Connecting deposition
and machining.

Problem

DED often relies on preset laser power, machine feed rate, and powder flow. Actual deposition can deviate from the intended geometry, leaving insufficient material and requiring additional deposition—or restarting the build. A key challenge for closed-loop control is adjusting powder delivery quickly enough to correct these deviations.

Thermal management presents another challenge. The substantial heat input creates temperature gradients that can lead to distortion, cracking, and residual stresses.

Approach

ARMS developed a Dynamic Powder Splitting System (DPSS) that rapidly adjusts powder delivery, enabling responsive closed-loop deposition control. The broader Adaptive, Productive, and Quality (APQ) framework combines monitoring of deposition height, width, and temperature with coordinated regulation of energy fluence and powder fluence.

To address thermal gradients, the ALP module uses an infrared camera to assess the temperature distribution after each deposited layer. The controller then automatically reorders the deposition sequence in the supplied NC program to reduce temperature gradients.

Demonstrated result

The developed control methods improved deposition productivity and geometric accuracy, while adaptive sequencing addressed thermal gradients during the build.