3D-Printed Collimator Layer Sequencing for Tolerance Uniformity
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Solution Overview
Problem
Conventional 3D printing methods fail to produce collimators with the required tolerances and uniformity for medical imaging applications, particularly due to the high viscosity of extruded filament materials and limitations in controlling the printhead's position and speed, leading to costly and unsatisfactory results.
Innovation Solution
Implementing layered-permutation sequence algorithms to specify the content of stereolithography files for 3D printers, allowing for the production of collimators with precise layering and non-repeating permutation sequences to achieve the necessary thickness and quality for medical modalities like SPECT systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional 3D printing methods are used to produce collimators, then manufacturing speed and cost are improved, but manufacturing precision and uniformity deteriorate due to high viscosity of extruded filament and printhead control limitations
Solution Approach 1:
The patent applies preliminary action by pre-processing the STL file to generate optimized toolpaths and extrusion parameters before the actual 3D printing process. This includes calculating precise extrusion rates, positioning trajectories, and layer-permutation sequences in advance to compensate for material viscosity variations and printhead dynamics, thereby achieving required manufacturing precision while maintaining additive manufacturing speed advantages
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting extrusion rate, printhead position, and layer permutation sequences based on the specific geometry of the collimator being printed. The system modifies printing parameters layer-by-layer and region-by-region to compensate for material flow variations, ensuring uniform wall thickness and precise hole patterns throughout the collimator structure
2Reliability
If high-density materials are embedded in extruded filament to increase radiation attenuation, then collimator performance is improved, but material viscosity increases making 3D printing more difficult
Solution Approach 1:
The patent addresses the viscosity issue through preliminary action by pre-mixing high-density materials (such as tungsten or lead compounds) uniformly into the filament matrix before extrusion, and by pre-calculating adjusted extrusion parameters to account for the increased viscosity. This ensures consistent material distribution and predictable flow characteristics throughout the printing process
Solution Approach 2:
The patent employs composite materials by combining high-density radiation-absorbing materials with polymer matrices to create filaments with optimized mechanical and radiological properties. The composite structure allows the filament to maintain sufficient flexibility for extrusion while providing the required radiation attenuation capability for medical imaging applications
3Ease of manufacture
If direct STL file generation from 3D CAD files is used, then manufacturing simplicity is improved, but manufacturing precision deteriorates due to inability to control extrusion position and speed accurately
Solution Approach 1:
The patent introduces an intermediary processing step between CAD model creation and 3D printing execution. A specialized software module acts as an intermediary that converts standard STL files into enhanced print instructions with embedded position-speed profiles, extrusion rate commands, and layer-permutation sequences. This intermediary layer translates simple geometric models into precise manufacturing instructions without requiring complex user intervention
Solution Approach 2:
The patent replaces manual or simple automated control mechanisms with an intelligent software-based control system that automatically generates and executes precise extrusion trajectories. The system substitutes basic G-code generation with advanced algorithms that calculate optimal extrusion timing, speed, and position based on the digital model, achieving high precision through computational rather than mechanical means
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
Enables the rapid and accurate manufacturing of collimators with improved performance and cost-effectiveness, capable of meeting the quality requirements for medical imaging applications, including SPECT systems, using off-the-shelf components.
Implementation Method 1
Systems and methods implement one or more layered-permutation sequence algorithms that specify the content of a stereolithography file to instruct a 3D printer to produce a collimator using an additive, layered process
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
A method of manufacturing a collimator (134) on a three-dimensional printer (510) includes obtaining design specifications (536) for the collimator, the design specifications including a channel perimeter pattern and an overall collimator thickness, determining a first quantity of deposit layer permutation types based on the channel perimeter pattern, determining a respective second quantity of permutation layer elements (310, 320, 330) for each respective one of the deposit layer permutations, generating respective sets of sequences for each respective one of the deposit layer permutations, the number of sets equal to the respective second quantity for the corresponding deposit layer permutations, assembling the respective sets of sequences into a three-dimensional print file (538), providing the three-dimensional file to the three-dimensional printer, and manufacturing the collimator by depositing additive layers of material based on contents of the three-dimensional file. A system for implementing the method and a non-transitory computer-readable medium are also disclosed.