Two-Step Energy Application for 3D Printing Coalescence Bleed
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Additive manufacturing systems face challenges in producing high-quality three-dimensional objects due to issues like coalescence bleed, which results in reduced accuracy and strength, and stair-stepping effects, leading to deformations and irregularities in the z-axis direction.
Innovation Solution
A two-step energy application method is employed in additive manufacturing, where a coalescing agent is selectively delivered to a first layer, and energy is applied to cause solidification, followed by energy propagation through subsequent layers to reduce heat propagation and mechanical stresses, enhancing inter-layer bonding and surface characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If energy is applied to solidify build material in a single step, then production efficiency is improved, but coalescence bleed occurs reducing accuracy and strength
Solution Approach 1:
The energy application process is divided into two distinct steps: a first energy application to initially solidify the build material, and a second energy application after adding subsequent layers to complete solidification and eliminate coalescence bleed. This segmentation resolves the contradiction by allowing both efficient initial solidification and precise final solidification without coalescence defects.
Solution Approach 2:
The first energy application performs preliminary solidification of the build material before subsequent layers are added. This preliminary action enables faster initial processing while the second energy application later completes the solidification process to eliminate coalescence bleed, thereby achieving both high productivity and high accuracy.
2Strength
If high energy is applied to achieve strong inter-layer bonding, then bonding strength is improved, but heat propagation causes coalescence bleed and deformations
Solution Approach 1:
The energy application is segmented into two steps with different energy levels: a first lower energy application that initially solidifies material with minimal heat propagation, and a second energy application after subsequent layers are added that provides sufficient energy for strong bonding without causing coalescence bleed in the newly added layers.
Solution Approach 2:
The first energy application performs preliminary bonding at lower energy to avoid excessive heat propagation, then subsequent layers are added before the second energy application provides the additional bonding strength needed, achieving both strong inter-layer bonding and shape accuracy.
3Productivity
If layers are added quickly to improve productivity, then production speed is improved, but stair-stepping effects increase causing surface irregularities
Solution Approach 1:
Subsequent layers are added as a preliminary action before the second energy application is performed. This allows rapid layer addition to maintain high productivity, while the delayed second energy application subsequently smooths the surfaces and eliminates stair-stepping effects to achieve high surface quality.
4Device complexity
If a single solidification process is used, then device complexity is reduced, but object strength and quality are compromised
Solution Approach 1:
The solidification process is segmented into two distinct energy application steps: a first energy application for initial solidification and a second energy application for final solidification and coalescence elimination. This segmentation, while increasing process complexity, is necessary to achieve the required object strength and quality that cannot be obtained with a single solidification process.
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 coalescence bleed, achieves strong inter-layer bonding, high accuracy, and desired surface characteristics, while minimizing stair-stepping, resulting in improved part density and surface smoothness along the z-axis.
Implementation Method 1
energy absorbed by build material on which coalescing agent has been delivered or has penetrated may also propagate into surrounding build material. The energy may be sufficient to cause surrounding build material to heat up.
Implementation Method 2
temporary application of energy to the build material... cause the build material to coalesce and solidify
Implementation Method 3
This may result in the subsequent solidification of portions of the build material
Data Source
AI summary
A three-dimensional object may be generated. Coalescing agent may be selectively delivered on a portion of a first layer of build material on a support member or previous layer. Energy may be applied to the first layer to cause the portion of the first layer to coalesce and solidify. A second layer of the build material may be provided on the first layer. While the second layer does not have coalescing agent delivered thereon, energy may be applied to the second layer such that energy may propagate through the second layer to the first layer to cause the portion of the first layer to coalesce and further solidify.