研究目的
Investigating the effect of temperature on the flow properties of a polyamide 12 powder for laser sintering.
研究成果
The powder displays easy flowing behavior between 100°C and 140°C. The study emphasizes the relations between physicochemical features and flowability of a polyamide powder, especially the role of moisture at ambient temperature and the possible plasticity occurring when temperature rises above 140°C. The results show great consistency with the already used maximum warming temperatures of this powder in the feed tank of LS machines and during the layer spreading.
研究不足
The study could not perform measurements above 160°C due to the lack of repeatability caused by partial melting of the powder. The consolidation level investigated may not be significant for direct evaluation of the propensity of the powder to be properly distributed in a LS apparatus.
1：Experimental Design and Method Selection:
Shear tests were carried out at temperatures from ambient up to values close to the melting temperature of the polymer using a High Temperature-Annular Shear Cell (HT-ASC).
2：Sample Selection and Data Sources:
A commercial polyamide 12 powder, Innov’PA (Exceltec, France), was used.
3：List of Experimental Equipment and Materials:
High Temperature-Annular Shear Cell (HT-ASC), SEM for morphology and surface features, Mastersizer 2000 (Malvern) for PSD measurements.
4：Experimental Procedures and Operational Workflow:
The powder was dried for 24 hours under vacuum at 80°C prior to the tests. Yield loci were measured at normal consolidation stress of 515, 640, 765, 890 Pa and temperatures of 25, 100, 140 and 160°C.
5：Data Analysis Methods:
The flow properties were analyzed using the Mohr analysis of a continuum solid and on Coulomb’s model for the failure behavior of a granular material.
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