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Composites are usually made near net shape. They usually require trimming, sanding, painting, drilling, grinding, and the like. Composites are weak in the directions transverse to the fibers and are subject to delaminating. Generally, the same types of tools that are used for metalworking can be used. Tooling companies sell special tools designed for composites with specific kinds of reinforcement. Carbon tends to be brittle and Kevlar tough. Tools tipped with carbide or impregnated with diamond flakes are common. Cooling may be necessary to prevent overheating and damaging the matrix material.

Assembly/Joining Adhesive bonding is the most common method used for joining polymer composites. The adhesives used can be one-part or two-part adhesives and cure at room temperature or elevated temperature. The materials are similar to those used for matrix materials and chosen with many of the same considerations in mind. Surface preparation is extremely important to the quality of the bond as is the choice cure cycle. Mechanical fastening uses methods similar to metal joining, that is, rivets, bolts, pins, and the like. Care must be used as a hole will reduce the strength of the composite and increase the potential for delamination. Often, reinforcing pads, doublers, must be used. Fastener materials, especially in carbon composites, can cause galvanic corrosion. Hence, nickel, nonmetal, and titanium are commonly used. Table 1.6 lists some of the property and performance considerations in the choice of assembly method.

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