Semisolid 3D Printing Path Planning to Avoid Printhead Contact
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Solution Overview
Problem
Extrusion-based 3-D printing, particularly with semisolid materials, faces issues of material flow continuation after a stop signal, leading to undesired extrusions and damage to printed objects due to low retractability and slow solidification, which are not adequately addressed by existing retraction methods.
Innovation Solution
A computer-implemented method determines optimized printhead paths by classifying polygons as parent and child, minimizing travel subpath intersections with printed material, and using safe outlines to avoid damage, ensuring deposition subpaths are performed in an order that reduces material overlap and minimizes printhead contact with printed surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If retraction of material is used upon receiving stop signal, then amount of undesired extruded material is decreased, but materials with low retractability and slow solidification cannot be adequately handled
Solution Approach 1:
The system performs preliminary actions by calculating and implementing a planned printhead trajectory that anticipates the material's continued flow after the stop signal. The trajectory is pre-computed to account for the material's low retractability and slow solidification characteristics, allowing the system to prepare and execute the appropriate movement sequence before the material fully solidifies or causes damage.
Solution Approach 2:
The system incorporates feedback mechanisms by continuously monitoring the printing process and adjusting the printhead trajectory in real-time. The control system receives feedback about the material's extrusion state and modifies the trajectory accordingly, adapting to the specific material properties (low retractability, slow solidification) to prevent undesired extrusion and damage.
2Productivity
If printhead moves quickly to improve productivity, then printing speed increases, but material flow control and precision of motion are compromised
Solution Approach 1:
The printing process is segmented into distinct phases: deposition subpaths where material is extruded and travel subpaths where the printhead moves between deposition locations. This segmentation allows the system to optimize each phase independently - maintaining high speed during travel subpaths while ensuring precise control and proper material flow during deposition subpaths, thereby achieving both productivity and precision.
Solution Approach 2:
The system dynamically adjusts the printhead trajectory and movement parameters based on the specific requirements of each deposition subpath. The control system calculates optimal trajectories that account for material properties, printing speed, and precision requirements, allowing the printhead to move quickly when needed while maintaining accurate control during material extrusion through real-time dynamic adjustment.
Data Source
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AI summary
The invention relates to a computer-implemented method for determining a path for 3-D printing, by extrusion of semisolid material, a slice of a 3-D model, the method comprising: classifying received polygons as parent and child, wherein a polygon is classified as parent polygon of a child; and determining a path for 3-D printing the slice, the path comprising deposition subpaths (i1, i2, p1) delimited by the polygons, and the path comprising travel subpaths; the step of determining the path comprising: ∘ for each parent polygon: configuring the path to perform the deposition subpath(s) delimited by the child(ren) (q111) of the parent polygon (q11), and to perform the deposition subpath delimited by the parent polygon after performing the deposition subpath(s) delimited by the children; and ∘ minimizing a sum of lengths of intersections of the travel subpaths with the 3-D portions of the slice.