Particle Shape and Flow behaviour in Laser Sintering: from modelling to experimental validation

激光烧结中的颗粒形状和流动行为：从建模到实验验证

• 批准号: EP/L017318/1
• 负责人: Oana Ghita
• 金额: $ 22.91万
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FL017318%2F1
• 关键词: Particle; Shape; Flow; behaviour; Laser

This project proposes to investigate the way the polymeric powders of different shapes and sizes flow, interact and sinter in the Laser Sintering process, through modelling and experimental validation. Laser sintering is part of the additive manufacturing technology, known for its benefits in industries where custom made products, lightweight and complex designs are required. In laser sintering a polymer powder bed is heated to just below its melt temperature. A laser is then focused onto the bed which scans a raster pattern of a single layer of the final part. The bed lowers slightly and a new layer of powder is applied. The process is then repeated until the component is made and the additive layer process is complete. The spreading and compaction of the powder is an important part of the LS process, a non-uniform layer of powder leads to high porosity and weaker bonding between layers and therefore a structure with poor mechanical performance. Similarly, the size and shape of particles can change the sintering process. Larger contact areas between particles lead to a good sintering profile and ultimately to a high density part and good mechanical properties. Surface area of particles, polymer viscosity and surface tension are characteristics which will be considered when modelling the flow and sintering process.

本项目拟通过建模和实验验证，研究不同形状和尺寸的聚合物粉末在激光烧结过程中的流动、相互作用和烧结方式。激光烧结是增材制造技术的一部分，以其在需要定制产品、轻量化和复杂设计的行业中的优势而闻名。在激光烧结中，聚合物粉末床被加热到刚好低于其熔体温度。然后将激光聚焦在床上，扫描最终部件的单层光栅图案。床稍微降低，然后再涂上一层新的粉末。然后重复该过程，直到组件制成并且添加层过程完成。粉末的扩散和压实是LS工艺的重要组成部分，粉末层不均匀导致孔隙率高，层与层之间的结合较弱，因此结构的力学性能较差。同样，颗粒的大小和形状可以改变烧结过程。颗粒之间较大的接触面积导致良好的烧结轮廓，最终得到高密度的零件和良好的机械性能。颗粒的表面积，聚合物粘度和表面张力是建模流动和烧结过程时要考虑的特征。

项目成果

Effects of particle elongation on the binary coalescence dynamics of powder grains for Laser Sintering applications

• DOI: 10.1016/j.powtec.2019.12.025
• 发表时间: 2020-03
• 期刊: Powder Technology
• 影响因子: 5.2
• 作者: S. Haeri;L. Benedetti;O. Ghita

Novel fibre-like crystals in thin films of Poly Ether Ether Ketone (PEEK)

• DOI: 10.1016/j.matlet.2016.08.024
• 发表时间: 2016-12-01
• 期刊: MATERIALS LETTERS
• 影响因子: 3
• 作者: Wang, Yuan;Chen, Binling;Ghita, Oana
• 通讯作者: Ghita, Oana

Discrete element simulation and experimental study of powder spreading process in additive manufacturing

• DOI: 10.1016/j.powtec.2016.11.002
• 发表时间: 2017-01-01
• 期刊: POWDER TECHNOLOGY
• 影响因子: 5.2
• 作者: Haeri, S.;Wang, Y.;Sun, J.
• 通讯作者: Sun, J.

A primary study into graphene/polyether ether ketone (PEEK) nanocomposite for laser sintering

• DOI: 10.1016/j.apsusc.2017.09.226
• 发表时间: 2018-01-15
• 期刊: APPLIED SURFACE SCIENCE
• 影响因子: 6.7
• 作者: Chen, Binling;Berretta, Silvia;Ghita, Oana
• 通讯作者: Ghita, Oana

Enhanced Ductility of PEEK thin film with self-assembled fibre-like crystals.

用自组装的纤维样晶体增强了Peek薄膜的延展性。

• DOI: 10.1038/s41598-018-19537-1
• 发表时间: 2018-01-22
• 期刊: Scientific reports
• 影响因子: 4.6
• 作者: Wang Y;Chen B;Evans K;Ghita O
• 通讯作者: Ghita O