U.S. patent application number 11/466897 was filed with the patent office on 2008-09-04 for machine and method for electrochemically polishing indentations within an aluminum wheel.
This patent application is currently assigned to Extrude Hone Corporation. Invention is credited to Steven J. Comaty, Horst Kissel, James Koroskenyi.
Application Number | 20080210571 11/466897 |
Document ID | / |
Family ID | 39107715 |
Filed Date | 2008-09-04 |
United States Patent
Application |
20080210571 |
Kind Code |
A1 |
Comaty; Steven J. ; et
al. |
September 4, 2008 |
Machine And Method For Electrochemically Polishing Indentations
Within An Aluminum Wheel
Abstract
A machine for electrochemically polishing indentations within
the wall of an aluminum workpiece, such as a wheel, has a cathode
attached to an upper platen. The workpiece is mounted upon a lower
platen which acts as an anode. Electrolyte is passed between the
cathode and the anode while simultaneously a current is applied
which passes through the cathode and the anode. The current is
selectively pulsed to maximize polishing but at the same time to
permit the flushing away of residual material and to cool the
cathode and the workpiece.
Inventors: |
Comaty; Steven J.;
(Rochester Hills, MI) ; Koroskenyi; James;
(Pittsburgh, PA) ; Kissel; Horst; (Rochester
Hills, MI) |
Correspondence
Address: |
KENNAMETAL INC.
1600 TECHNOLOGY WAY
LATROBE
PA
15650-0231
US
|
Assignee: |
Extrude Hone Corporation
Irwin
PA
|
Family ID: |
39107715 |
Appl. No.: |
11/466897 |
Filed: |
August 24, 2006 |
Current U.S.
Class: |
205/673 ;
204/230.2; 205/640 |
Current CPC
Class: |
B23H 9/02 20130101; C25F
7/00 20130101; B23H 9/00 20130101; C25F 3/20 20130101 |
Class at
Publication: |
205/673 ;
204/230.2; 205/640 |
International
Class: |
C25F 3/16 20060101
C25F003/16; C25F 7/00 20060101 C25F007/00; C25F 7/02 20060101
C25F007/02 |
Claims
1. A machine for electrochemically polishing indentations of known
geometry within the wall of an aluminum workpiece, wherein a
workpiece space defines the space in which a workpiece would occupy
in the machine and wherein the machine comprises: a) an upper
platen; b) a cathode extending from the upper platen, wherein the
cathode is associated with an indentation and wherein the cathode
has a shape similar to that of the indentation but smaller and is
adapted to be positioned adjacent to the indentation to define a
gap therebetween for the introduction of an electrolyte between the
cathode and the indentation; c) a lower platen aligned with the
upper platen, wherein the lower platen is adapted to receive the
workpiece and wherein the upper platen and the lower platen are
movable relative to one another such that in a first position the
cathodes may be distanced from the lower platen and in a second
position the cathode is close to the lower platen with the cathode
adjacent to the location of the indentation of a workpiece mounted
to the lower platen; d) anode shoes for contact with the workpiece,
wherein the shoes are electrically conductive such that when the
shoes contact the workpieces, the workpiece itself acts as an
anode; e) an entry passageway to introduce electrolyte within the
gap between the cathode and the indentation of the workpiece; f) an
exit passageway to remove electrolyte from the gap between the
cathode and the indentation of the workpiece; g) a power supply to
provide current between the cathode of the upper platen and the
anode of the lower platen through the electrolyte therebetween; and
h) a controller for controlling the current between the cathode and
the anode.
2. The machine according to claim 1, wherein the workpiece is a
wheel.
3. The machine according to claim 1, wherein at least two cathodes
extend from the upper platen, wherein each cathode is associated
with an indentation, wherein each cathode has a shape similar to
that of the indentation but smaller and is adapted to be positioned
adjacent to the indentation to define a gap therebetween for the
introduction of an electrolyte between the cathode and the
indentation, and wherein the upper platen and the lower platen are
movable relative to one another such that in a first position the
cathodes may be distanced from the lower platen and in a second
position the cathodes are close to the lower platen with the
cathodes adjacent to the locations of the indentation of a
workpiece mounted to the lower platen.
