Abrading – Abrading process – Utilizing fluent abradant
Reexamination Certificate
2000-09-12
2003-01-07
Eley, Timothy V. (Department: 3724)
Abrading
Abrading process
Utilizing fluent abradant
C451S051000, C451S060000, C451S061000, C451S076000, C134S024000
Reexamination Certificate
active
06503126
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to abrasive flow machining and, more particularly, the use of abrasive flow machining to polish the region of intersection between a branch outlet and a passageway in a body.
2. Background Art
Abrasive flow machining is used for working metals and related materials, particularly for machining and finishing internal shapes, bores, orifices and complex three-dimensional shapes and as an alternative to certain other difficult machining operations. Abrasive flow machining is particularly used for deburring, radiusing, resizing, and polishing/finishing operations.
Abrasive flow machining incorporates the use of a plastic or semi-solid media containing abrasive particles distributed substantially uniformly throughout. The purpose of the semi-solid media is to transport the abrasive particles through a passage of a workpiece to achieve the desired machining results as illustrated in U.S. Pat. No. 5,054,247, which is hereby incorporated by reference.
Abrasive flow machining may incorporate the use not only of a plastic or semi-solid media containing abrasive particles, but may additionally include a liquid or oil-based media also containing abrasive particles distributed substantially uniformly throughout. A liquid media will provide easier cleanup through passageways and medium delivery tubes.
Nevertheless, whether the abrasive media is a semi-solid media, a liquid, or oil-based media, ideally, the media may range in look and feel from a highly viscous material to an extremely low viscosity fluid. The most effective media for a specific application will depend upon the geometric characteristics of the application and the materials to be abraded or polished.
The application-specific media would have such viscosity and rheology that it flows at a suitable rate through an outlet or orifice under an imposed or gravitational force where the rate is defined by the abrasive flow processing requirements.
Considerations for media selection for a particular application may be based upon a number of considerations. Preferably, the media must flow through a delivery tube and through passageways requiring surface, radius, or opening machining by the abrasive flow process. Furthermore, the media must exhibit sufficient Theological behavior during flow through passageways to achieve the desired machining action. Additionally, the media must maintain coherence during flow sufficient to achieve the radiusing action where and when it is required. Finally, the media must provide a machining action and lubrication to such a degree to maintain the required flow rates and perform the appropriate abrasive processing.
Suitable types of media that possess the desired rheological behaviors required for this application include those identified in U.S. Pat. No. 5,679,058, entitled “Abrasive Jet Cutting Medium”, assigned to the assignee of the present invention and herein incorporated by reference. Also appropriate for this application is media that contains a supraparticle structure or a sufficiently flexible and shearable, yet sufficiently cohesive microstructure.
When the workpiece consists of a body having a passageway with multiple openings extending over the length of the passageway, such as, for example, a fuel rail or automobile manifold, the abrasive flow machining in the region of the intersection of the multiple branch outlets with the passageway of the body is accomplished by flowing the abrasive media through the passageway to each branch outlet. For purposes of discussion, a body having a passageway will encompass a manifold, pipe, tube, or conduit with at least one inlet and two or more outlets.
Directing attention to
FIG. 1
, a sectioned schematic is illustrated of a body
10
having a passageway
11
including multiple branch outlets
15
each defined by an opening
20
extending through a wall
25
of the body
10
. A typical branch outlet
15
having an opening
20
will be discussed with the understanding that such a discussion may also be applied to any of the remaining branch outlets and associated openings. The opening
20
of a branch outlet
15
is typically created by a drilling operation which leaves, as illustrated in
FIG. 2
, a burr
30
around the periphery
35
of the opening
20
. The burr
30
protrudes from the opening
20
and creates a discontinuity on the body inner surface
40
at the intersection region
37
defined by the intersection of the periphery
35
of the opening
20
with the body wall
25
.
FIG. 1
illustrates a prior art technique for removal of burrs
30
and subsequent polishing of the underlying surface by abrasive flow machining. In particular, a flowable abrasive media
45
is introduced into a passageway
11
from one end
55
of the passageway
11
. The media
45
is moved under pressure toward opposite end
60
of the passageway
11
. The burr
30
is removed and the underlying surface polished by the flow of the abrasive media
45
over the surface of the burr
30
. For a body
10
having multiple branch outlets, as illustrated in
FIG. 1
, it is necessary to direct the flow of the media
45
through at least one branch outlet
15
at a time.
It should be appreciated the abrasive flow technique is most effective with ample media flow through any one branch outlet
15
and, therefore, while it may be possible to pass the media
45
through a number of different branch outlets, it is oftentimes preferred to direct the media
45
through a single branch outlet
15
to maximize the effectiveness of the abrasion technique.
To accomplish this, the body
10
is mounted within an assembly having a plurality of plugs which may be selectively activated to seal one or more branch outlets
15
thereby preventing flow of the media
45
through that branch outlet
15
. For purposes of discussion, a single plug
65
will be addressed with the understanding that this plug is representative of the remaining plugs. As illustrated in
FIG. 1
, when the plug
65
is moved away from the branch outlet
15
, the media
45
flows past the opening
20
and is ejected at the branch outlet
15
.
Using this technique, the burr
30
, illustrated in
FIG. 2
, is largely removed from the periphery
35
of the opening
20
as illustrated in FIG.
3
.
While this technique is effective in removing a large portion of the burr
30
, as illustrated in
FIG. 3
, there is still a portion of the burr
30
remaining. This is created by the unidirectional flow of the media
45
in the passageway
11
and results not only in a small burr
30
remaining but, furthermore, results in a non-uniform radiusing of the periphery
35
of the opening
20
. In particular, the abrasion of an upstream surface
70
on the periphery
35
of the opening exceeds that of a downstream surface
75
, as illustrated in FIG.
3
.
Additionally, the assembly used for manipulating the plurality of plugs, which act to block media
45
flow through the branch outlets, is a fairly complex assembly and must be customized for each body. Such an arrangement is very costly and setup using such an arrangement is time-consuming. Furthermore, physical interference caused by the assembly makes it difficult to capture and contain the media
45
as it leaves the branch outlet
15
. Finally, using the arrangement illustrated in
FIG. 1
, the entire passageway
11
is filled with abrasive media
45
and then the media
45
is selectively released through the desired outlet
15
to initiate the abrasion process. This creates a surplus of media
45
within the passageway
11
that must be removed when the abrasion process is complete.
A method is needed for directing the flowable abrasive media
45
through the passageway
11
in an efficient manner without the need of the complex assembly utilizing movable plugs, without requiring the associated extensive setup time, and without the need to completely fill the passageway with media prior to the abrasion process.
Furthermore, a method is desired to eliminate the non-uniform abrasion about the periphery
35
o
Eley Timothy V.
Extrude Hone Corporation
Webb Ziesenheim & Logsdon Orkin & Hanson, P.C.
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