An integrated analytical model for the forecasting of the molten pool dimensions in Selective Laser Melting

Abstract

Selective laser melting (SLM) is one of the most promising processes in the Additive Manufacturing of metals because of the possibility to fabricate complex geometry parts with a wide range of materials. The molten pool dimensions are notoriously crucial for the production of high quality parts, in terms of mechanical properties and roughness, and to control the ‘balling’ phenomenon. In the past, several studies have been conducted to monitor temperature gradient and thermal history, stress and deformation field, balling occurrence, effect of volume shrinkage and the effect of process parameters on temperature evolution. Up to now, very few works are available in literature on the effects of the process parameters on the molten pool shape and dimensions: moreover, they also neglect the simultaneously effect of various physical factors. In this work, an integrated analytical model, consisting of three sub-models (thermal, optical and melting sub-models), with the purpose to forecast the molten pool dimensions in terms of width and depth, was developed. An experimental plan has been carried out, processing the 18 maraging 300 steel, to demonstrate the capability and the accuracy of the presented model. The obtained results demonstrate that the integrated analytical model led to optimal forecasting.

Theoretical-Numerical Investigation of a New Approach to Reconstruct the Temperature Field in PBF-LB/M Using Multispectral Process Monitoring

“…In this subsection, the proposed methodology and the findings from the previous section are applied to investigate a different temperature field in order to evaluate the applicability of the methodology. The temperature distribution resembles a moving laser beam and is calculated after [36] with the following equation:…”

“…It allows the inclusion of material properties such as thermal diffusivity κ and thermal conductivity K and process parameters like the scanning speed of the laser v laser and the laser power P ′ 0 of the point source. Technically, Equation ( 23) is only valid up to the melting temperature of the considered material [36]. However, it is used here nonetheless to describe the whole temperature distribution in the measurement area, since it is assumed to sufficiently resemble real circumstances.…”

Analysing the probability of detection of shallow spherical defects by means of Active Thermography

“…Furthermore, the specimens were manufactured using the random island strategy; each island had a size of 5x5 mm 2 . The islands were scanned by the laser randomly on each layer and this was useful to reduce the residual thermal stresses [30]- [31]. However, as the specimen grew in a layer-by-layer manner in the Z direction, there was a 1 mm translation, in X and Y directions, of the islands of a layer with respect to those of the previous layer: this solution prevented the porosities formation between layers (see Figure 4).…”

The Effect of Selective Laser Melting Fabrication Parameters on the Tensile Strength of an Aged New Maraging Steel Alloy with 8% Cr, Reduced Ni Content (7%), and No Co or Mo

“…The SLM manufacturing process is part of the powder bed fusion (PBD) processes, which are additive manufacturing processes (AMs) [7,[31][32][33][34][35]. Using SLM technology enables the manufacturing of tailor-made components [36][37][38]. The usage of this technology involves physical phenomena, such as melting, a complex heat transfer process, and the solidification of the melted metal powder [39].…”