Extrusion Deposition Feedback Control for 100% Fill Density
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Solution Overview
Problem
Existing extrusion deposition modeling (EDM) systems struggle to achieve precise control of flow rate, leading to inconsistent fill density and structural weaknesses in 3D printed objects due to voids, which undermine mechanical strength and integrity.
Innovation Solution
A closed-loop control method is implemented to adjust flow rates based on real-time scanning and comparison of deposited layer profiles with expected values, using a control algorithm to calculate corrected flow rates for subsequent layers, ensuring consistent 100% fill density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual monitoring and adjustment of flow rate is used, then the process is simple to operate, but the manufacturing precision is insufficient to achieve 100% fill density
Solution Approach 1:
The patent implements a feedback control system where an optical scanner measures the actual width of deposited material layers, and a controller compares this measured width to the target width to calculate flow rate corrections. This closed-loop feedback mechanism automatically adjusts flow rate to achieve precise 100% fill density, resolving the contradiction between ease of operation and manufacturing precision by automating the adjustment process while maintaining operational simplicity.
Solution Approach 2:
The system performs self-diagnosis and self-correction by automatically scanning deposited layers, comparing dimensions to target values, and adjusting flow rate without operator intervention. This self-service capability eliminates the need for manual monitoring while achieving precise flow rate control, thereby improving manufacturing precision while maintaining ease of operation.
2Productivity
If flow rate is not precisely controlled, then the process is simpler and faster, but voids are created in the deposited structure reducing mechanical strength
Solution Approach 1:
The feedback control system continuously monitors deposited layer dimensions and adjusts flow rate in real-time to ensure 100% fill density is achieved without compromising deposition speed. By automatically correcting flow rate deviations, the system maintains high productivity while preventing void formation that would weaken the mechanical structure.
Solution Approach 2:
The system performs preliminary scanning and measurement of deposited layers before proceeding to the next deposition step. This preliminary action allows the controller to calculate and apply flow rate corrections in advance, ensuring that each layer is deposited with precise fill density, thereby preventing voids and maintaining mechanical strength without slowing down the overall process.
3Device complexity
If flow rate corrections are made reactively, then the system is simpler to control, but cumulative errors occur leading to poor part quality
Solution Approach 1:
The patent implements a feedback mechanism that proactively measures and corrects flow rate deviations by scanning deposited layers and calculating corrections before cumulative errors occur. The controller continuously adjusts flow rate based on actual measured dimensions, transforming reactive control into proactive control, thereby maintaining consistent 100% fill density while keeping the control system relatively simple.
Solution Approach 2:
The system performs preliminary measurements and calculations before each deposition step, proactively identifying and correcting potential deviations in flow rate. This preliminary action prevents cumulative errors from developing, ensuring consistent fill density throughout the entire build process without requiring complex real-time adjustment mechanisms.
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
The method ensures precise control of flow rates, achieving consistent 100% fill density and improved mechanical integrity of 3D printed objects by minimizing voids and enhancing structural strength.
Implementation Method 1
optically scanning the deposited first layer to obtain profile data of the first layer
Data Source
AI summary
In the context of additively manufacturing a solid object using extrusion deposition, closed-loop control of flow rate is achieved using a distance measuring tool to scan a surface of a layer that has been deposited using a first flow rate, comparing data from the scan to a desired target value and using a control algorithm to calculate a corrected second flow rate to be applied when depositing a subsequent layer. In some embodiments, the control algorithm is a proportional-integral control algorithm. In some embodiments, a solid object shape may result in some layers having multiple isolated regions and separate closed-loop control instances may be applied to the separate regions.