DLP Printing Control via Absorbance Ratio Calibration
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Solution Overview
Problem
Traditional DLP printing methods require extensive material usage and repeated experiments to establish an accurate relationship between exposure time and forming thickness, which is cumbersome and wasteful, especially for soft materials where layer thickness measurement is challenging.
Innovation Solution
A DLP printing control method that introduces solid and liquid absorbance per unit thickness and a curing threshold time, using a single-layer curing model based on energy accumulation to calibrate the exposure time for desired thickness, incorporating a solid-liquid absorbance ratio to correct deviations and optimize material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional forming experiments are conducted to obtain time-thickness data points, then the relationship between exposure time and forming thickness can be established, but a large amount of photocurable material is consumed and the process becomes cumbersome
Solution Approach 1:
The patent uses optical density measurements as a proxy copy for direct thickness measurement. By measuring the optical density of the photocurable material before and after curing, the system can calculate layer thickness without physically measuring or destroying the formed structure. This copying approach eliminates material waste while maintaining measurement accuracy.
Solution Approach 2:
The patent replaces mechanical thickness measurement methods with optical absorption-based measurement. Instead of using physical calipers or microscopes to measure layer thickness, the system uses UV-Vis spectroscopy to measure optical density changes, which are then converted to thickness values through the Beer-Lambert law. This substitution eliminates the need for complex measurement equipment and reduces material consumption.
2Adaptability or versatility
If forming experiments are repeated when material composition changes, then accurate time-thickness data can be obtained for new materials, but material waste increases and efficiency decreases
Solution Approach 1:
The patent changes the measurement parameter from direct thickness measurement to optical density measurement. By measuring optical density at different wavelengths and using the Beer-Lambert law, the system can determine thickness for any material composition without re-running forming experiments. This parameter change makes the measurement method universally applicable to different photocurable materials.
Solution Approach 2:
The patent creates a universal measurement method based on optical density that works for all photocurable materials regardless of composition. The Beer-Lambert law provides a universal relationship between optical density and thickness that applies to any absorbing material, eliminating the need for material-specific calibration experiments and enabling direct prediction of forming thickness for new materials.
3Measurement precision
If direct thickness measurement is performed on soft materials, then layer thickness data can be obtained, but measurement accuracy is compromised due to the difficulty of forming stable measurement models
Solution Approach 1:
The patent replaces mechanical thickness measurement with optical measurement. By measuring optical density changes before and after curing using UV-Vis spectroscopy, the system can determine thickness without physically contacting or mechanically measuring the soft material. This substitution eliminates the difficulties of creating stable measurement models for soft, deformable materials.
Solution Approach 2:
The patent introduces optical density as an intermediary parameter between the curing process and thickness measurement. Instead of directly measuring the difficult-to-capture thickness of soft materials, the system measures the optical density of the material, which serves as a stable intermediary that can be accurately measured and then converted to thickness values through established optical laws.
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 reduces material waste, improves prediction accuracy, and enables precise control of the printing process by directly obtaining DLP printing parameters through simpler tests, applicable even for materials with weak mechanical properties.
Implementation Method 1
a digital micromirror device (DMD) reflects ultraviolet (UV) light carrying graphic information to convert a photosensitive resin in a liquid state into a solid with a certain thickness
Implementation Method 2
measuring a liquid absorbance Al and a solid absorbance As per unit thickness of the photocurable material with the light absorber
Data Source
AI summary
A control method for digital light processing (DLP) printing based on an absorbance of a photocurable material includes: adding a light absorber to a photocurable material for DLP printing, measuring a liquid absorbance and a solid absorbance per unit thickness of the photocurable material at different concentrations of the light absorber, calculating an actual solid-liquid absorbance ratio, and comparing the ratio with a theoretically predicted value of a solid-liquid absorbance ratio to obtain an actual concentration of the light absorber in the photocurable material; measuring a curing threshold time of the photocurable material, substituting the solid absorbance per unit thickness, the liquid absorbance per unit thickness and the curing threshold time into a single-layer curing model to obtain a relationship between an exposure time tT and a curing thickness H; this method can accurately obtain the exposure time corresponding to the thickness of any material that needs to be printed.