Cleaning operations are a critical element in the maintenance and repair of Department of Defense (DoD) and Department of Energy weapons systems. Cleaning performance verification procedures have been slow and expensive to develop because most available verification methods are not suitable for real-time measurement.
This project seeks to identify, develop, and evaluate an operable inline/online cleaning performance verification method, consisting of a visual cleaning performance indication (VCPI) method that will accurately assess part cleanliness.
The Air Force Research Laboratory has provided information describing the contaminants and has assisted with cleaning processes of importance to the Air Force, while Carderock has provided similar information for the Navy. Initially, target contaminants were identified for large surface cleaning operations. Commercially-available, environmentally and health safe dyes that attach to the target contaminants were then selected. Next, exploratory tests on bulk contaminants and surface contaminated coupons were conducted to demonstrate the selective labeling of target contaminants. Feasibility tests of the VCPI concept were conducted utilizing test coupons, major DoD contaminants, and the best VCPI combinations and delivery methods for cleaning operations. The relationship between color visibility and residual contaminant levels for the VCPI-treated contaminated coupons was demonstrated, and the VCPI components and their compatibility with DoD cleaning operations and construction materials were determined.
Commercially-available VCPI candidates have been identified. These candidates have been down selected against the safety, environmental impact, and VCPI process requirements criteria. The VCPI method has been shown to selectively label a broad range of contaminants without labeling the material surface or imparting detrimental effects on the material with respect to paint adhesion or corrosion rate. Future testing should include parts and eventually large surfaces such as aircraft and ships. For porous coatings, such as paints and rubbers, the VCPI technique indicates that residual hydrophobic contaminants migrate into the coating and are not easily removed by current cleaning protocols. The dye label will appear as a stain in these porous surface cases unless the residual contaminant is removed.
The use of this technology will result in the reduction of hazardous and non-hazardous waste and processing costs by avoiding excessive and inadequate cleaning methods and by enhancing the ease of evaluation and implementation of environmentally-friendly cleaning alternatives.