Uncured Resin and Creating Smooth results - Deft Resin

I am curious or perhaps I don’t fully understand the reason for cleaning a print (using Deft resin). For instance, if I want a smooth result, I would expect that the layer of uncured resin sticking to a print would harden with UV exposure (405nm) and even be smoother than a print cleaned because it would cover the print lines? Yet, it seems with my prints, the uncured resin does not cure even after exposure to UV light. I find that odd. I would expect it to cure just like it does from the led display light. I am confused.

Make sure it is UV light with a wavelength of 405nm, and the curing time is appropriately longer. Make sure that the quality of the resin applied to the model is correct. If it does not cure, there should be a problem with the quality of the resin.