Abstract:
A method and apparatus are disclosed for abrading the inner surface at the intersection region of a branch outlet with the wall of a body having a passageway. Using abrasive flow machining, it is possible to abrade the intersection region to provide a smooth transition between the wall and the branch outlet.

Description:
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  of the opening  20  caused by the unidirectional flow of the flowable abrasive media  45 . 
     SUMMARY OF THE INVENTION 
     In a first embodiment of the invention, for a body having a wall with an inner surface along a passageway and at least one branch outlet defined by an opening extending through the wall, a method for abrading the inner surface at an intersection region defined by the intersection of the periphery of the opening at the wall comprises the steps: 
     a) positioning a first media delivery tube within a first end of the passageway, wherein the first tube has an inlet and an outlet and wherein the outlet is proximate to the periphery of the opening; 
     b) supplying a flowable abrasive media through the inlet of the first tube to the outlet; and 
     c) guiding the media from the outlet of the first tube through the opening. 
     Guiding the media may involve positioning a deflector within the passageway to direct the flow of media through the opening. 
     In a second embodiment of the invention, a second media delivery tube may be positioned within the passageway opposite the first media delivery tube and media provided through it such that the opposing flow of media from the first and second tubes is directed through the opening. 
     In a third embodiment of the invention, the first and second media delivery tubes are combined into a single tube having a tube outlet between two inlets. The tube outlet is aligned with the opening in the passageway and media is directed through the opening. 
     In a fourth embodiment, baffles are attached to the first delivery tube around the tube outlet, thereby defining a flow path from the tube outlet directly through the opening. 
     Both methods and assemblies are associated with each of these embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a sectioned schematic illustration of a body having a passageway with multiple branch outlets, wherein one branch outlet is being processed by a flowable abrasive media using a prior art technique; 
     FIG. 2 is an enlarged perspective view of an opening with a burr to be removed using the abrasive machining process; 
     FIG. 3 is a perspective view of an opening of a branch outlet subjected to unidirectional flow of the flowable abrasive media in an abrasive machining process; 
     FIG. 4 is a sectional schematic illustration of one embodiment of the subject invention utilizing a media delivery tube and a deflector; 
     FIG. 5 is a sectional schematic illustration of an arrangement similar to that in FIG. 4, wherein the media delivery tube and deflector are in opposite positions within the passageway of the body; 
     FIG. 6 is a sectional schematic illustration of a perspective of an opening subjected to bidirectional flow of flowable abrasive media in an abrasive machining process; 
     FIG. 7 is a sectional schematic illustration of a second embodiment of the subject invention, whereby two media delivery tubes are introduced from opposite ends of the passageway; 
     FIG. 8 is a sectional schematic illustration of a third embodiment of the subject invention, whereby a single media delivery tube has an opening positioned adjacent a branch outlet in which abrasive media is to be introduced; 
     FIG. 9 is a sectional schematic illustration of a fourth embodiment of the subject invention, whereby a single media delivery tube using baffles directs the abrasive media through the opening of the branch outlet; 
     FIG. 10 illustrates a cross-sectional view along arrows X—X in FIG. 9; 
     FIG. 11 is a sectional schematic illustration of an arrangement similar to that in FIG. 9, but with the media delivery tube introduced from an opposite end of the passageway; 
     FIG. 12 is a cross-sectional view along arrows XII—XII in FIG. 11; and 
     FIG. 13 is a perspective view of the media delivery tube illustrated in FIGS. 9-12. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Unlike methods used in the past, the method according to each embodiment of the subject invention in each instance introduces flowable abrasive media  45  within the passageway  11  through the use of at least one media delivery tube  100 . 
     As previously mentioned, the abrasive media  45  may be a semi-solid media, a liquid, or an oil-based media. 
     FIG. 4 illustrates a body  10  similar to that in FIG. 1, wherein the body  10  has a wall  25  with an inner surface  40  along a passageway  11  and at least one branch outlet  15  defined by an opening  20  extending through the wall  25 . In a first embodiment, the subject invention is directed to a method and apparatus of abrading the inner surface  40  at an intersection region  37  defined by the intersection of the periphery  35  of the opening  20  at the wall  25 . 
     The media delivery tube  100  has an inlet  105  and an outlet  110 . The media delivery tube  100  is positioned within the passageway  11  such that the outlet  110  is proximate to the periphery  35  of the opening  20  to be processed. 
