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Download fileOptimum sintering region for laser sintered nylon-12
journal contribution
posted on 2015-05-07, 10:43 authored by Mike Vasquez, Barry Haworth, Neil HopkinsonIt is well known that the mechanical properties of laser sintered Nylon-12 improve
with increased applied energy. However properties can reach a maximum after which, the application
of additional energy can a lead to a decline in part properties. It is thought that the reason
for this decline is that the additional energy causes polymer chain degradation or other changes
in molecular structure. This paper aims to use thermogravimetric analysis (TGA) to investigate
the thermal degradation of nylon-12 and explain the deterioration of mechanical properties when
high energy density conditions are applied during processing. The key findings are the application
of modelling methods to predict the temperatures achieved during laser sintering of nylon-
12. It is shown that temperatures in the laser sintering machine can achieve levels above 3008C. At
these temperatures, TGA data show that mass loss occurs and could cause mechanical property
breakdown. This practical work coupled differential scanning calorimetry and TGA as a means of
identifying thermal transitions in the material. The term ‘stable sintering region’ is proposed as a
novel concept for the laser sintering community, and can have implications for better understanding
of how process parameters can affect parts built in the machine. In addition, the concept
could be used in the material selection process when screening potential new polymers for the
process. One limitation of laser sintering, compared to other polymer processes such as injection
moulding, is the limited understanding of the connection between machine parameters and part
properties. This work aims to improve that understanding by discussing the pattern of thermal
behaviour, including degradation, seen in polyamide exposed to high laser parameters.
Funding
This work was supported by Loughborough University Innovative Manufacturing and Construction (IMCRC) funded by the UK Engineering and Physical Sciences Research Council (ESRC) [project 251].
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Materials
Published in
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART B-JOURNAL OF ENGINEERING MANUFACTUREVolume
225Issue
B12Pages
2240 - 2248 (9)Citation
VASQUEZ, M., HAWORTH, B. and HOPKINSON, B., 2011. Optimum sintering region for laser sintered nylon-12. Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 225, (B12), pp. 2240 - 2248.Publisher
Sage Publications Ltd on behalf of the Institution of Mechanical Engineers / © The AuthorsVersion
- AM (Accepted Manuscript)
Publisher statement
This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/Publication date
2011Notes
This article was published in Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture [Sage Publications Ltd on behalf of the Institution of Mechanical Engineers / © The Authors]. The definitive version is available at: http://dx.doi.org/10.1177/0954405411414994ISSN
0954-4054Publisher version
Language
- en