Effect of clad height, substrate thickness and scanning pattern on cantilever distortion in direct metal deposition

Abstract

In metal additive manufacturing, moving heat sources cause spatial and time-dependent variations of temperature and strain that can lead to part distortions. Distortion prediction and optimized deposition parameters can increase the dimensional accuracy of the generated components. In this study, an analytical approach for modeling the effect of clad height and substrate thickness is experimentally validated. Additionally, the influence of the scanning pattern as a function of clad height and substrate thickness is determined experimentally. The analytical model is based on the cool-down phase mechanism and assumes the formation of constant thermal shrinking forces for each deposited layer. The model accurately predicts longitudinal cantilever distortion after experimental calibration when compared with similar experimental conditions. For multi-layer deposition, the scanning pattern has the largest influence on distortion for thin-walled substrates. An optimized deposition strategy with longitudinal scanning vectors leads to a distortion reduction of up to 86%. The results highlight the potential of mechanical modeling and scanning strategy optimizations to increase the shape accuracy for industrial applications in the field of additive manufacturing.

Parameters Development for Optimum Deposition Rate in Laser DMD of Stainless Steel EN X3CrNiMo13-4

“…( 1) and ( 2), described in Sect. 1 A linear regression method is developed using MATLAB software to correlate the clad geometry ( A c , A m , A R ) as well as Ḋ against a combination of process parameters f (s , v , ṁ), given by: for 2 ≤ s ≤ 3 [mm] and 600 ≤ v ≤ 1400 [mm/min] and 9 ≤ ṁ ≤ 21 [g/min]. The combined parameter X is established from optimizing the exponents , , to maximize the regression coefficient R 2 .…”

“…In Laser Direct Metal Deposition (DMD), the laser beam melts the powder feedstock and a thin layer of the metallic substrate and generates a melt pool of powder and substrate materials. Thus a layer of metal is deposited on the substrate during relative movement between the substrate and the laser nozzle [1,2]. The powder particles are delivered into the melt pool by carrier gas, and the melt pool is protected from oxidation by a shielding gas.…”

Optimizing laser power of directed energy deposition process for homogeneous AISI M4 steel microstructure

“…Some advantages of DED process over PBF (laser (L-PBF) or electron beam (EB-PBF)) are their high versatility and controllability, increased build rates and volumes, and lower material powder required [20]. PBF processes generally allow building high resolution parts [21]; while DED processes are generally suitable for near net shape products, cladded parts operating in extreme conditions, and repaired high-valued components [6,22]. The current study is focused on improving DED part quality by optimizing the laser power function thanks to 2D finite element (FE) simulations.…”