The fiber placement process automatically places multiple individual pre-impregnated tows onto a mandrel at high speed, using a numerically controlled placement head to dispense, clamp, cut and restart each tow during placement. Minimum cut length (the shortest tow length a machine can lay down) is the essential ply-shape determinant. The fiber placement heads can be attached to a 5-axis gantry or retrofitted to a filament winder or delivered as a turnkey custom system. Machines are available with dual mandrel stations to increase productivity. Advantages of fiber placement fabrication include speed, reduced material scrap and labor costs, parts consolidation and improved part-to-part uniformity. The process is employed when producing large thermoset parts with complex shapes.
Tape laying is an even speedier automated process in which prepregged tape, rather than single tows, is laid down continuously to form parts. It is often used for parts with highly complex contours or angles. Tape layup is versatile, allowing breaks in the process and easy direction changes, and can be adapted for both thermoset and thermoplastic materials. Capital expenditures for computer-driven, automated equipment can be significant, however. Suitable for both simple and complex parts, thermoset tape laying is the current method of choice for wing skin panels on the F-22 Raptor fighter jet.