Shaped Inductor Brazing for Complex Profiles

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Solution Overview

Problem

Conventional induction brazing methods are limited in their ability to effectively braze parts with complex shapes, as they require strict geometric alignment and controlled atmospheres, making it difficult to achieve reproducible and efficient heating cycles, especially for parts without an axis of revolution or symmetry.

Innovation Solution

A process that adapts the thermal cycle by regulating temperature homogenization using thermal mapping, accounting for the emissivity coefficient of the materials, and employing a brazing station with a shaped inductor and pressure means to ensure uniform heating close to the joint plane, allowing for variable clearances and short heating cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional induction brazing uses a solenoid-shaped inductor surrounding the parts, then heating is achieved for isotropic applications, but it cannot effectively braze parts with complex shapes lacking an axis of revolution or symmetry

Engineering Contradiction:
Improveapplicability to complex shape partsVSAvoidreproducibility of heating cycle
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by using a shaped inductor with a flat face that conforms to the specific geometry of the joint plane, allowing the heating field to be locally adapted to complex part shapes rather than using a universal solenoid shape. This enables effective induction heating of parts without axial symmetry while maintaining reproducible thermal cycles through localized field concentration at the joint plane.

Inventive Principle:
Principle #3Local quality

2Reliability

If strict geometric alignment and controlled atmosphere are required for induction brazing, then brazing quality is maintained, but the process becomes difficult to implement for parts with variable clearances and complex profiles

Engineering Contradiction:
Improvebrazing qualityVSAvoidgeometric alignment requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the heating process by using a shaped inductor that concentrates the electromagnetic field specifically at the joint plane, separating the heating function from the overall part geometry. This allows variable clearances and complex profiles elsewhere in the parts without affecting brazing quality, as only the joint plane requires precise positioning relative to the inductor face.

Inventive Principle:
Principle #1Segmentation

3Temperature

If a solenoid-shaped inductor is used for induction brazing, then heating can be achieved, but the heating cycle cannot be sufficiently localized and reproducible for complex shape parts

Engineering Contradiction:
Improveheating localization and reproducibilityVSAvoidpart geometry compatibility
Core Design Contradiction:
TemperatureVSShape

Solution Approach 1:

The patent employs asymmetry by designing a shaped inductor with a flat face that breaks the rotational symmetry of conventional solenoid inductors. This asymmetric geometry is specifically tailored to match the joint plane configuration, enabling reproducible and localized heating for parts with complex, non-revolutionary shapes while maintaining temperature control through the flat reference surface.

Inventive Principle:
Principle #4Asymmetry

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 significantly reduces the non-quality rate of brazing from 30-40% to less than 3%, enhances the quality and efficiency of the brazing process, and allows for the brazing of complex shapes with reduced solder quantity, while ensuring electrical, thermal, and magnetic safety.

Implementation Method 1

electromagnetic induction as a heating mode is advantageous: conventionally produced by a generator coupled to an inductor, it allows a rapid rise in temperature

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

Induction brazing generally involves a solenoid-shaped inductor surrounding the parts to be brazed

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 3

The inductor is coupled to an optical pyrometer for temperature control based on the melting point of the solder flux

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentEP2598274B1Induction brazing process for complex shape workpieces, and single-station, or multi-station, brazing unit
Publication Date: 2017.06.21 SAFRAN HELICOPTER ENGINES
  • EP2598274B1 patent drawingFigure 1
  • EP2598274B1 patent drawingFigure 2~3
  • EP2598274B1 patent drawingFigure 4~5

AI summary

The present invention relates to brazing parts having complex profiles, while enabling reproducible implementation conditions to be defined. In particular, the invention provides for adjusting the heat cycle during brazing by controlling and mapping heat, while taking the emissivity coefficient of the material to be brazed into account. According to one embodiment, a brazing station of the invention comprises a power generator (40) capable of supplying a predetermined voltage (U1) to a transformer (60) connected to a circuit forming a shape inductor (11), said circuit having the overall shape of the parts (3, 4) to be brazed. Pressure means exert a load on the parts (3, 4) to be brazed. A camera (13) establishes a heat map. A laser-sighted infrared pyrometer (12) measures the brazing temperature by means of radiation (R) after parameterizing an emissivity coefficient, the other parameters being fixed. A controller (50) supplies a set power to the generator (40) on the basis of the measured temperature.