Thermal Insulation Platform for Selective Melting
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Solution Overview
Problem
Selective laser melting (SLM) methods using high energy beams face issues with rapid temperature fluctuations, leading to residual stresses and cracking in parts, especially in superalloys used in aviation, due to quick heating and cooling cycles, which existing solutions like heated supports or enclosures cannot fully mitigate at high temperatures.
Innovation Solution
A method involving the creation of a thermal insulation platform using columns of material between the fabrication plate and the part, formed by depositing and melting/sintering powder layers, which reduces heat conduction and maintains a pre-heating temperature, thereby minimizing thermal stresses and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the laser beam directly heats the powder to melting temperature, then the fabrication speed is improved, but rapid cooling causes thermal stresses and cracking
Solution Approach 1:
The patent applies preliminary heating by depositing powder layers and selectively melting them to form columns before building the main part. This pre-heats the fabrication plate and creates thermal insulation, allowing faster subsequent fabrication without thermal stresses or cracking.
Solution Approach 2:
The patent introduces columns of melted material as an intermediary between the fabrication plate and the part being built. These columns act as thermal insulation, mediating the heat transfer and preventing rapid cooling that causes stresses and cracking.
2Reliability
If heated supports or enclosures are used to mitigate thermal stresses, then part quality is improved, but equipment complexity increases
Solution Approach 1:
The patent makes the fabrication process self-service by using the powder layers themselves to create thermal insulation. The columns formed during normal fabrication operations provide the heating function, eliminating the need for separate heated supports or enclosures.
Solution Approach 2:
The patent gives the powder layers a dual function: they serve as both the building material for the part and as thermal insulation to prevent cracking. This multi-functionality eliminates the need for separate heating equipment.
3Temperature
If the fabrication plate is made of highly conductive material for heat dissipation, then cooling efficiency is improved, but thermal stresses increase
Solution Approach 1:
The patent applies local quality by creating columns of melted material at specific locations between the fabrication plate and the part. These localized columns provide thermal insulation precisely where needed, allowing the plate to remain conductive for overall heat dissipation while preventing local thermal stresses.
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 effectively reduces residual stresses and cracking in parts by maintaining a stable temperature during fabrication, allowing for the production of high-quality parts without modifying existing equipment, particularly beneficial for superalloys used in high-temperature applications.
Implementation Method 1
selective melting or selective sintering of powder beds by high energy beams, and more particularly by laser beam
Implementation Method 2
it may use an electron beam, providing the beam has sufficient energy to melt the particles of powder
Implementation Method 3
the columns of material of said first series of layers of powder particles form a thermal insulation platform between the fabrication plate and said single-piece element
Implementation Method 4
a region of the first layer 10 of powder is raised to a temperature higher than the melting temperature TM of the powder by scanning the laser beam 95
Implementation Method 5
selective melting or selective sintering of powder beds
Data Source
AI summary
A method provides a device having a feeder vessel, a building vessel with a bottom and a fabrication plate that is movable in vertical translation, a transfer system suitable for depositing powder from the feeder vessel to the building vessel as a powder layer of constant thickness, and a high energy beam optical system suitable for scanning the surface of the deposited powder layer. A powder is placed in the feeder vessel. A first series of powder layers is deposited on the fabrication plate. The particles of powder are melted or sintered to form a plurality of columns of material that are separated from one another by particles of powder. A second series of layers of powder is deposited on the first series of layers of powder particles to form a single-piece element. A thermal insulation platform is formed between the fabrication plate and said single-piece element.