Non-Contact Cure State Measurement

Manufacturing processes are typically delayed from several minutes to several hours while coatings, sealants, and adhesives sufficiently cure to allow subsequent operations. Local environmental conditions can accelerate or decelerate cure depending on the chemistry of the materials, which makes degree of cure a variable over time and ultimately results in built-in down-time to assure sufficient cure is achieved. A technology for determining the relative state of cure for a variety of known coatings, sealants, and adhesives, without compromising the integrity of the applied material, would be a manufacturing enhancement and production time reduction factor. The technology must ultimately be able to accommodate slight variations of chemistry within the chemical classes such as exist among different vendors or due to effects of various fillers and must be measured on substrates consistent with aircraft manufacture. In this SBIR we will develop a design concept for a non-contact cure state measurement instrument that is based on Laser-Induced Fluorescence (LIF) Spectroscopy. Develop a protocol for defining the state of cure for each application category (coating, sealant, adhesive). Demonstrate the proposed approach on the coating (epoxy or urethane), sealant (polythioether or polysulfide), or adhesive (epoxy, acrylic, urethane).