Monochromatic Lighting for Additive Manufacturing Ink Absorption
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Solution Overview
Problem
Current additive manufacturing techniques using broad spectrum halogen lamps are inadequate for heating build materials patterned with colored and colorless inks, as they emit only a small portion of light within the absorption band, leading to inefficient heating and undesirable effects, limiting the production of colored objects to black and grey.
Innovation Solution
The use of monochromatic light sources that match the peak light absorption of coalescing agents, with a spectral intensity of at least 1×10^12 Wm^-3sr^-1, to efficiently heat and solidify build materials, along with a carriage assembly that carries individually addressable light sources and inkjet printheads for targeted lighting.
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 a wide range of wavelengths is emitted, but only a small portion falls within the absorption band of colored and colorless inks, leading to inadequate heating efficiency
Solution Approach 1:
The patent changes the wavelength parameter of the light source from a broad spectrum (halogen lamp) to a narrow band monochromatic light source. This parameter change ensures that the emitted light falls within the peak absorption band of the coalescing agent, dramatically improving heating efficiency and enabling the use of colored and colorless inks for producing multi-colored objects.
Solution Approach 2:
The patent applies local quality by matching the light source characteristics to the specific absorption properties of different coalescing agents. Different monochromatic light sources with specific wavelengths are selected to match the peak absorption bands of different colored inks, optimizing the heating process for each material type.
2Productivity
If black ink is used as coalescing agent to absorb broad spectrum light, then heating is effective, but the color of manufactured objects is limited to black and grey
Solution Approach 1:
The patent changes the light source from broad spectrum to monochromatic, enabling the use of colored coalescing agents. This parameter change allows the build material to retain its original color while still achieving effective heating through targeted wavelength absorption, thus producing colored objects instead of being limited to black and grey.
Solution Approach 2:
The patent converts the previously harmful effect of light reflection by colored inks (which caused inadequate heating) into a beneficial feature. By using monochromatic light sources that match the absorption bands of colored coalescing agents, the reflected light is minimized and absorption is maximized, enabling both colored objects and efficient heating.
3Temperature
If broad band halogen lamps are used, then general heating is provided, but power consumption is high and unwanted heating effects occur outside the absorption band
Solution Approach 1:
The patent changes the spectral distribution parameter of the light source from a broad band to a narrow band monochromatic output. This concentrates the energy within the specific absorption band of the coalescing agent, improving heating efficiency while reducing power consumption and eliminating unwanted heating effects outside the target area.
Solution Approach 2:
The patent extracts only the necessary wavelength component from the broad spectrum light, using monochromatic light sources that emit specifically within the absorption band of the coalescing agent. This extraction of the useful portion eliminates waste energy and unwanted heating effects.
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 enables the rapid and efficient heating of build materials to coalescing temperatures, allowing for the production of colored objects beyond black and grey by ensuring sufficient radiative energy absorption within a narrow wavelength band, reducing power consumption and unwanted heating effects.
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 lighting device for an additive manufacturing machine includes first light sources each to emit monochromatic light within a first band of wavelengths that includes a peak light absorption of a liquid coalescing agent and second light sources each to emit monochromatic light within a second band of wavelengths different from the first band of wavelengths. Each of the first light sources or each of multiple groups of the first light sources is individually addressable to emit monochromatic light independent of any other of the first light sources or of any other group of the first light sources and each of the second light sources or each of multiple groups of the second light sources is individually addressable to emit monochromatic light independent of any other of the second light sources or of any other group of the second light sources.