Aerospace cutting tools and the aerospace industry have changed in the last decade. Ten years ago, composite machining was a new technology and aero engines and airframes were produced from exotic alloys. Materials evolve, as do the tools for the production of engine and airframe components. It is in this way that cutting tools have evolved from HSS to solid carbide and then carbide with coatings to accommodate exotic materials and, more recently, composites.
Carbide has since improved with new and finer grades that offer improved strength and productivity. Improved grades of carbide and new geometries and coatings enhance productivity. However, with aerospace cutting tools, the search has been to have a single tool capable of multiple operations.
Composite aircraft skins are penetrable by diamond tools graduated for a specific composite type, composite grade specific cutters. The same is also true of PCD tooling used for milling and routing composite sheets.
High tolerance machining
The development of diamond coatings and carbide grades for composite and exotic alloy machining are only one element of change over the last ten years. Tight tolerance bands, complex cutter forms, and then adding the specific coating for the particular tool are the challenges faced by the manufacturers.
Tolerance levels of critical components are high when aircraft work at extreme speeds with the pressure and forces acting on critical parts. The faster the turbine rotation, the tighter the manufacturing tolerance required. There is no room for loose tolerances in the modern industry. To make parts to these increasingly critical tolerances with ever more complex components and form tools is the challenge.
Aerospace standard tools for a specific material or tolerance, demand that all cutters have individual inspection reports. Certificates of conformity enable OEMs to push their quality control procedures onto the supplier thus relieving repetitive in-house quality control processes. Tools supplied to the aero industry are mostly in fact no longer standard items. 60% of aerospace cutting tools are specials.