Modular drills provide advantages: Drilling Performance

By Abdelatif Atarsia

Drilling large holes in aircraft structures, whether a wing, a wing box structure or another aircraft component, is neither easy nor cheap. Cutting tools, mainly drills and reamers, with diameters from 12.7 to 38.1 mm (0.5″ to 1.5″) or larger are used on advanced drilling unit machines to drill, open and ream holes in different stacked, or sandwiched, materials, such as carbon fiber-reinforced plastic, aluminum and titanium.

To complete this process, aerospace manufacturing engineers and shop floor personnel usually apply long, expensive tools, such as solid-carbide ones, to produce the relatively small number of holes needed in each structure, leading to an extremely high cost per good hole.

Aircraft joining drills from 12.7 to 38.1 mm in diameter or larger are used to drill stacked materials. Image courtesy of YG-1 Tool (USA)

Process cost includes setup time, tool change time, tool price and the logistics of producing a solid drill, which takes at least twice as long to make as a modular drill head. To reduce the cost, YG-1 Tool (USA) Co. in Vernon Hills, Illinois, introduced its newly developed modular head drills and bodies to the aerospace market. These modular drills maintain the existing geometries successfully produced by solid drills but at a fraction of the price. Although a drill head and body initially cost about 50% more than a solid drill, replacing the head costs 75% to 90% less than a solid drill.