4. The machine according to claim 1, wherein the controller further
includes a pulsing circuit for allowing the current to be
intermittently applied to the cathode thereby permitting the
electrolyte to more effectively flush residue from the anode.
5. The machine according to claim 4, wherein the controller has at
least a machining mode and a polishing mode, and wherein in the
machining mode, the current is high to remove a substantial amount
of material from the workpiece while, in a polishing mode, the
current is lower to remove a substantially less amount of material
from the workpiece
6. The machine according to claim 1, wherein the indentation is a
window extending through the wall of the workpiece, the entry
passageway surrounds the cathode so that the electrolyte may be
introduced around the perimeter of the cathode, and the exit
passageway is the window so that the electrolyte may be drained
through the window.
7. The machine according to claim 6, wherein the passageway is a
series of ports about the perimeter of the cathode.
8. The machine according to claim 6, wherein the passageway is a
sleeve about the perimeter of the cathode.
9. The machine according to claim 1, wherein the indentation is a
pocket in the wall of the workpiece, the entry passageway is a slot
on one side of the pocket and the exit passageway is a slot on the
opposite side of the pocket such that electrolyte may be introduced
within the gap from one side of the pocket and discharged from the
opposing side of the pocket.
10. The machine according to claim 1, wherein the cathode is
removably attached to the upper platen so that different cathodes
may be installed to accommodate indentations of different
shapes.
11. The machine according to claim 1, wherein the upper platen is
slidably mounted for moving between the first position and the
second position.
12. The machine according to claim 1, wherein the upper platen and
the lower platen are electrically insulated from the anodes and the
cathodes attached thereto.
13. The machine according to claim 1, further including flexible
non-porous material surrounding each cathode and entry passageway,
wherein the material is adapted to mate against the workpiece to
provide a water-tight seal between the upper platen and the
workpiece.
14. The machine according to claim 1, wherein the anode shoes are
movable from a first position away from the workpiece space to a
second position within the workpiece space such that the shoes
would contact a workpiece mounted within the workpiece space.
15. The machine according to claim 1, wherein the lower platen is
indexable such that a workpiece having multiple indentations may be
rotated to align different indentations with the cathode.
16. The machine according to claim 1, further including a collector
tank for collecting electrolyte after it has passed through the gap
between the cathode and the anode.
17. A method for electrochemically polishing indentations of known
geometry within the wall of an aluminum workpiece, wherein a
workpiece space defines the space in which a workpiece would occupy
in the machine and wherein the method comprises the steps of: a)
mounting an aluminum workpiece upon a platen; b) attaching at least
one anode to the workpiece; c) positioning at least one cathode
within an indentation of the workpiece, thereby defining a gap
between the cathode and the anode; d) introducing a flow of
electrolyte within the gap; e) introducing a current between the
cathode and the anode; and f) pulsing the current to permit the
flowing electrolyte to flush the indentation surface.
18. The method according to claim 17, wherein the workpiece is a
wheel.
19. The method according to claim 17, wherein the step of pulsing
the current is a two step process in which in a machining step the
current is greater to remove a substantial amount of material while
in a subsequent polishing step the current is less to remove a
substantially less amount of material.
20. The method according to claim 19, wherein the current for the
machining step is approximately 50 milliseconds on and 25
milliseconds off.
21. The method according to claim 19, wherein the current for the
polishing step is approximately 40 milliseconds on and 20
milliseconds off.
22. The method according to claim 17, wherein the current is
between approximately 12,000 and 15,000 amperes and the voltage is
between approximately 0 and 25 volts direct current.
23. The method according to claim 17, wherein the current is pulsed
at a rate of between approximately 20-25 milliseconds on and
between approximately 8-30 milliseconds off.
24. The method according to claim 17, wherein the flow of
electrolyte is in the range of 25-55 gallons per minute.
