基于FDM工艺的3D打印机成型精度研究

发布时间：2018-03-28 19:34

本文选题：熔融沉积成型　切入点：成型精度　出处：《华北电力大学》2017年硕士论文

【摘要】：熔融沉积快速成型技术(FDM)是目前快速成型诸多工艺中应用最为广泛的一种。作为3D打印技术的一种,熔融沉积工艺采用喷头将丝状热熔性材料熔化,然后通过材料沉积制造物体。采用FDM技术的3D打印机具有机械机构简单、设备操作容易、材料成本低等优点,目前在市场上取得了较为广泛的应用。但是,现有的FDM3D打印机成型精度普遍较低,如何提高熔融沉积成型的成型精度是目前快速成型的一个重要研究方向。本文首先分别从前期数据处理、成型加工过程以及后处理过程三个方面介绍了影响成型精度的各种因素,分析了各因素带来的误差及相应的解决对策,为后续FDM工艺成型精度的研究提供了理论指导。快速成型技术的数据处理直接影响成型件的表面质量、成型精度和成型效率。为了提高成型件的成型精度和降低表面粗糙度,本文分别对FDM工艺的分层切片处理技术和支撑添加技术进行了研究。首先,介绍了一种适应性分层方法,根据模型轮廓参考曲线上的曲率变化情况确定分层厚度。该方法有效减小了台阶效应带来的误差,在保证成型精度的前提下极大地减小了成型时间。然后,讨论了支撑的添加规则,通过正交试验对FDM工艺中支撑添加技术进行了研究,在保证成型精度的前提下,得到了使支撑易于去除的最佳工艺参数。并通过试验确定了零件悬空部分不加支撑即可成形的极限尺寸,具有重要的实际参考价值。喷头结构的设计直接影响成型件的质量,稳定足够的摩擦驱动力是提高成形质量的关键。本文首先通过理论计算推导出摩擦驱动力的计算公式,分析了摩擦驱动力的影响因素,确定通过改善机械机构的方法来提高摩擦驱动力。然后设计了一种远端送丝机构,增加了减速装置,驱动力更加稳定。最后,运用有限元软件ANSYS进行热分析,通过分析喷头的温度场和应力场,研究了喷头的热量分布,为喷头的温度控制和结构优化设计提供了参考。
[Abstract]:Melt deposition Rapid Prototyping (FDM) is one of the most widely used rapid prototyping processes. As a 3D printing technology, the melt deposition process uses spray head to melt the filamentous hot melt material. The 3D printer using FDM technology has the advantages of simple mechanical mechanism, easy operation and low material cost, so it has been widely used in the market. The existing FDM3D printer has low molding accuracy. How to improve the forming accuracy of melt deposition molding is an important research direction of rapid prototyping at present. In this paper, three aspects of forming process and post processing process are introduced. The factors that affect the forming accuracy are introduced, and the error caused by each factor and the corresponding solutions are analyzed. The data processing of rapid prototyping technology directly affects the surface quality, forming accuracy and forming efficiency of the molded parts, in order to improve the forming accuracy and reduce the surface roughness of the molded parts. In this paper, the layered slicing technology and support adding technology of FDM process are studied respectively. Firstly, an adaptive layering method is introduced. The delamination thickness is determined according to the curvature change on the model contour reference curve. This method effectively reduces the error caused by the step effect and greatly reduces the forming time under the premise of ensuring the forming accuracy. In this paper, the rule of adding support is discussed, and the technology of adding support in FDM process is studied by orthogonal test. Under the premise of guaranteeing the forming precision, The optimum process parameters for easy removal of support are obtained, and the limit size of the suspended part can be formed without bracing is determined by experiments, which has important practical reference value. The design of nozzle structure directly affects the quality of forming parts. Stable enough friction driving force is the key to improve forming quality. In this paper, the formula of friction driving force is deduced through theoretical calculation, and the influencing factors of friction driving force are analyzed. It is determined that the friction driving force can be increased by improving the mechanical mechanism. Then a remote wire feeding mechanism is designed to increase the deceleration device and the driving force is more stable. Finally, the thermal analysis is carried out by using the finite element software ANSYS. By analyzing the temperature field and stress field of the nozzle, the heat distribution of the nozzle is studied, which provides a reference for the temperature control and structural optimization design of the nozzle.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH16

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