In normal operation, jet engine fan blades are subject to foreign object damage (FOD) and erosion. A cost efective alternative to new replacement parts is to repair the damaged or worn blades. In a typical fan blade repair, the damaged leading edge section is removed and a "patch" is electron beam welded in place. The electron beam welding process,  which is performed in vacuum, is ideal for preventing oxidation and maintaining the material properties of the titanium fan blade. In the final step, the patch is machined and contoured to the original shape.