Ultrasonic Waveguide Temperature Inspection for Additive Manufacturing
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Solution Overview
Problem
Current temperature control methods for additive manufacturing on a powder bed are limited in accessing the internal temperature of parts, especially during rapid heat supply processes like laser fusion, and fail to provide comprehensive and adaptive monitoring of thermal history, which is crucial for ensuring the quality and reliability of produced parts.
Innovation Solution
The method employs ultrasonic volume measurement by analyzing the round-trip propagation speed of ultrasonic waves in waveguides manufactured simultaneously with the parts, comparing experimental values with simulated results to estimate the temperature field, using an iterative process that updates a digital simulation model to account for changing geometry and heat input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional temperature inspection methods (thermocouples, peripheral measurements) are used, then device complexity is reduced, but measurement precision and accessibility to internal temperature are insufficient
Solution Approach 1:
The patent introduces waveguides as intermediary structures manufactured simultaneously with the part. These waveguides serve as mediators that transmit ultrasonic waves through the powder bed and part to enable internal temperature measurement without direct sensor insertion, thus achieving precise internal temperature monitoring while avoiding the complexity of embedding traditional temperature sensors.
Solution Approach 2:
The patent replaces traditional mechanical temperature sensing systems (thermocouples, resistance thermometers) with ultrasonic wave-based temperature inspection. By using ultrasonic wave propagation characteristics to infer temperature, the system achieves internal temperature measurement without mechanical contact, solving the accessibility problem while reducing device complexity.
2Reliability
If comprehensive temperature monitoring is implemented, then reliability of temperature data is improved, but productivity and manufacturing time increase due to iterative measurement and model updating
Solution Approach 1:
The patent implements preliminary action by manufacturing waveguides simultaneously with the part during the additive manufacturing process itself. This allows temperature monitoring infrastructure to be prepared in advance, enabling reliable temperature measurement without adding post-processing steps or separate instrumentation installation time.
Solution Approach 2:
The patent ensures continuity of useful action by performing ultrasonic measurements and model updates iteratively throughout the manufacturing process. Rather than discrete interruptions, the system continuously monitors temperature and updates the digital twin model, maintaining reliable temperature data throughout manufacturing without significant productivity loss.
3Manufacturing precision
If adaptive temperature control is implemented with real-time monitoring, then manufacturing precision is improved, but device complexity increases due to iterative measurement and simulation model updating
Solution Approach 1:
The patent implements feedback by using ultrasonic wave propagation measurements to continuously monitor temperature in the powder bed and part, then feeding this information back to update the digital twin simulation model. This closed-loop feedback system enables adaptive temperature control, improving manufacturing precision by adjusting manufacturing parameters based on real-time temperature data.
Solution Approach 2:
The patent uses copying by creating a digital twin (simulation model) that replicates the physical manufacturing system. The digital model copies the geometry, material properties, and thermal behavior of the actual system, allowing virtual experimentation and parameter optimization without affecting the physical process, thus improving precision while managing complexity.
4Adaptability or versatility
If waveguides are manufactured simultaneously with parts, then adaptability to changing geometry is improved, but manufacturing precision of waveguides themselves becomes a constraint
Solution Approach 1:
The patent applies segmentation by dividing the manufacturing system into independent components: the part being manufactured, the waveguides for temperature monitoring, and the powder bed. The waveguides are manufactured as separate but integrated elements with standardized cross-sections, allowing their geometry to be independently controlled while adapting to different part configurations, thus balancing adaptability with manufacturing precision.
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
This approach allows for precise and adaptive temperature control, enabling effective monitoring of both the powder bed and the internal temperature of parts, improving the quality and reliability of additive manufacturing by providing real-time temperature estimation and homogeneity assessment.
Implementation Method 1
measuring a time of flight of an ultrasonic wave in a waveguide which is manufactured simultaneously with manufacture of the part or parts
Implementation Method 2
analysis of the round-trip propagation speed of ultrasonic waves in waveguides... to estimate the temperature field prevailing in the powder bed and/or in the part(s) being produced
Implementation Method 3
an additive manufacturing process by powder bed fusion... involving partial or total fusion of static powder... using a laser
Implementation Method 4
heat input, for example by laser... rapid heat supply processes like laser fusion
Data Source
Figure 1~2
Figure 3a~3c
Figure 4
AI summary
The present invention concerns a method for inspecting the temperature during an additive manufacture of a part by powder bed fusion in an additive manufacturing system, the fusion being obtained by scanning an activation source over the powder bed, the method comprising the steps of: - producing at least one ultrasound wave guide, layer by layer, simultaneously to the manufacture, on a construction tray, of at least one part in the powder bed, said at least one wave guide being secured to the construction tray and having a minimum value of the smallest dimension of the cross-section greater than the ratio "c/f", "c" denoting the speed of propagation of the ultrasound wave in the controlled material and "f" the main frequency of the ultrasound wave; - for a layer 'n': - measuring a time of flight for an ultrasonic beam emitted in combined transmitter-receiver mode in said at least one wave guide; - obtaining, by simulation, a value of the propagation of an ultrasonic beam in a temperature field, the simulation being based on a model representative of the additive manufacturing system for said layer 'n'; - comparing the measurement of the time of flight in said at least one wave guide to the propagation value obtained by simulation; - updating the simulation model depending on the result of the comparison; - repeating the preceding steps; and - generating an estimation of the temperature field prevailing in said at least one wave guide from the result of the comparisons.