Binder Jetting Control for Layer Thickness Compensation
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Solution Overview
Problem
In powder additive manufacturing with binder-jetting, the permeation of fabrication liquid leads to increased powder density and reduced layer thickness, causing errors in the thickness of the fabricated three-dimensional object.
Innovation Solution
A control system that adjusts the supply of powder and discharge of fabrication liquid based on powder information to compensate for the reduction in layer thickness, ensuring accurate layer formation and maintaining the designed thickness of the three-dimensional object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fabrication liquid is discharged onto powder layer to solidify it, then the powder is consolidated and three-dimensional structure is formed, but the fabrication liquid permeates the powder layer causing reduced layer thickness and dimensional errors
Solution Approach 1:
The patent applies preliminary action by forming a base layer of overhang parts at the (k+1)th layer position before discharging fabrication liquid onto the kth layer. This preventive measure stops liquid permeation to lower layers before it occurs, maintaining layer thickness precision while still allowing consolidation where needed.
Solution Approach 2:
The patent implements local quality by selectively forming base layers only at overhang part positions where liquid permeation would cause harm. The controller identifies overhang regions from three-dimensional design data and applies the base layer formation process locally to those specific areas, rather than uniformly across the entire powder bed.
2Quantity of substance
If fabrication liquid permeates powder layer, then powder density increases due to liquid bridging force, but the thickness of powder layer is reduced causing errors in three-dimensional object dimensions
Solution Approach 1:
The patent prevents the harmful effect of liquid permeation before it occurs by pre-forming base layers at overhang positions. This eliminates the liquid bridging force that would otherwise compress subsequent powder layers, thereby maintaining both powder density control and dimensional accuracy in the final three-dimensional object.
3Reliability
If base layer is formed at (k + 1)th layer to prevent liquid permeation, then liquid permeation to lower layer is prevented, but additional process step is required
Solution Approach 1:
The patent achieves universality by using the same powder supplying mechanism for both regular layer formation and base layer formation at overhang positions. The process integrates seamlessly into the existing binder jetting workflow, requiring only controller logic to identify overhang regions and adjust powder supply accordingly, rather than introducing separate hardware systems.
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 improves the precision of three-dimensional object fabrication by maintaining the intended layer thickness, preventing errors caused by liquid bridging and ensuring consistent object quality.
Implementation Method 1
the density of the powder increases due to liquid bridging force of the fabrication liquid and the thickness of a layer of the powder is reduced
Data Source
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Figure 5
AI summary
A control apparatus (12) controls a three-dimensional object fabrication apparatus (11) including a storing unit (501) configured to store therein powder (27), a supplying unit (502) configured to supply the powder (27) to the storing unit (501) in layers, and a discharge unit (503) configured to discharge, onto the powder (27), a fabrication liquid (55) for solidifying the powder (27). The control apparatus (12) includes a controller (511, 512) configured to control a total amount of the powder (27) supplied from the supplying unit (502) to the storing unit (501) based on fabrication data (510) indicating a shape of a three-dimensional object and powder information (521) indicating a change in dimension of a layer of the powder (27) due to permeation of the fabrication liquid (55).