Additive Manufacturing Green Block Density via CIP
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Solution Overview
Problem
Existing additive manufacturing techniques face challenges in achieving high material density in three-dimensional printed models, particularly due to the limitations of sintering processes which often result in incomplete compaction and residual air within the material structure.
Innovation Solution
The method involves building a green block layerwise using a powder material and a solidifiable non-powder material, followed by compaction and Cold Isostatic Pressing (CIP) to increase density, and subsequent sintering to produce a three-dimensional model, where the solidifiable non-powder material is selectively applied to trace the contour of the model and separate support elements, and CIP is used to enhance the material's density up to 95% of the wrought density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional sintering processes are used to bind powder material, then the manufacturing process is simple, but the material density remains low with residual air pockets
Solution Approach 1:
The patent applies preliminary compaction before sintering to pre-densify the green compact, removing air pockets and improving material density before the sintering process begins. This preliminary action ensures better consolidation and reduces residual porosity in the final product.
Solution Approach 2:
The patent replaces conventional mechanical compaction with Cold Isostatic Pressing (CIP), which uses fluid pressure to apply isotropic compression from all directions simultaneously. This mechanical substitution achieves more uniform and effective densification compared to traditional unidirectional pressing methods.
2Manufacturing precision
If Cold Isostatic Pressing is applied to increase density, then material density improves to near 100% of wrought density, but the process time and equipment complexity increase
Solution Approach 1:
The CIP process is applied as a preliminary step before sintering to achieve maximum density in the green compact. By densifying the material beforehand, the subsequent sintering process is optimized and can be performed more efficiently, reducing overall process time despite the added CIP step.
3Strength
If support elements are integrated in the green block, then structural support during printing is improved, but removal complexity and potential damage to the model increase
Solution Approach 1:
The patent designs support elements to be temporarily integrated into the green block during the additive manufacturing process, then extracts them through dissolution or removal after the model is formed. This approach provides necessary structural support during printing while enabling easy removal afterward without damaging the final model.
Solution Approach 2:
The support elements act as intermediary structures that facilitate the manufacturing process by providing temporary support, then are removed or dissolved to leave only the final model. This intermediary role allows the support to serve its function during printing and then be cleanly eliminated afterward.
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 effectively increases the material density of 3D printed models to near 100% of the wrought density by removing residual air and solidified non-powder material, resulting in improved structural integrity and reduced printing time.
Implementation Method 1
printing a pattern with a solidifiable non-powder material to trace the contour of the green usable model
Implementation Method 2
applying cold isostatic pressing after completing the building of the green block, wherein the cold isostatic pressing is configured to increase the density of the green usable model
Implementation Method 3
sintering the green usable model after the cold isostatic pressing to produce a three-dimensional model
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
A method for producing a three-dimensional model via additive manufacturing includes building a green block in a layerwise manner with a powder material and a solidifiable non- powder material. The green block includes a green usable model. The solidified non-powder material is removed from the green block to extract the green usable model from the green block and the density of the green usable model is increased by applying Cold Isostatic Pressing (CIP). The green usable model is then sintered to produce a three-dimensional model.