The Air Logistics Center’s primary method to remove organic protective coatings (i.e., paint and primers) from aircraft structures is with methylene chloride-based chemical stripping compounds, which are considered environmentally hazardous chemicals. In the near future, protective coatings must be removed by cost-effective, environmentally-clean processes. The disadvantages of chemical paint stripping include long processing times, the use of expensive and hazardous chemicals, and exposure of personnel to special disposal techniques required to minimize environmental impact. Methylene chloride and other hazardous chemicals currently are regulated by the Environmental Protection Agency.
The prime objective of this program was to develop an automated, low-cost paint removal capability for large aircraft with minimal environmental impact. The program established an automated stripping process with the following characteristics: a 94 percent reduction in hazardous waste generation, a 95 percent increase in system availability, and a 50 percent reduction in manhours.
The overall program accomplished the following: definition of the needs and requirements for an automated system; optimization of the paint removal process/system; validation of process acceptability relative to the mechanical properties of aircraft substrates of selected aircraft; design and fabrication of a cell based on these assessments; validation of system capabilities in-house; and installation, demonstration, and acceptance testing at the Oklahoma City Air Logistics Center, OK. The completed Large Aircraft Robotic Paint Stripping (LARPS) system utilized highpressure water to remove paint from C-135 and B-1 aircraft and provided the technical capability to strip almost all other aircraft in the Department of Defense and commercial inventories. An additional part of the project was undertaken to demonstrate a high-pressure water coatings removal process for use in a naval shipyard. This represented a joint initiative with the U.S. Navy that was fully funded by the Navy.
The LARPs validation test was completed at the contractor’s facility (Robotic System) and at the Oklahoma City Air Logistics Center. The validation test verified its functionality. This project was completed in FY 1995 and transitioned to the Environmental Security Technology Certification Program (ESTCP) for further demonstration and validation of the technology.
No hazardous waste will be generated by the LARPS system. The limited amount of water left after repeated recirculation by the closed-looped system is considered regulated waste water by state and Federal agencies. Paint chips are disposed of without containing residual chemical strippers. The total projected savings/cos t avoidance is estimated to be $4.6 million/year. This is a high-priority project to reduce hazardous waste, exposure of personnel to a hazardous environment, cost, and aircraft production flow time.