Additive Manufacturing Light Source Calibration via Pyramidal Test Structures
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Solution Overview
Problem
Current additive manufacturing devices face challenges in achieving uniform light output from projector-based light sources, leading to inconsistent energy delivery and increased build times, requiring costly calibration equipment and frequent recalibration due to light source degradation.
Innovation Solution
A calibration object with multi-layer pyramidal test structures is used to evaluate light output across the build area, allowing for the determination of light output at each sector and adjustment of controllable elements to achieve uniform energy delivery without additional equipment, enabling dynamic optimization of build times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If light source brightness is reduced to compensate for hotspots, then uniformity of light output is improved, but build time increases due to reduced energy flux
Solution Approach 1:
The patent applies local quality by adjusting the intensity of individual pixels or regions of the light source based on measured hotspot locations. Each controllable element of the light source is independently adjusted to compensate for local variations in light output, allowing different parts of the build area to receive appropriate light intensity without uniformly reducing overall brightness.
Solution Approach 2:
The patent implements preliminary action by performing light source calibration before actual part production. A calibration object is printed first to map light output variations, and compensation values are calculated and stored. This preliminary characterization allows the system to use optimized exposure times during production, avoiding the need to use conservative uniform exposure settings that would increase build time.
2Measurement precision
If traditional calibration equipment is used to measure light output, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies self-service by using the additive manufacturing device itself to perform the calibration measurements. The light source and build area of the device are used to print a calibration object, and the device's own imaging system captures images of this object to determine light output variations. This eliminates the need for external light meters or specialized calibration equipment.
Solution Approach 2:
The patent introduces a calibration object as an intermediary medium between the light source and the measurement process. This calibration object with known geometric features acts as a mediator that converts light intensity variations into measurable image data, allowing the system to indirectly measure light output without requiring direct optical measurement equipment.
3Productivity
If full range of energy output is used, then productivity is improved, but manufacturing precision deteriorates due to overcuring in hotspot areas
Solution Approach 1:
The patent implements dynamics by dynamically adjusting exposure parameters based on spatial location within the build area. The system uses pre-calibrated compensation values to vary exposure time or intensity for different regions, allowing the light source to operate at full power in most areas while applying localized adjustments only where needed to prevent overcuring.
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 allows for the creation of a uniformly intense light source, minimizing build times by dynamically adjusting exposure based on light output variations, reducing the need for costly recalibration and equipment, and ensuring consistent part production.
Implementation Method 1
Some classes of additive manufacturing devices produce polymer parts solidified from a photopolymer resin which has been exposed in a layer-wise fashion to electromagnetic radiation generated by a light source
Data Source
AI summary
Systems, methods and computer program products are disclosed that facilitate measuring the light output of an additive manufacturing device light source without utilizing additional equipment, such as a light meter. Once the light source output has been measured, such information can be utilized for a variety of purposes, including, but not limited to: (i) delivering a uniform amount of light energy over time to each portion of a layer being formed; (ii) adjusting the intensity of each controllable element (e.g., pixel) of the light source to the measured minimum, thereby creating a uniformly intense light source; and (iii) minimizing the build time of layers or portions of a layer being formed based on the maximum intensity available within a given area of the build area.