Doctoral thesis information of researcher Nguyen Thai Son (revised version after the Institute-level Thesis Evaluation Committee)

Full name of researcher: Nguyen Thai Son

Scientific supervisors: Assoc. Prof. Dr. Tran Ngoc Hien and Assoc. Prof. Dr. Nguyen Chi Sang

Field: Mechanical Engineering - Code: 9520103

Training institution: National Research Institute of Mechanical Engineering - Ministry of Industry and Trade

Thesis title: “Study on the influence of some technological parameters on the quality of 3D-SLM printed parts from Ti6Al4V material” 

Summary of new findings of the thesis

1. Scientific significance

• The study identified the main technological parameters affecting the 3D printing process from Ti6Al4V titanium alloy powder material using the selective laser melting (SLM) method.
• Established a heat source model, a heat transfer model, and analyzed the temperature distribution during printing as a basis for determining an appropriate set of printing technological parameters.
• Established a mathematical model of the relationship between printing technological parameters affecting the output indicators, namely the quality of 3D printed products, providing a scientific basis for determining an appropriate set of printing technological parameters.
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2. Practical significance

The research results serve as teaching materials, research references, and a basis for application in enterprises utilizing additive manufacturing technology to improve product quality.   

3. New contributions of the thesis

The new contributions of the thesis include:

• Completed the theoretical study on the metal 3D printing technological process applicable to printing Ti6Al4V titanium alloy powder material.
• Simulation analysis of the thermal process during printing, which is a complex process that decisively influences the quality of the printed product. From this analysis result, the temperature distribution state during printing can be predicted to ensure the molten state of the material corresponding to the respective set of printing technological parameters.
• Developed predictive models for printed product quality, including laser power (U), scanning speed (V), layer thickness (t) affecting the quality indicators of 3D printed products: dimensional accuracy (D), surface roughness (R_a), and product porosity. This includes developing single and multi-objective functions describing the relationship between the set of SLM printing technological parameters and the output quality indicators.

 For the detailed content of the thesis by researcher Nguyen Thai Son, please see here.