3D Infill Toolpaths With Adaptive Bead Width to Minimize Overfill
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Solution Overview
Problem
Current 3D printing technologies face challenges in accurately generating toolpaths for infill structures, leading to issues such as overfill and underfill, which can result in mechanical defects and reduced part stiffness.
Innovation Solution
A method is developed to determine toolpaths with adaptive width, utilizing a geometric framework that includes a medial axis skeleton and beading schemes to minimize over- and underfill. This approach allows for various control schemes to adjust bead spacing and extrusion widths, ensuring seamless filling of 2D contours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If uniform inward offsets with nozzle size are used to generate contour-parallel toolpaths, then the outline shape accuracy is improved, but overfill and underfill areas are created causing pressure build-up and part stiffness reduction
Solution Approach 1:
The patent applies local quality by varying the bead width locally across different regions of the toolpath. Instead of using a uniform bead width throughout, the system adjusts the extrusion width dynamically based on the local geometry and spacing requirements, allowing tight spacing in some areas while maintaining adequate spacing in others, thereby eliminating overfill and underfill issues
Solution Approach 2:
The patent implements dynamics by making the bead width a dynamic parameter that changes continuously along the toolpath. The extrusion width is adjusted in real-time based on the local contour parallel distance calculations, transforming the static uniform offset approach into a dynamic adaptive system that responds to local geometric conditions
2Manufacturing precision
If adaptive width toolpaths are used to eliminate over- and underfill, then the manufacturing precision is improved, but the device complexity increases due to multiple control schemes
Solution Approach 1:
The patent applies segmentation by dividing the infill region into multiple contour-parallel toolpaths with varying bead widths. Each toolpath is segmented with specific width characteristics based on its local position and spacing requirements, allowing the complex adaptive width control to be broken down into manageable discrete paths that can be generated and controlled separately
3Manufacturing precision
If the bead width variation is reduced to below a factor of 2, then the printing accuracy is improved, but the adaptability to different geometric features is reduced
Solution Approach 1:
The patent applies parameter changes by systematically varying the bead width parameter across different regions of the toolpath. Instead of maintaining a constant width, the system changes the width parameter adaptively based on local geometric conditions, allowing it to handle diverse geometric features while maintaining overall precision through controlled variation rather than extreme ranges
Data Source
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AI summary
The invention relates to a method of determining toolpaths for an infill structure for a digital 3D model. The invention provides for a framework for planning toolpaths with control over the adaptive width for minimizing over- and underfill and introduce a beading scheme which reduces the bead width variation compared to the state of the art. We show that this framework supports various control schemes (so-called 'beading schemes') for determining the bead spacing and extrusion widths. Furthermore we present an approach to accurately realize adaptive bead width. The proposed method provides for a geometric framework allowing various adaptive bead width control schemes used to generate contour-parallel toolpaths which minimize under- and overfill.