High Speed, Substrate Safe Low Observable Coating Laser Stripping

WP-2146

Objective

The current baseline processes for low-observable (LO) coating removal consist of using one or two of the following materials and processes: chemical strippers, hand sanding, wheat starch blasting, plastic scrapers, and solvent-soaked Scotch-Brite® pads. These methods use hazardous materials, generate hazardous waste, emit solvents and hazardous air pollutants, and cause ergonomic damage to workers. Moreover, removal of the specialty coatings is particularly difficult and time consuming due to coating thickness, coating chemistry, and the fillers that are added.

The objective of this project is to develop an environmentally friendly laser coating removal process for rapid and substrate-safe stripping of specialty coatings from U.S. Air Force (USAF) stealth aircraft as well as Army helicopters and ground vehicles.

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Technical Approach

The advent of four recent technology breakthroughs will be applied to make selective stripping of LO coatings possible: (1) high-powered (6 kW to 15 kW) fiber lasers, which can be easily adapted for full aircraft type stripping efforts due to the fiber optic beam delivery method; (2) a novel patent-pending polygon scanner; (3) an innovative non-destructive coating thickness sensor for LO coatings; and (4) a second sensor based on either thermal, acoustic, or chemical species. Development of an algorithm for data fusion of the sensor information to apply the appropriate amount of laser power to be delivered at the precise location will enable coating strip rates between 0.7 to 3.5 square feet per minute (ft2/min) to be achieved, which is the time to remove all the layers of the specialty coating, whether 10 or more than 75 mils thick, down to the base primer layer. Wheat starch removal rate of the B-2 specialty coating is 0.09 ft2/min. A small effort will look at leveraging these novel technologies for extremely rapid removal of Army chemical agent resistant coating (CARC) on thick-plate aluminum armored vehicles (light armored vehicles, advanced armored vehicles, HUMVEEs, etc).

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Benefits

The laser coating removal process has the potential to greatly increase the strip rates above the current LO coating removal methods without damaging the composite substrates. Laser coating removal is also an environmentally friendly method that does not produce a secondary waste stream, only the ablated coating will remain and will be captured in a high-efficiency particulate air (HEPA) filter system, reducing or eliminating worker exposure to hazardous materials and eliminating the hazardous waste streams associated with current materials and processes. Additionally, the laser coating removal process is an automated process that will reduce labor costs and long-term impacts and costs associated with worker damage caused by the ergonomically challenging manual and media blasting methods currently used for LO coating removal. Laser coating removal also has the potential for selective coating removal; therefore, race-tracking of an area or removal of the LO material while leaving the primer intact are possible scenarios. (Anticipated Project Completion - 2015)

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Points of Contact

Principal Investigator

Mr. Alan Fletcher

Air Force Research Laboratory

Phone: 937-255-7481

Fax: 937-656-4419

Program Manager

Weapons Systems and Platforms

SERDP and ESTCP

Document Types

  • Fact Sheet - Brief project summary with links to related documents and points of contact.
  • Final Report - Comprehensive report for every completed SERDP and ESTCP project that contains all technical results.
  • Cost & Performance Report - Overview of ESTCP demonstration activities, results, and conclusions, standardized to facilitate implementation decisions.
  • Technical Report - Additional interim reports, laboratory reports, demonstration reports, and technology survey reports.
  • Guidance - Instructional information on technical topics such as protocols and user’s guides.
  • Workshop Report - Summary of workshop discussion and findings.
  • Multimedia - On demand videos, animations, and webcasts highlighting featured initiatives or technologies.
  • Model/Software - Computer programs and applications available for download.
  • Database - Digitally organized collection of data available to search and access.