent office on 2017-03-09 for powdered metal compacting.
This patent application is currently assigned to Caterpillar Inc.. The applicant listed for this patent is Caterpillar Inc.. Invention is credited to Zachary S. Birky.
Application Number | 20170066054 14/847301 |
Document ID | / |
Family ID | 58190634 |
Filed Date | 2017-03-09 |
United States Patent
Application |
20170066054 |
Kind Code |
A1 |
Birky; Zachary S. |
March 9, 2017 |
POWDERED METAL COMPACTING
Abstract
A system and a method of making an object from powdered metal
are provided. The method includes feeding the powdered metal into a
first end of a die. The die is rotated to pull a first portion of
the powdered metal into a pressing zone. The first portion of the
powdered metal is pressed using high pressure. The die is further
rotated to release the first portion of the powdered metal from a
second end of the die. A second portion of the powdered metal is
then pulled into the first end of the die.
Inventors: |
Birky; Zachary S.;
(Washington, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Caterpillar Inc. |
Peoria |
IL |
US |
|
|
Assignee: |
Caterpillar Inc.
Peoria
IL
|
Family ID: |
58190634 |
Appl. No.: |
14/847301 |
Filed: |
September 8, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22F 2003/145 20130101;
B22F 3/10 20130101; B22F 5/003 20130101; B22F 2003/145 20130101;
B22F 3/03 20130101; B22F 2998/10 20130101; B22F 2003/247 20130101;
B22F 2998/10 20130101; B22F 2005/004 20130101; B22F 3/004 20130101;
B22F 3/24 20130101 |
International
Class: |
B22F 3/12 20060101
B22F003/12; B22F 3/00 20060101 B22F003/00; B22F 3/24 20060101
B22F003/24; B22F 3/06 20060101 B22F003/06; B22F 3/17 20060101
B22F003/17 |
Claims
1. A method of making an object from powdered metal, the method
comprising: feeding the powdered metal into a first end of a die;
rotating the die to pull a first portion of the powdered metal into
a pressing zone; pressing the first portion of the powdered metal
using high pressure; rotating the die further, to release the first
portion of the powdered metal from a second end of the die, wherein
the die rotates in one direction only; and pulling a second portion
of the powdered metal into the first end of the die.
2. The method of claim 1 further comprising, rotating the die
continuously or semi-continuously.
3. The method of claim 1 further comprising, rotating a roller in a
direction opposite to the direction of the die, wherein the roller
is disposed adjacent to the die.
4. The method of claim 1 further comprising: sintering the pressed
portion of the powdered metal using high temperature to form a
corresponding compact portion; cutting the compact portion to form
an individual compacted piece; and shaping the individual compacted
piece to form the object.
5. The method of claim 4 further comprising, subjecting the
individual compacted piece to secondary processing.
6. The method of claim 5, wherein the secondary processing is
forging, machining, bending, shearing, coining, milling, or any
combination thereof.
7. The method of claim 1, wherein the feeding is continuous
feeding.
8. The method of claim 1 further comprising, forming a spiral ring,
a planar ring, or an I-beam from the powdered metal.
9. The method of claim 1 further comprising, pressing the powdered
metal under focused pressure at a high compression rate to form the
object having a near uniform density.
10. The method of claim 9, wherein the powdered metal is pressed
from 10-100 tons per square inch within 1-10 seconds.
11. The method of claim 1, wherein the powdered metal is pressed at
a temperature between 20-200.degree. C.
12. A system of compacting powdered metal, the system comprising: a
feeder configured to feed the powdered metal at a continuous or
stepwise rate; a die configured to receive the powdered metal from
the feeder and to rotate about a first axis, wherein the die
rotates in one direction only; a roller disposed adjacent to the
die, the roller configured to rotate about a second axis in a
direction opposite to that of the die.
13. The system of claim 12, wherein the die is configured to rotate
continuously or semi-continuously.
14. The system of claim 12, wherein the die comprises teeth along
an outer edge.
15. The system of claim 12, wherein the die is a screw-type die,
configured to move axially along a plane perpendicular to the
roller.
16. The system of claim 12, wherein the die comprises a preformed
sinter lock joint.
17. The system of claim 12, wherein the die comprises a start-stop
joint.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to compacting of powdered
metal, and more particularly relates to a system and a method for
compacting powdered metal.
BACKGROUND
[0002] Powder metallurgy has been gaining widespread popularity in
the realm of manufacturing processes. Powder metallurgy is a highly
developed method of manufacturing precision metal components, and
can be understood as a methodology that produces components from
metallic powders. Usually, powder metallurgy includes mixing metal
powders, compacting or pressing the mixed powders in a die, and
sintering the compacted powder for bonding the particles of the
compacted powder.
