Electrical Discharge Machining (EDM) of Holes in F-35 Structure

ABSTRACT: Perfect point EDM Corporation has developed a patented technology that is commercially available for aircraft fastener removal known as the edrill system. The unique device is a handheld Electro-Discharge Machining (EDM) unit. The handpiece is similar in size to a small conventional drill motor. Using a tubular electrode the edrill cuts through even the hardest metals at a rate unmatched by conventional drilling techniques. A typical cut through a Titanium fastener (nominal 1/4"size) is about 13 seconds with no more pressure required than to contain the dielectric water used in the process, greatly reducing operator fatigue. Unlike conventional drilling, the edrill leaves no residual heat or debris. It has become evident that the edrill is just as valuable in hole drilling operations in hard alloys used in aircraft construction. A particular problem area in aircraft manufacturing is composite stack materials. Conventional drilling is extremely difficult in metal / Carbon Fiber Resin Process (CRFP) stacks and has potential for damaging the CRFP material. In Phase I Perfect Point demonstrated a process that minimizes the potential damage risks while reducing operator effort and increasing efficiency. Phase II will allow development of a system prototype suitable for manufacturing integration. BENEFIT: The resulting technological advances may be commercialized in the form of tools to be used in the airplane manufacturing process that could result in a significant reduction of manufacturing costs. The commercial product(s) would be of interest to any manufacturer of commercial or military aircraft in which thick, exotic, multiple material stacks (including mixes of composite and metal) are used.