Robotic arc directed energy deposition (DED) provides maximum build volume, flexibility, and affordability for building large components, adding features to components, and repair. In particular, arc DED AM can be used to replace nickel aluminum bronze (NAB) and stainless steel (SS) castings on high mix, low volume, and long lead schedule marine components. This paper describes a National Shipbuilding Research Program (NSRP) project that converted a range of gas metal arc (GMA) welding systems into DED systems using robotic computer aided manufacturing (CAM) software. It also developed a large format multi-process “hybrid” robotic DED gantry testbed for shipbuilding applications and developed DED technology for NAB and SS propeller blades.
For both materials, procedures were developed and evaluated to the procedure qualification requirements in NAVSEA S9074-A4-GIB-010/AM-WIRE DED – Requirements for Metal Directed Energy Deposition Additive Manufacturing (AM). Here single-sided integrated build platform standard qualification builds (SS-IBP SQBs) were made and compared to filler, wrought, and cast material equivalents for acceptance criteria for DED AM procedure requirements but design property “fitness for service” approval was outside scope of project and is a topic for future work. The procedures were then used to prototype a small NAB high-skew propeller blade, and a large hollow SS high-skew propeller blade. Both builds used 4-axis build models that were segmented into portions and incrementally re-positioned to manage the high skew blade sections. Based on the results here, robotic GMA DED AM will provide a solution to supply chain problems for propellers. Ongoing work is in-place to improve as-deposited surface finish by application of gravity-aligned deposition in the build models, and commercialization of NAB DED propeller manufacturing with an American manufacturing company. Ongoing work will also improve the economics of these DED AM for large-format metal digital/additive manufacturing by developing sensors and controls for “lights-out” robotic systems.
Learning Objectives:
- Shows the path of implementation of a component under NAVSEA
- An understanding of Robotic Arc Direction Energy Deposition of Large Format Marine Propellers.