[0003] The process of compacting or pressing the mixed powders into
a geometrical form is commonly referred to as powder pressing.
Generally, the mixed powders are pressed in a press-type machine by
using a punch-and-die arrangement at room temperature. In the punch
and die arrangement, pressure applied by a press on powders is not
focused. This causes non-uniform pressing of the mixed powders
which leads to a difference in density that can occur in different
parts of the resulting component. Due to such inconsistency in the
density of components, manufacturing large components from mixed
powders poses a difficulty. Moreover, dimensions of components that
can be manufactured from mixed powders are also limited. Further,
in order to have higher density of mixed powders in the components,
compaction pressure has to be increased substantially which would
demand larger presses and stronger tools to withstand such high
pressures. Owing to the cost of large presses and stronger tools,
the whole process would become uneconomical. Moreover, the
traditional techniques involve separate steps for introducing the
mixed powders for pressing, pressing the mixed powders, and then
releasing the pressed product. Therefore, the entire process would
become time-intensive and tedious.
[0004] CN Patent Number CN1059303A (the '303 patent) describes a
production process for manufacturing powder metallurgy mechanical
structure parts. The process includes placing the metal powder into
a finished-product shaped mold cavity for pressure-sintering parts
so as to make hot-press moulding sintering. Further, the formed
moulded blank is put into a precision mold and is placed into a
swing-forging machine capable of two-way pressurizing so as to make
compaction by cold-forging. Finally, the work piece proceeds for
secondary processing.
SUMMARY OF THE DISCLOSURE
[0005] In one aspect of the present disclosure, a method of making
an object from powdered metal is provided. The method includes
feeding the powdered metal into a first end of a die, and rotating
the die to pull a first portion of the powdered metal into a
pressing zone. The method further includes pressing the first
portion of the powdered metal using high pressure. Following the
pressing of the powdered metal, the die is rotated to release the
first portion of the powdered metal from a second end of the die,
where the die rotates in one direction only. Further, a second
portion of the powdered metal is pulled into the first end of the
die.
[0006] In another aspect of the present disclosure, a system for
compacting powdered metal is provided. The system includes a
feeder, a die and a roller. The feeder is configured to feed the
powdered metal at a continuous or stepwise rate. The die is
configured to receive the powdered metal from the feeder and to
rotate about a first axis, where the die rotates in one direction
only. The roller is disposed adjacent to the die and is configured
to rotate about a second axis in a direction opposite to that of
the die.
[0007] Other features and aspects of this disclosure will be
apparent from the following description and the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic view of a system for compacting
powdered metal, according to one embodiment of the present
disclosure;
[0009] FIG. 2 is a schematic view of a system for compacting
powdered metal by continuous process of manufacturing, according to
another embodiment of the present disclosure; and
[0010] FIG. 3 is a flowchart of a method of making an object from
powdered metal, according to an embodiment of the present
disclosure.
DETAILED DESCRIPTION
[0011] Reference will now be made in detail to specific embodiments
or features, examples of which are illustrated in the accompanying
drawings. Wherever possible, corresponding or similar reference
numbers will be used throughout the drawings to refer to the same
or corresponding parts.
[0012] FIG. 1 illustrates a schematic view of a system 100 for
compacting powdered metal, according to an embodiment of the
present disclosure. In the present embodiment, the system 100 is
configured to manufacture a ring gear. The system 100 may include a
feeder 102, a die 104, and a roller 106. The feeder 102 may feed
the powdered metal 108 to a pressing zone 110 between the die 104
and the roller 106 for the pressing operation.
[0013] The powdered metal 108 may be, for example, of any
conventional or known powdered metal formulation. The powdered
metal 108 may include a single alloyed or unalloyed metallurgical
powder or a blend of one or more such powders. In one example, the
powdered metal 108 may include, but is not limited to low alloy
ferrous materials, stainless steel, copper alloys, aluminum alloys,
and titanium alloys.
[0014] Further, the powdered metal 108 may also include other
metallurgical and non-metallurgical additives or binders. Addition
of such additives or binders in the powdered metal 108 is herein
referred to as binder treatment or bonding. Binder treatment is
performed for reducing segregation as well as for improving
flowability, green strength, green density, dimensional change,
pressing and ejection of objects. Such binders or additives may
include, but are not limited to graphite, metallic alloying
elements, carbon, copper, nickel and lubricants. The powdered metal
108 and additives may be selected based on the properties of the
objects to be manufactured.
