Incremental Build Material Spreading for Uniform Layer Density
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Solution Overview
Problem
Additive manufacturing systems face challenges in achieving uniform spreading and high density of build material layers due to interparticle frictional forces, leading to surface imperfections and mechanical defects in 3D printed objects.
Innovation Solution
The system employs a multi-pass spreading method with incremental bed movements to distribute smaller amounts of build material, reducing interparticle forces and ensuring a smoother, more uniform surface, using a bed that is movable in a vertical direction, a build material depositor, and a spreader to traverse across the bed, with a controller managing the process to achieve the desired layer thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single-pass spreading method is used to deposit build material layers, then the manufacturing process is faster and simpler, but the surface uniformity and density of the layers deteriorate due to interparticle frictional forces
Solution Approach 1:
The spreading process is divided into multiple passes instead of a single pass. The build material layer is spread incrementally across several traverses of the spreader mechanism, allowing the material to be distributed more uniformly while reducing the cumulative effect of interparticle frictional forces that cause surface imperfections.
2Loss of time
If build material is spread in a single pass, then the process time is reduced, but the layer density and geometric uniformity worsen due to frictional forces between particles
Solution Approach 1:
The spreading operation is segmented into multiple passes with the spreader traversing the build material layer repeatedly. Each pass distributes material more evenly, and the cumulative effect of multiple light passes achieves better density than a single heavy pass, while the total time increase is manageable compared to the quality improvement.
3Manufacturing precision
If a multi-pass incremental spreading method is used to improve surface uniformity and reduce interparticle frictional forces, then the manufacturing precision and density improve, but the process time and complexity increase
Solution Approach 1:
The spreading process is segmented into multiple incremental passes controlled by a controller that coordinates the spreader mechanism. While this increases process complexity compared to a single pass, the segmentation enables precise control over material distribution, significantly improving surface uniformity and layer density.
4Manufacturing precision
If incremental bed movements are used to distribute smaller amounts of build material, then the surface finish and geometric uniformity improve, but the number of operations and process complexity increase
Solution Approach 1:
The bed movement and material distribution process is segmented into incremental steps rather than a single large movement. The spreader traverses the build area multiple times in smaller increments, distributing material more uniformly and reducing geometric defects, though this requires more operational steps than a single-pass approach.
Data Source
AI summary
In one example in accordance with the present disclosure, an additive manufacturing system is described. The additive manufacturing system includes a bed moveable in a vertical direction. The bed is to receive a build material that is to form a three-dimensional (3D) printed object. The additive manufacturing system also includes a build material depositor to deposit the build material on the bed and a build material spreader to traverse across the bed to spread the build material. The additive manufacturing system also includes a solidification system to selectively solidify a layer of build material. The additive manufacturing system also includes a controller. The controller is to lower the bed by a first amount in preparation for receiving build material and iteratively raise the bed in increments in between passes of the build material spreader across the bed, wherein an increment is a portion of the first amount.