Search Results

This paper deals with orbital drilling of sandwich constructions for space applications. Sandwich constructions for space applications are typically made up of thin layers of carbon fiber composite skins separated by an aluminum or carbon honeycomb core. Drilling holes in such structures is required for assembly purposes. A common and significant problem occurs when drilling such structures with conventional methods, namely delamination on the exit side of the composite layers. In this study orbital drilling is investigated as a means of eliminating delaminations and other frequently encountered problems with conventional drilling of laminated composite structures. Holes of different sizes were drilled in sandwich panels using orbital drilling. Both automatic (CNC) and semi-automatic (portable) orbital drilling were investigated. Damage in the vicinity of the holes was assessed by means of microscopic evaluation.

The new materials and material combinations such as composites and titanium combinations used on today's new airplanes are proving to be very challenging when drilling holes during manufacturing and assembly operations. Orbital hole drilling technology has shown a great deal of promise for generating burr free, high quality holes in hard metals and in composite materials. This paper will show some of the orbital drilling development work Boeing is doing with Novator to overcome the obstacles of drilling holes in a combination of both hard metals and composites. The paper will include a new portable orbital drilling system designed for these challenging applications as well as some test results achieved with this system.