基于新LOM技术的金属零件自适应切片软件的开发

针对以金属板材为造型材料的分层实体制造中存在的精度问题,提出了一种新LOM方法直接快速制造金属功能零件。在传统LOM切片算法的基础上推导出了新的分层切片算法,并开发了适用于新LOM方法的自适应切片软件。     

金属零件分层快速制造关键技术研究

针对以金属板材为造型材料的分层实体制造方法中存在的问题,提出了用新LOM切割和用热扩散焊连接金属分层板的新方法。对比分析了新旧LOM方法的原理误差,推导出基于新LOM的分层切片算法,通过试验测定出热扩散焊连接金属分层板在堆积成形方向上尺寸变化较小,结合区域原子发生了明显的扩散,新的晶粒组织已经形成,且焊缝结合强度在100MPa以上,显微硬度与母材没有明显差别。样模制作表明新LOM方法加热扩散焊连接工艺是实现金属零件分层快速制造的有效途径之一。     

LOM原型制造精度的影响因素及保证技术研究

在简要介绍LOM技术的基本原理和LOM原型制造工艺的基础上，分析直接或间接影响LOM原型制造精度的各种因素，进而研究相应的保证技术，并提出了构建LOM原型制造精度集成化保证系统的意义及有效途径。     

基于新LOM的金属功能零件分层快速制造研究

基于新LOM方法和热扩散工艺，以1.0mm数量级的不锈钢板做造型材料，尝试了金属功能零件的分层快速制造，介绍了新LOM方法的原理，进行了金属分层板的连接实验和样模制作。研究结果表明，新LOM方法加工的零件曲面光滑，没有明显的台阶效应；热扩散焊在堆积成形方向上尺寸变化小，且为系统误差，结合强度达到100MPa；零件最大综合制造误差为0.485mm，但大部分位置处的误差在0.3mm以下。     

硅橡胶模具与LOM原型的热耦合温度场数值模拟

分析了硅橡胶模具在热硫化成型过程中与LOM原型的热边界条件，介绍了硅橡胶模具与LOM原型热耦合温度场的数值模拟方法，并详述了其实施步骤，进而设计了该热耦合温度场的有限元模拟软件，并计算了一典型算例的边界热耦合情况。     

OpenGL在金属功能零件LOM切片软件中的应用研究

介绍了LOM切片软件中STL文件可视化的方法,利用OpenGL技术实现了STL模型的线框图形和三维实体真实感的显示,并给出了具体算法,实现了直接查找STL源文件以及切片处理后文件的错误.     

EVA热熔胶厚度对LOM型快速成形件精度的影响和改进措施

在实验测试的基础上，对影响LOM型快速成形件精度的因素之一——热熔胶厚度场作了全面的分析，提出了提高LOM型快速成形精度的改进措施。     

LOM原型制作质量分析及控制

简要介绍了LOM原型的制作工艺过程，从工程应用和服务需要出发，分析了影响成形件质量和精度的因素，给出了控制其质量的几种有效方法。     

分层实体制造(LOM)成形过程中的热力耦合有限元分析

在分层实体制造（LOM工艺）过程中,原型件存在着翘曲变形的问题,采用热力耦合的有限元分析方法对LOM成形过程进行分析,为优化工艺参数、获得高精度的原型件提供依据。在有限元分析过程中,针对LOM成形过程的特殊性,对其材料模型的选取、材料增长过程的描述、动态的边界条件等进行了特别的处理。采用了单元的activate/deactivate技术来对LOM成形过程的材料增长过程进行描述。     

LOM工件热变形分析与度量

分析了薄形材料选择性切削（Laminated Object Manufacturing,简称LOM）成型的工件热变形和开裂的机理，对ZIPPY快速成形机制作的工件测量和使用表明，热变形会严重影响OM轼件的精度和性能，本文提出用片层翘曲量、长度方向相对翘曲率、厚度方向相对翘曲率描述LOM工件的热翘曲变形。     

一种经济型精密快速原型制造技术

在分析目前已有的各种快速原形制造技术缺点的基础上,提出了一种新型的基于刀具切线切割轮廓的厚层叠层制造技术。该技术通过改造三坐标钻铣床为五坐标数控铣床,利用现有的三维CAD软件,配置切片软件,达到了降低成本、提高精度和效率的目的。介绍了系统的组成方案以及初步的成形实验。     

Direct slicing and G-code contour for rapid prototyping machine of UV resin spray using PowerSOLUTION macro commands