     The term “proximate” , as applied herein, is intended to define the position of the delivery tube outlet  110  relative to an opening  20 . To be proximate, the outlet  110  must release abrasive media  45  within the passageway  11  at a distance from the opening  20  so that the flow of abrasive media  45  will act upon the opening  20 . The delivery tube outlet  110  cannot extend into a projection of the opening  20  within the passageway  11 . 
     Flowable abrasive media  45  is supplied through the inlet  105  of the media delivery tube  100  to the outlet  110 . The media  45  is supplied under pressure from a reservoir. 
     To prevent the media  45  from traveling through other branch outlets or further down the passageway  11 , the media  45  is guided from the outlet  110  of the delivery tube  100  through the opening  20 . In the embodiment illustrated in FIG. 4, this is accomplished by positioning a deflector  115  within the passageway  11  proximate to the periphery  35  of the opening  20 , but at a position opposed to that of the delivery tube  100 , thereby obstructing the flow of the media  45  to direct it through the opening  20  in a first direction identified by arrow  120  from the passageway end  55  toward the branch outlet  15 . Abrasive media  45  provided through the delivery tube  100  will then be directed to travel past the opening  20  and through the branch outlet  15 , thereby providing to the periphery of the opening the necessary processing to remove a significant portion of a burr  30  (FIGS.  2  and  3 ). 
     For purposes of discussion, only a single branch outlet  15  with an opening  20  will be discussed with the understanding that the arrangement of the delivery tube  100  and the deflector  115  may be moved within the passageway  11  to accommodate any of the other openings and associated branch outlets. 
     Because the arrangement illustrated in FIG. 4 provides only unidirectional flow, the same asymmetry illustrated by the periphery  35  of opening  20  in FIG. 3 occurs. As a result, after the step of guiding the media  45  in a first direction  120 , as illustrated in FIG. 5, the delivery tube  100  must be repositioned within the second end  60  of the passageway  11  such that the delivery tube outlet  110  is proximate to the periphery  35  of the opening  20 . It is further necessary to reposition the deflector  115  within the first end  55  of the passageway  11  proximate to the periphery  35  of the opening  20 , thereby obstructing the flow of the media  45  to direct it through the opening  20  from the second direction indicated by arrow  125 . 
     It should be appreciated that positioning the delivery tube  100  and the deflector  115  may involve securing the body  10  in a fixed position and moving the delivery tube  100  and deflector  115  within the passageway  11  to properly position them next to an opening of a branch outlet. It is also possible to maintain the delivery tube  100  and deflector  115  in fixed positions and to move the body  10  to accommodate the openings of different branch outlets on the body  10 . 
     To prevent the media  45  from flowing between the delivery tube  100  and the inner surface  40  of the wall  25 , the media delivery tube  100  at the intersection region  37  may have a shape and cross-sectional area close to that of the shape and cross-sectional area of the passageway  11 . However, it is also possible, when the cross-sectional areas and/or shapes are significantly different, to introduce seals  130  extending from the delivery tube  100  radially outward to minimize the gap between the delivery tube  100  and the inner surface  40  of the wall  25  in the area of the intersection region  37 . The same concept may be applied to the deflector  115  and FIG. 5, for example, illustrates seals  135  about the deflector  115 . 
     By repositioning the delivery tube  100  and the deflector  115 , the flow of abrasive media  45  may be provided in a second direction in conjunction with abrasive media  45  already supplied from a first direction, thereby providing bidirectional flow and the subsequent uniform abrasion of the periphery  35  of the opening  20 , as illustrated in FIG.  6 . 
     FIG. 7 illustrates an arrangement whereby a first delivery tube  100  having an inlet  105  and an outlet  110  is positioned within the passageway  11  such that the outlet  110  is proximate to the opening  20  of the branch outlet  15 . As opposed to introducing a deflector  115 , as discussed with respect to FIGS. 4 and 5, a second media delivery tube  200  may be positioned within the passageway  11 . The second delivery tube  200  has an inlet  205  and an outlet  210 . The outlet  210  is proximate to the periphery  35  of the opening  20  in an opposing relationship with that of the outlet  110  of delivery tube  100 . Flowable abrasive media  45  may now be provided through the inlets  105 ,  205  of both the first delivery tube  100  and the second delivery tube  200  positioned on each side of the opening  20  such that the flow of media  45  is directed through the opening  20  in a bidirectional manner. In this fashion, the periphery  35  of the opening  20  is processed in a symmetric manner, as illustrated in FIG.  6 . 
