Abstract Scope |
Standard requirements for directed energy deposition (DED) additive manufacturing (AM) parts were needed for a new NAVSEA Technical Publication. DED procedure qualification schemes were developed for single-sided integrated build platform (SS-IBP), single-sided non-integrated build platform (SS-NIBP) and double-sided integrated build platform (DS-IBP) applications. The latter may be preferred for distortion control and build productivity where acceptable platform interface properties are possible. These procedure qualification requirements were developed for arc, laser, and electron beam welding-based DED processes using wire or powder consumables. Each procedure qualification scheme included a standard qualification build (SQB) design, nondestructive evaluation test map, property specimen test matrix and qualification records for each application and process combination. Since these metal AM processes cover a range of feature size capabilities that are defined by minimum deposit bead width, SQBs were designed for full scale (~> 5 mm), sub-scale (~2 – 5 mm) and mini-scale (< 2 mm) deposit width features. As a result, there are nine baseline SQB designs for both plate and pipe, eighteen total that include different combinations of specimens depending on the material, scale and application. Each SQB evaluated both thin (single pass wide wall for X & Z specimens) and thick (multi-pass wide block sections for X, Y and Z specimens) features to evaluate potential for anisotropy. Each DED procedure qualification scheme has been demonstrated using either arc, laser and electron beam DED processes based on feature size capability to evaluate buildability and establish typical properties with specific process – material combinations. Good results on full scale SQBs made with gas metal arc pulse (GMA-P) DED on nickel aluminum bronze (NAB) and high strength steel (MIL-100S-1) are reported here. Test criteria logic was primarily on plate and / or wire requirements for integrated build plate interface specimens, and wire requirements for deposit material specimens. |