Building Platform Position Referencing for Precise AM Alignment
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Solution Overview
Problem
Existing additive manufacturing devices face challenges in achieving precise alignment and strong bonding between prefabricated lower parts and additively manufactured upper parts, particularly in applications requiring high geometrical accuracy such as dental applications, where the alignment accuracy needs to be within +/- 50 µm.
Innovation Solution
A method and system for determining the position data of a building platform within the coordinate system of an additive manufacturing device, utilizing a support plate with optically detectable reference marks and laser target parts, and a vision measuring device to acquire high-resolution images and laser mark positions, enabling precise alignment and bonding through the combination of external and internal position data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a prefabricated lower part is used as a building platform, then manufacturing complexity is reduced and productivity is improved, but alignment precision between the upper and lower parts deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-defining the position of the building platform relative to the laser coordinate system using reference marks on the support plate and building platform holder. The system performs preliminary calibration by capturing images of reference marks, calculating transformation matrices, and storing the position data before actual manufacturing. This preliminary positioning ensures that when the building platform is used for additive manufacturing, the laser beam can accurately target the correct locations on the prefabricated lower part, achieving both high productivity and precision.
2Device complexity
If the building platform position is manually calibrated, then device complexity is reduced, but measurement precision and alignment accuracy deteriorate
Solution Approach 1:
The patent replaces manual mechanical calibration with an automated optical measurement system. Instead of manually positioning and measuring the building platform, the system uses a camera to capture images of optically detectable reference marks, processes the image data to determine the building platform holder's position and orientation, and automatically calculates the transformation matrix between the building platform coordinate system and the laser coordinate system. This substitution of mechanical manual operations with optical measurement and computational processing achieves high measurement precision while keeping the device relatively simple.
3Productivity
If the building platform is reused across multiple manufacturing cycles, then productivity is improved and costs are reduced, but positioning accuracy deteriorates due to accumulated errors
Solution Approach 1:
The patent implements feedback by using the optically detectable reference marks on the support plate and building platform holder as permanent positioning references that remain across multiple manufacturing cycles. Before each manufacturing cycle, the system recaptures images of these reference marks, recalculates the transformation matrix, and updates the building platform position data in the laser coordinate system. This feedback mechanism compensates for any minor variations or accumulated errors that may occur during platform removal and reinstallation, ensuring consistent positioning accuracy across multiple reuse cycles.
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 accurate positioning of the building platform with precision better than 50 µm, enhancing the quality of three-dimensional components and enabling the use of the building platform in multiple manufacturing cycles, reducing costs and material distortion.
Implementation Method 1
directing a laser beam with a scanner optics on a layer of a powder material, which typically forms a working surface in the process chamber of the additive manufacturing device. The laser beam melts or sinters the powder material locally
Implementation Method 2
acquiring a pre-manufacturing image of the support plate that has the laser marks on the laser target parts and is mounted within the process chamber
Data Source
Figure 1
Figure 2~3
Figure 4A~4C
AI summary
A method relates to determining a position data of a building platform (37) provided at a support plate (31) within a process chamber (3) of an AM device (1). The position data relates to a coordinate system (X, Y, Z) of the scanner optics (5). The support plate (31) includes building platform holes (33) for building platform holders (35) for building platform (37), optically detectable reference marks (39) on a surface (31A) of the support plate (31), and at least two receptors (41) for laser target parts (43). The method comprises: - obtaining a first position dataset including a precision position of at least one building platform holder (35) in one of the building platform holes (33) with respect to the reference marks (39); - when the support plate (31) is mounted in the process chamber (3) and the building platform (37) is inserted into the at least one building platform holder (35), marking a laser mark on the laser target parts (43) in the receptors (41), respective laser mark positions defined in the coordinate system (X, Y, Z) of the scanner optics (5); - acquiring a pre-manufacturing image of the support plate (31) having the laser marks when mounted within the process chamber (3); - obtaining from the pre-manufacturing image a second position dataset including positions of the reference marks (39) with respect to the laser marks; and - determining the position data of the building platform (37) within the coordinate system (X, Y, Z) of the scanner optics (5) from the first position dataset, the second position dataset, and the laser mark positions.