Selective powder sintering for 3-D printing has
recently become an increasingly affordable solution for
manufacturing made-to-order elements of almost any shape or
geometry. This technique involves heating a bed of powder (such as
polyamide, PA12) to just below its melting point, using an IR light
source to selectively melt a cross section of the powder, then
adding more powder and repeating to form a 3-D object. To reduce
costs and increase printing speed, a photothermal sensitizer is
often added to the powders. Typically carbon-based, with a strong
broadband absorption, adding these sensitizers to the polymer
powders increases the conversion of incident light to heat, which
means greater print speeds. However, carbon-based sensitizers can
only produce black or gray objects. To create white or colorful
prints, visibly transparent equivalents are needed.
