Digital Ply Tracing Software for Composite Repairs

With the increasing usage of composites for aerodynamic surfaces, the use of bonded composite repair processes are becoming more common. The repair process remains a largely manual process, with repair technicians scarfing or stepping, tracing the plies, fabricating repair patches and finally bonding the patch. The patch fabrication process becomes increasingly tedious and tiring due to cutting and tracing of each individual ply twice for thermal surveying and the final repair patch. We have developed a system that can replace the tracing and cutting components of the fabrication process using low cost, commercial off the shelf (COTS) tools. We present the ply boundary extraction method used and detail the nesting algorithm used to produce the final plies. Our software is benchmarked against the manual process with a list of successfully cut materials using a low cost fabric cutter with a steel drag blade. Our system provides up to 60% improvement in ply fabrication times for lower strength materials (e.g. fiberglass) and comparable times for high strength materials (e.g. carbon fiber).