Abrading – Abrading process – Utilizing fluent abradant
Reexamination Certificate
1998-12-21
2001-05-22
Rose, Robert A. (Department: 3723)
Abrading
Abrading process
Utilizing fluent abradant
C451S061000
Reexamination Certificate
active
06234872
ABSTRACT:
TECHNICAL FIELD
The present invention relates to hole polishing and, more particularly, to a free flow abrasive hole polishing system for improving air flow and resultant component cooling efficiency.
BACKGROUND OF THE INVENTION
Currently there are many aircraft engine parts produced which have a large number of small holes for delivery of cooling air to protect the subject part from high temperature damage. In most cases, such parts have a hole size referenced on the drawing but the acceptance criteria is air flow (air passed through the subject holes per unit time). Because of the number of holes normally found in such parts and the required uniformity of air distribution, the tolerance on hole size is quite small. Many times such holes are undersized, or as specified, and do not deliver the required air flow. In such cases, the options for increasing hole size are limited and expensive.
Several approaches that have been used in the past are to process the holes through a re-drill operation at the high risk of generating scrap since locating and maintaining the exact centerline of the hole during re-drilling on many hundreds of holes is nearly impossible.
Another approach is to abrasive flow machine the holes. However, because the carrier has high resistance to flow, abrasive particles at the media-hole wall interface will remain at the surface. This results in material removal at both the peaks and valleys by the grinding action of the abrasives. Further disadvantages of this method include limited abrasive particles per unit time, considerable tooling cost, processing time, and in some cases destruction of parts due to distortion because of the high pressures required to move the process media (a putty-like substance containing abrasive particles) through the small holes.
These existing processes are expensive, time consuming, and have a high probability of causing the part to be scrapped.
It would be desirable, then, to be able to apply an improved abrasive hole polishing system which is not subject to the foregoing disadvantages. The objects, features and advantages of the present invention will become more readily apparent in the following description when taken in conjunction with the appended drawings.
SUMMARY OF THE INVENTION
The present invention provides a free flow abrasive hole or aperture polishing technique whereby the abrasive particle has integral mass and velocity and does not follow the carrier. The free flow abrasive hole polishing, according to the present invention, will apply to all components which have small air cooling apertures or holes which are undersize for the delivery of a specified air flow.
In accordance with the present invention, a free flow abrasive hole polishing system and method improves air flow and resultant component cooling efficiency for an apertured article. The free flow abrasive hole polishing system mixes an abrasive particle component with a carrier media to create a free flowing abrasive particle carrier media mixture. This mixture is pumped through apertures defined by aperture walls in the article to improve air flow and resultant cooling efficiency of the article. Since the abrasive particles have mass and velocity and the free flowing media does not have resistance to flow, the abrasive particles impinge on peaks of the aperture walls, predominantly removing high spots in the aperture walls.
In the drawings as hereinafter described, a preferred embodiment is depicted; however, various other modifications and alternative constructions can be made thereto without departing from the true spirit and scope of the invention.
REFERENCES:
patent: 3699725 (1972-10-01), Feldcamp
patent: 3729871 (1973-05-01), Taylor
patent: 3823514 (1974-07-01), Tsuchiya
patent: 4203257 (1980-05-01), Jamison et al.
patent: 4512859 (1985-04-01), Inoue
patent: 5054247 (1991-10-01), Rhoades et al.
patent: 5247766 (1993-09-01), Kildea
patent: 5702288 (1997-12-01), Liebke et al.
patent: 5807163 (1998-09-01), Perry
patent: 363028566 (1988-02-01), None
General Electric Company
Gressel Gerry S.
Hess Andrew C.
Rose Robert A.
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