Additive Manufacturing Layer Inspection via Spatial Thermal Excitation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Additive manufacturing of workpieces faces challenges in detecting defects within layers due to rough surfaces and surface variations, which complicate the differentiation of anomaly signals from thermal and deformation signals caused by both defects and defect-free surfaces.
Innovation Solution
A method involving a spatially structured heating pattern that thermally excites the uppermost workpiece layer at multiple points, allowing for precise detection of defects by generating different signal responses based on their position and extent, and utilizing high-frequency image recording and analysis to determine deformation and temperature profiles over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal excitation is applied to detect defects in additively manufactured workpieces, then defect detection capability is improved, but surface roughness and variations cause false signals that worsen measurement precision
Solution Approach 1:
The patent segments the thermal excitation process into multiple discrete heating zones across the workpiece surface. By dividing the excitation into spatially separated regions, the system can analyze thermal responses independently from each zone, improving the ability to distinguish true defect signals from surface roughness artifacts in each segment.
Solution Approach 2:
The patent applies local quality by using spatially selective thermal excitation where different regions of the workpiece receive targeted heating. This allows the measurement system to focus on specific local areas with known or suspected defects, adapting the excitation intensity and pattern to local conditions while maintaining overall measurement precision.
2Reliability
If multiple measurement points are used to improve defect detection coverage, then detection completeness is improved, but system complexity increases
Solution Approach 1:
The patent implements a universal measurement system where a single thermal excitation source and detection apparatus can operate across multiple measurement points and different workpiece configurations. The system adapts its parameters dynamically, eliminating the need for separate specialized equipment for each measurement location while maintaining comprehensive defect detection coverage.
Solution Approach 2:
The patent transitions from point-by-point sequential measurement to a multi-dimensional thermal excitation approach where entire surface regions are excited simultaneously. This spatial dimensionality change allows comprehensive coverage of multiple measurement points without proportionally increasing system complexity, as the thermal field naturally propagates across the workpiece surface.
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 reliable and precise detection of defects in near-surface regions, allowing for early correction of layer defects during the manufacturing process, improving the quality of material layers and distinguishing anomalies from surface effects.
Implementation Method 1
Selected powder particles on the uppermost side of the powder bed are locally selectively melted or at least partially melted by means of a laser beam or electron beam and are in this way bonded to one another on cooling
Implementation Method 2
thermally exciting the layer stack at the defined point in time with a first pulsed thermal excitation having a pulse duration of between 0.5 ms and 50 ms
Implementation Method 3
recording a plurality of images of the respective uppermost workpiece layer after the first pulsed thermal excitation with an image recording rate of at least 1 kHz
Data Source
AI summary
A method for additively manufacturing a workpiece includes obtaining a dataset that defines the workpiece in a layer stack. The method includes producing the layers in sequential production steps using a layer forming tool. At a defined point in time, the stack has an uppermost layer and zero or more layers underneath. The method includes thermally exciting the layer stack with a first pulsed thermal excitation. The first pulsed thermal excitation includes a spatially structured heating pattern that heats the uppermost workpiece layer in parallel at mutually spatially distant excitation points. The method includes recording images of the uppermost workpiece layer after the first pulsed thermal excitation and inspecting the layer stack using the images in order to obtain an inspection result. The inspection result is based on a time-based individual deformation profile or a time-based individual temperature profile determined from the images.