Thickness Inspection of Composite Parts
Short Abstract:
Spirit AeroSystems Inc. has developed a precision inspection system for automatically inspecting the thickness of composite stringers utilizing an array of laser displacement sensors. These parts have complex geometry and many changes in ply layup count. In addition, these parts are long, with the longest stringer being approximately 17 ft. Challenges associated with part orientation and ply ramp location proved prohibitive for consistent inspection. Spirit’s response for an improved technique is the inspection of double omega stringers (iDOS), which utilize two laser displacement sensors, calibrated to each other through a built-in calibration standard. iDOS is easily programmable to calculate the thickness at any required cross-section of a given part. The two lasers are mounted on a moving gantry that extends out into the inspection volume, which is located between two precision conveyor belts, each 12 ft long. A simple projection laser is utilized to identify the starting location of the stringer or strap in relation to the line displacement array. Utilizing the combination of a linear traverse and conveyor system, full coverage of a wide variety of part types was obtained with readily obtainable off-the-shelf components. iDOS provides a precise and fully autonomous inspection solution to a once highly manual and time-consuming process.
