For optimum ultraviolet (UV) curing efficiency, the material to be cured must match the specific spectral output of a UV bulb. This output, measured in nanometers at each wavelength throughout the UV range, is the defined spectral measurement used to quantify one UV bulb type from another. Each bulb has its own unique characteristic, or footprint, which separates one type of bulb from another. The chemical composition within the bulb gives the type of bulb its unique spectrum. In the UV curing process, each bulb is classified by the output in each UV spectral range, identified as UVA, UVB, UVC or UVV. UV curable materials utilize photo initiators, which are formulated to react to energy from specific wavelengths of UV light. The UV energy provides the ability for cross-linking, thus changing any liquid or paste to a semi-solid or solid form. Matching the photo initiator wavelength to the specific wavelength of the UV bulb will help assure a proper cure for the ink, coating or adhesive.
This match is paramount to proper curing, and thus, the success of any curing process. Matching the bulb output to the material’s curing characteristics will help to assure a successful cure. Factors such as UV material formulation, coating thickness and process speed play an important role in selecting the correct UV curing system. Once the equipment is selected, the bulb type is matched to the material requirements for proper material cure.