Abstract

In additive manufacturing of metallic materials, an accurate description of the thermal histories of the built part is important for further analysis of the distortions and residual stresses, which is a big issue for additively manufactured metal products. In the present paper, a computationally volumetric heat source model based on a semianalytical thermal modeling approach is proposed. The proposed model is applied to model the thermal response during a selective laser melting (SLM) process. The interaction between the laser and the material is described using a moving volumetric heat source. High computational efficiency can be achieved with considerable accuracy. Several case studies are conducted to examine the accuracy of the proposed model. By comparing with the experimentally measured melt-pool dimensions, it is found that the error between the predictions obtained by the proposed model and the experimental results can be controlled to less than 10%. High computational efficiency can also be achieved for the proposed model. It is shown that for simulating the thermal process of scanning a single layer with the dimension of 2 mm × 2 mm, the calculation can be finished in around 110 s.

Highlights

  • Additive manufacturing (AM), defined by ASTM international [1] as “the process of joining materials to make parts from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing and formative manufacturing methodologies”, opens up a new era to design novel structural materials with complex geometries

  • In the present paper, taking the selective laser melting (SLM) process as an example, a volumetric heat source model based on the semianalytical thermal approach proposed by Yang et al [14,15] is developed to predict the thermal histories of the built part in SLM

  • A computationally efficient volumetric heat source model based on the semianalytical thermal approach is proposed to simulate the thermal response of the produced part in the AM process

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Summary

Introduction

Additive manufacturing (AM), defined by ASTM international [1] as “the process of joining materials to make parts from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing and formative manufacturing methodologies”, opens up a new era to design novel structural materials with complex geometries. Since the transient temperature response is the root cause of part distortions and residual stresses, a computationally efficient thermal model for the AM process of metals is the key step to increase the build quality and repeatability leading to products with superior mechanical properties. Phase transitions within the melt pool can be neglected as a second-order effect to improve the computational efficiency [10,11] Even with these simplifications, the challenge of the thermal modeling of AM process in part scale is still how to accurately predict the thermal transient within a reasonable amount of time. In the present paper, taking the SLM process as an example, a volumetric heat source model based on the semianalytical thermal approach proposed by Yang et al [14,15] is developed to predict the thermal histories of the built part in SLM. The article concludes with a reiteration of the most salient points of the study

Model Description
Semianalytical Thermal Model
Volumetric Heat Source
Results and Discussions
A Single Laser Scan on a Semi-Infinite Space
A Single Laser Scan on a Finite Space
Building a New Layer with Multiple Laser Scans
Limitations and Future
Conclusions

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