     Just as previously mentioned with the embodiments described in FIGS. 4 and 5, either the delivery tubes  100 ,  200  or the body  10  may be fixed, while the other is moved into the desired position. 
     While FIG. 7 has described an embodiment in which a first delivery tube  100  and a second delivery tube  200  are positioned within a passageway  11 , each of these tubes is an independent piece. 
     Directing attention to FIG. 8, it is entirely possible for a single delivery tube  300  to have a first inlet  305  and a second inlet  307  with an outlet  310  between them. As a result, the step of supplying flowable abrasive media  45  is comprised of not only supplying media  45  through the first inlet  305  but, furthermore, providing media  45  through the second inlet  307  of the delivery tube  300  to the outlet  310 . In such a fashion, the flow of media  45  from each inlet  305 ,  307  approaches the intersection region  37  from a different direction, thereby providing bidirectional flow with the subsequent uniform abrasion of the periphery  35  of the opening  20  as illustrated in FIG.  6 . 
     Just as before, the body  10  may be fixed and the delivery tube  300  moved within the body  10  or, in the alternative, the delivery tube  300  may be fixed and the body  10  moved over it to index the outlet  310  to provide media  45  to different branch outlets along the length of the passageway  11 . 
     What has been discussed so far is a method for guiding the abrasive media  45  once it leaves the outlet of the delivery tube by physically blocking the entire passageway downstream of the tube outlet. It is also possible to selectively guide the flow of the media  45  to a particular opening  20  of a branch outlet  15 . 
     FIG. 9 illustrates an arrangement by which guiding the media  45  is accomplished by a delivery tube  400  having an inlet  405  and an outlet  410 , wherein the outlet has baffles  415 ,  420 ,  425 ,  430  (FIG. 13) extending from the delivery tube outlet  410 . The baffles  415 ,  420 ,  425 ,  430  surround the intersection region  37 , thereby defining a flow path for the media  45  from the delivery tube inlet  405  to the delivery tube outlet  410  and through the opening  20 . The arrangement illustrated in FIG. 13 provides the opportunity for selectively directing media  45  to one particular outlet  15  (FIG. 9) by moving the delivery tube  400  along the passageway  11 . While described as a plurality of distinct parts, the baffles  415 ,  420 ,  425 ,  430  may also be combined to form a single piece that is attached to or integral with the delivery tube  400 . 
     When there are multiple branch outlets at the same longitudinal location along a passageway, the volume of media  45  that may be supplied through the passageway  11  may be insufficient to satisfy the volume requirements necessary for proper abrasion of multiple branch outlets at the same longitudinal location. For that reason, it may be necessary to selectively direct media  45  into one or more branch outlets at a time to the exclusion of other branch outlets at the same longitudinal location. In these instances, the delivery tube  400  with the associated baffle arrangement provides this selective guidance of media  45 . 
     The baffling on the delivery tube  400  also permits the tube  400  to be rotated to selectively direct media  45  from one branch outlet  15  to a second branch outlet  435  (FIGS. 10 and 12) which may be at a same longitudinal location within the passageway  11 , however, at a different angular orientation. By redirecting the outlet  410  from alignment with the branch outlet  15  to alignment with the branch outlet  435 , media  45  may be supplied to the branch outlet  435  to the exclusion of branch outlet  15 . 
     In a fashion similar to that discussed with FIGS. 4 and 5, the delivery tube  400  provides media  45  with unidirectional flow along arrow  440  and, as a result, it is necessary to remove the delivery tube  400  from the end  55  of the passageway  11  and to insert it in end  60  of the passageway  11 . Particularly, after the step of guiding the media  45  to the delivery tube  400  in a first position of FIG. 9, it is necessary to reposition the delivery tube  400  within the passageway  11 , wherein the delivery tube outlet  410  is proximate to the periphery  35  of the opening  20 , thereby obstructing the flow of the media  45  to direct it through the opening  20  from a second direction indicated by arrow  445 . 
     Just as previously mentioned with other embodiments, it is entirely possible to fix the location of the body  10  and to move the delivery tube  400  for positioning within the body  10  or, in the alternative, it is possible to fix the delivery tube  400  and to move the body  10  over the delivery tube  400  to properly index the tube  400  within the body  10 . 
     What has been described is a method and apparatus for abrading the inner surface of a body having a passageway with at least one branch outlet defined by an opening extending through the wall. 
     The invention has been described with reference to the preferred embodiments. Obvious modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of appended claims or the equivalents thereof.