[0015] The feeder 102 may feed the powdered metal 108 for pressing
operation. In one embodiment, the feeder 102 may be configured to
feed the powdered metal 108 at a continuous rate. In an alternate
embodiment, the feeder 102 may be configured to feed the powdered
metal 108 at a stepwise rate. In such an embodiment, the powdered
metal 108 may be fed for a predefined duration of time and then the
feeder 102 would stop feeding the powdered metal 108 for another
predefined duration of time before feeding the powdered metal 108
again. For example, the feeder 102 may feed the powdered metal 108
for 15 seconds and then may stop feeding the powdered metal 108 for
the following 10 seconds. After 10 seconds, the feeder 102 may
resume feeding the powdered metal 108 for the pressing
operation.
[0016] Further, the feeder 102 may feed the powdered metal 108 into
the die 104 either automatically or manually. In the present
embodiment, the feeder 102 is a hopper that may receive the
powdered metal 108 from a supply source (not shown). The hopper may
then feed the powdered metal 108 to the pressing zone 110 between
the die 104 and the roller 106 for pressing. In one embodiment, the
hopper may be vibrating for inducing flow of the powdered metal
108. Other feeding mechanisms that are already known in the art can
also be employed for feeding the powdered metal 108 for the
pressing operation.
[0017] The powdered metal 108 fed by the feeder 102 may be received
by the die 104. The die 104 may include a first end 112 and a
second end 114. In some embodiments, feeder 102 feeds the powdered
metal 108 into the first end 112 of the die 104. In certain
embodiments, the first portion of the powdered metal 108 is
released from the second end 114 of the die 104 after the pressing
operation.
[0018] In the present embodiment, the die 104 is an internal
roller. Further, since the object to be manufactured is a ring
gear, the geometry of the die 104 allows for the formation of a
ring gear. Therefore, as can be seen, the die 104 includes teeth
116 along an outer edge 118. The dimensions of the die 104 can be
adjusted according to the dimensions of the object, i.e., the ring
gear. In one embodiment, the die 104 may include a joint 122. In
some embodiments, joint 122 may be a preformed sinter lock joint.
The preformed sinter lock joint can allow formation of a physical
shape that in turn, can allow the start and stop location of, e.g.,
the ring gear, to be mechanically connected prior to sintering,
such that a strong bond is created at the location during
sintering. In certain embodiments, joint 122 may be a start-stop
joint.
[0019] The roller 106 may be disposed adjacent to the die 104. The
gap or the distance between the die 104 and the roller 106 may be
adjusted to generate the corresponding dimensions of the object. In
one example, the distance between the die 104 and the roller 106 is
about 3-140 millimeters (mm). Moreover, the distance between the
die 104 and the roller 106 may vary based on various operating
conditions. Such operating conditions may include, but are not
limited to dimensions of the die 104, dimensions of the roller 106,
pressure to be applied, type of powdered metal 108, dimensions of
the final product, geometry of the final product, and geometry of
the die 104 and geometry of the roller 106.
[0020] In order to produce a pressed metal unit 124, i.e., the
product that is obtained after pressing the powdered metal 108, the
die 104 and the roller 106 may rotate about a first axis XX and a
second axis XX', respectively. The die 104 is allowed to rotate in
one direction only. The roller 106 may rotate about the second axis
XX' in a direction opposite to the rotation of the die 104. The
relative rotation of the die 104 and the roller 106 may allow for
multiple functions to be accomplished simultaneously. For example,
the relative rotation may pull the powdered metal 108 from the
feeder 102, press the powdered metal 108 to obtain the pressed
metal unit 124 and then release the pressed metal unit 124.
[0021] In one embodiment, the die 104 may continuously rotate about
the first axis XX. For example, the die 104 may move continuously
for more than one complete rotation. The continuous rotation would
allow for continuous formation of the pressed product. In another
embodiment, the die 104 may rotate about the first axis XX in a
semi-continuous manner. For example, the die 104 may move
semi-continuously for one complete rotation or less.
[0022] The process of manufacturing being offered by the system 100
can be either a continuous process or a semi-continuous process.
For example, in the semi-continuous process of manufacturing the
object, the feeder 102 may feed the powdered metal 108 to the die
104 at a stepwise rate and the die 104 may rotate about the first
axis XX in a semi-continuous manner. The operation of the feeder
102 and the die 104 may be synchronized in a manner that both the
feeder 102 and the die 104 may start and stop at the same time. In
one example, the die 104 may rotate to complete one rotation at a
time. Therefore, during each rotation, the powdered metal 108 may
be pressed between the die 104 and the roller 106 to produce one
pressed metal unit 124, as shown in FIG. 1. For example, in the
present embodiment, the die 104 may complete one rotation about the
XX axis to produce one planar ring gear as the object.
