Sealant Application Process and Technology Development

Advanced Materials & Processes (AMP) has identified a viable approach for applying Class B or C sealants that will meet quality criteria for thickness, porosity, continuity, and application time. The project will develop a rapid dispensing process for consistent application of the minimum weight of sealants to solid surfaces. Current methods are time consuming and applicator dependent, resulting in unwanted variation in quality and excessive weight. The process will give consistent results in confined spaces. The process will uniformly spread sealant over the faying surface in a minimum amount sufficient to provide a continuous bead of sealant "squeeze out" along all flange edges after the parts are assembled. Polysulfide sealants typically have a part A and a part B with a viscosity of about 2000+ Poise with a mix ratio that is critical to the performance of the sealant. AMP has identified hand held, pneumatic and electric proportional pumps/dispensers and disposable static mixers with bead and ribbon nozzles as a potential solution to meet the need for accurate control of variable mix ratio, thickness, porosity, and application time. Once this accurate control is established, then robotic application of the sealant with optical confirmation of continuity and bead size will be modeled and then implemented.