Additive Manufacturing Focus Calibration via Test Patterns
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Solution Overview
Problem
Accurate solidification of selective parts in additive manufacturing, particularly in metal objects, is challenging due to difficulties in focusing the laser effectively.
Innovation Solution
A method for calibrating the focus of a solidifying device using a calibration system that creates test patterns at different focus settings, determining characteristics, and interpolating to find an optimal focus setting, which can be applied to various positions and power settings, ensuring accurate focus across the build surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser focus settings are adjusted for different positions and power settings in additive manufacturing, then manufacturing precision is improved, but device complexity increases due to the need for calibration systems and multiple test patterns
Solution Approach 1:
The patent applies preliminary action by performing focus calibration before actual manufacturing. The system pre-determines optimal focus settings for different positions and power settings by creating test patterns and analyzing their characteristics. This preliminary calibration stored in a lookup table eliminates the need for real-time complex adjustments during manufacturing, thereby improving focus accuracy while managing device complexity through advance preparation.
Solution Approach 2:
The calibration system applies self-service by using the manufacturing apparatus itself to perform the calibration. The same laser and build plate used for manufacturing are utilized to create and analyze test patterns. The system automatically determines optimal focus settings through image analysis of the test patterns, eliminating the need for external specialized calibration equipment and reducing overall device complexity.
2Manufacturing precision
If multiple test patterns are created at different focus settings to determine optimal focus, then manufacturing precision is improved, but loss of time increases due to additional calibration steps
Solution Approach 1:
The patent performs focus calibration as a preliminary action before production runs. By determining optimal focus settings for various positions and power settings in advance and storing them in a lookup table, the system eliminates the need for repeated time-consuming calibration during manufacturing. The one-time calibration investment pays off through rapid access to pre-determined optimal settings during actual production.
Solution Approach 2:
The system creates multiple test patterns at different focus settings (excessive action) to ensure comprehensive coverage of the parameter space. By testing more focus settings than the minimum required, the system captures the optimal settings more accurately and creates a more robust lookup table, improving solidification accuracy while the calibration time is incurred only once during setup.
3Reliability
If focus calibration is performed for various positions and power settings, then reliability of additive manufacturing is improved, but productivity decreases due to extended calibration procedures
Solution Approach 1:
The patent performs comprehensive focus calibration for various positions and power settings as a preliminary action before production. The results are stored in a lookup table that enables rapid retrieval of optimal settings during manufacturing. This one-time extensive calibration improves process reliability by ensuring optimal focus conditions are always available, while minimizing impact on productivity through fast lookup during actual production runs.
Solution Approach 2:
The system creates a copy of optimal focus settings in the form of a lookup table that stores pre-determined parameters for various positions and power settings. Instead of performing complex real-time calculations or repeated calibration during manufacturing, the system copies and retrieves appropriate settings from the lookup table, maintaining high reliability while preserving manufacturing throughput.
4Measurement precision
If image analysis is used to determine characteristics of test patterns, then measurement precision is improved, but device complexity increases due to additional sensing and processing requirements
Solution Approach 1:
The calibration system applies self-service by using the existing imaging capabilities of the manufacturing apparatus to analyze test patterns. The same camera or sensor system used for monitoring manufacturing processes is utilized for focus calibration. The system automatically processes images to determine characteristics such as pattern sharpness, contrast, or geometric features, eliminating the need for separate specialized measurement equipment and reducing overall device complexity while maintaining high measurement precision.
Solution Approach 2:
The imaging system serves multiple functions: it monitors the manufacturing process, creates test patterns, analyzes pattern characteristics for focus calibration, and potentially performs quality inspection. By making the imaging system universal and multi-functional, the patent improves measurement precision for focus calibration without adding dedicated specialized equipment, thereby managing device complexity through versatile component utilization.
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 method improves the accuracy of focus settings, ensuring precise solidification of metal objects by determining a calibrated focus setting that enhances the overall quality and reliability of additive manufacturing processes.
Implementation Method 1
a solidifying device arranged for emitting a beam of electromagnetic radiation on the surface level for solidifying a selective part of said material
Implementation Method 2
The solidifying device comprises a focus member that is arranged for adjusting a focus setting of said beam of electromagnetic radiation
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
The invention relates to a method for calibrating an apparatus (1) for producing an object by means of additive manufacturing. The apparatus comprises a process chamber (3), as well as a support (5) for positioning the object (2) in relation to a surface level of a bath of material (4) to be solidified. A solidifying device (7) is arranged for emitting a beam of radiation (71) on the surface level for solidifying a selective part of said material. The solidifying device (7) comprises a focus member (76) for adjusting a focus setting. The method according to the invention comprises the steps of controlling the solidifying device for making test patterns (a - i) at different focus settings. A calibration system (8) with a sensor unit (81) is used for determining characteristics of test patterns, and a calibrated focus setting is determined based on the characteristics.