Even though fiber-reinforced composites can be fabricated into multiple shapes, machined holes for fastening composites parts will likely always be needed. As they drill more holes in greater numbers of composite parts, aerospace manufacturers and their suppliers are looking for more resilient hard-surfaced tools. In response, some tooling specialists are making chemical vapor deposition diamond-coated tools more production-efficient, in comparison with tools tipped with polycrystalline diamond. Waterjet machining is also being improved for aerospace composite work. Piercing by abrasive waterjet has been significantly improved to reduce fiber damage and take advantage of the tool-less nature of the process. Other kinds of aerospace composites likewise require variations to standard machining processes. Ceramic-matrix and metal-matrix composites are being used more in high-heat engine applications and other areas to reduce weight. An alternative tool-based approach machines various composites by combining mechanical and nonmechanical energies, lowering tool forces and increasing hole quality.