Spindle Peening Offset Fixture for CNC Vane Turning

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Solution Overview

Problem

The relative positions of spindle/trunnion surfaces on compressor spindle vanes are disrupted post-processing, particularly due to airfoil peening, leading to dimensional nonconformances and increased costs, despite efforts to control and minimize peening distortion.

Innovation Solution

A turning fixture with a fixture insert that applies a force to the compressor spindle vane during machining to create an offset matching the anticipated peening distortion, using a rod that translates through a chamber to deflect the airfoil, allowing for controlled distortion and maintaining spindle alignment on the same axis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If airfoil peening is performed to strengthen the compressor spindle vane, then the strength and durability of the airfoil are improved, but the relative position of the spindles shifts causing dimensional nonconformances

Engineering Contradiction:
Improveairfoil strengthVSAvoidspindle position accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The fixture applies preliminary force to the airfoil during the turning operation to pre-distort the part in the opposite direction of anticipated peening distortion. This preliminary action ensures that when peening occurs, the spindles end up in the correct final position, resolving the dimensional nonconformance issue while maintaining the strength benefits of peening

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If peening distortion is minimized through process control, then manufacturing precision is improved, but some distortion always remains causing dimensional nonconformances

Engineering Contradiction:
Improvespindle position accuracyVSAvoiddimensional conformance reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The fixture applies a counteracting force during turning to pre-compensate for the inevitable peening distortion. By applying this preliminary anti-action, the system proactively counterbalances the distortion that will occur during peening, ensuring reliable dimensional conformance despite the inherent limitations of peening process control

Inventive Principle:
Principle #9Preliminary anti-action

3Manufacturing precision

If the focus shifts to the CNC turning operation to offset peening distortions, then manufacturing precision can be maintained, but the device complexity increases with the turning fixture

Engineering Contradiction:
Improvespindle position accuracyVSAvoidturning fixture complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The fixture applies force locally at specific points on the airfoil using strategically positioned arms and a central rod. This localized approach achieves the necessary distortion compensation with minimal fixture complexity, as the force is concentrated at critical locations rather than requiring complex mechanisms to act on the entire part

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach ensures conforming spindle dimensions at inspection by accounting for peening distortion during the turning operation, reducing costs associated with poor quality and improving engine performance by proactively managing known finishing distortions.

Implementation Method 1

a rod is insertable through the lower portion through the chamber, the rod being configured to apply a force to a compressor spindle vane inserted between the upper portion and the lower portion

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

the rod being configured to apply a force to an airfoil of the compressor spindle vane inserted between the upper portion and the lower portion

Methodology Applied
Scientific EffectElastic Deformation: Deformation

Data Source

PatentEP4431227A1Spindles peening offset fixture for CNC turning
Publication Date: 2024.09.18 RTX CORP
  • EP4431227A1 patent drawingFigure 1~2
  • EP4431227A1 patent drawingFigure 3~4
  • EP4431227A1 patent drawingFigure 5~6

AI summary

A turning fixture including a fixture insert attached to the turning fixture, the fixture insert comprising an upper portion having an upper portion body, the upper portion body includes a central span with a first arm and second arm opposite the first arm, a cavity is defined between the first arm and the second arm along the central span on an inner side of the upper portion body; the fixture insert including a lower portion having a lower portion body that includes a chamber located centrally between a first end and a second end; and a rod is insertable through the lower portion through the chamber, the rod being configured to apply a force to a compressor spindle vane inserted between the upper portion and the lower portion.