Powderbed Laser Alignment Compensation for Z-Axis Irregularities
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Manual calibration of additive manufacturing machines for laser alignment is labor-intensive and prone to errors due to powderbed position, tilt, and flatness variations, which can lead to misalignment and reduced build quality.
Innovation Solution
A non-manual system that measures z-axis differences between the powderbed and calibration plate, determines offset corrections using sensor data and machine learning, and updates the calibration table to account for height, tilt, and flatness variations, ensuring accurate laser alignment across successive layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual calibration with burn-paper marks is used, then calibration offsets can be obtained, but the process is labor intensive and prone to measurement errors
Solution Approach 1:
The patent replaces manual mechanical measurement methods with an automated optical sensing system. Sensors capture images of the calibration plate, and image processing algorithms automatically determine burn mark positions and calculate calibration offsets, eliminating manual measurement errors and significantly reducing calibration time.
Solution Approach 2:
The system creates a digital copy (image) of the calibration plate with burn marks, processes this copy through image analysis algorithms, and derives calibration data from the digital representation rather than physical measurement. This copying approach enables automated, repeatable, and error-free calibration offset determination.
2Reliability
If conventional calibration approaches are used, then calibration offsets can be determined, but errors are introduced by z-axis height differences and powderbed unevenness
Solution Approach 1:
The patent addresses z-axis height errors by incorporating depth information from stereo vision or focused depth-of-field analysis. The system transitions from 2D image analysis to 3D spatial understanding, using focal plane detection to identify which features lie in focus and thereby compensating for height variations and powderbed unevenness.
Solution Approach 2:
The calibration plate with burn marks serves as an intermediary reference object that bridges the laser system and the powderbed. By measuring the calibration plate's known features and comparing them to expected positions, the system indirectly determines alignment errors without directly measuring the powderbed surface, thereby improving reliability.
3Manufacturing precision
If manual calibration is performed, then initial alignment can be achieved, but recalibration frequency increases due to recoater inconsistencies
Solution Approach 1:
The system establishes a feedback loop where sensors continuously monitor the calibration plate or powderbed surface, detect deviations from expected positions, and trigger automatic recalibration when thresholds are exceeded. This closed-loop approach maintains manufacturing precision while minimizing interruptions to the build process, as recalibration occurs only when necessary rather than at fixed intervals.
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 reduces calibration errors, improves build accuracy, and decreases the frequency of recalibration, enhancing the overall quality and consistency of additive manufacturing processes.
Implementation Method 1
additive manufacturing processes that use laser energy to fuse successive layers of powderbed material
Implementation Method 2
direct metal laser melting (DMLM)...laser energy to fuse successive layers
Implementation Method 3
direct metal laser sintering (DMLS)...laser energy to fuse successive layers
Data Source
AI summary
A system for additive manufacturing machine energy beam alignment error compensation includes, a calibration table having x-y planar offsets to correct laser alignment errors representing energy beam positional offsets between beam-steering commanded energy beam locations and fiducial marks generated on a burn-paper, a recoater mechanism that distributes successive layers of powder, one or more sensors monitoring the powderbed surface proximal to the beam scan unit, and a processor unit configured to perform a method. The method including collecting sensor data representing height variations across at least a portion of the powderbed surface, deriving dimensional data from the collected data, analyzing the dimensional data to determine a distribution of differences between the powderbed surface and a reference plane containing the burn-paper when the fiducial marks were generated, and calculating z-axis calibration offset points for inclusion in the calibration table x-y planar offsets. A method and a non-transitory medium are also disclosed.