Laser Head Calibration Plate for X-Y Positioning and Z Focus
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Solution Overview
Problem
Current calibration methods for additive manufacturing devices with optical sources fail to optimize beam focusing and positioning, leading to non-linear deformations and suboptimal corrections in X, Y, and Z axes, resulting in inconsistent energy transmission and object quality.
Innovation Solution
An automatic calibration system with a calibration plate and firing support, using mobile optical measuring equipment and a double rail support, allows for precise determination of correction tables by acquiring images of reference marks and theoretical target positions, processing these images to identify calibration patterns and apply necessary corrections to the head system for improved focusing and positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional calibration methods with static measurement equipment are used, then the calibration process is simple, but the calibration accuracy in X and Y axes is insufficient due to non-linear deformations
Solution Approach 1:
The patent applies the dynamics principle by using mobile optical measuring equipment that can be positioned at different locations on the powder bed to acquire images of reference marks. This mobility allows the system to capture calibration data from multiple positions and angles, thereby compensating for non-linear deformations and improving calibration accuracy in X and Y axes compared to static measurement systems.
Solution Approach 2:
The patent uses a calibration plate with reference marks as an intermediary element. This calibration plate serves as a mediator between the optical source and the powder bed, providing known reference positions that the mobile measuring equipment can detect. By comparing the detected reference mark positions with their theoretical positions, the system calculates correction values to compensate for deformations.
2Measurement precision
If conventional calibration methods are used, then the device complexity is low, but the focusing accuracy (Z calibration) cannot be optimized
Solution Approach 1:
The patent extends calibration from the traditional two-dimensional X-Y plane to include the third dimension Z (focusing). The mobile optical measuring equipment captures images that contain information about both lateral position and focal depth. By analyzing the clarity and focus of reference marks in captured images, the system determines optimal focusing positions, thereby achieving Z-axis calibration alongside X-Y positioning calibration.
Solution Approach 2:
The system implements feedback by using the captured images of reference marks to evaluate both positioning accuracy and focusing quality. The mobile measuring equipment detects the actual positions and focus states, compares them with theoretical values, and feeds back correction information to optimize both lateral positioning and axial focusing, thereby improving overall calibration accuracy.
3Manufacturing precision
If correction tables are used to compensate for deformations, then positioning can be corrected, but the energy transmission consistency across the powder bed remains suboptimal
Solution Approach 1:
The patent replaces purely mechanical correction table-based systems with an optical measurement and feedback system. Instead of relying solely on pre-calculated correction tables from static measurements, the mobile optical measuring equipment performs dynamic measurements and provides real-time feedback for optimizing both positioning and focusing. This substitution enables more precise control of energy transmission by accurately determining the optimal focal position for each location on the powder bed.
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 solution enhances the calibration accuracy in X and Y axes and optimizes focusing (Z calibration), ensuring consistent and precise energy transmission across the powder bed, thereby improving the quality and consistency of the additive manufacturing process.
Implementation Method 1
acquisition of at least one image of the calibration pattern and at least one reference mark, processing of the image(s) thus obtained to identify a calibration pattern
Implementation Method 2
consolidating selected zones on successive layers of powdered material by a total or partial selective fusion carried out with a focused radiation source, such as an optical source (high power laser for example)
Implementation Method 3
the more the laser beam is correctly focused at the level of the powder bed, the greater and more controlled the energy transmitted to the melting point
Data Source
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Figure 4a
AI summary
The invention relates to an assembly for calibrating a head system of a power radiation source of an additive manufacturing device, comprising: - a calibration plate that has a plurality of reference markings, and - a firing support made of at least one material that is sensitive to the radiation from the source, said support leaving the reference markings of the calibration plate visible when it is installed thereupon, characterised in that the firing support comprises a plurality of windows which are distributed so as to lie over the different reference markings on the calibration plate and leave them visible when the firing support is installed on the calibration plate. The invention also relates to a method for calibrating such a system.