Selective Laser Melting Oscillating Beam Strategy
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Solution Overview
Problem
Conventional selective laser melting (SLM) processes have low build rates due to significant 'laser idle' times and repositioning movements, leading to long manufacturing cycles and high costs, especially for complex parts like those in gas turbines.
Innovation Solution
Implementing a linear or quasi-linear 2D heat source with high frequency sinusoidal oscillations in transverse and/or longitudinal directions, reducing 'laser idle' time and optimizing solidification conditions by minimizing repositioning delays and creating a more uniform irradiation profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional centro-symmetrical laser spot configurations with multiple parallel passes are used, then uniform irradiation conditions are achieved, but production rate is reduced due to significant laser idle time
Solution Approach 1:
The laser beam is pre-positioned and accelerated before reaching the start point of each track, so that the beam is already at optimal position and speed when melting begins, minimizing idle time. The beam is kept active during repositioning movements where possible, eliminating unnecessary on/off cycles.
Solution Approach 2:
The laser beam remains active during repositioning movements between tracks, eliminating idle time. The scanning strategy optimizes track continuity to minimize beam interruptions, keeping the useful action of melting continuous throughout the manufacturing process.
2Manufacturing precision
If small diameter laser beam with multiple parallel trajectories is used, then equal laser radiation distribution is ensured, but manufacturing time increases due to frequent repositioning movements
Solution Approach 1:
The laser beam diameter and power are dynamically adjusted during scanning. The beam is focused to small diameter during melting passes for precision, and defocused or repositioned dynamically during transitions, optimizing both quality and speed without manual intervention.
Solution Approach 2:
Scanning parameters including beam diameter, power, and speed are continuously optimized and adjusted based on real-time process conditions, material properties, and track position, allowing equal radiation distribution to be maintained while minimizing repositioning time through adaptive parameter changes.
3Productivity
If high scanning speed is used, then productivity increases, but porosity appears due to reduced laser energy density
Solution Approach 1:
The system incorporates feedback mechanisms that monitor melting quality and energy absorption in real-time, automatically adjusting laser power and scanning speed to maintain optimal energy density and prevent porosity formation while maximizing productivity.
Solution Approach 2:
The laser beam is applied in periodic pulses or modulated sequences that optimize energy delivery timing, ensuring sufficient energy density for complete melting and pore elimination while maintaining high average scanning speeds for productivity.
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 increases production rates by at least 25% and reduces costs per part by maximizing productive time, improving part quality and reducing thermal gradients that cause overheating and material evaporation.
Implementation Method 1
The powder is molten by laser or electron beam
Implementation Method 2
laser-powder interaction phenomena
Implementation Method 3
The key process step in SLM is the selective laser melting of the powder layers
Implementation Method 4
high frequency sinusoidal oscillations in transverse and/or longitudinal directions
Data Source
Figure 1a~1d
Figure 2
Figure 3
AI summary
The invention refers to a method for selective laser melting additive manufacturing a three-dimensional metallic or ceramic article / component entirely or partly, comprising the steps of successively building up said article / component layer by layer directly from a powder bed of a metallic or ceramic base material by means of remelting the layers with a high energy laser beam, moving repetitively across the areas, which are to be solidified, wherein the movement of the laser beam is made of a superposition of a continuous linear movement and at least one superimposed oscillation with a determined frequency and amplitude and wherein the oscillation is created by a beam deflection device and the same beam deflection device is also used for linear positioning movement.