[0023] FIG. 2 illustrates a system 200 for compacting powdered
metal 108 by the continuous process of manufacturing, according to
another embodiment of the present disclosure. In the present
embodiment, the feeder 102 may feed the die 104 at a continuous
rate and a die 204 may continuously rotate about the first axis XX.
The die 204 is allowed to rotate in one direction only. In one
example, the die 204 may be a screw-type die as shown in FIG.
2.
[0024] In such a case, a longer strip of pressed powdered metal 108
may be obtained than that obtained, for example, in the
semi-continuous process. The longer strip may include a plurality
of identical pressed metal units 224 similar to the object to be
manufactured. For example, in the present embodiment, the
continuous process may produce a spiral product that can be further
processed, for example, by cutting at appropriate locations to
generate a plurality of identical planar products as final objects.
Therefore, the continuous process may be used for bulk production
of the objects.
[0025] In one example, the feeder 102, the die 104, 204 and the
roller 106 may be of stainless steel. Further, the die 104, 204 and
the roller 106 are of high strength and wear resistant
material.
INDUSTRIAL APPLICABILITY
[0026] The present disclosure relates to the system 100, 200 for
compacting powdered metal 108. The system 100, 200 may include the
feeder 102, the die 104, 204 and the roller 106 for compacting the
powdered metal 108 for producing pressed metal units 124, 224
similar to the objects to be manufactured, that may further be
sintered or subjected to secondary processing. The system 100, 200
allows for pressing of the powdered metal 108 by using a continuous
process and a semi-continuous process. The continuous process may
allow bulk production of the objects from the powdered metal 108 by
producing a strip of identical pressed metal units 124, 224.
Further, the semi-continuous process may produce one pressed metal
unit 124 at a time. The pressed metal units 124, 224 so produced
can then be sintered for obtaining the objects as the final
product. The present disclosure also relates to a method 300 of
making an object from powdered metal 108.
[0027] FIG. 3 illustrates a flow chart of a method 300 of making
the object from powdered metal 108, according to an embodiment of
the present disclosure. At step 302, the method 300 includes
feeding the powdered metal 108 into the first end 112 of the die
104. In particular, the powdered metal 108 can be fed into the
pressing zone 110 between the die 104 and the roller 106. The
feeder 102 may feed the powdered metal 108 for the pressing
operation. In one embodiment, the feeder 102 may continuously feed
the powdered metal 108 into the pressing zone 110.
[0028] At step 304, the method 300 includes rotating the die 104 to
pull a first portion of the powdered metal 108 into the pressing
zone 110. The die 104 is allowed to rotate in one direction only.
The pressing zone 110 can be understood as the region between the
die 104 and the roller 106 where the powdered metal 108 is being
pressed. For example, the powdered metal 108 is pressed between the
die 104 and the roller 106 in the pressing zone 110. In one
embodiment, the die 104 can be rotated continuously. In another
embodiment, the die 104 can be rotated semi-continuously.
[0029] At step 306, the first portion of the powdered metal 108 may
be pressed using high pressure. In one embodiment, the powdered
metal 108 may be pressed under focused pressure at a high
compression rate to form pressed metal units 124 having a near
uniform density. In one example, the powdered metal 108 may be
pressed from 10-100 tons per square inch (tsi) within a duration of
1-10 seconds. In another example, the powdered metal 108 is pressed
at a temperature between 20-200.degree. C.
[0030] The first portion of the powdered metal 108 may be pressed
in the pressing zone 110 between the die 104 and the roller 106
that is placed adjacent to the die 104. The die 104 and the roller
106 may be rotating in a direction opposite to each other for
producing the pressed metal units 124 by pressing the powdered
metal 108. In one example, the ramp rate of pressure to be applied
on the first portion of the powdered metal 108 can vary between
10-100 tsi in 1-10 seconds. For example, each unit area of the
first portion may be pressed for a total of 10 seconds such that
the pressure on the unit area increases at a ramp rate of about 10
to 20 tsi per second. In another example, the pressure on the unit
area ramps up from 0-100 tsi within 5 seconds at a rate of about 10
to 20 tsi per second, and then ramps down from 100-0 tsi within the
next 5 seconds, again at a rate of about 10 to 20 tsi per
second.
[0031] At step 308, the method 300 includes rotating the die 104
further to release the first portion of the powdered metal 108 from
a second end 114 of the die 104. Therefore, the pressed metal units
124 are being released out of the pressing zone 110, and further
released out of the second end 114 of the die 104. At step 310,
following the release of the first portion, a second portion of the
powdered metal 108 may be pulled into the first end 112 of the die
104 for pressing operations.
