随着三维(3D)打印零件的个性化定制与特殊功能化日益发展,单一材质的3D打印零件已经无法满足实际工况要求,多材料零件3D打印技术已经成为快速成型行业的研究热点。目前多材料零件3D打印的关键技术之一是其建模问题。首先,提出一种基于控制点的梯度源建模方法。该方法在几何建模中认为几何模型均是由空间中的点所组成,在材料建模中以“梯度源”建模思想按照材料组分梯度变化公式对多材料零件进行颜色渐变表示。接着,利用VS2013和OpenGL编程语言对单梯度源零件进行可视化建模表示与分析。最后,在单梯度源建模基础上,引入运算符号“?”对两种不同梯度源进行加权运算,对三种材料零件进行可视化建模表示与分析。所提建模方法经光学加工技术制造出的多材料零件,能够较好地避免在多材料零件中材料成分急剧变化,从而引起应力集中与热失效等不良效果。

As the booming of personalized customization and special functions of three-dimensional (3D) printed parts, single material 3D printed parts can no longer meet the demand of actual working conditions, and 3D printing technology of multi-material parts has become a research hotspot in the rapid prototyping industry. Modeling is one of the key technologies for 3D printing of multi-material parts. In this paper, first, a method of gradient source modeling based on control points is proposed. In geometric modeling, this method considers that spatial geometric models are composed of points in space, and in material modeling, and the idea of “gradient source” is used to represent multi-material parts with color gradient according to the formula of material component gradient change. Then, VS2013 and OpenGL programming languages are used for visual modeling representation and analysis of single gradient source parts. Finally, on the basis of single-gradient source modeling, two different gradient sources are weighted by using operation symbol “?”, and three kinds of material parts are presented and analyzed visually. The multi-material parts manufactured by the proposed modeling method by optical processing technology can well avoid adverse effects such as stress concentration and thermal failure caused by the rapid change of material composition in the multi-material parts.