Precision Machining of Composite Structures

Composite hybrid stacks are very difficult to post process with traditional methods. Carbon and glass fiber reinforced polymers are very abrasive and wear traditional tooling quickly. Furthermore, metallic honeycomb reinforcement has different characteristics requiring different speeds and feeds accelerating tool wear further. Using a laser to machine composite hybrid stacks will eliminate a need for expensive tooling. The Phase I research demonstrated feasibility for laser machining hybrid composite stacks. The Phase I research showed the heat affected zone could be kept below 0.010” without interlayer delamination, blow out plies, or other mechanical damage. The Phase II will develop a prototype machine capable of machining countersinks in hybrid composite stacks up to 1” thick. Phase II base will: 1. Utilize multiphysics simulations to predict the machining process. 2. Develop feedback to control the machining process. 3. Implement a localized safety system so the process can be portable without being hazardous to workers. 4. Manufacture, characterize, and non-destructively inspect the machined specimens. Phase II option will: 1. Develop a refined correlation between physical machining process and simulations. 2. Refine the user interface. 3. Refine and finalized the feedback systems developed in phase II base. 4. Demonstrate machine effectiveness with test coupons.