Powder Layer Irradiation Patterns for Stress-Reduced Additive Manufacturing
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Solution Overview
Problem
Additive manufacturing of complex components, particularly in turbomachines, faces challenges with high internal stress and crack susceptibility due to complex melting and solidification conditions of laser or electron beams, which are exacerbated by high temperatures and intricate geometries, making reproducibility difficult and costly.
Innovation Solution
A two-part irradiation pattern is employed, comprising a first partial pattern for continuous irradiation and a second partial pattern for pulsed irradiation, connecting continuous irradiation vectors to reduce internal stress and improve weldability, using a combination of continuous and pulsed laser or electron beam operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous laser beam irradiation is used for additive manufacturing, then productivity is improved, but internal stress and crack susceptibility increase
Solution Approach 1:
The patent applies periodic action by alternating between continuous laser irradiation (for productivity) and pulsed laser irradiation (for stress reduction). The pulsed mode is activated at specific intervals, particularly at layer transitions and after a defined number of continuous irradiation vectors, creating a periodic cycle that combines both benefits of speed and reliability.
Solution Approach 2:
The irradiation process is segmented into distinct phases: continuous irradiation phases for efficient material processing and pulsed irradiation phases for stress management. This segmentation allows the system to switch between modes based on process requirements, dividing the overall manufacturing process into manageable segments with different objectives.
2Productivity
If high laser power is used to melt powder quickly, then productivity is improved, but thermal load and distortion increase
Solution Approach 1:
The patent uses periodic action to alternate between high-power continuous irradiation (for fast melting) and pulsed irradiation with lower average power (for thermal management). This periodic switching allows the system to accumulate productivity gains during continuous phases while using pulsed phases to allow thermal diffusion and reduce peak temperatures.
Solution Approach 2:
The patent dynamically changes laser parameters including power level, pulse duration, and duty cycle. During continuous irradiation, high power is maintained for efficiency. During pulsed irradiation, parameters are adjusted to reduce average thermal input while maintaining effective melting during pulse peaks, thereby controlling thermal load and distortion.
3Adaptability or versatility
If complex component geometries are manufactured additively, then adaptability is improved, but internal stress and crack susceptibility increase
Solution Approach 1:
The patent applies local quality by implementing different irradiation strategies in different spatial and temporal contexts within the same build process. Complex geometries receive continuous irradiation for efficiency, while specific locations (layer transitions, high-stress areas) trigger pulsed irradiation for stress control. This localized adaptation of irradiation mode optimizes both geometric capability and structural reliability.
Solution Approach 2:
The system incorporates feedback mechanisms that monitor build progress and detect conditions requiring stress management. Based on this feedback, the control system automatically transitions between continuous and pulsed modes, adapting the irradiation strategy to the specific geometric and thermal state of the component being built.
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
The method significantly reduces internal stress and crack susceptibility, enabling efficient production of high-strength components with improved structural integrity and reduced thermal load, suitable for turbomachine components like rotor blades and burner parts.
Implementation Method 1
selective laser melting (SLM) or laser sintering (SLS)
Implementation Method 2
electron-beam melting (EBM)
Implementation Method 3
pulsed irradiation
Data Source
AI summary
A method for selectively irradiating a powder layer in additive manufacturing of a component. The method including: determining an irradiation pattern of the layer for additive manufacturing, wherein a first partial pattern is defined which is intended for continuous irradiation and comprises a plurality of irradiation vectors and wherein a second partial pattern is defined, which is intended for a pulsed irradiation, with the first and the second partial pattern being selected in such a manner that the second partial pattern connects irradiation vectors of the first partial pattern, and irradiating the layer in accordance with the irradiation patterns defined. A computer program product, an irradiating device, and a control unit for controlling an irradiating device are included.