Hejmady Prakhyat, Cleven Lucien C, van Breemen Lambèrt C A, Anderson Patrick D, Cardinaels Ruth
Polymer Technology, Department of Mechanical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Rev Sci Instrum. 2019 Aug;90(8):083905. doi: 10.1063/1.5106406.
We present a unique laser sintering setup that allows real time studies of the structural evolution during laser sintering of polymer particles. The device incorporates the main features of classical selective laser sintering machines for 3D printing of polymers and at the same time allows in situ visualization of the sintering dynamics with optical microscopy as well as X-ray scattering. A main feature of the setup is the fact that it provides local access to one particle-particle bridge during sintering. In addition, due to the small scale of the device and the specific laser arrangement process, parameters such as the temperature, laser energy, laser pulse duration, and spot size can be precisely controlled. The sample chamber provides heating up to 360 °C, which allows for sintering of commodity as well as high performance polymers. The latter parameters are controlled by the use of a visible light laser combined with an acousto-optic modulator for pulsing, which allows small and precise spot sizes and pulse times and pulse energies as low as 500 μs and 17 μJ. The macrostructural evolution of the particle bridge during sintering is followed via optical imaging at high speed and resolution. Placing the setup in high flux synchrotron radiation with a fast detector simultaneously allows in situ time-resolved X-ray characterizations. To demonstrate the capabilities of the device, we studied the laser sintering of two spherical PA12 particles. The setup provides crucial real-time information concerning the sintering dynamics as well as crystallization kinetics, which was not accessible up to now.
我们展示了一种独特的激光烧结装置，它能够对聚合物颗粒激光烧结过程中的结构演变进行实时研究。该装置融合了用于聚合物3D打印的经典选择性激光烧结机的主要特性，同时还能通过光学显微镜以及X射线散射对烧结动力学进行原位可视化观察。该装置的一个主要特点是在烧结过程中能够对单个颗粒间的桥接部位进行局部观察。此外，由于该装置规模较小且激光排列过程特殊，温度、激光能量、激光脉冲持续时间和光斑尺寸等参数都能得到精确控制。样品腔可加热至360°C，这使得普通聚合物和高性能聚合物都能进行烧结。后述参数通过使用可见光激光器结合用于脉冲调制的声光调制器来控制，从而实现小而精确的光斑尺寸以及低至500μs的脉冲时间和17μJ的脉冲能量。通过高速高分辨率的光学成像跟踪烧结过程中颗粒桥接部位的宏观结构演变。将该装置置于高通量同步辐射源中并配备快速探测器，同时还能进行原位时间分辨X射线表征。为展示该装置的性能，我们研究了两个球形PA12颗粒的激光烧结过程。该装置提供了有关烧结动力学以及结晶动力学的关键实时信息这些信息在此之前是无法获取的。
