Visual fiber placement inspection

An apparatus for inspecting a composite structure formed from one or more composite tows by an automated fiber placement machine, the apparatus comprising:

• a composite comparison device (CCD), for comparing a visual image of at least a portion of the composite structure to a virtual image of the at least a portion of the composite structure;
• a composite programming system (CPS);
• and
• a machine control system (MCS);
• the CPS being configured for determining where all tows will be dropped and/or added to meet boundary and interband gap/overlap criteria set out by a designer of a composite structure, and providing CPS outputs including, a numerical control (NC) file and a theoretical ply profile;
• the NC file representing the path of a compaction roller in a fiber placement head of a fiber placement machine, and being provided as an input to the MCS;
• the theoretical ply profile representing each band of tows as it is laid, as a course, onto the surface of a tool, or the surface of a previously laid ply of the composite structure, and being provided as an input to the CCD;
• the MCS being configured for utilizing the NC file for driving the fiber placement machine and/or a tool in such a manner as to lay a tow, or band of tows, at a desired location on the tool;
• the MCS also being configured for providing synchronization commands to the CCD, so that both the MCS and the CCD can be calibrated to the same position along each course;
• the CCD being configured for capturing a visual image of the actual lay-up surface of the tows, as they are laid down by the placement head, and for comparing the actual ply profile as captured in the visual image to the theoretical ply profile.