Laser Power Control for Additive Manufacturing via Event-Driven Geometry Metadata
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Solution Overview
Problem
Existing laser additive manufacturing processes face challenges in maintaining consistent laser power levels due to variations in melt pool size and temperature gradients, leading to defects such as shape irregularities and cracks, as they rely on either constant power or reactionary feedback systems that struggle to adapt to dynamic changes during the deposition process.
Innovation Solution
The method shifts from a position-based predictive system to an event-driven system, where connectivity information is pre-processed and encoded in machine code, allowing for real-time laser power adjustments at event-driven intervals, such as when the laser turns on or off, to better match the actual build process and account for timing deviations and operator interventions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If constant laser power is used, then the system operation is simplified, but the deposition quality deteriorates due to variations in melt pool size and temperature gradients
Solution Approach 1:
The patent applies dynamics by transitioning from constant laser power to dynamically adjusted laser power that varies with the deposition process. The system calculates and adjusts laser power at different positions along the deposition path, allowing the power level to adapt to changing melt pool conditions, temperature gradients, and energy balance requirements throughout the layer deposition process.
Solution Approach 2:
The patent implements parameter changes by modifying the laser power parameter throughout the deposition process rather than maintaining a constant value. The system calculates optimal laser power levels at different positions along the toolpath, adjusting parameters such as power density, energy input, and traverse speed to maintain optimal deposition conditions and prevent defects.
2Manufacturing precision
If feedback systems are used to regulate laser power, then deposition quality improves, but the system complexity increases and response time is delayed
Solution Approach 1:
The patent applies preliminary action by calculating and determining the optimal laser power levels in advance before the actual deposition process begins. The system pre-calculates power requirements at different positions along the deposition path based on geometric representation, material properties, and process parameters, eliminating the need for real-time feedback sensors and reducing system complexity.
Solution Approach 2:
The patent uses feedback principles by incorporating the calculated laser power levels into the control system that actually delivers the laser energy. The pre-calculated power values are fed back into the laser control system, creating a closed-loop approach where the planned power distribution is implemented and monitored during the deposition process.
3Manufacturing precision
If feedback systems are used to regulate laser power, then deposition quality improves, but the response time increases due to reactionary nature
Solution Approach 1:
The patent eliminates response time delays by performing all power level calculations in advance before the deposition process starts. The system pre-determines the optimal laser power at every position along the toolpath based on the geometric representation and process parameters, so no real-time feedback or reactionary adjustments are needed during actual deposition.
Solution Approach 2:
The patent implements a feedforward approach where the calculated power levels are prepared in advance and delivered to the laser system before the deposition process begins, eliminating the reactionary delay inherent in feedback systems that wait for conditions to drift before responding.
4Ease of operation
If constant laser power is used, then the system is simpler to operate, but defects such as shape irregularities and cracks increase
Solution Approach 1:
The patent prevents defects by dynamically changing the laser power parameter throughout the deposition process. The system adjusts power levels to account for variations in melt pool size, temperature gradients, and energy balance conditions, thereby preventing shape irregularities, lack-of-fusion, and cracks that occur with constant power operation.
Solution Approach 2:
The patent improves reliability by making the laser power dynamic rather than static. The power level adapts to the changing conditions during deposition, allowing the system to maintain optimal energy balance and prevent the formation of defects such as globular transfer, shape irregularities, and cracks.
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 improves the stability and accuracy of the additive manufacturing process by providing timely and responsive laser power control, reducing errors and resulting in a more consistent and high-quality build structure.
Implementation Method 1
a laser or other energy source, to melt powdered or wire metal, via a laser or other energy source, into solidifying beads
Implementation Method 2
melt powdered or wire metal, via a laser or other energy source, into solidifying beads
Implementation Method 3
regulating power to the laser at each point on the additive path in accordance with the required power predicted by the predictive algorithm
Data Source
AI summary
A laser power control method for additive manufacturing includes a pre-processing component and an intra-processing component. The pre-processing component creates in the system controller a machine code expressed additive-path-with-geometry-metadata that includes a path description. The path description represents the path of the beam source on the build and includes a geometry index for the build. The intra-processing component calculates required power for the beam at intervals and events on the beam path based upon the additive-path-with-geometry-metadata and calculations of the energy balance at the melt pool and the total energy for each point P(s) on the path.