Abstract

Selective laser melting (SLM) is a metal-based additive manufacturing (AM) technique. Many factors contribute to the output quality of SLM, particularly the machine and material parameters. Analysis of the parameters’ effects is critical, but using traditional experimental and numerical simulation can be expensive and time-consuming. This paper provides a framework to analyze the sensitivity and uncertainty in SLM input and output parameters, which can then be used to find the optimum parameters. The proposed data-driven approach combines machine learning algorithms with high-fidelity numerical simulations to study the SLM process more efficiently. We have considered laser speed, hatch spacing, layer thickness, Young modulus, and Poisson ratio as input variables, while the output variables are numerical predicted normal strains in the building part. A surrogate model was constructed with a deep neural network (DNN) or polynomial chaos expansion (PCE) to generate a response surface between the SLM output and the input variables. The surrogate model and the sensitivity analysis found that all five parameters were important in the process. The surrogate model was combined with non-intrusive optimization algorithms such as genetic algorithms (GA), differential evolution (DE), and particle swarm optimization (PSO) to perform an inverse analysis and find the optimal parameters for the SLM process. Of the three algorithms, the PSO performed well, and the DNN model was found to be the most efficient surrogate model compared to the PCE.

Highlights

  • Selective laser melting (SLM) is an additive manufacturing (AM) process in which a 3D structure is constructed by successively melting material powder layers

  • We presented a framework to analyze and optimize the SLM process other than the more widely-used experimental and numerical techniques

  • We found that the deep neural network model was faster than the polynomial chaos expansion (PCE) model, so we adopted the DNN model for the rest of the analyses

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Summary

Introduction

Selective laser melting (SLM) is an additive manufacturing (AM) process in which a 3D structure is constructed by successively melting material powder layers. Most of the reported UA and SA methods in AM are experiment-based, which leads to a high material wastage and makes the process expensive [6] In another approach, numerical models can be used to quantify the uncertainties in the SLM process. As the discretization of SLM problems requires fine spatial meshes and a high number of time steps, the overwhelming demand for computational resources makes high-fidelity simulations too expensive computationally in the contexts of uncertainty propagation or inverse analysis studies To alleviate this difficulty, we advocate the use of the data-driven approach, which consists of two major stages: (1) A database of high-fidelity solutions computed for a certain number of samples of the input data in the offline stage, which allows a surrogate model to be obtained using a regression method on a reduced basis;.

Literature Review
Mathematical Model
Surrogate Modeling
Deep Neural Networks
N mh i i
N mh i i l y
Polynomial Chaos Expansion
Polynomial
Genetic Algorithm (GA)
Particle Swarm Optimization (PSO)
Differential Evolution (DE)
Application to an Additive Manufacturing Benchmark Test
Baseline Machine Parameters
Mesh Convergence Study
Validation of the Finite Element Model
Deep Neural Network (DNN) Surrogate Modeling
Uncertainty Quantification
Sensitivity Analysis
Optimization
Findings
Conclusions
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