Abstract: Native code for a CNC stitching machine is generated by generating a geometry model of a preform; generating tool paths from the geometry model, the tool paths including stitching instructions for making stitches; and generating additional instructions indicating thickness values. The thickness values are obtained from a lookup table. When the stitching machine runs the native code, it accesses a lookup table to determine a thread tension value corresponding to the thickness value. The stitching machine accesses another lookup table to determine a thread path geometry value corresponding to the thickness value.

Abstract: A stitching system includes a gantry that is movable along a material support table. Mounted to the gantry are a plurality of stitching heads and bobbins. The stitching heads are individually controllable in a z-direction, and the bobbins are individually controllable in the z-direction. Each stitching head is paired with a bobbin. Each pair of stitching heads and the bobbins is controlled synchronously in the z-direction. The stitching system is well-suited for stitching preforms of aircraft wing covers and other preforms having variable thickness and compound, contoured three-dimensional surfaces.

Abstract: A method and apparatus for aligning an actual surface with the internal coordinate system of a machine working thereon is disclosed. A part program controls the motions of a tape laying machine for depositing composite tape on the surface of a mandrel marked with a plurality of reference points. A probe assembly is attached to the tape laying head of the machine and can be used to measure the coordinates of the reference points on the mandrel surface relative to the internal coordinate system of the machine. These measurements and corresponding points on a representative surface permit a transformation function to be generated based upon the rotation and translation of one surface with respect to the other. The geometric data of instructions of the part program are transformed from their orientation relative to the reference surface to a new orientation relative to the mandrel surface by the transformation function before being applied to the tape laying machine.