Researchers at Virginia Tech have introduced a novel dimensionless parameter called the 'DED-Arc number' to correlate wire arc additive manufacturing process parameters with bead morphology. Defined as the ratio of actual energy input to the theoretical energy required to melt the material, this parameter unifies process parameters, material intrinsic properties, and melt pool dynamics into a single independent variable. Validation through single-track deposition experiments on aluminum (ER5556) and low-carbon steel (ER70S-6)—materials with significantly different thermal properties—showed that the DED-Arc number effectively identifies material-specific processing windows: optimal deposition ranges of 50–170 for ER5556 and 10–60 for ER70S-6, corresponding to contact angles of 50–90° and height deviations below 0.6 mm. Compared to traditional linear energy density methods, this parameter more accurately reflects material-dependent melt pool behavior. The achievement lays the groundwork for establishing universal process maps, potentially reducing manual trial-and-error costs in developing parameters for new materials and accelerating the validation and industrial application of DED-Arc technology in aerospace, automotive, and other sectors.