The additive manufacturing evolution continues to create better options for making or fixing even the toughest parts. Optomec, which makes directed energy deposition (DED) systems for 3D printing of metal parts, has just demonstrated an additive plugin that—combined with the Siemens Sinumerik 840D numeric control machine—yields simultaneous, five-axis control and can thus print, coat or repair large and complex metal parts more quickly, cheaply and easily while enabling the building of parts not possible before.
Called LENS, the Optomex plugin’s control moves a part seamlessly beneath the laser deposition head, making overhangs obsolete, eliminating the need for support structures and minimizing material removal post processing, cutting build time and saving costs.
LENS product manager Tom Cobbs says the LENS manufacturing process has been optimized for repair of defense and aerospace components. “It is currently in use repairing components at service bureaus and overhaul facilities around the world," says Cobbs.
Repair of high-value metal components on aircraft, especially engines, is essential for maximizing part lifetime and reducing lifecycle maintenance costs. However, “repair methods that add material to worn or damaged areas require exceptional process control and outstanding material quality,” Cobbs notes. “The LENS repair process is highly targeted, precisely adding material to worn or damaged areas with minimal heat effect, enabling repair of the most sensitive thin-walled components such as those found in gas turbine engines. The resulting LENS repairs have mechanical properties that can be equivalent or even superior to wrought materials.”
Cobbs says most aerospace manufacturers are exploring the possibilities of using LENS and DED processes for several reasons: reducing weight by new designs, repair of both safety-critical and other components, and enhancing materials by grading or coating to resist wear or corrosion. He acknowledges that qualifying a new part or process in aerospace takes time. But several aerospace OEMs are edging closer to using additive manufacturing for new build and aftermarket purposes.
Fortunately, LENS control of the Siemens machine is capacious and highly flexible. The machine has a work envelope of 860 X 600 X 610-mm, sufficient to build or repair middle-sized to large parts, such as turbine blades. And LENS can print a variety of materials, including several types of steel, nickel-based alloys, titanium, aluminum, magnesium, cobalt-based wear-resistant alloys and carbide precipitates such as tungsten carbide.