Abstract
Merging of particle pairs during selective laser sintering (SLS) of polymers is vital in defining the final part properties. Depending on the sintering conditions, polymers can undergo full or partial sintering whereby incomplete sintering results in poor mechanical properties. At present, the underlying mechanisms and related conditions leading to various consolidation phenomena of polymer particles are not well understood. In the present work, a novel in-house developed experimental setup is used to perform laser sintering experiments on polystyrene (PS) particle doublets while performing in situ visualization of the sintering dynamics. From the recorded images, the evolution of the growth of the neck radius formed between both particles is analyzed as a function of time. Sintering conditions such as heating chamber temperature, laser pulse energy and duration, laser spot size and particle size are precisely controlled and systematically varied. A non-isothermal viscous sintering model is developed that allows qualitative prediction of the observed effects of the various parameters. It is shown that the sintering kinetics is determined by a complex interplay between the transient rheology caused by the finite relaxation times of the polymer and the time-dependent temperature profile which also affects the polymer viscosity. The combination of a full material characterization with sintering experiments under well-defined conditions has resulted in a general understanding of the effects of material and process parameters on laser sintering. Thereby a strong foundation is laid for the route towards rational design of laser sintering.
| Original language | English |
|---|---|
| Pages (from-to) | 1373-1387 |
| Number of pages | 15 |
| Journal | Soft Matter |
| Volume | 15 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - 14 Feb 2019 |
Funding
Ruth Cardinaels obtained her PhD at KU Leuven (Belgium) in 2010. After her PhD, she continued to work there in the Soft Matter Rheology and Technology section as a postdoctoral research fellow of the Research Foundation – Flanders. During this period she was also a visiting postdoctoral researcher at the Mechanical Engi- neering department of Princeton University (USA). Since 2014 she is an Assistant Professor in the Polymer Technology section of Prof. P. Anderson in the Mechanical Engineering Department at Eindhoven University of Technology (The Netherlands). Her research involves the study of multiphasic soft matter systems by means of optical, rheological, rheo-optical and rheo-dielectric techniques.