TY - GEN
T1 - Influence of degradation behavior of polyamide 12 powders in laser sintering process on produced parts
AU - Wudy, K.
AU - Drummer, D.
AU - Kühnlein, F.
AU - Drexler, M.
PY - 2014
Y1 - 2014
N2 - Additive manufacturing technologies, such as selective laser melting of polymers enable manufacturing of complex parts without tools and forms. Due to high temperature during processing, a degradation of the used plastic powder occurs. The unmolded material in the building chamber, the so-called partcake, can be removed from the finished component after building and reused for another process. To realize reproducible part properties refreshing of partcake powder is necessary. This paper presents results on the investigations of degradation behavior of polyamide 12 powder during selective laser melting process. The influence of different ambient conditions, e.g. ambient air, nitrogen and vacuum, is investigated in a model experiment. Oven aged polymer powders were analyzed with regard to their process relevant material properties. Considered material properties are phase transition temperatures, melting viscosity or molecular weight. The results of the investigations show, that the influence of high process temperatures on used material can be reduced using other ambient conditions. Process relevant material properties are minor affected by storage under vacuum. In addition to that the influence of different ambient conditions as well as a material pretreatment on the degradation behavior of sls materials, e.g. exclusion of intermolecular located oxygen, is analyzed. To correlate these results of the model experiment with real manufacturing process laser sintering experiments are done. PA12 powder is used for several building processes with refreshing. Produced specimens and resulting partcake powder are analyzed and correlated to the results of model experiment. Correlating effects, regarding process relevant material properties as well as aging influenced mechanical properties of specimens can be detected.
AB - Additive manufacturing technologies, such as selective laser melting of polymers enable manufacturing of complex parts without tools and forms. Due to high temperature during processing, a degradation of the used plastic powder occurs. The unmolded material in the building chamber, the so-called partcake, can be removed from the finished component after building and reused for another process. To realize reproducible part properties refreshing of partcake powder is necessary. This paper presents results on the investigations of degradation behavior of polyamide 12 powder during selective laser melting process. The influence of different ambient conditions, e.g. ambient air, nitrogen and vacuum, is investigated in a model experiment. Oven aged polymer powders were analyzed with regard to their process relevant material properties. Considered material properties are phase transition temperatures, melting viscosity or molecular weight. The results of the investigations show, that the influence of high process temperatures on used material can be reduced using other ambient conditions. Process relevant material properties are minor affected by storage under vacuum. In addition to that the influence of different ambient conditions as well as a material pretreatment on the degradation behavior of sls materials, e.g. exclusion of intermolecular located oxygen, is analyzed. To correlate these results of the model experiment with real manufacturing process laser sintering experiments are done. PA12 powder is used for several building processes with refreshing. Produced specimens and resulting partcake powder are analyzed and correlated to the results of model experiment. Correlating effects, regarding process relevant material properties as well as aging influenced mechanical properties of specimens can be detected.
KW - degradation
KW - polyamide 12
KW - selective laser melting of polymers
UR - http://www.scopus.com/inward/record.url?scp=84903149661&partnerID=8YFLogxK
U2 - 10.1063/1.4873873
DO - 10.1063/1.4873873
M3 - Conference contribution
AN - SCOPUS:84903149661
SN - 9780735412279
T3 - AIP Conference Proceedings
SP - 691
EP - 695
BT - Proceedings of PPS 2013 - 29th International Conference of the Polymer Processing Society, Conference Papers
PB - American Institute of Physics Inc.
T2 - 29th International Conference of the Polymer Processing Society, PPS 2013
Y2 - 15 July 2013 through 19 July 2013
ER -