3D Printing Dead Zone Control via Mode Switching
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Solution Overview
Problem
In three-dimensional rapid prototyping, the expansion of a 'dead zone' during the manufacturing process can lead to channel formation and delamination issues due to increased pressure and flow rate of the photohardening inhibitor, constraining the build platform speed and affecting the accuracy and speed of object creation.
Innovation Solution
The system alternates between continuous and discontinuous modes of solidification energy exposure, adjusting the build platform speed and inhibitor flow to maintain a stable dead zone, and varies exposure times and intensities based on the object's cross-sectional area and geometric parameters to prevent excessive dead zone expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the build platform is moved continuously upward to accelerate the build process, then productivity is improved, but the dead zone expands causing channel formation and delamination
Solution Approach 1:
The patent applies periodic action by alternating between continuous build mode (for small cross-sectional areas) and discontinuous build mode (for large cross-sectional areas). In discontinuous mode, the build platform moves up and then pauses to allow photohardening inhibitor to replenish in the dead zone, preventing excessive expansion. This periodic switching between operational modes resolves the contradiction by adapting the build speed to the instantaneous cross-sectional area being formed.
Solution Approach 2:
The system dynamically adjusts the build platform speed based on the cross-sectional area of the object being formed. When the cross-sectional area exceeds a threshold, the system automatically switches from continuous to discontinuous mode, reducing speed to allow inhibitor replenishment. This dynamic adaptation prevents dead zone expansion while maintaining high productivity when possible.
2Productivity
If the build platform speed is increased, then productivity is improved, but pressure drop increases causing inhibitor flow rate to increase and dead zone to expand
Solution Approach 1:
The system employs feedback control by monitoring the cross-sectional area of the object being formed and automatically adjusting the build platform speed accordingly. When the cross-sectional area is large, the system detects the risk of excessive pressure drop and inhibitor depletion, then switches to discontinuous mode to allow inhibitor replenishment. This feedback mechanism maintains optimal inhibitor concentration in the dead zone while maximizing build speed.
Solution Approach 2:
In discontinuous mode, the system performs preliminary action by pausing the build platform movement before the dead zone becomes excessively large. This pause allows photohardening inhibitor to replenish in advance, preventing the pressure drop and flow rate increase that would otherwise occur during continuous high-speed operation.
3Manufacturing precision
If the dead zone is maintained thin to prevent channel formation, then manufacturing precision is improved, but build speed must be reduced
Solution Approach 1:
The system dynamically adjusts build platform speed based on real-time cross-sectional area measurements. For small cross-sectional areas, continuous high-speed operation maintains thin dead zone. For large cross-sectional areas, the system switches to discontinuous mode with reduced speed, allowing controlled dead zone thickness while preventing channel formation. This dynamic adjustment optimizes both precision and productivity.
Solution Approach 2:
The system uses periodic switching between continuous and discontinuous modes to maintain appropriate dead zone thickness. During continuous mode, high speed produces thin dead zone. During discontinuous mode, the pause allows inhibitor replenishment that maintains dead zone thickness control. This periodic action prevents channel formation while maximizing overall build speed.
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 allows for faster and more accurate production of three-dimensional objects by controlling the dead zone expansion, reducing the likelihood of channel formation and delamination, and optimizing the build process for larger cross-sectional areas.
Implementation Method 1
photo-polymer hardening using light or laser curing methods
Data Source
AI summary
A method and apparatus for making a three-dimensional object by solidifying a solidifiable material are shown and described. A photohardening inhibitor is admitted into a surface of a photohardenable material to create a “dead zone” where little or no solidification occurs. The dead zone prevents the exposed surface of the photohardenable material from solidifying in contact with a container bottom or film. As the solidified object areas get larger and the build platform speed increases, the dead zone increases which can cause the formation of channels in the resulting objects and delamination. A number of techniques including continuous/discontinuous mode switching, multiple illuminations of portions of the same layer, and the use of gray scaling are disclosed for regulating the size of the dead zone.