The process of particle coalescence due to surface tension, usually referred to as sintering, is very important in processes involving polymer, ceramic, or metal aggregates, especially in additive manufacturing. A model was developed for part shrinkage by determining the rate of void and volume reduction of a square unit cell in a lattice arrangement of cylindrical particles. Neck growth between cylinders in contact is determined by assuming planar extensional flow for a Newtonian fluid. The model provides growth of neck width, which is easily converted to void area reduction and relative density, as a function of dimensionless time. The results obtained were compared to previously published numerical simulations of shrinkage and to experimental data available in the literature, involving polypropylene (PP) particles from one study and liquid glass particles from two others. Also, predictions of neck width were compared to experimental data in fused filament fabrication (FFF) of PLA.

由于表面张力引起的颗粒聚结过程（通常称为烧结）在涉及聚合物、陶瓷或金属聚集体的过程中非常重要，尤其是在增材制造中。通过确定圆柱形颗粒晶格排列中方形晶胞的空隙率和体积减少率，开发了零件收缩模型。通过假设牛顿流体的平面拉伸流动来确定接触圆柱体之间的颈部增长。该模型提供了颈部宽度的增长，这很容易转换为空隙面积减少和相对密度，作为无量纲时间的函数。将获得的结果与先前公布的收缩数值模拟和文献中可用的实验数据进行比较，涉及来自一项研究的聚丙烯 (PP) 颗粒和来自其他两项研究的液体玻璃颗粒。此外，将颈部宽度的预测与 PLA 熔融长丝制造 (FFF) 的实验数据进行了比较。