Utilization of CNC machining in composite part rework

A composite repair system comprising:

• an automated scarfing tool configured to remove plies in a rework zone of a composite structure;
• a database comprising a model of the composite structure having a rectangular shaped theoretical scarfing bottom surface;
• a computer system configured to select a scarf repair model based on a maximum longitudinal distance between two extremities of the composite structure and an aspect ratio of the rework zone, wherein the aspect ratio of the rework zone is a ratio of a width of a longitudinal edge of the rework zone and the maximum longitudinal distance between the two extremities of the composite structure;
• and
• the computer system further configured to identify an actual scarfing bottom surface in a local axis system for the rework zone and modify parameters for a rework program for the automated scarfing tool based on deviations between the theoretical scarfing bottom surface and the actual scarfing bottom surface;
• wherein the automated scarfing tool is further configured to cut reference lines on a tool side surface of the composite structure parallel to all four edges of the theoretical scarfing bottom surface until all four of the edges are cut at a same depth.

A method for repairing a composite structure, the method comprising:

• defining a rework zone on the composite structure;
• selecting a scarf repair model based on a maximum longitudinal distance between two extremities of the composite structure and an aspect ratio of the rework zone, wherein the aspect ratio of the rework zone is a ratio of a width of a longitudinal edge of the rework zone and the maximum longitudinal distance between the two extremities of the composite structure;
• separating the rework zone into sections;
• identifying a theoretical scarfing bottom surface for each of the sections of the rework zone from a model of the composite structure;
• measuring reference locations in each of the sections of the rework zone;
• identifying an actual scarfing bottom surface for each of the sections of the rework zone based on measurements collected at the reference locations;
• modifying parameters for a rework program for an automated scarfing tool based on deviations between the measurements collected at the reference locations;
• and
• removing plies in each of the sections of the rework zone using the automated scarfing tool.