支具大流量3D打印工艺参数对挤料力的影响

Effect of Multiple Process Parameters on Extrusion Force in High-Flow 3D Printing of Braces

大流量3D打印技术是实现支具快速成型的有效方式,然而,在大流量熔融沉积成型(FDM)的背景下,柱塞式挤出机需要更高的挤料力实现丝材的熔融挤出,更易发生丝材磨损与弯曲现象,导致打印失败。针对柱塞式挤料机在支具大流量3D打印过程中挤料不稳定以及易失效的问题,将挤料力作为挤料过程稳定性的观察指标,来研究工艺参数对挤料力的影响。通过设计大流量挤出机构、建立熔体黏度仿真模型与搭建挤料力测量装置,采用仿真与实验相结合的方式,分析不同工艺参数组合下挤料力的变化趋势,研究流道结构、挤料速度与喷头温度对挤料过程的影响。结果表明:在流道结构参数方面,提高流道过渡出口直径可以减小挤料力,有利于提高挤料过程稳定性;在挤料速度与喷头温度方面,不同的打印工艺参数组合会导致三种不同的挤料过程,通过选择合理的工艺参数,可以使挤料力保持在稳定挤料区间;当挤料力控制在113 N以下时,挤料装置能实现24867.03 mm^(3)/min的大流量稳定挤出;实际打印模型耗时测试结果表明,其相比于普通FDM打印机效率提高了约23倍。

High-flow 3D printing technology is an effective way to achieve rapid prototyping of braces.However,in the context of high-flow Fused Deposition Modeling(FDM),plunger-type extruders demand higher extrusion forces to achieve fused extrusion of filaments,making them more susceptible to filament wear and bending,ultimately leading to printing failures.Aiming at the problem of unstable extrusion and easy failure of the plunger-type extruder in the process of supporting high-flow 3D printing,the extrusion force was taken as an observation index of the stability of the extrusion process to study the influence of process parameters on the extrusion force.By designing a high-flow extrusion mechanism,establishing a melt viscosity simulation model,and constructing an extrusion force measuring device,using a combination of simulation and experiment,the trend of the extrusion force under different combinations of process parameters was analyzed,and the effects of runner structure,extrusion speed,and nozzle temperature on the extrusion process were studied.The results show that increasing the diameter of the channel transition outlet can reduce the extrusion force in terms of channel structure parameters,which is conducive to improving the stability of the extrusion process.In terms of extrusion speed and nozzle temperature,different combinations of printing process parameters can lead to three different extrusion processes,and the extrusion force can be kept in the stable extrusion interval by choosing reasonable process parameters.When the extrusion force is controlled below 113 N,the extrusion device can realize a stable extrusion with a large flow rate of 24867.03 mm^(3)/min.It was improved the efficiency by about 23 times compared with the ordinary FDM printer through the actual printing model time-consuming test.