Predictive Laser Power Scheduling for Additive Deposition
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Solution Overview
Problem
Existing additive metal deposition techniques face challenges in regulating laser power effectively during the process, leading to variations in geometry and material properties due to constant power levels or reactionary feedback systems that can only correct after deviations occur.
Innovation Solution
A predictive method calculates the optimum laser power at intervals along the additive path by creating an idealized geometry model comprising a melt pool, hot zone, and bulk portion, using a geometric representation, thermodynamic characteristics, and thermophysical properties to adjust power dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If constant laser power is used throughout the deposition process, then the system operation is simplified, but variations in geometry and material properties occur due to changing energy balance conditions
Solution Approach 1:
The patent implements dynamic laser power adjustment by calculating optimal power levels at multiple intervals along the deposition path based on predicted thermodynamic conditions. The system transitions from static constant power to dynamic variable power control, adjusting power in real-time according to the changing energy balance conditions as the build structure grows and moves relative to the laser source.
Solution Approach 2:
The system performs preliminary thermodynamic modeling and power schedule calculation before the actual deposition process. By predicting the energy balance conditions at each point along the additive path in advance, the system pre-determines the optimal power levels needed, eliminating the need for complex real-time adjustments during deposition.
2Manufacturing precision
If feedback systems are used to regulate laser power, then deposition quality issues can be addressed, but the systems are reactionary and can only correct after deviations occur
Solution Approach 1:
The patent implements predictive power regulation by calculating the optimal laser power schedule before deposition based on thermodynamic modeling. This preliminary action allows the system to anticipate and prevent deviations rather than react to them, eliminating the time delay inherent in feedback systems that must first detect then correct issues.
Solution Approach 2:
While the primary innovation is predictive, the system incorporates feedback mechanisms to verify that actual deposition conditions match predicted conditions, allowing for minor adjustments and ensuring continuous quality control throughout the process.
3Length of moving object
If the workpiece is positioned further from the laser source at the start, then there is space for deposition, but too little energy is input into the deposition
Solution Approach 1:
The system dynamically adjusts laser power based on the changing distance between the workpiece and laser source throughout the deposition process. As the workpiece moves closer to the laser, the system automatically reduces power to compensate for increased energy concentration, and increases power when the workpiece is farther away, maintaining consistent deposition quality throughout the build process.
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 method allows for precise control of laser power, reducing defects and improving the quality of additive layers by predicting energy needs based on dynamic geometry and thermodynamics, resulting in more consistent and stable deposition processes.
Implementation Method 1
a laser or other energy source, to melt powdered or wire metal
Implementation Method 2
The heat source is under computer numerical control and is focused onto a workpiece, producing the melt pool
Implementation Method 3
melting powdered or wire metal into solidifying beads, which are deposited side by side and layer upon layer
Data Source
AI summary
A power schedule calculation method utilizes an idealized geometry to predict laser power levels on an additive path during laser deposition. The method calculates beam power for any point along the path traveled to form a build having a geometry. Each point along the path has associated with it an idealized geometry comprising a melt pool, hot zone and bulk portion. The method comprises creating a geometric description representing the geometry of the build during the process, creating a path description representing the path of the beam source through space during the process, calculating the idealized geometry for the point on the path based upon the geometric description and path description, calculating an energy balance at the melt pool for the point on the path, calculating total energy needed at the point on the path and calculating optimum beam source power. In the calculations, build temperature is based upon a calculation of hot zone temperature derived from the idealized geometry.