聚合物材料的增材制造(AM)提供了许多好处,从快速成型到最终使用材料零件的生产。粉末床融合(PBF),更具体地说,选择性激光烧结(SLS),是一种非常有前途的AM技术。然而,直到现在,大多数SLS研究已针对聚酰胺粉末。此外,仅提出了基本模型,这些模型较少针对可持续生产环境中最合适的操作条件的识别。在目前的实验和理论研究相结合,几个SLS处理参数的影响(例如,激光功率,部分床层温度,和层厚度)通过比色法研究了热塑性弹性体聚酯,形态学,物理,和印刷零件的力学分析。结果表明,存在最佳的SLS加工窗口,其中印刷的聚酯材料具有更高的密度和更好的机械性能以及较低的黄变指数,特别是在使用17-20W的激光功率时。进一步强调的是,当前模型在预测发生热降解的激光功率方面不够准确。因此,提出了更新和更多的基本方程,制定了指南,以更好地评估激光功率的降解和烧结过程中达到的最高温度。这通过利用激光的反射和吸收并考虑粉末材料的粒度分布来进行。
Additive manufacturing (AM) of polymeric materials offers many benefits, from rapid prototyping to the production of end-use material parts. Powder bed fusion (PBF), more specifically selective laser sintering (SLS), is a very promising AM technology. However, up until now, most SLS research has been directed toward polyamide powders. In addition, only basic models have been put forward that are less directed to the identification of the most suited operating conditions in a sustainable production context. In the present combined experimental and theoretical
study, the impacts of several SLS processing parameters (e.g., laser power, part bed temperature, and layer thickness) are investigated for a thermoplastic elastomer polyester by means of colorimetric, morphological, physical, and mechanical analysis of the printed parts. It is shown that an optimal SLS processing window exists in which the printed polyester material presents a higher density and better mechanical properties as well as a low yellowing index, specifically upon using a laser power of 17-20 W. It is further highlighted that the current models are not accurate enough at predicting the laser power at which thermal degradation occurs. Updated and more fundamental equations are therefore proposed, and guidelines are formulated to better assess the laser power for degradation and the maximal temperature achieved during sintering. This is performed by employing the reflection and absorbance of the laser light and taking into account the particle size distribution of the powder material.