Light Beam Additive Manufacturing with 2D Effective Spot Scanning
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Solution Overview
Problem
Current additive manufacturing techniques using light beams, such as laser sintering, face challenges in achieving efficient and high-quality fusion of building materials due to limitations in energy distribution and scanning patterns, leading to issues like geometrical deformations, cracks, and prolonged production times.
Innovation Solution
The method involves creating an effective laser spot with a two-dimensional energy distribution by repetitively scanning a primary spot in two dimensions, allowing for a larger effective spot size that can be dynamically adapted in size and shape to optimize fusion, using techniques like varying beam power and scanning patterns to ensure thorough heating and rapid production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional laser beam scanning method is used to fuse building material, then the fusion process can be performed, but the production time is prolonged and productivity is low
Solution Approach 1:
The patent divides the fusion process into two distinct phases: a pre-heating phase using a first scanning pattern with lower energy density, and a fusion phase using a second scanning pattern with higher energy density. This segmentation allows efficient preparation of the material before actual fusion, reducing overall production time while maintaining quality.
Solution Approach 2:
The patent applies preliminary pre-heating action to the building material using the first scanning pattern before the actual fusion process. This pre-heating prepares the material by raising its temperature and reducing thermal gradients, enabling faster subsequent fusion and reducing total production time.
2Productivity
If high energy density is applied to achieve rapid fusion, then production speed increases, but temperature fluctuations increase leading to geometrical deformations and cracks
Solution Approach 1:
The patent segments the energy application into two distinct scanning patterns: a first pattern that distributes energy broadly for pre-heating with minimal thermal stress, and a second pattern that concentrates energy for rapid fusion. This segmentation allows high-speed fusion without excessive temperature fluctuations that cause deformations.
Solution Approach 2:
The patent applies different energy densities to different regions and stages of the process: lower energy density for pre-heating and higher energy density for fusion. This local differentiation of energy application ensures precise temperature control during fusion, preventing geometrical deformations while maintaining high productivity.
3Productivity
If the laser spot size is increased to cover larger areas, then productivity improves, but energy distribution becomes less uniform leading to poor fusion quality
Solution Approach 1:
The patent uses two distinct scanning patterns with different spot sizes and energy distributions. The first pattern uses a larger effective spot for broad pre-heating coverage, while the second pattern uses a more focused spot for precise fusion. This segmentation allows large area coverage without sacrificing fusion quality.
Solution Approach 2:
The patent dynamically changes laser parameters including spot size and energy density between the two scanning phases. During pre-heating, a larger spot with lower energy density is used for broad coverage. During fusion, parameters are adjusted to provide concentrated energy for high-quality bonding, thus maintaining both productivity and precision.
4Device complexity
If conventional single scanning pattern is used, then the process is simple, but it cannot efficiently pre-heat material leading to prolonged production time
Solution Approach 1:
The patent introduces a segmented two-stage scanning approach with distinct pre-heating and fusion patterns. While this adds some complexity, it dramatically reduces pre-heating time by efficiently distributing energy across the material surface before fusion, thereby reducing overall production time.
Solution Approach 2:
The patent ensures continuous useful action by seamlessly transitioning from pre-heating to fusion without interrupting the laser beam. The first scanning pattern continuously pre-heats the material while the second pattern continuously fuses, maximizing productivity and reducing total process time.
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 enables rapid and efficient fusion of substantial areas with improved productivity and quality, reducing temperature fluctuations and allowing for flexible adaptation to different materials and object shapes, while minimizing aggressive heating and maintaining high-quality results.
Implementation Method 1
The powder is spread across a build area using a counter-rotating leveling roller, and is preheated to a temperature close to the melting point and/or glass transition temperature of the building material.
Implementation Method 2
Once the material has been distributed and preheated, a focused laser beam is projected onto the layer of building material, and the laser spot is displaced over a region of said layer so as to progressively fuse the material in this region.
Implementation Method 3
Another AM technology involving the use of electromagnetic energy beams (typically laser beams) is the so-called beam deposition (BD) process. In this kind of process, the building material is heated while it is being deposited, by applying an energy beam to the building material.
Data Source
AI summary
The method comprises the steps of:a) supplying building material; andb) fusing the building material using a light beam (2);wherein steps a) and b) are carried out so as to progressively produce the object out of the fused building material.In step b), the beam (2) is projected onto the building material so as to produce a primary spot on the building material, the beam being repetitively scanned in two dimensions in accordance with a first scanning pattern so as to establish an effective spot (21) on the building material, said effective spot having a two-dimensional energy distribution.The effective spot (21) is displaced in relation to the object being produced to progressively produce the object by fusing the building material.