Turbomachine Monoblock Diffusion Welding for Non-Circular Sections

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Solution Overview

Problem

Existing methods for manufacturing one-piece parts for turbomachines, such as AGB shafts, are limited in producing non-circular sections due to difficulties in winding metal wires around non-cylindrical mandrels.

Innovation Solution

The method involves forming independent metal rings that are preformed to specific shapes and stacked on a mandrel, allowing for the creation of parts with circular or non-circular sections through hot isostatic compression, enabling the production of parts with complex geometries like polygonal or triangular sections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If metal wires are wound around a mandrel to form a blank, then the manufacturing process is simple and continuous, but it is difficult or impossible to produce parts with non-circular sections

Engineering Contradiction:
Improveease of manufacturingVSAvoidability to produce non-circular sections
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The continuous metal wire is divided into discrete rings that can be individually formed and stacked. Each ring can be independently shaped to create the desired cross-sectional geometry (circular, triangular, rectangular, etc.), while the stacking process maintains manufacturing efficiency. This segmentation resolves the contradiction by enabling geometric versatility without sacrificing manufacturing simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The rings are pre-formed to the desired shape before being stacked on the mandrel. This preliminary shaping action allows the rings to have non-circular cross-sections (triangular, rectangular, etc.) while maintaining a simple stacking process. The pre-forming step enables geometric versatility without complicating the overall manufacturing workflow.

Inventive Principle:
Principle #10Preliminary action

2Strength

If the shaft is made in two parts for mechanical strength and vibration reasons, then the mechanical strength and vibration characteristics are improved, but the structure becomes more complex and requires intermediate bearings

Engineering Contradiction:
Improvemechanical strengthVSAvoidstructural complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

Multiple discrete rings are stacked and diffusion-welded together to form a single integrated one-piece shaft. This merging of multiple components into one monolithic structure eliminates the need for intermediate bearings and complex assembly, while maintaining the mechanical strength through the diffusion welding process that creates a homogeneous metal structure throughout the shaft.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shaft is constructed from multiple metal rings that are diffusion-welded together to create a composite structure with homogeneous metal properties. This composite approach allows the shaft to achieve the mechanical strength of a multi-part construction while appearing as a single-piece component, eliminating the need for intermediate bearings and reducing structural complexity.

Inventive Principle:
Principle #40Composite materials

3Strength

If ceramic fibers are added to reinforce the part, then the stiffness and natural vibrational frequencies are increased, but the manufacturing process becomes more complex

Engineering Contradiction:
ImprovestiffnessVSAvoidmanufacturing process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

Ceramic fibers are incorporated into the metal ring structure to create a composite material that increases stiffness and raises natural vibrational frequencies. The fibers are embedded within the metal matrix during the ring formation process, allowing the composite structure to be manufactured using the same stacking and diffusion welding process, thereby avoiding significant increases in manufacturing complexity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Ceramic fibers are strategically placed within specific regions of the metal rings to provide localized reinforcement where stiffness is most needed. This local quality approach allows the structure to achieve enhanced mechanical properties without uniformly complicating the entire manufacturing process, as the fiber incorporation follows the same stacking and welding methodology.

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 allows for the efficient manufacturing of one-piece parts with increased stiffness and elevated natural vibrational frequencies without the need for intermediate bearings, while maintaining mechanical strength and reducing material density.

Implementation Method 1

submitting the blank to a diffusion welding treatment by hot isostatic compression to obtain a one-piece part

Methodology Applied
Scientific EffectDiffusion welding: Diffusion Welding

Implementation Method 2

submitting the blank to a diffusion welding treatment by hot isostatic compression

Methodology Applied
Scientific EffectHot isostatic compression: Hot Isostatic Pressing

Data Source

PatentEP2709783B1Process for manufacturing a monoblock part for a turbomachine by diffusion welding
Publication Date: 2017.11.15 SAFRAN AIRCRAFT ENGINES SAS
  • EP2709783B1 patent drawingFigure 1~5
  • EP2709783B1 patent drawingFigure 6~12

AI summary

The invention relates to a process for manufacturing a single part for a turbomachine by diffusion welding, the process comprising steps consisting in: producing a blank of the part around a mandrel (12), the blank comprising a plurality of independent superposed coaxial annular ring layers (10) made of metal wire, the layers being stacked one on top of the other around the mandrel; and subjecting the blank to an isostatic hot compression so as to obtain a single part; and optionally machining this part.