研究目的
To analyze fundamentally the resulting maximum temperatures during laser exposure in selective laser sintering (SLS) and to compare in situ infrared thermography measurements with offline Laser-High-Speed-DSC (Laser-HS-DSC) experiments.
研究成果
The comparison between the two process-oriented thermal analytical methods, offline Laser-HS-DSC and in situ infrared thermography, shows similar tendencies of increasing temperature with either increasing laser power or impact time. However, a direct comparison of measurement results is not possible due to differing boundary conditions.
研究不足
The direct comparison of measurement results between Laser-HS-DSC and in situ infrared thermography is not possible due to differing boundary conditions, such as amount of molten powder and the actual value of applied laser power.
1:Experimental Design and Method Selection:
A dual approach was used to investigate the influence of laser power and impact time on maximum temperatures during laser exposure. The Laser-HS-DSC was used to analyze the laser beam material interaction, and these results were compared with infrared camera measurements in a SLS system.
2:Sample Selection and Data Sources:
A commercial available polyamide 12 (PA 12) powder was used for the experiments. For Laser-HS-DSC measurements, a low amount of virgin powder particles was used to assure the reproducibility of the investigations.
3:List of Experimental Equipment and Materials:
A combination of a commercial Flash-DSC and an integrated optical system, consisting of a CO2 laser, lenses and a beam splitter, was used for Laser-HS-DSC. For single spot exposure experiments, a temperature-stabilized laser sintering system was used. An infrared (IR) thermographic system was applied for characterizing the exposure process in situ.
4:Experimental Procedures and Operational Workflow:
The experiments were performed on a measuring chip several times one following the other. The samples were heated at 1,000 K/s to 170 °C, which corresponds to the temperature of the building chamber. During an isothermal phase of 5 seconds, the laser exposure was conducted with various frequencies from 1 kHz to 10 kHz.
5:Data Analysis Methods:
The temperature profile, the maximum temperature, decay time and the heating rate were evaluated. The heating rate was calculated according to the equation provided in the paper.
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