Complementary use of pulsed and continuous wave emission modes to stabilize melt pool geometry in laser powder bed fusion
| Autor: | Leonardo Caprio, Matteo Pacher, Barbara Previtali, Ali Gökhan Demir, Luca Mazzoleni |
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| Rok vydání: | 2019 |
| Předmět: |
0209 industrial biotechnology
Materials science Geometry 02 engineering and technology Surface finish Stainless steel law.invention PW emission 020901 industrial engineering & automation law Thermal Electrical and Electronic Engineering Selective laser melting Porosity Molten pool monitoring CW emission 021001 nanoscience & nanotechnology Laser Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials Selective laser melting Molten pool monitoring CW emission PW emission Stainless steel Continuous wave Coaxial 0210 nano-technology Intensity (heat transfer) |
| Zdroj: | Optics & Laser Technology. 113:15-26 |
| ISSN: | 0030-3992 |
| Popis: | The most common defects in laser powder bed fusion (LPBF) namely porosity, geometrical errors, roughness and thermal deformations are principally linked with the energy input to the process. In common practice, a single set of process parameters is used to produce a whole component independently from the dimensions of the actual scan path within a given layer. However, melt pool stability is highly dependent on the scanned geometry. A possible strategy to maintain a constant melt pool is the mixed use of pulsed wave (PW) and continuous wave (CW) emission regimes. Accordingly, this work investigates the complementary use of continuous and modulated emission at fixed energy density on large and thin sections respectively. The proposed approach is tested on AISI 316L stainless steel and melt pool observations are conducted employing a coaxial monitoring system built for purpose. Temporally resolved measurements of intensity and geometrical properties of the melt pool were extracted as well as a three-dimensional spatial mapping of the molten pool area. The results demonstrate that moving from CW to a PW regime at the transition zones to thinner sections is effective in maintaining a constant melt pool size thus avoiding heat build-up and part extrusion from the powder bed. |
| Databáze: | OpenAIRE |
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