What are causes for incomplete cure of UV/blue-visible light cure products?
There are many other factors that could inhibit the cure of the bulk of the adhesive including the distance of the light source from the adhesive, package geometry, absorbance by intervening substrates, the use of an inappropriate light source, or even the use of a bulb past its work life. Typically, the incomplete cure of an adhesive can be attributed to insufficient intensity of light at the bondline. The most common factor causing in-sufficient intensity is too large a distance between the light source and the adhesive. The light intensity can decrease by as much as 75 percent (depending on the source used) for each doubling of the distance between the tip of the light wand and the adhesive bondline. For this reason, the light wand should be kept as close to the adhesive as possible and fixed in position. It is also important to understand how package geometry can affect the intensity of light at the adhesive layer.
