Induction Heating for Uniform Powder Bed Temperature Control

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Solution Overview

Problem

The existing methods for manufacturing metal parts using selective laser melting on a powder bed, particularly for titanium and cobalt-based alloys, suffer from significant residual stresses due to thermal gradients, leading to deformations and cracks, as they lack effective temperature control and uniform heating.

Innovation Solution

A device with a cylindrical sintering tank equipped with induction heating means on its side walls, along with a vertically movable bottom and temperature measurement and regulation systems, ensures controlled temperature gradients and uniform heating throughout the powder bed, minimizing residual stresses during solidification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional heating methods (heating plates, convection, or high energy beam preheating) are used, then some temperature control is achieved, but the heating is not homogeneous throughout the powder thickness and only localized temperature control is possible

Engineering Contradiction:
Improvetemperature controlVSAvoidtemperature uniformity
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The invention transitions from single-point or surface heating (0D/1D) to three-dimensional volumetric heating by embedding induction heating means throughout the powder bed. This allows temperature control in all spatial dimensions (x, y, z), achieving homogeneous heating throughout the entire powder thickness rather than only at the surface or localized areas.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The invention introduces induction heating means as an intermediary mechanism between the laser beam and the powder bed. These heating means act as mediators that convert electromagnetic energy into thermal energy directly within the powder particles, enabling precise and uniform temperature control without relying on conventional conduction or convection methods.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If laser fusion is used to melt powder for part production, then complex shaped parts can be produced rapidly, but significant residual stresses and thermal gradients are generated causing deformations and cracks

Engineering Contradiction:
Improveproduction speedVSAvoidresidual stresses
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The invention applies preliminary heating through induction heating means before and during the laser fusion process. By pre-heating the powder bed to reduce thermal gradients before laser melting, the system prevents the formation of excessive residual stresses and thermal shock that would otherwise cause deformations and cracks, thereby counteracting harmful effects before they occur.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The invention dynamically adjusts temperature parameters during the manufacturing process by controlling multiple induction heating zones. By changing temperature parameters (heating rate, temperature distribution, thermal gradients) in real-time according to part geometry and laser processing conditions, the system maintains optimal thermal conditions that enable rapid production while minimizing residual stresses.

Inventive Principle:
Principle #35Parameter changes

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 production of metal parts with minimal residual stresses by regulating temperature zones within the powder bed, ensuring homogeneous heating and reducing deformations and cracks during the manufacturing process.

Implementation Method 1

the sintering tank has the shape of a cylinder whose side walls carry a plurality of induction heating means

Methodology Applied
Scientific EffectInduction heating: Induction Heating

Implementation Method 2

the material is presented in the form of a powder which is melted under the action of a high power laser

Methodology Applied
Scientific EffectLaser melting: Laser

Data Source

PatentEP2670547B2Sintering and laser fusion device, comprising a means for heating powder by induction
Publication Date: 2018.08.08 SAFRAN AIRCRAFT ENGINES SAS
  • EP2670547B2 patent drawingFigure 1~2
  • EP2670547B2 patent drawingFigure 3

AI summary

The invention relates to a device for producing or building up a metal part by sintering and laser fusion, said device comprising a laser beam generator, a means for deflecting said beam in order to scan the surface of the part (5) to be produced, and a sintering pan (6) containing a metal powder (7) used to cover the surface of the part (5) and to be melted by the laser beam in order to thicken the part. The invention is characterised in that it also comprises at least one means (12) for heating powder contained in an area of said sintering pan by induction.