The Influence of Static and Dynamic Platform Characteristics on Hole Quality, Cycle Time and Tool Wear When Drilling Aerospace Metal Alloy Stacks

The need to drill several thousand holes per aircraft through composite and hybrid material stacks is a large challenge for the aerospace assembly process. The ability to produce high quality holes for the lowest tooling costs is at the forefront of requirements for aircraft assembly factories worldwide. Consequently, much research has been conducted into tool design and development, however, the effect of drilling platform characteristics has not been well covered in literature.
Respectively, this research has compared the drilling abilities of a 5-axis precision CNC platform, a hybrid parallel kinematic machine and an articulated robotic arm fitted with a drilling module. In-process force measurement and post process hole and tool analysis methods were used to better understand the effect of static and dynamic platform characteristics on the achievable hole quality, cycle time and tool wear when drilling aerospace metal alloy stacks.
Consequently, tool supplier recommended drilling parameters were found to perform well on the precision CNC platform but were less than optimum for the hybrid parallel kinematic machine and articulated robotic arm fitted with a drilling module. As a result, commercially viable optimised drilling parameters were generated for each platform, leading to improved hole quality, reduced cycle time and a maintained rate of tool wear. This paper has initiated the development of commercially relevant research questions however, further research with more challenging conditions, materials and machining programmes are required as further research.