Laser Stripping of Helicopter Blades, Phase II
Problem:
Due to
operational requirements, NADEP Cherry Point must refurbish on average,
approximately 150 main rotor blades each month. Sikorsky refurbishes
approximately 80 additional blades per month. To refurbish each blade, workers
must remove at least the topcoat (paint) from each blade. Because these blades
use lightweight fiberglass composite substrates, coatings must be removed
manually using air-driven orbital sanders. The process requires an extensive
amount of tedious labor in a dusty, uncomfortable environment. Workers complain
of repetitive stress injuries and fatigue. Lost time is significant. Because
coatings contain toxic chemicals, personnel must wear extensive personal
protection equipment to avoid dust inhalation. Conventional paint removal
techniques, such as chemicals, plastic media blasting, or glass (sand) blasting,
are known to damage the substrate and, therefore, are not viable. In many
cases, this media will become contaminated with lead and chromates found in the
coatings, thus producing secondary hazardous waste streams that require costly
disposal. Hand sanding with air-driven orbital sanders can also cause damage to
the substrate resulting in delays due the additional rework operations required.
This manually controlled sanding method is, however, the only coating removal
method currently approved for blade refurbishment operations at NADEP Cherry
Point.
Approach:
Coordination between the electromechanical positioner and the laser beam scanner. This coordination is needed to achieve optimum removal efficiency with minimum thermal impact to the substrate.
Implementation of target point surface color recognition and the associated real time feedback to the laser-firing controller. This feature ensures that the lasers stop firing when the target’s coating layer is removed even if the coating thickness at different points on the blade varies randomly.
Integration of multiple individual laser coating-removers into a unified and coordinated firing pattern.
System engineering to
provide laser safety, user-friendly controls, operator interfaces, waste
collection, emission control, problem diagnostics, all in a reliable mass
production repair environment.
Anticipated Deliverables:
Fully functional prototype system installed at NADEP Cherry Point
Operation and System and Maintenance Manual
OEM Approved Depainting Device (based on Phase I: OEM Approved Depainting Process)
Final Report (based on evaluation of the NADEP Cherry Point system)
Capital Appropriation Request from Sikorsky (deliverable to project team members, only)
Participants:
NCMS Contact: Customer Care, (734) 995-0300, customercare@ncms.org