25. The method according to claim 18, wherein for a wheel having a
diameter of 20 inches, the flow rate is between 45-50 gallons per
minute.
26. The method according to claim 18, wherein for a wheel having a
diameter of 18 inches, the flow rate is between 30-35 gallons per
minute.
27. The method according to claim 17, wherein the electrolyte is
recirculated to provide electrolyte within the gap.
28. The method according to claim 17, wherein the electrolyte is
filtered to remove residue before recirculation.
30. A method for electrochemically polishing indentations of known
geometry within the wall of an aluminum workpiece, wherein a
workpiece space defines the space in which a workpiece would occupy
in the machine and wherein the method comprises the steps of: a)
mounting an aluminum workpiece upon a platen; b) attaching at least
one anode to the workpiece; c) positioning at least one cathode
within the indentation within the workpiece, thereby defining a gap
between the cathode and the anode; d) introducing a flow of
electrolyte within the gap; and e) introducing a pulsing current
between the cathode and the anode, wherein the current is on for a
predetermined period to polish the workpiece indentation and then
off for a predetermined shorter period to permit the flowing
electrolyte to flush the indentation surface.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to electrochemical
polishing and more specifically to electrochemically polishing
aluminum wheels.
[0003] 2. Description of Related Art
[0004] Electrochemical machining (ECM) is a process for removing
material from a metal workpiece to impart a smooth surface which
appears to be polished. Such a process takes place using an
electrolyte having a high ionic strength. The workpiece to be
machined serves as the anode and the electrode of the
electrochemical machining apparatus serves as the cathode. In the
polishing process an electric current runs between the anode and
the cathode. Under these conditions, the electrode serves as a
shaping tool. The workpiece, which serves as the anode, dissolves
locally, for example, in the form of metal hydroxide while hydrogen
is formed at the electrode surface. This electrochemical machining
method enables patterns or arbitrarily shaped holes to be formed in
a metal workpiece in a relatively simple and accurate manner. The
electrochemical machining process may also be used to polish a
workpiece by removing less material from the workpiece with the
goal of achieving a smoother surface finish, as opposed to purely
removing material to produce a predetermined shape.
[0005] However, electrochemically polishing large workpieces
requires a large current and in the past, as a result of such a
limitation, electrochemical polishing has been limited to
relatively small surfaces. Additionally, with a continuous current,
material is removed from the workpiece and the electrolyte always
contains residue of the workpiece.
[0006] A method and apparatus are needed, whereby a larger
workpiece, such as a wheel, may be electrochemically polished in an
efficient manner that removes residue and that results in a
superior finish.
SUMMARY OF THE INVENTION
[0007] One embodiment of the subject invention is directed to a
machine for electrochemically polishing indentations of known
geometry within the wall of an aluminum workpiece, such as a wheel.
The workpiece space defines the space in which a workpiece would
occupy in the machine. The machine has an upper platen with a
cathode extending from the upper platen, wherein the cathode is
associated with an indentation and, wherein the cathode has a shape
similar to that of the indentation but smaller and is adapted to be
positioned adjacent to the indentation to define a gap therebetween
for the introduction of an electrolyte between the cathode and the
indentation. A lower platen is aligned with the upper platen,
wherein the lower platen is adapted to receive the wheel and,
wherein the upper platen and the lower platen are movable relative
to one another such that, in a first position, the cathode may be
distanced from the lower platen and, in a second position, the
cathode is close to the lower platen with the cathode adjacent to
the location of the indentation of the workpiece mounted to the
lower platen The machine also has anode shoes for contact with the
wheel, wherein the shoes are electrically conductive such that when
the shoes contact the workpieces, the workpiece itself acts as an
anode. An entry passageway introduces electrolyte within the gap
between the cathode and the indentation of the workpiece and an
exit passageway removes electrolyte from the gap between the
cathode and the indentation of the workpiece. A power supply
provides current between the cathode of the upper platen and the
anode of the lower platen through electrolyte therebetween and a
controller controls the current between the cathode and the
anode.