[0032] In one embodiment, the pressed portion of the powdered metal
108, i.e., the pressed metal units 124 may be sintered by using
high temperature to form a compact portion or a compacted piece,
based on the continuous process or the semi-continuous process,
respectively. The compact portion can be understood as a strip of
pressed metal units 124 obtained after the continuous process of
manufacturing.
[0033] As is generally known, in sintering, the temperature of the
pressed metal unit 124 may be increased to a predefined
temperature, also referred to as sintering temperature. The pressed
metal unit 124 may then be kept at the sintering temperature for a
predefined duration of time. In one example, the predefined
temperature can be kept about 70% to 90% of the melting point of
the powdered metal 108. This would result into bonding between the
particles of the powdered metal 108 pressed together in the pressed
metal unit 124.
[0034] In case of the continuous process of manufacturing, the
compact portion obtained after the sintering operation may be cut
to form individual compacted pieces. In an alternate embodiment,
the compact portion or the strip of pressed metal units 124 may be
cut to form individual compacted pieces before the sintering
operation. The individual compacted pieces can then be
sintered.
[0035] Following the sintering, the individual compacted pieces may
be shaped to form the object. In one example, the object may be a
spiral ring, a planar ring, an I-beam, or another shape of a
complex cross-section. In one embodiment, the system 100, 200 may
be modified to manufacture an I-beam. In such an embodiment, the
shape of the die 104 may be changed for pressing the powdered metal
108 to manufacture the I-beam. Therefore, in such embodiments, the
overall principle of the pressing and manufacturing of the object
would remain as described in the previous embodiment with a ring
gear. In some embodiments, the dimension and geometry of the die
104 may change based on the object to be manufactured.
[0036] In one embodiment, the object so obtained can then be sent
for secondary processing. The secondary processing may include, but
is not limited to forging, machining, bending, shearing, coining,
milling, or any combination thereof.
[0037] The system 100, 200 and method 300 of the present disclosure
provides focused pressure across the component or the powdered
metal 108 during the pressing operation. During the pressing
operation, each unit area of the powdered metal 108 in the pressing
zone 110, 210 between the die 104, 204 and the roller 106 would
experience an increase from zero load to maximum load and then back
to zero load. Such uniform distribution of the pressure may assist
in manufacturing objects with near uniform density.
[0038] Further, as the load is focused on a smaller area of the
powdered metal 108 during the pressing operation, the localized
pressure, for example in the pressing zone 110, 210, is
substantially higher than that obtained using conventional
techniques such as, a punch and die technique. The continuous or
semi-continuous processes allow higher/focused pressure to be
applied while pressing or compacting the powdered metal 108. The
processes further provide better control of the pressure and
density on the powdered metal 108 which in turn assist in
manufacturing of complex parts.
[0039] Also, since density can be kept nearly uniform across the
entire surface of the powdered metal 108 during the pressing
operation, the system 100, 200 and the method 300 enable
manufacturing of large size components with a near uniform density
that cannot be produced using conventional techniques such as, a
punch and die technique. For example, ring gears with large
diameters can be made by using the system 100, 200 and the method
300. In one example, gears with a diameter of 36 inches to 60
inches can be easily made by using the method 300 and the system
100, 200 of the present disclosure.
[0040] In addition a higher level of efficiency can be
accomplished. For example, by using the continuous process of
manufacturing, large complex linear strips including a plurality of
pressed metal units 124, 224 can be manufactured. The strip can
then be cut into individual smaller units after the pressing
operation for performing operations, such as shaping and sintering.
In one example, the length of such linear strips can be up to 80
feet. As a result, a large volume of products can be obtained in a
substantially short time by using the continuous process of
manufacturing.
[0041] Moreover, the system 100, 200 and the method 300 allow for
filling of the powdered metal 108, pressing of the powdered metal
108, and removal of the powdered metal 108 in a single step. As a
result, inconvenience and time associated with executing these
steps separately are substantially reduced. Therefore, the present
disclosure offers an effective, easy, productive, flexible,
time-saving, convenient, and cost-effective system 100, 200 and
method 300 for compacting powdered metal 108.
[0042] While aspects of the present disclosure have been
particularly shown and described with reference to the embodiments
above, it will be understood by those skilled in the art that
various additional embodiments may be contemplated by the
modification of the disclosed machines, systems and methods without
departing from the spirit and scope of what is disclosed. Such
embodiments should be understood to fall within the scope of the
present disclosure as determined based upon the claims and any
equivalents thereof.
* * * * *