Comparison between the dynamic response of selective laser melting (SLM) parkts and conventionally manufactured parts

WCU Author/Contributor (non-WCU co-authors, if there are any, appear on document)
Lee Clark Sechrest (Creator)
Western Carolina University (WCU )
Web Site:
Sudhir Kaul

Abstract: Selective Laser Melting (SLM) is a relatively new manufacturing process in additive manufacturing (commonly referred to as 3D printing). The process uses a laser sintering technique to build metal parts layer by layer by using the raw material in a powder form. A high intensity laser is used to melt each layer of the metal powder and attach it to the rest of the part. This process is a significant enhancement of additive manufacturing processes since it can be used to manufacture production parts, not just rapid prototypes for visual or educational use. The goal of this research has been to determine the main distinctions between parts made by SLM and parts made by conventional manufacturing processes such as rolling or forging. Specifically, dynamic response and dynamic properties have been compared in this research. Properties such as tensile strength, hardness, natural modes etc. have also been investigated. The dynamic properties have been compared by using simple geometries such as beam structures and relatively complex geometries such as small turbine wheels. A laser vibrometer and a tensile tester have been used to perform all the testing for dynamic and static characterization. Test results have provided a comprehensive understanding of the structural properties of parts made by the SLM process. Test results have also provided some insight into the influence of process parameters on the dynamic properties of the parts manufactured by SLM. The overarching aim of this research has been to determine whether parts manufactured by this new additive manufacturing technique are comparable to conventionally manufactured parts. Results indicate that the static properties (tensile strength, yield strength, etc.) of parts manufactured by SLM are statistically similar to other parts. Also, static properties are not seen to vary significantly with the choice of parameters associated with the SLM process. However, it is observed that the damping ratios corresponding to the bending modes are higher for parts made by SLM, regardless of process parameters. It is also observed that natural frequencies corresponding to the bending modes decrease while natural frequencies corresponding to the torsional modes increase. Furthermore, parameters such as layer thickness and number of scans are seen to significantly influence the natural frequency. These observations indicate that the fatigue life of parts made by SLM can vary significantly. Therefore, the choice of process parameters needs to be investigated further, and it may be necessary to make modifications to the geometry of a part.

Additional Information

Language: English
Date: 2016
DMLS, Dynamic Response, EOS M290, SLM
Lasers -- Industrial applications
Rapid prototyping
Metals -- Testing
Manufacturing processes
Manufactures -- Technological innovations
Three-dimensional printing

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