[0008] Another embodiment of the subject invention is directed to a
method for electrochemically polishing indentations of known
geometry within the wall of an aluminum workpiece. A workpiece
space defines the space in which the workpiece would occupy in the
machine. The method comprises the steps of: [0009] a) mounting an
aluminum workpiece upon a platen; [0010] b) attaching at least one
anode to the workpiece; [0011] c) positioning at least one cathode
within the indentation within the workpiece, thereby defining a gap
between the cathode and the anode; [0012] d) introducing a flow of
electrolyte within the gap; [0013] e) introducing a current between
the cathode and the anode; and [0014] f) pulsing the current to
permit the flowing electrolyte to flush the indentation
surface.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0015] FIG. 1 is a front view of a typical wheel that may be
polished using the machine and method in accordance with the
subject invention;
[0016] FIG. 2 is an enlarged section of a portion of the wheel
illustrated in FIG. 2;
[0017] FIG. 3 is a perspective view of a portion of the top platen
with an anode extending therefrom;
[0018] FIG. 4 is a sketch of the apparatus in accordance with the
subject invention;
[0019] FIG. 5 is a sketch of the machine illustrated in FIG. 4 but
with the upper platen and lower platen adjacent to each other to
perform the machining process; and
[0020] FIG. 6 is a plan view of a cathode used to polish a closed
pocket.
DETAILED DESCRIPTION OF THE INVENTION
[0021] FIGS. 1 and 2 illustrate details of a typical workpiece,
such as a wheel 10, which in these figures is an aluminum wheel
having a cylindrical profile defining a wheel rim 15 which supports
a tire (not shown) and a hub 20 having a plurality of lug holes 25
extending therethrough for securing the wheel 10 with lugs (not
shown) extending from the body of a vehicle.
[0022] The wheel 10 has a plurality of indentations 30 of known
geometry within the wall 35 of the wheel 10. In particular, an
indentation 30 may be either a window 40 extending through the wall
35 of the wheel 10 or a pocket 45 which extends only partially
through the wall 35 of the wheel 10. It should be appreciated that
the electrochemical polishing process associated with the window 40
is slightly different than the process associated with the pocket
45. In particular, the electrolyte may be flushed through the
window 40 during the process while the electrolyte must be
introduced and removed from the pocket 45.
[0023] For the electrochemical process to be effective, it is
necessary for the anode to conform fairly closely to the shape of
the workpiece to be polished. Directing attention to FIG. 3, the
cathode 50 is shaped to have a substantially similar profile to
that of the window 40 (FIG. 2). The cathode 50 must be slightly
smaller than the profile of the window 40 to create a gap. The gap
exists for two reasons. First of all, it is necessary to introduce
an electrolyte within the gap to promote the chemical reaction
which removes material from the window 40. Second of all, the gap
must be maintained to prevent electrical arcing between the cathode
and the anode since such arcing would pit the walls 42 of the
window 40. Cathodes 50 are typically made of solid brass.
[0024] Briefly turning to FIG. 1 and with respect to FIG. 3, it
should be apparent that the cathode 50 may be placed in any one of
the windows 40 and the locator pin 55 on the upper platen may be
placed within the lug hole 25 to properly space the cathode 50. The
cathode 50 is attached to an upper platen 60. The upper platen 60
has surfaces 65 which contact the perimeter 43 of the window to
vertically position the cathode 50 within the window 40.
[0025] Directing attention to FIG. 4, a machine 100 is illustrated
for electrochemically polishing indentations 30 such as the window
40 of known geometry within the wall 35 of an aluminum wheel 10. A
wheel space 12 is used to define the volume that would be occupied
when an actual wheel 10 is placed within the machine 100. The
machine 100 has an upper platen 60 with two cathodes 50 extending
therefrom. Each cathode 50 is associated with an indentation 30 and
each cathode 50 has a shape similar to that of the indentation 30,
but smaller. Each cathode 50 is adapted to be positioned adjacent
to the indentation 30 to define a gap therebetween, for the
introduction of an electrolyte between the cathode 50 and the
indentation 30.
