State-of-the-art of numerical simulation of laser powder Directed Energy Deposition process

Additive manufacturing (AM) has been experiencing considerable growth in recent years, especially for metal application. Directed Energy Deposition (DED) is one of the emerging technologies in metal AM. DED selectively deposits material and melts it with a focused high-energy source. Accurate numerical modelling of the DED technique is an important step for the comprehension and the technological improvement of the process, providing significant gains in terms of time and costs. This paper aims to review the existing knowledge on DED numerical simulation, highlighting principal advantages and limitations of different approaches. The key inputs required to model the process properly, and the predictable outcomes are discussed

Effect of process parameters on AISI 316L single tracks by laser powder directed energy deposition

Laser Powder Directed Energy Deposition (LP-DED) process involves complex physical phenomena, which considerably affect the deposition quality. In process optimization, it is a general approach to firstly analyze single tracks to identify process parameters that guarantee an adequate adhesion to the substrate. This paper aims to evaluate the deposition efficiency and the contact angle of AISI 316L single tracks as process parameters vary. Thus, experiments were performed by varying laser power, travel speed, and feeder rotation. Results help both in clarifying the relationship between process parameters and single tracks characteristics and identifying the best combination of process parameters to enhance deposition quality and process efficiency

Thermo-mechanical modelling of the Directed Energy Deposition (DED) process for the optimization of deposi-tion strategies

Directed Energy Distribution (DED) process involves a continuous and subsequent deposition of layers, by means of a laser heat source that melts the feedstock material supplied in form of powders or wires. Laser power, pow- der flow rate, travel speed affect temperature gradient distribution and residual stresses in components. Due to this, the main process parameters’ influence on DED process was investigated, followed by a fine-tuning. The main objective of this work was to compare four simulations with different scanning strategies for the to-be-printed component, focusing on deformation re- sults. To achieve this objective, the 3DExperience software was essential in sim- ulating DED process accurately. Setting up the Finite Element Method (FEM) model, mesh type, material properties, and boundary conditions followed a strict procedure. As final step, once the best case in terms of deformations from a production perspective has been highlighted, the component is subjected to post-processing machining to respect the designed dimensioning and tolerances

A multi-element psychosocial intervention for early psychosis (GET UP PIANO TRIAL) conducted in a catchment area of 10 million inhabitants: study protocol for a pragmatic cluster randomized controlled trial

Multi-element interventions for first-episode psychosis (FEP) are promising, but have mostly been conducted in non-epidemiologically representative samples, thereby raising the risk of underestimating the complexities involved in treating FEP in 'real-world' services