Recoating Roller and Stripper for 3D Printing Powder Layering
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Solution Overview
Problem
Existing methods for producing three-dimensional objects using powdery construction materials face challenges with cohesive powders that tend to clump, leading to increased powder consumption and work due to inefficient layer application and agglomerate breakup.
Innovation Solution
A recoating module with a roller and blade device that applies and densifies powdery construction material between two recoating elements, where the roller rotates in the same direction as the recoater to break up agglomerates and a stripper prevents excess powder from contaminating the applied layer, ensuring only necessary powder is used and minimizing waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a counter-rotating roller is used to push and roll out the powdery construction material, then agglomerates are broken-up and layer smoothness is improved, but more powder is transported than necessary leading to increased powder consumption
Solution Approach 1:
The invention extracts only the necessary amount of powder from the excess powder transported by the roller. The stripping element removes the surplus powder that would otherwise be wasted, allowing the system to maintain the beneficial agglomerate-breaking function while eliminating the harmful excess powder consumption.
Solution Approach 2:
The stripping element discards the excess powder that is transported by the roller beyond what is needed for the layer. This selective discarding maintains layer quality while reducing powder consumption, as only the necessary amount remains on the construction field.
2Manufacturing precision
If a recoating device with space between recoating elements is used, then agglomerates are broken-up and homogeneous layer is generated, but device complexity increases
Solution Approach 1:
The roller serves multiple functions: it transports the powder, breaks up agglomerates through rotation and shear effects, and applies the powder to the construction field. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while achieving homogeneous layer formation.
Solution Approach 2:
The space between the two recoating elements acts as an intermediary zone where powder is stored and prepared before application. This space allows the roller to effectively break up agglomerates and distribute powder uniformly without requiring complex additional mechanisms.
3Manufacturing precision
If the roller rotates during application with moving direction equal to recoating device, then agglomerates are destroyed with particular efficiency, but powder may access the applied layer from elevated location causing contamination
Solution Approach 1:
The stripping element extracts and removes the excess powder that would otherwise fall from the elevated roller surface onto the applied layer. This eliminates the contamination risk while preserving the beneficial shear effects that occur during roller rotation for agglomerate breakup.
Solution Approach 2:
The stripping element performs a preliminary action to prevent the harmful effect of powder contamination before it can occur. By removing excess powder from the roller surface before the roller completes its rotation, the system prevents contamination of the freshly applied layer while maintaining efficient agglomerate breakup.
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 method produces a homogeneous and efficient layer application with reduced powder consumption, effectively addressing the issue of cohesive powders and improving the quality of the applied layer without increasing work or powder usage.
Implementation Method 1
Due to the rotational movement, in particular the shear effect in case of the same moving direction of the bottom side of the roller and of the recoating device, agglomerates of the construction material can be destroyed with particular efficiency.
Implementation Method 2
selectively solidifying the applied layer of the construction material at positions, which correspond to a cross-section of the object to be produced
Implementation Method 3
An example of such a method is known under the name 'selective laser sintering or laser melting'. Therein, a powder is selectively solidified by selective irradiation with a laser beam.
Data Source
AI summary
A method (V) for producing a three-dimensional object (2) by applying and selectively solidifying a powdery construction material (13) layer by layer includes the steps:a) applying (Z) a layer of the construction material (13) onto a construction field in a working plane (10) by means of a recoating device (14) moving in a moving direction (B) over the working plane,b) selectively solidifying (Y) the applied layer of the construction material (13) at positions, which correspond to a cross-section of the object (2) to be produced, andc) repeating (X) the steps a) and b) until the object is completed.The construction material is stored during step a) in a recoating unit (40a-e) arranged at the recoating device (14) within a space between two recoating elements (42a, 42b) mutually spaced apart from each other in the moving direction of the recoating device. At least one recoating element (42b) arranged rearward with respect to the moving direction (B) of the recoating device (14) includes a roller (43a, 43b), by means of which the construction material is applied to the working plane.