Numerical Modeling of Distortion of Ti-6Al-4V Components Manufactured Using Laser Powder Bed Fusion

Abstract

The laser powder bed fusion (L-PBF) process is a powder-based additive manufacturing process that can manufacture complex metallic components. However, when the metallic components are fabricated with the L-PBF process, they frequently encounter the residual stress and distortion that occurs due to the cyclic of rapid heating and cooling. The distortion detrimentally impacts the dimensional and geometrical accuracy of final built parts in the L-PBF process. The purpose of this research was to explore and predict the distortion of Ti-6Al-4V components manufactured using the L-PBF process by using numerical modeling in Simufact Additive 2020 FP1 software. Firstly, the numerical model validation was conducted with the twin-cantilever beam part. Later, studies were carried out to examine the effect of component sizes and support-structure designs on the distortion of tibial component produced by the L-PBF process. The results of this research revealed a good agreement between the numerical model and experiment data. In addition, the platform was extended to predict the distortion in the tibial component. Large distortion arose near the interface between the tibial tray and support structure due to the different stiffness between the solid bulk and support structure. The distortion of the tibial component increased with increasing component size according to the surface area of the tibial tray, and with increasing thickness of the tibial tray. Furthermore, the support-structure design plays an important role in distortion reduction in the L-PBF process. For example, the maximum distortion of the tibial component was minimized up to 44% when a block support-structure design with a height of 2.5 mm was used instead of the lattice-based support. The present study provides useful information to help the medical sector to manufacture effective medical components and reduce the chance of part failure from cracking in the L-PBF process.

Process Optimization and Distortion Prediction in Directed Energy Deposition

“…Numerical simulation analysis using the finite element method (FEM) is a valuable tool for predicting DED distortion and residual stress [12]. For instance, Ninpetch et al [13] developed a 3D FEM model to predict these factors in a titanium tibial tray fabricated using Laser Powder Bed Fusion (LPBF), a related AM technology. Their findings highlighted the significant influence of heat source power and layer thickness on distortion near the interface between the tray and support structure due to differing stiffness between the solid part and support.…”

Simulation of 316L Stainless Steel Produced the Laser Powder Bed Fusion Process

“…In order to reduce the weight of parts, additive manufacturing technology is increasingly used in a wide range of industries [1][2][3][4][5][6][7][8][9][10][11][12]. The most commonly used technology is laser powder bed fusion technology (LPBF).…”

“…Due to the complexity of the process, LPBF technology involves more than 100 processing parameters, the essential ones being scanning speed, laser power, coating thickness, distance between subsequent laser transitions, and scanning strategy [2]. Parts produced using this technology are accompanied by distortion as well as residual stress, which, as a result, has a negative impact on the required dimensional and geometric accuracy of the parts [3]. Due to the thermal processes that take place in the metal printing process (heating and cooling cycles), large thermal gradients occur, as a result of which high thermal stresses are created [4,5].…”

“…In the simulation mode, the volume fraction was compared, as were the deviations obtained from the standard method of generating support material and using the support optimisation function. By using the support material optimisation function, a different distribution of support was achieved compared to the conventional method, obtaining the following values: − generation of support without optimisation Σ volume 71,875.6 mm 3 − generation of support with optimisation of Σ volume 42,693.7 mm 3 The purpose of applying these simulation tools to the metal additive manufacturing process is to understand the process itself, as it differs from classical 3D printing, where the manufacturing process consists of adding molten plastic layer by layer [38,39]. It is also necessary to consider the size of the elements, which is one of the decisive factors in the process of metal printing, when using a simulation tool designed to predict the behaviour of the material in the process and the deviation [40].…”

A Ti-6Al-4V Milling Force Prediction Model Based on the Taylor Factor Model and Microstructure Evolution of the Milling Surface

“…In the field of aerospace engineering, the material removal per unit time in the actual processing of titanium alloy workpieces is much less than that of other materials. Therefore, the question of how to select a reasonable processing method and improve the machining efficiency and quality has become an important research topic [ 5 ].…”