Drilling CFRP aerostructures at production pace

As the production of carbon fiber reinforced polymer (CFRP) aerostructures accelerates in the aerospace sector, maintaining stability in composite production becomes crucial. The challenge often shifts downstream to the assembly and drilling of these CFRP components. The International Air Transport Association (IATA) noted a 5.3% rise in passenger demand, highlighting supply chain challenges as a significant issue for airlines by 2025. This demand pressures manufacturers to consistently produce CFRP structures without compromising quality as output increases.

Drilling remains a critical process in composite manufacturing, especially for CFRP wings and fuselage sections. Joints must integrate seamlessly into production to avoid concessions that necessitate additional inspection and rework. In CFRP structures, any concession can trigger extensive repair processes due to the high value and sensitivity of the parts, often leading to cascading rework.

CFRP drilling is particularly vulnerable at the breakthrough point. Uncontrolled exits can cause fiber splitting, delamination, and weakened areas around the hole. Therefore, manufacturers prioritize controlled breakthroughs as a primary quality objective. Unlike metals, composites can vary significantly, especially after local rework, affecting drilling and fastening as production rates increase.

Dry drilling is preferred for CFRP to avoid the abrasive paste formed by lubricant mixed with carbon dust, which can damage tools. Reliable carbon dust extraction is essential for operator health and maintaining stable cutting conditions. Vibratory drilling can assist by breaking swarf into smaller, more manageable pieces, ensuring consistent cutting conditions.

Desoutter Tools' Setitec semi-automatic drilling system addresses the need for repeatability in demanding drilling, reaming, and countersinking tasks. It utilizes quick-change heads with RFID and separates speed from feed control, ensuring consistent operations and reduced cycle times. Semi-automation proves valuable as production volumes rise, allowing engineers to set and maintain parameters like speed, feed, and clamping force for consistent outcomes.

CFRP aerostructures are often drilled as hybrid stacks, combining CFRP with metals like aluminum or titanium. Each material requires different drilling speeds and feeds for optimal hole quality. Electric drilling systems offer independent control of feed and speed, allowing for adaptable parameters through the layers, unlike pneumatic systems that require conservative settings.

The efficiency of electric systems is evident in time savings per hole. For example, drilling a stack with 1.5 inches of CFRP and 0.75 inches of titanium took 46 seconds with an electric process, compared to 2 minutes and 4 seconds with a pneumatic process—a 63% reduction. This improvement compounds across the numerous holes in an aerostructure assembly.

To manage variability inherent in composites, manufacturers are turning to data analytics for better visibility. DeMeter provides real-time monitoring, supporting early detection of process drift and ensuring product conformity. Its latest update includes curve analytics to detect anomalies, aiding in faster root cause analysis and corrective actions.

While upstream advancements like faster tape laying are important, true production efficiency is achieved downstream when each hole meets specifications without concessions. Key factors include dry drilling, effective dust extraction, controlled breakthroughs, and stable parameters across material stacks, ensuring CFRP aerostructures can scale with demand.