Laser Power Modulation for Powder Bed Temperature Control
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Solution Overview
Problem
Existing selective additive manufacturing processes face challenges in controlling the temperature field during the consolidation of powder layers, leading to residual stresses, micro-cracks, and deformations due to excessive temperature gradients and material evaporation, which affect the mechanical characteristics of the manufactured objects.
Innovation Solution
A process that adjusts the power of a laser beam based on estimated temperature variations across the powder layer, calculated using the distance and time interval between emission points, to consolidate zones while maintaining a predetermined temperature threshold, thereby modulating the power to control the temperature field and prevent excessive heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-power laser sources are used to fuse powder layers, then consolidation speed and productivity are improved, but temperature gradients become excessive causing residual stresses and micro-cracks
Solution Approach 1:
The patent applies dynamics by making the laser power variable rather than constant. The laser power is dynamically adjusted based on real-time temperature measurements and predictive models, allowing the system to maintain high productivity while preventing excessive temperature gradients that cause defects.
Solution Approach 2:
The patent implements feedback control by continuously measuring the temperature field during laser consolidation and using this information to adjust subsequent laser power settings. A predictive model estimates future temperature variations, enabling proactive power adjustment to maintain temperature within optimal ranges and prevent residual stresses and micro-cracks.
2Productivity
If laser power is increased to reduce processing time, then productivity improves, but material evaporation increases causing loss of substance and harmful effects
Solution Approach 1:
The patent applies preliminary action by using a predictive model to estimate temperature variations before they occur. This allows the system to pre-adjust laser power settings to prevent material evaporation, maintaining high processing speeds while avoiding excessive temperatures that would cause substance loss.
Solution Approach 2:
The patent changes the laser power parameter dynamically based on measured and predicted temperature conditions. By adjusting power levels in real-time rather than maintaining constant high power, the system achieves fast processing while keeping temperature below evaporation thresholds, thus preventing material loss.
3Device complexity
If conventional constant power laser processing is used, then device complexity is low, but temperature field control precision is insufficient leading to deformations and cracks
Solution Approach 1:
The patent implements feedback control by continuously measuring the temperature field during laser consolidation and using this information to adjust subsequent laser power settings. This feedback mechanism enables precise temperature field control, preventing deformations and cracks while maintaining reasonable system complexity through the use of predictive models and adaptive algorithms.
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 reduces temperature gradients and prevents material evaporation, resulting in improved mechanical properties and reduced residual stresses in the manufactured objects by maintaining the temperature within a safe range, enhancing the quality and stability of the additive manufacturing process.
Implementation Method 1
emitting a laser beam onto a first point of the layer of additive manufacturing powder so as to consolidate a first zone of the layer of powder
Implementation Method 2
The consolidated zones correspond to successive cross sections of the three-dimensional object. Consolidation takes place for example layer by layer, through total or partial selective melting carried out using a power source.
Implementation Method 3
Consolidation takes place for example layer by layer, through total or partial selective melting carried out using a power source.
Implementation Method 4
adjusting a power of the laser beam depending on an estimated temperature variation of the layer of powder at a second point, separate from the first point, of the layer of powder that is caused by the emission of the laser beam
Data Source
AI summary
A process for the selective additive manufacture of a three-dimensional object from a layer of powder comprises: applying a layer of additive manufacturing powder to a support or to a previously consolidated layer, emitting a laser beam onto a first point of the layer of additive manufacturing powder so as to consolidate a first zone of the layer of powder comprising the first point, adjusting a power of the laser beam depending on an estimated temperature variation of the layer of powder at a second point, separate from the first point, and emitting a laser beam onto the second point with the adjusted power so as to consolidate a second zone of the layer of powder comprising the second point, the emission of the laser beam onto the first point and onto the second point being temporally separated by the predetermined time interval.