【作者】 李广慧；

【导师】 王丽萍；

【作者基本信息】 哈尔滨理工大学 ， 材料加工工程， 2003， 硕士

【摘要】 本文分析了国内外选择性激光烧结成型（SLS）技术的研究现状。首先从理论上分析了激光与材料相互作用原理和热塑性塑料的物理、化学性质，并且研究了粉末激光烧结机理。讨论了各工艺参数对激光烧结过程的影响。针对影响烧结聚苯乙烯制件表面粗糙度和尺寸精度的工艺参数，以制件表面粗糙度和收缩为测量指标，设计并进行了三因素三水平正交试验。利用方差分析方法，获得了聚苯乙烯材料激光烧结的最佳工艺参数组合以及各工艺参数的影响规律。试验表明，激光烧结层厚度、制件摆放角度、激光烧结间距等对表面精度的影响大。激光烧结功率、制件的形状尺寸等对制件尺寸精度影响大。本文基于新技术在新工艺中的作用，采用试验和理论分析的方法，研究激光烧结参数对聚苯乙烯材料加工精度的影响，通过对试验数据的分析研究，探讨了烧结制件中出现的几种缺陷的形成原因，得出了各参数对烧结制件精度的影响规律。并提出了减少烧结缺陷的措施和方法，这对激光烧结成型工艺在热塑性塑料中的应用有一定指导意义。分析了由于成型原理所产生的制件表面阶梯效应，提出了制件表面粗糙度的计算方法，给出了CAD模型切片时，切片厚度的选取方法。为了兼顾成型效率和制件精度，本文提出了基于三角形面片外法线方向判别的定精度切片算法，并采用定精度方法进行切片。本方法有目的地控制成型制件的表面粗糙度，为开发变层厚烧结控制系统，提供了理论依据。更多还原

【Abstract】 The SLS technology actuality in our country and abroad is analyzed. Firstly the interactional principle of laser and material, the physical and chemical properties of the thermoplastic plastic is studied in theory, and the laser sintering mechanism of powder is also studied. The influence of process parameter to laser sintering process is discussed. In the view of the process parameter that influences the sintering surface roughness, dimension precision of PS part and the surface roughness and shrinkage being guideline, the 3-factor and 3- horizontal orthodoxy experiment is designed and processed. The best process parameter combination and the influence rule for PS material is got by the application of square error analysis method. The experiment indicates that the laser sintering power, the thickness of sintering layer, the placement angle influence the surface precision greatly, and scanning space influence the dimension precision of the part greatly. Based on the new technology application in new process, this paper makes use of the method of experiment and theory analysis, studies the influence of laser sintering parameter to PS material machining precision, and the rule of the influence of each parameter to sintering part is got through the analysis and study of experiment data and discussion of the formation reason of several disfigurement in sintering part. The measure and method of minimize the sintering disfigurement is presented, which could be a guidance to the optimization of process parameter in the thermoplastic application of laser sintering prototyping.The surface ladder effect produced by prototyping principle is analyzed, and the calculation method of the part surface roughness is presented. The selecting method of slice thickness and sintering layer thickness when slicing the CAD model and sintering is presented. To give attention to the prototyping efficiency and part<WP=6>precision, the variational thickness slice algorithms is presented based on the distinguishing of triangle plane outer-normal direction. This method controls the surface roughness of prototyping part, which provides theory basis for the development of system of variational thickness control.更多还原