[0026] A lower platen 105 is aligned with the upper platen 60. The
lower platen 105 is adapted to receive the wheel 10. The upper
platen 60 and the lower platen 105 are movable relative to one
another such that, in a first position (FIG. 4), the cathodes 50
may be distant from the lower platen 105 and, in a second position
(FIG. 5), the cathodes 50 on the upper platen 60 are close to the
lower platen 105 and within the indentations 30 of a wheel 10
mounted to the lower platen 105. In FIGS. 4 and 5, the indentation
30 is the window 40. This positioning provides a gap 107 through
which electrolyte may flow to transmit current therebetween.
[0027] FIG. 4 illustrates the machine 100 in a first position with
the cathodes 50 distanced from the lower platen 105. This
arrangement is used for set-up so that the wheel 10 may be
introduced to or removed from the lower platen 105. The lower
platen provides a non-conductive base 110, which may be a
glass-filled phenolic material, with locating bolts 112 protruding
therefrom which engage one or more of the lug holes 25 in the wheel
10. The machine 100 includes anode shoes 115 which contact the
wheel 10. The shoes 115 are electrically conductive such that when
the shoes 115 contact the wheel 10, the wheel 10 itself acts as an
anode. The anode shoes 115 are movable from a first position
illustrated in FIG. 4, wherein the shoes 115 are away from the
wheel 10 to a second position (FIG. 5), wherein the shoes 115
contact the wheel 10. It should be appreciated that in the event
the wheel 10 is not mounted within the machine 100, the anode shoes
in the second position would be positioned within a wheel space 12
identical to the location of the wheel 10.
[0028] The anode shoes 115 are attached to linear cylinders 120
capable of indexing the anode shoes 115 in the first position, as
illustrated in FIG. 4, or in the second position, as illustrated in
FIG. 5. A power supply 125 provides current between the cathode 50
of the upper platen 60 and the anode 115 of the lower platen 105,
but permits such current to pass between these two parts through
the introduction of electrolyte therebetween. The combination of
the electrolyte 127 therebetween and a current passing between the
cathode 50 and the wheel 10, which acts as the anode through the
electrolyte 127, promotes the chemical reaction which removes
material from the window 40 of the wheel 10. A controller 129
controls the current between the cathode 50 and the wheel 10 acting
as an anode.
[0029] In order to promote the quality of polishing provided by the
machine 100, the controller 129 further includes a pulsing circuit
131 for allowing the current to be intermittently applied to the
cathode 50, thereby permitting the electrolyte 127 to more
effectively flush residue from the wheel 10. The controller 129
provides at least a machining mode and a polishing mode. In the
machining mode, the current is high to remove a substantial amount
of material from the wheel 10. In the polishing mode, the current
is lower to remove a substantially less amount of material from the
wheel 10. As a result, a wheel 10 with a relatively rough finish
may first be "machined" and then "polished" to produce a finished
product. With such a two-stop process, it may be possible to
eliminate a preliminary mechanical grinding step which heretofore
preceded the electrochemical machining process.
[0030] While the parameters for pulsing the current used for this
process is dependent upon a variety of factors such as workpiece
size, the gap between the cathode and the workpiece and the
composition of the electrolyte, in general, the pulsing of the
current for the machining mode is approximately 50 milliseconds on
and 25 milliseconds off for a typical workpiece. For the polishing
mode, the pulsing of the current is approximately 40 milliseconds
on and 20 milliseconds off. Overall, the current may be pulsed at a
rate of between 20-25 milliseconds on and 8-30 milliseconds off.
The inventors have discovered that the pulsing process itself
greatly improves the efficiency of the polishing process and that
this two stage machining/polishing method further enhances the
effectiveness of the pulsing process.
[0031] Additionally, as a general guideline for a typical
workpiece, the current may be between 12,000-15,000 amperes and the
voltage may be between approximately 0-25 volts direct current.
[0032] It should be appreciated that a flow of electrolyte 127 is
necessary for normal operation of the machine 100. The flow of
electrolyte 127 not only promotes the transfer of current between
the anode and the wheel 10, but furthermore, provides a mechanism
for removing heat and residue from the working region of the wheel
10.
