Additive Manufacturing Cooling Structure for Vacuum Heat Dissipation
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Solution Overview
Problem
Additive manufacturing processes using powdery materials face long cooling times due to poor heat transfer in vacuum environments, which can lead to uncontrolled changes in the workpiece structure, especially when using electron beam melting, as conventional cooling methods are either inefficient or risk oxidation.
Innovation Solution
The method involves creating a cooling structure within the powder bed using the energy beam during the manufacturing process, which allows for heat dissipation through conduction and is designed to extend to the topmost layer, ensuring efficient heat dissipation without contaminating the workpiece, and can be actively cooled if needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cooling is performed in vacuum during additive manufacturing, then oxidation is avoided, but cooling time becomes excessively long
Solution Approach 1:
A cooling structure is created during the additive manufacturing process itself, before the workpiece needs to be cooled. The cooling structure is formed as part of the powder bed arrangement, with cooling channels that are prepared in advance to receive coolant, enabling rapid cooling to begin immediately after manufacturing without requiring post-process cooling operations.
Solution Approach 2:
A cooling structure acts as an intermediary thermal management system between the hot workpiece and the vacuum environment. This cooling structure includes cooling channels that can be filled with coolant, serving as a thermal bridge to extract heat from the workpiece rapidly while maintaining the vacuum atmosphere, thus avoiding direct contact between coolant and workpiece.
2Loss of time
If air is introduced to accelerate cooling, then cooling time is reduced, but oxidation of the workpiece occurs
Solution Approach 1:
The cooling structure with cooling channels serves as an intermediary system that enables rapid cooling without introducing air or oxygen to the workpiece. The cooling channels are filled with coolant that circulates through the structure, extracting heat while maintaining the vacuum atmosphere and preventing oxidation.
Solution Approach 2:
The natural convective cooling mechanism (which requires air introduction) is replaced with a controlled thermal conduction system through the cooling structure. Heat is extracted through the cooling channels via thermal conduction, substituting the need for air-based convection with a vacuum-compatible thermal management approach.
3Loss of time
If noble gas is used to accelerate cooling, then cooling rate improves and oxidation is avoided, but process cost increases
Solution Approach 1:
Instead of using expensive noble gases for cooling, the invention employs a reusable cooling structure made from standard materials. The cooling channels are formed in the powder bed and can be filled with inexpensive coolant, providing a cost-effective alternative to noble gas cooling while achieving rapid cooling rates.
Solution Approach 2:
The cooling structure acts as an intermediary that eliminates the need for expensive noble gases. By providing dedicated cooling channels filled with coolant, the system achieves rapid cooling through thermal conduction without requiring the expensive noble gas atmosphere, thus reducing process costs while maintaining cooling effectiveness.
4Productivity
If cooling structure is created during manufacturing, then cooling efficiency improves, but device complexity increases
Solution Approach 1:
The cooling structure is merged with the powder bed arrangement and manufacturing system. The cooling channels are formed as part of the powder bed structure during the additive manufacturing process, combining the manufacturing and cooling functions into a single integrated system rather than adding separate cooling equipment.
Solution Approach 2:
The cooling structure serves multiple functions: it acts as a thermal management system for rapid cooling, provides structural support for the powder bed, and can be integrated with the manufacturing platform. This multi-functionality reduces the need for separate cooling components, thereby limiting the increase in overall system complexity.
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 cooling times by enhancing heat transfer through conduction, avoiding contamination risks, and maintaining the workpiece's integrity by dissipating heat only after completion, thus improving the efficiency of the additive manufacturing process.
Implementation Method 1
individual powder particles of a powdery material are selectively bonded point by point in a powder bed with an energy beam, thus producing a dimensionally stable workpiece with a 3D structure layer by layer
Implementation Method 2
The material can be solidified to form a workpiece by sintering of the powder particles or complete melting of the powder particles and subsequent solidification of the material by means of an energy beam
Implementation Method 3
a cooling structure is produced in the powder bed by selective bonding of the powdery material to the energy beam, the cooling structure being arranged to dissipate heat
Implementation Method 4
the melting of the material with an electron beam takes place under vacuum, since the collision of the electrons with air molecules would lead to large energy losses and scattering
Implementation Method 5
During the production of the workpiece, temperatures of over 1000° C. are reached at the material surface due to the energy input of the electron beam
Data Source
AI summary
A method of additively manufacturing a workpiece (22) from a powder material, comprises the steps of:(a) providinga device (15, 17) for receiving a powder bed (20) of the powdery material, in particular in a vacuum process chamber (11), anda beam generator (12) adapted to direct an energy beam (13) to laterally different locations of the powder bed (20);b) layer-by-layer application of the powdery material to the powder bed (20);c) creating the workpiece (22) in the powder bed (20) layer by layer by selectively bonding the powdery material to the energy beam (13);d) during the production of the workpiece (22), in addition to the workpiece (22), a cooling structure (30) is produced in the powder bed (20) by selective bonding of the powdery material to the energy beam (13), the cooling structure (30) being adapted to dissipate heat.