@HERE The ceiling does not have a reflector simply because there is not much surface area left after you cut away for the return vents, the fan, and the lamps, especially when you include the margin around these cutouts necessary for manufacturing. I do acknowledge that a reflective surface is always superior to a non-reflective surface, but the difference in the case of the ceiling would be barely measurable, certainly not a significant amount as would be required for a 100% difference in cure time.
Is this a tall part or relatively short?
What is the material being cured? Do you have a data sheet?
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