PLA熔融沉积成型工艺的优化研究

发布时间：2018-03-08 11:45

本文选题：PLA　切入点：熔融沉积成型　出处：《合肥工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：熔融沉积成型系统的低成本是相比其他快速成型工艺的一大优势,因而得到了广泛应用。在熔融沉积成型过程中,工艺参数对成型零件的特性能够产生重要的影响。本文通过理论分析,以大量的试验研究为基础,对成型过程中的主要工艺参数进行分析研究,从而提高了成型件的尺寸精度、成型时间和弹性性能。本文所做的主要工作及取得的研究成果如下:(1)系统地介绍了影响熔融沉积成型零件精度的因素,从原理性、成型工艺过程和后处理三个方面进行分析,并针对各影响因素,提出了相应的改进措施,为优化成型过程中的工艺参数,提高成型件的尺寸精度、成型时间和弹性性能提供了方法支撑。(2)以成型零件的出丝过程为对象,研究挤出丝材的截面模型,建立丝材的宽度模型;考虑材料收缩特性对成型件宏观尺寸的影响,构建成型件内外轮廓的补偿量模型;研究成型加工过程中的台阶效应,建立台阶误差的理论模型。(3)以成型零件的尺寸精度为研究对象,设计标准件,通过正交试验,采用不同的多指标正交试验分析方法研究分层厚度、路径宽度和轮廓数对尺寸精度的影响,分别得出尺寸误差最小时的工艺参数水平组合。通过试验,研究路径宽度对成型件外观形貌的影响,得到不同尺寸零件外观形貌最优时的路径宽度水平。(4)采用PLA材料,研究成型过程中的工艺参数对成型件弹性性能的影响,通过一套玩具器械反应成型件的弹性性能,建立工艺参数与系统评价指标间的映射关系及其模型,进行单因素试验和响应面试验,优化成型过程中的约束条件,并对模型预测最优方案进行试验验证,为最大限度地利用成型件的弹性性能提供指导。
[Abstract]:The low cost of the melt deposition molding system is one of the advantages over other rapid prototyping processes, so it has been widely used. The process parameters can have an important influence on the characteristics of the forming parts. Based on the theoretical analysis and a large number of experimental studies, the main process parameters in the forming process are analyzed and studied, thus improving the dimensional accuracy of the molded parts. The main work and research results in this paper are as follows: (1) the factors that affect the precision of fused deposition forming parts are introduced systematically, and analyzed from three aspects: principle, forming process and post treatment. According to the influence factors, the corresponding improvement measures are put forward, which can provide method support for optimizing the process parameters, improving the dimensional accuracy, forming time and elastic properties of the forming parts. The cross section model of extruded wire is studied and the width model of wire is established. Considering the effect of material shrinkage on the macro dimension of the forming part, the compensation model of the inside and outside contour of the forming part is constructed. The step effect in the molding process is studied. The theoretical model of step error is established. (3) taking the dimensional accuracy of forming parts as the research object, the standard parts are designed. Through orthogonal test, different multi-index orthogonal test methods are used to study the delamination thickness. The influence of path width and contour number on dimension precision is obtained, and the horizontal combination of process parameters when the dimension error is minimum is obtained. The influence of path width on the appearance and morphology of the molded parts is studied by experiments. The PLA material was used to study the influence of the process parameters on the elastic properties of the molded parts. Through a set of toy instruments, the elastic properties of the molded parts were studied. The mapping relationship between process parameters and system evaluation indexes and its model are established. Single factor test and response surface test are carried out to optimize the constraint conditions in the molding process. It provides guidance for the maximum use of the elastic properties of the molded parts.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH16

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