3D Metrology for Additive Manufacturing
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Solution Overview
Problem
Current three-dimensional printing systems are slow, have low throughput, and are expensive to operate, necessitating the development of techniques to enhance precision, increase throughput, and reduce costs.
Innovation Solution
The implementation of 3D metrology techniques, including fringe scanning, simultaneous fringe projections, interferometry, and x-ray imaging, to monitor and measure the topography of a substrate in real-time and in situ during additive manufacturing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional 3D printing systems operate without real-time metrology, then the system structure remains simple, but manufacturing precision and detection capability deteriorate due to inability to monitor topography changes during printing
Solution Approach 1:
The patent introduces an optical fringe projection system as an intermediary measurement device that projects fringe patterns onto the powder bed and built part surfaces. This optical mediator enables non-contact, high-precision topography measurement without mechanically interfering with the printing process, thereby improving measurement precision while adding only moderate system complexity
Solution Approach 2:
The patent replaces potential mechanical contact measurement methods with optical fringe projection and interferometry techniques. This substitution eliminates mechanical wear and contact forces that could disturb the powder bed, achieving higher measurement precision with a more elegant optical-based system rather than complex mechanical scanning devices
2Manufacturing precision
If real-time 3D metrology is implemented during printing, then manufacturing precision improves through defect detection, but productivity decreases due to potential process interruption
Solution Approach 1:
The patent implements metrology measurements at multiple preliminary stages: before powder bed preparation, after powder layer deposition, and during/after each printing layer formation. By performing measurements preliminarily at these critical checkpoints, the system detects topography deviations and defects early, enabling corrective actions before they propagate and compromise overall printing precision, thereby maintaining high productivity through preventive rather than reactive measurement
Solution Approach 2:
The patent establishes closed-loop feedback mechanisms where metrology measurements of powder bed topography and built part surfaces feed back to the control system. This feedback enables real-time adjustment of printing parameters, powder bed preparation, and layer deposition to maintain manufacturing precision while keeping measurements integrated into the continuous printing process, thus avoiding productivity loss from process interruptions
3Manufacturing precision
If comprehensive topography monitoring is performed at every printing stage, then manufacturing precision improves, but loss of time increases due to multiple measurement cycles
Solution Approach 1:
The patent implements continuous or near-continuous metrology monitoring where the optical fringe projection system operates throughout the printing process without stopping. The system continuously projects fringe patterns and captures surface topography changes as the powder bed is prepared and layers are deposited, maintaining manufacturing precision through uninterrupted measurement while eliminating idle measurement time that would occur with periodic stopping and starting of the printing process
Solution Approach 2:
The patent performs critical metrology measurements preliminarily at key stages such as measuring powder bed topography before layer deposition and measuring completed layers immediately after printing. By timing these measurements preliminarily at these specific moments, the system achieves comprehensive monitoring of layer shape accuracy while minimizing total measurement time by avoiding redundant measurements during intermediate processing steps
4Difficulty of detecting and measuring
If advanced 3D metrology systems are deployed, then detection capability improves for identifying defects, but device complexity increases due to multiple measurement systems
Solution Approach 1:
The patent employs a universal optical fringe projection system that serves multiple measurement functions: characterizing powder bed topography, monitoring built part surface geometry, and detecting defects across different printing stages. This multi-functional optical platform replaces what would otherwise require separate specialized measurement devices for each function, thereby improving comprehensive defect detection capability while controlling overall system complexity through a unified measurement architecture
Solution Approach 2:
The patent merges multiple metrology techniques (fringe projection, interferometry, and imaging) into an integrated optical measurement system. By combining these techniques into a single coordinated system rather than operating them as separate independent devices, the patent enhances defect detection capability through complementary measurement approaches while reducing device complexity through integration and shared optical components
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
These techniques enable rapid and precise topographical measurements, allowing for early detection and diagnosis of operating problems and printing defects, thereby improving precision, increasing throughput, and reducing operational costs.
Implementation Method 1
fringe scanning, simultaneous fringe projections, interferometry
Implementation Method 2
fringe scanning, simultaneous fringe projections, interferometry
Implementation Method 3
x-ray imaging
Implementation Method 4
illuminating a substrate with electron beam illumination patterns
Data Source
AI summary
3D metrology techniques are disclosed for determining a changing topography of a substrate processed in an additive manufacturing system. Techniques include fringe scanning, simultaneous fringe projections, interferometry, and x-ray imaging. The techniques can be applied to 3D printing systems to enable rapid topographical measurements of a 3D printer powder bed, or other rapidly moving, nearly continuous surface to be tested. The techniques act in parallel to the system being measured to provide information about system operation and the topography of the product being processed. A tool is provided for achieving higher precision, increasing throughput, and reducing the cost of operation through early detection and diagnosis of operating problems and printing defects. These techniques work well with any powder bed 3D printing system, providing real-time metrology of the powder bed, the most recently printed layer, or both without reducing throughput.