Monochromatic LED Lighting for Additive Manufacturing
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Solution Overview
Problem
Existing additive manufacturing techniques using broad-spectrum halogen lamps are inadequate for heating build materials patterned with colored and colorless inks, as they absorb only a small portion of the light, leading to insufficient heating and undesirable effects.
Innovation Solution
The use of monochromatic light sources that match the peak light absorption of the coalescing agents, with a spectral intensity of at least 1×10^12 Wm^-3 sr^-1, to efficiently generate heat and coalesce the build material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If broad-spectrum halogen lamps are used for heating build material, then the lighting system can cover a wide wavelength range, but the colored and colorless inks absorb only a small portion of the light resulting in insufficient heating efficiency
Solution Approach 1:
The patent changes the wavelength parameter of the light source from broad-spectrum halogen to monochromatic LED light. By selecting a specific wavelength (e.g., 450nm blue light) that matches the peak absorption of the coalescing agent, the system achieves efficient energy transfer and heating without the waste inherent in broad-spectrum illumination.
Solution Approach 2:
The patent applies localized quality by matching the light wavelength specifically to the absorption characteristics of the coalescing agent used. Different colored inks (yellow, magenta, cyan) have different peak absorptions, and the system selects the appropriate monochromatic wavelength for each, ensuring optimal local heating efficiency at the ink-coalescing agent interface.
2Duration of action of stationary object
If broad-spectrum halogen lamps are used, then general illumination is provided, but heating time is excessive and manufacturing productivity is reduced
Solution Approach 1:
By changing from broad-spectrum to monochromatic light with wavelength matched to the coalescing agent's peak absorption, the system dramatically reduces heating time. This parameter change in light wavelength enables rapid coalescence and significantly improves manufacturing throughput.
Solution Approach 2:
The monochromatic LED lighting enables the system to rush through the heating phase quickly by concentrating energy at the optimal wavelength, skipping the prolonged ineffective heating period that characterizes broad-spectrum halogen lamp operation.
3Use of energy by stationary object
If broad-spectrum halogen lamps are used, then illumination is provided across all wavelengths, but energy waste occurs due to light outside the absorption band
Solution Approach 1:
The system changes the spectral parameter of the light source from broad-spectrum to monochromatic, eliminating energy waste by emitting only at wavelengths that are effectively absorbed by the coalescing agent. This parameter optimization ensures near 100% energy utilization efficiency.
Solution Approach 2:
The patent extracts only the useful portion of the spectrum by using monochromatic LED light at the specific wavelength matching the coalescing agent's peak absorption. This extraction eliminates the wasteful broad-spectrum emission of halogen lamps and concentrates energy where it is needed.
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 rapid and efficient heating of build materials with colored and colorless inks, reducing heating time and improving the manufacturing process for color objects beyond black and grey.
Implementation Method 1
exposing the patterned build material to monochromatic light within a band of wavelengths that includes a peak light absorption of the coalescing agent
Implementation Method 2
Light absorbing components in the coalescing agent absorb light to generate heat that sinters, melts or otherwise coalesces the patterned build material
Data Source
AI summary
In one example, a non-transitory processor readable medium having instructions thereon that when executed cause an additive manufacturing machine to expose build material to a light source emitting monochromatic light within a band of wavelengths that includes a peak light absorption of a liquid coalescing agent to be dispensed on to the build material.