Rapid prototyping processes produce parts layer by layer directly from 3D CAD models. An important technique is required to slice the geometric model of a part into layers and to generate a motion code of the cross-sectional contour. Several slicing methods are available, such as slicing from sterolithgraphy (STL) files, tolerate-error slicing, adaptive slicing, direct slicing, and, adaptive and direct slicing. This paper proposes direct slicing from 3D CAD models and generating a G-code contour of each layer using PowerSOLUTION software (Delcam International, Birmingham, UK). PowerSOLUTION includes two main modules: PowerSHAPE is used to build 3D CAD models and PowerMILL is used to produce G-Code tool paths. It provides macro language, picture files and cutting paths for secondary development work.The authors used macro commands to write an interface generating direct slicing from 3D CAD models and G-code contours for all layers. Most well-known controllers in the market accept the G-Code. Therefore, it is easier to apply this scheme in a CNC-machining center to produce rapid prototyping such as laminated object manufacturing (LOM) for complex geometries. The interface was successfully applied the interface to the UV resin spray rapid prototyping (UVRS-RP) machine that was developed to produce RP.     

Fast parallel algorithm for slicing STL based on pipeline

In Additive Manufacturing field, the current researches of data processing mainly focus on a slicing process of large STL files or complicated CAD models. To improve the efficiency and reduce the slicing time, a parallel algorithm has great advantages. However, traditional algorithms can’t make full use of multi-core CPU hardware resources. In the paper, a fast parallel algorithm is presented to speed up data processing. A pipeline mode is adopted to design the parallel algorithm. And the complexity of the pipeline algorithm is analyzed theoretically. To evaluate the performance of the new algorithm, effects of threads number and layers number are investigated by a serial of experiments. The experimental results show that the threads number and layers number are two remarkable factors to the speedup ratio. The tendency of speedup versus threads number reveals a positive relationship which greatly agrees with the Amdahl’s law, and the tendency of speedup versus layers number also keeps a positive relationship agreeing with Gustafson’s law. The new algorithm uses topological information to compute contours with a parallel method of speedup. Another parallel algorithm based on data parallel is used in experiments to show that pipeline parallel mode is more efficient. A case study at last shows a suspending performance of the new parallel algorithm. Compared with the serial slicing algorithm, the new pipeline parallel algorithm can make full use of the multi-core CPU hardware, accelerate the slicing process, and compared with the data parallel slicing algorithm, the new slicing algorithm in this paper adopts a pipeline parallel model, and a much higher speedup ratio and efficiency is achieved.     

基于STL模型垂直切片的支撑自动生成算法研究

针对光固化等快速成形工艺中须对零件加支撑的需求，本文提出一种新的支撑自动生成算法。该算法基于STL模型提取零件的悬吊点、下棱线、待支撑下表面的轮廓线等待支撑区域的关键特征，根据它们在形平面的投影特征来优化布置分层基准线并进行垂直切片，应用所提出的基于垂直截面轮廓内待支撑边生成支撑多边形的算法，生成相应的变厚度薄壁形支撑。实际应用表明，该算法能够对成形零件的待支撑区域自动添加准确有效的支撑。     

快速成形制造中基于模型连续性的快速分层算法研究

提出了基于模型连续性进行分层的思想,通过建立ＳＴＬ模型的分层面新相交三角形面片表文件,提取模型的活性拓扑结构的方式,显著降低了内存的占用量,并加快了拓扑信息提取时间。     

金属增材制造负载均衡异构并行切片算法

增材制造模型的几何复杂程度和体积不断提高，模型切片所需时间大幅增加，极大影响了数据处理效率。提出了一种自适应负载均衡的异构并行切片算法，利用不断增长的GPU超强并行计算能力对传统切片算法进行了GPU并行化研究，利用模拟退火算法对切片任务进行负载均衡装箱，使各线程间的任务量一致。实验结果证明，该算法提高了模型的切片效率，尤其适合大型或超大型三维模型的快速切片任务。     

Adaptive direct slicing of a commercial CAD model for use in rapid prototyping

Slicing a 3D graphic model into layers of 2D contour plots is an essential step for all rapid prototyping (RP) machines. Various methods are available, such as stereo lithography (STL) file slicing, direct slicing and adaptive direct slicing. Amongst these, adaptive direct slicing is the most advanced for its capability of adapting the slicing thickness according to the curvature of any contour. In this study, an adaptive direct slicing method complete with the algorithm for calculating the thickness of each layer is proposed. As an illustration of the method, the algorithm was programmed within the commercial CAD software package, PowerSHAPE. The method was shown to be fast and accurate in comparison with STL file slicing and direct slicing, which both used a constant layer thickness. An erratum to this article can be found at     

一种快速成形自适应分层层厚新算法

将现有的两种自适应层厚算法加以结合,阐述一种基于STL文件的快速成形自适应分层层厚的新算法。该算法弥补了上述两种算法原理上各自的不足,通过对该新算法的测试得到比较满意的结果。