U.S. patent application number 13/022814 was filed with the patent office on 2011-12-08 for abrasive blast contour machining to remove surface and near-surface crack initiation.
Invention is credited to Prabir R. Bhowal, Kenneth A. Frisk, David M. Nissley, Darryl Slade Stolz, Ronald A. Talarico, Kevin Young.
Application Number | 20110300779 13/022814 |
Document ID | / |
Family ID | 44587633 |
Filed Date | 2011-12-08 |
United States Patent
Application |
20110300779 |
Kind Code |
A1 |
Talarico; Ronald A. ; et
al. |
December 8, 2011 |
ABRASIVE BLAST CONTOUR MACHINING TO REMOVE SURFACE AND NEAR-SURFACE
CRACK INITIATION
Abstract
A multi-axis machine includes a controller operable to control a
nozzle which ejects a particulate material relative to a part
surface to maintain a compound angle and predetermined stand off
distance to remove surface and near-surface crack initiation
sites.
Inventors: |
Talarico; Ronald A.; (East
Berlin, CT) ; Stolz; Darryl Slade; (Newington,
CT) ; Frisk; Kenneth A.; (West Hartford, CT) ;
Nissley; David M.; (Marlborough, CT) ; Bhowal; Prabir
R.; (Rocky Hill, CT) ; Young; Kevin; (Byron
Center, MI) |
Family ID: |
44587633 |
Appl. No.: |
13/022814 |
Filed: |
February 8, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61352483 |
Jun 8, 2010 |
|
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Current U.S.
Class: |
451/38 ;
451/75 |
Current CPC
Class: |
B24C 1/08 20130101 |
Class at
Publication: |
451/38 ;
451/75 |
International
Class: |
B24C 3/32 20060101
B24C003/32; B24C 1/00 20060101 B24C001/00 |
Claims
1. A multi-axis machine comprising: a nozzle operable to eject a
particulate matter; and a controller operable to control said
nozzle relative to a part surface to maintain a compound angle and
predetermined stand off distance to remove surface and near-surface
crack initiation sites.
2. The multi-axis machine as recited in claim 1, wherein said
nozzle directs an aluminum oxide powder at a constant pressure.
3. The multi-axis machine as recited in claim 1, wherein said
compound angle is never perpendicular to a workpiece surface.
4. The multi-axis machine as recited in claim 1, further comprising
maintaining a uniform erosion rate across all features of a
workpiece surface.
5. The multi-axis machine as recited in claim 4, wherein said
uniform erosion rate removes at least 0.002 inches of material.
6. A method of surface machining comprising: removing surface and
near-surface crack initiation sites with a particulate matter.
7. The method as recited in claim 6, wherein said removing
comprises: maintaining a compound angle and predetermined stand off
distance between a nozzle which ejects the particulate matter and a
workpiece surface.
8. The method as recited in claim 6, wherein said removing
comprises: maintaining a uniform erosion rate across all features
of a workpiece surface
9. The method as recited in claim 8, wherein the uniform erosion
rate removes at least 0.002 inches of material.
10. The method as recited in claim 8, wherein maintaining the
uniform erosion rate comprises: moving the nozzle through a
multi-axis motion machine with variable velocity control.
Description
BACKGROUND
[0001] The present disclosure claims priority to U.S. Provisional
Patent Disclosure Ser. No. 61/352,483, filed Jun. 8, 2010.
[0002] The present disclosure relates to a surfacing technique, and
more particularly to an abrasive machining technique that
eliminates crack initiation sites.
[0003] Conventional machining of alloy 718 material may introduce
damage to surface and near surface carbide particles inherent to
the 718 alloy. These surface carbide particles are cracked by
interaction of the machining tools and the brittle carbides. Under
fatigue loading conditions, these carbides may serve as
preferential locations for crack initiation which may limit the
useful life of the material.
SUMMARY
[0004] A multi-axis machine according to an exemplary aspect of the
present disclosure includes a controller operable to control a
nozzle which ejects a particulate material, relative to a part
surface to maintain a compound angle and predetermined stand off
distance to remove surface and near-surface crack initiation
sites.
[0005] A method of surface machining according to an exemplary
aspect of the present disclosure includes removing surface and
near-surface crack initiation sites with a particulate matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Various features will become apparent to those skilled in
the art from the following detailed description of the disclosed
non-limiting embodiment. The drawings that accompany the detailed
description can be briefly described as follows:
[0007] FIG. 1 is a general schematic view of a multi-axis system
for use with the present disclosure;
[0008] FIG. 2 is a schematic view of a nozzle position with respect
to a workpiece to illustrate a first component of the compound
angle;
[0009] FIG. 3 is a sectional view of the workpiece in FIG. 2 taken
along line 3-3 to illustrate a second component of the compound
angle; and
[0010] FIG. 4 is a perspective view of a nozzle position with
respect to an example workpiece.
