Non-Reciprocity of Exposure of UV-Curable Materials and the Implications for System Design
R.W.Stowe, Heraeus Noblelight America
Abstract: Using exposure data of various (mostly commercial) coatings, inks and paints, this study demonstrates that differences in irradiance profile will result in different material behavior (properties) and consequently, exposure requirements. Using various quantifiable performance characteristics, this study demonstrates the reciprocity failure of UV exposure. This paper introduces the "E-Ip" chart, showing the relationship between Peak Irradiance, Ip, to Exposure, E, for UV curable materials and simple methods for creating it. To differing degrees, curable materials will exhibit different E-I thresholds of physical property development. Evaluation of the non-reciprocity of any subject material is important to 3-D and multi-lamp system design. It also leads to more precise and more useful exposure requirement specifications for commercial materials, and provides a means of communicating material responsivity essential for production design.