Directed Feed Additive Manufacturing With Split Meltpool Heating
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Solution Overview
Problem
Existing additive manufacturing (AM) processes are inflexible and unable to independently control bead shape, deposition rate, and overall process temperature, leading to suboptimal production of near net-shape 3D articles with potential fusion defects.
Innovation Solution
Employing multiple energy sources, including a first energy source to initiate the meltpool and a second energy source to control the lateral width of the meltpool, allowing independent adjustment of bead width and process energy, with optional third energy source for feedstock melting, to achieve precise control over the AM process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single energy source is used to form and control the meltpool, then the device complexity is reduced, but the manufacturing precision of bead shape parameters deteriorates
Solution Approach 1:
The single energy source is segmented into multiple energy sources, each responsible for specific functions: one energy source controls meltpool formation and temperature, while another energy source controls meltpool width and bead shape. This segmentation enables independent control of different bead shape parameters, resolving the contradiction between device simplicity and manufacturing precision.
2Productivity
If the energy source power is increased to improve build rate, then the productivity increases, but the manufacturing precision of bead shape parameters deteriorates
Solution Approach 1:
The total energy input is segmented across multiple energy sources with distinct functions. One energy source can be optimized for high power to increase build rate, while another energy source maintains precise control over bead shape parameters. This allows simultaneous optimization of productivity and manufacturing precision that cannot be achieved with a single energy source.
Solution Approach 2:
Different regions of the meltpool are treated with different energy sources having different power levels and control characteristics. The energy source controlling meltpool width operates locally at the meltpool boundaries to maintain precise bead shape, while the energy source controlling overall temperature operates globally to enable high build rates. This local quality approach resolves the contradiction between global productivity and local precision.
3Productivity
If the feedstock feed rate is increased to improve build rate, then the productivity increases, but the manufacturing precision of layer height and surface finish deteriorates
Solution Approach 1:
The energy distribution is optimized locally at the meltpool region to match the increased feedstock feed rate. The energy source controlling meltpool width and shape adjusts its parameters locally to ensure proper fusion and surface finish even at higher deposition rates. This local adaptation enables high productivity while maintaining manufacturing precision.
Solution Approach 2:
The energy source parameters (power, focal position, scan speed) are dynamically changed in response to feedstock feed rate adjustments. When feed rate increases to improve build rate, the energy source parameters are simultaneously optimized to maintain appropriate layer height and surface finish quality. This dynamic parameter adjustment resolves the contradiction between productivity and manufacturing precision.
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
Enables improved net-shaping of 3D articles with faster build rates and enhanced control over microstructure and cooling conditions, reducing fusion defects and improving production efficiency.
Implementation Method 1
a first energy source is directed onto the already-existing part, the first energy source impinging at a first region which moves with and leads the meltpool, whereby the first energy source initiates the formation of the meltpool
Implementation Method 2
a second energy source is directed onto the already-existing part, the second energy source impinging at a second region which moves with and follows the first region, whereby the second energy source grows the lateral width of the meltpool
Implementation Method 3
The melted feedstock layer fuses to the substrate
Implementation Method 4
The melted feedstock layer fuses to the substrate
Data Source
AI summary
A method of producing a 3D article by additive manufacture is provided. The method includes the steps of: forming a meltpool in an already-existing part of the article, and moving the meltpool relative thereto; feeding a directed feedstock into the moving meltpool to deposit and fuse a layer of material on the already-existing part; and repeating the forming and moving and feeding steps to build up successive layers of material. In performance of the forming and moving step: a first energy source impinges at a first region of the already-existing part which moves with and leads the meltpool, whereby the first energy source initiates the formation of the meltpool; and a second energy source impinges at a second region on the already-existing part which moves with and follows the first region, whereby the second energy source grows the lateral width of the meltpool before the feedstock is fed therein.