Additive Manufacturing of High Purity Copper Using Absorptive Intermediary
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Solution Overview
Problem
Laser-based additive manufacturing techniques face challenges in fusing successive layers of highly reflective materials like high purity copper and aluminum due to insufficient absorption of laser energy, leading to poor electrical conductivity and the need for reducing copper alloy purity.
Innovation Solution
A method involving the deposition of a layer of absorptive material with higher absorptivity than the additive manufacturing stock powder, followed by fusing the stock powder using a focused energy source, such as a laser, to form a multi-layer powder bed fusion component with greater than 95% purity, including materials like copper and noble metals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional laser powder bed fusion is used to manufacture highly reflective materials like high purity copper, then the manufacturing process can be performed, but the laser energy is not sufficiently absorbed by the material to fuse successive layers together adequately
Solution Approach 1:
An absorptive material layer is introduced as an intermediary between the laser energy source and the highly reflective copper powder. This intermediate layer absorbs the laser energy and transfers it to the copper powder, enabling adequate heating and fusion of successive layers that would otherwise reflect the laser energy insufficiently.
Solution Approach 2:
The process creates a composite structure during manufacturing by combining the absorptive material with the copper powder in the powder bed. This composite approach allows the system to leverage the high absorptivity of the absorptive material while maintaining the electrical conductivity and purity characteristics of the high purity copper.
2Reliability
If the purity of copper alloy is reduced to assure proper powder bed fusion, then adequate fusion can be achieved, but the electrical conductivity properties become very poor
Solution Approach 1:
The absorptive material serves as a mediator that enables proper powder bed fusion of high purity copper without requiring alloying. By providing the necessary energy absorption function, it allows the use of copper with greater than 95% purity (preferably greater than 99.9%) while achieving adequate layer fusion, thus maintaining electrical conductivity properties.
3Use of energy by moving object
If a layer of absorptive material is deposited onto the workpiece before depositing stock powder, then laser energy absorption is improved, but an additional deposition step is required
Solution Approach 1:
The absorptive material layer is deposited in advance (preliminarily) onto the workpiece or previous layer before the copper powder is deposited. This preliminary action ensures that when the laser subsequently processes the copper powder, the energy absorption function is already in place, enabling effective fusion without requiring modification of the laser parameters or additional process steps during the actual fusion operation.
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 enables the additive manufacturing of highly reflective materials with superior electrical conductivity properties, achieving bonding between layers and maintaining high purity, particularly for components like high purity copper and aluminum.
Implementation Method 1
the absorptive material has a higher absorptivity at the wavelength of the focused energy source than the absorptivity of the stock powder at that wavelength
Implementation Method 2
The focused energy source can be a laser, e.g., with a 1064 nm wavelength
Data Source
AI summary
A method of additive manufacturing includes depositing a layer of absorptive material onto a workpiece, depositing a layer of additive manufacturing stock powder onto the workpiece, and fusing the stock powder to the workpiece using a focused energy source at a wavelength wherein the absorptive material has a higher absorptivity at the wavelength of the focused energy source than the absorptivity of the stock powder at that wavelength. The focused energy source can be a laser, e.g., with a 1064 nm wavelength, for example.