ScarfRep, Automated Scarf Replication and Repair

The F-35 Lightning II Joint Strike Fighter uses a pre-molded "hard" patch approach for scarf repair of damaged composite structure. This composite repair is a time-consuming, labor-intensive process that is prone to technician-dependent repair quality. Part of the repair process involves fabricating a temporary female tool for patch ply lay-up, and is particularly time-consuming because two molds have to be made, both of which have long cure times (8-hours each). Systems & Materials Research Corporation (SMRC) will develop ScarfRep, an automated scarf replication and repair system to support aircraft outer mold line composite repair using a pre-cured block to make the temporary female tool. In Phase I, feasibility of ScarfRep will be proven by demonstrating the production of temporary female tooling directly by machining pre-cured plaster-like blocks eliminating the time-consuming cure steps in the current process. The block fabrication process is enabled by using structured light scanning to acquire scarf geometry, and convert this information into tool paths for CNC machining. The ScarfRep temporary female tooling will be used to form epoxy and bismaleimide composite hard patches that meet quality and dimensional tolerance requirements.