DETAILED DESCRIPTION
[0011] FIG. 1 schematically illustrates a multi-axis system 20. The
system 20 generally includes a particulate matter supply 22, a
nozzle 24 to dispense the particulate matter, a positioning
apparatus 26 and a control 28. The nozzle 24 is located relative a
workpiece W by the positioning apparatus 26 under direction of the
control 28. The particulate matter supply 22 in the disclosed
non-limiting embodiment supplies a 500 grit aluminum oxide powder
through the nozzle 24 which may be a 5/16'' (7.9375 mm) diameter
nozzle. The positioning apparatus 26 provides multi-axis motion
with variable velocity control to consistently position the nozzle
24 relative to each surfaces S of the workpiece W under direction
of the control 28. The control 28 is utilized to implement the
operational functionality of the positioning apparatus 26 to direct
the nozzle 24 relative to the workpiece W. In terms of hardware
architecture, the computing device can include a processor, memory,
and one or more input and/or output (I/O) device interface(s) that
are communicatively coupled via a local interface. It should be
understood that the system 20 is schematically depicted herein with
conventional systems, however, various other configurations may
alternatively or additionally provided to effectuate the surface
machining technique disclosed herein.
[0012] The surface machining technique disclosed herein utilizes
the multi-axis motion with variable velocity control through the
positioning apparatus 26 to assure a uniform erosion rate is
achieved upon the desired surfaces S of the workpiece W. The
control 28 locates the nozzle 24 relative to the surface S of the
workpiece W at a constant compound angle and predetermined stand
off distance which is consistently maintained as the nozzle 24
traverses the various surfaces S1-Sn (FIGS. 2 and 3) of the
workpiece W. The compound angle generally includes an alpha
(.alpha.) and beta (.beta.) component which may or not may not
remain same relative to each surface S1-Sn of the workpiece W (FIG.
3) depending on desired amount of erosion at each surface of the
workpiece.
[0013] As the particulate matter strikes the workpiece W, the
particulate matter erodes the material to produce a surface free of
the damaged layer caused by previous conventional machining
operations. That is, the previous conventional machining operations
result in a damaged layer with surface and near-surface crack
initiation sites. The surface machining technique disclosed herein
eliminates this damaged layer to improve the fatigue life up to ten
times compared to the life of conventionally machined alloy
718.
[0014] The surface machining technique uniformly removes high
amounts of material as compared to conventional abrasive blasting
processes. In other words, rather than a surface treatment/cleaning
process typical of conventional abrasive blast processing, the
disclosed surface machining technique uses specific media,
machining angles and gun distances to achieve tightly controlled
and relatively significant material removal rates more typical of a
machining processes. Material removal typical of the surface
machining technique in one non-limiting embodiment disclosed herein
is 0.002-0.003'' (0.05-0.07 mm) of material removal compared to a
conventional abrasive surface treatment/cleaning process that
removes only approximately 0.0005'' (0.001 mm) of surface
contaminants with little regard to final product size.
[0015] The material removal rate disclosed herein is for alloy 718
and may be varied dependant on the surface damage experienced by
other alloys. That is, use of different grit sizes and materials
may be utilized to remove surface damage of any type. The surface
machining technique disclosed herein has been found to remove both
hard surface material conditions and slightly distorted surface
structure with equal efficiency on several high strength aerospace
alloys, with no compromise in size control.
[0016] Since the surface machining technique enhances Low Cycle
Fatigue (LCF) life, the surface machining technique disclosed
herein provides for a competitive advantage over those that use a
typically-processed alloy 718 part. Possible components that could
necessitate enhanced LCF life are: different flight envelopes which
increase stresses or temperatures, requirements for larger surface
damage, i.e., handling damage, allowances in the field, or reverse
engineering a material in a gas turbine engine program with lower
life margins.
[0017] It should be understood that like reference numerals
identify corresponding or similar elements throughout the several
drawings. It should also be understood that although a particular
component arrangement is disclosed in the illustrated embodiment,
other arrangements will benefit herefrom.
[0018] Although particular step sequences are shown, described, and
claimed, it should be understood that steps may be performed in any
order, separated or combined unless otherwise indicated and will
still benefit from the present disclosure.
[0019] The foregoing description is exemplary rather than defined
by the limitations within. Various non-limiting embodiments are
disclosed herein, however, one of ordinary skill in the art would
recognize that various modifications and variations in light of the
above teachings will fall within the scope of the appended claims.
It is therefore to be understood that within the scope of the
appended claims, the disclosure may be practiced other than as
specifically described. For that reason the appended claims should
be studied to determine true scope and content.
* * * * *