[0033] Directing attention to FIG. 4, from a reservoir 135
electrolyte 127 is delivered through a pump 138 through a conduit
140 to an entry passageway 143, which in FIG. 4 is a sleeve 145
surrounding each cathode 50 so that the electrolyte 127 may be
introduced around the perimeter of the cathode 50. FIG. 3 further
illustrates that this sleeve 145 extends through the upper platen
60 and surrounds the cathode 50. It should be noted in FIG. 3 that
a seal 147 surrounds the sleeve 145. The seal 147 is comprised of a
flexible nonporous material surrounding the cathode 50 and entry
passageway 143. While the sleeve 145 is illustrated as the
mechanism for dispersing the electrolyte 127 about the perimeter of
the cathode 50, this sleeve 145 may in the alternative be a
plurality of ports about the perimeter of the cathode 50 to achieve
the same result. The entry passageway 143 conforms to the perimeter
of the cathode 50 and when a cathode 50 having a different geometry
is used, the associated entry passageway 143 again conforms to the
perimeter of the new cathode 50.
[0034] Directing attention to FIG. 5, when the upper platen 60 is
positioned against the wheel 10, the seal 147 is urged against the
wheel 10 thereby providing a watertight seal between the upper
platen 60 the wheel 10 to contain the electrolyte 127. Examining
both FIGS. 4 and 5, the electrolyte 127 travels through the sleeve
145 around the cathode 50 and through an exit passageway 150 which
in FIG. 4 is the window 40 of the wheel 10. In this arrangement,
the electrolyte 127 may be drained through the window 40 into a
collection tank 153 where it is then returned to the reservoir 135
to be used again. As illustrated in FIG. 4, the electrolyte 127 in
the reservoir 135 is diverted to a reclamation station 155 to
remove impurities from the electrolyte 127 that were introduced
during the polishing process. One reclamation technique involves
the introduction of iron nitrate with the spent electrolyte after
which time the fluid is centrifuged. This technique is better
described in a co-pending U.S. patent application Ser. No.
11/465,839 titled "Process For Regenerating Electrolytes In
Electrochemical Polishing Applications" filed Aug. 21, 2006 and
assigned to the same assignee as the present application. It should
also be noted in FIG. 4 that the wheel 10 rests upon the collector
tank 153, such that the wheel 10 provides a seal against the tank
153 to minimize the loss of electrolyte.
[0035] The cathodes 50 of the subject invention are customized to
act upon the window 40 of the wheel 10, illustrated in FIGS. 1 and
2. It should be appreciated that each cathode 50 is removable and
may be replaced with a differently shaped cathode to accommodate
indentations of different shapes on wheels. FIGS. 3, 4 and 5
illustrate the cathode 50, which is removably attached to the upper
platen 60. The upper platen 60 is slideably mounted upon posts 160
so that it may be moved between the first position, wherein the
upper platen 60 is spaced from the wheel 10 (FIG. 4), then to the
second position, wherein the upper platen 60 is adjacent to the
wheel 10 (FIG. 5). It should also be appreciated that the upper
platen 60 and the lower platen 105 are electrically insulated from
the anode, which is the wheel 10, and from the cathodes 50.
[0036] From inspection of FIG. 1, it is apparent that there are
multiple windows 40 within a wheel 10. In one embodiment of the
subject invention, two windows 40 are polished simultaneously
although a single window may also be polished. The subject
invention is also designed to index the wheel 10 or another
workpiece so that different windows can be polished by the same
cathode. However, because the electrochemical polishing process
requires a high current, prior art designs for electrochemical
polishing use a single cathode. Additionally, the lower platen 105
is indexable such that wheel 10 having multiple indentations 30 may
be rotated to align different indentations 30 with the cathodes 50
for polishing. In particular, a CNC controlled servo-drive motor
163 drives a pulley 165 which drives a belt 167 to rotate a second
pulley 170 which rotates a shaft 172, thereby rotating the lower
platen 105 and the wheel 10 attached thereto. By doing so, it is
possible to index the wheel 10 so that different windows 40 are
aligned with the cathodes 50 for polishing. As a result, polishing
the eight windows 40 in the wheel 10, illustrated in FIG. 1,
requires indexing the wheel 10 only four times as opposed to
indexing the wheel 10 eight times when there is a single cathode 50
operating upon a window 40.
[0037] The electrolyte 127 is comprised of a solution of sodium
nitrate (NaNO.sub.3) and water. The flow of electrolyte 127 for a
typical application may be between 25-55 gallons per minute. As a
particular example, for a wheel 10 having a diameter of 20 inches
and indentations 30 proportional to that size, the flow of
electrolyte may be between 45-50 gallons per minute. For a wheel 10
having a diameter of 18 inches and indentations 30 proportional to
that size, the flow of electrolyte may be between 30-35 gallons per
minute. The gap 107 between the cathode 50 and the wall 35 of the
window 40 is typically about 0.75 millimeters, however, in regions
where a greater degree of polishing is required during the
operation, this gap may be slightly smaller, keeping in mind that a
gap that is too small will result in undesirable arcing between the
cathode 50 and the anode, which is the wheel 10.
[0038] With the electrolyte 127 flowing around the cathodes 50, the
pulsing circuit 131 of the controller 129 is capable of turning the
current on and off so that the electrolyte has a chance not only to
cool the wheel 10, but furthermore, to wash away any impurities it
may have accumulated on the wall 35 of the window 40 in the wheel
10.
[0039] So far the discussion has been directed to electrochemically
polishing a window 40 within a wheel 10. As illustrated in FIGS. 1
and 2, the indentation 30 may also be a pocket 45 which does not
extend through the wall 135 of the wheel 10. As a result, for
polishing a pocket 45, the electrolyte 127 must be directed in a
different fashion. FIG. 6 illustrates the upper platen 60 having a
cathode 180 extending therefrom. A seal 182 surrounds the cathode
180 to provide a water-tight seal when the upper platen 60 is
placed over the pocket 45. The purpose of this design is to deliver
electrolyte 127 over the sides and the face of the cathode 180. In
particular, an entry passageway 185 on one side of the cathode 180
introduces the electrolyte 127 to what is now an enclosed chamber
187. The electrolyte 127 flows across the cathode 180 and is
removed from the chamber 187 through an exit passageway 189 where
the electrolyte is then delivered to the collection tank 153,
illustrated in FIG. 4. With respect to the wheel 10 illustrated in
FIG. 1, the upper platen 60 illustrated in FIG. 6, has two locating
pins 190 (FIG. 6), which fit within the lug holes 25 adjacent to
the pocket 45 to be polished.
[0040] The subject invention is also directed to a method for
electrochemically polishing indentations 30 of known geometry
within the wall 35 of an aluminum wheel 10. A wheel space defines
the space in which a wheel 10 would occupy in the machine 100. The
method is comprised of the steps of mounting an aluminum wheel 10
upon a platen 105 and attaching at least one anode through, for
example, anode shoe 115 to the wheel 10. At least one cathode 50 is
positioned within the indentation 30 of the wheel 10, thereby
defining a gap 107 between the cathode 50 and the anode. An
electrolyte 127 is introduced within the gap and a current is then
introduced between the cathode 50 and the anode. The current is
pulsated to permit the flowing electrolyte 127 to flush impurities
from the surface of the indentation 30. The electrolyte is
recirculated during the polishing process, but furthermore, the
electrolyte is reclaimed through a reclamation process, such as
that process previously described herein.
[0041] While specific embodiments of the invention have been
described in detail, it will be appreciated by those skilled in the
art that various modifications and alternatives to those details
could be developed in light of the overall teachings of the
disclosure. The presently preferred embodiments described herein
are meant to be illustrative only and not limiting as to the scope
of the invention which is to be given the full breadth of the
appended claims and any and all equivalents thereof.
* * * * *