Optical counting of guided particles in a vortex beam as an optical tube by laser-two-focus method

In this study, microscopic particles such as aerosols were counted by Laser-Two-Focus method, L2F, after being trapped and guided by an optical tube. This prevents particles diffusivity as they pass through the Gaussian beam in the L2F method by optical forces such as radiation pressure and photophoretic forces. In optical tube, particles can guid to the center of the beam where the intensity gets zero. A single-charged Bessel Gaussian beam, BG₀₁, is used as the particle guidance beam in this method, which is generated by passing the first-order Laguerre-Gaussian beam, LG₀₁, from an axicon lens. LG₀₁ beam are also produced by using holographic interference grid mask. The results of the theory and simulations showed that by optical guiding of particles in the L2F-method measurement, their transverse turbulence can be reduced by about 60% and then the probability of measuring all particles to be increased by about 30%. Measurements of in-laboratory aerosols less than 3.5 μm with this method showed a 20% increase in their condensation of them compared to the conventional L2F method.     

金属零件的直接快速制造和再制造

对金属零件的直接快速制造和再制造技术的研究进展,进行了综述,并重点介绍了RM直接制造金属型的新工艺,提出了今后的研究和发展方向。     

Rapid prototyping fabrication and finite element evaluation of the three-dimensional medical pelvic model

This paper presents a non-uniform, periodic closed B-spline approximation algorithm for the fabrication of a medical pelvic model, based on rapid prototyping, and also gives the finite element evaluation of the pelvic model. Rapid prototyping (RP), when used in fabricating medical prosthesis, has a strict requirement for closeness and impermeability of STL files. Incorrect data structure in STL files will cause the subsequent slicing process not to proceed. The non-uniform periodic closed B-spline curve approximation method was applied to processing CT data. The precision and size of STL files was improved to optimize the RP model of the pelvis. Finally, the model of the pelvis was evaluated with the finite element method. Results suggest that a high similarity has been achieved in terms of shape, size and biomechanical properties of the pelvic model and the normal one, which validates our argument that rapid prototyping with non-uniform, periodic closed B-spline algorithm is suitable for the fabrication of a pelvic model, which will prove to be significant in the design of pelvic prostheses .     

Cutting path generation of linear hotwire cutter for VLM-ST

Most rapid prototyping (RP) processes adopt a solid CAD model, which will be sliced into thin layers of constant thickness in the building direction. Each cross-sectional layer is successively deposited and, simultaneously, bonded onto the previous layer; eventually, the stacked layers form a physical part of the model. A new thick-layered RP process, the transfer-type variable lamination manufacturing process using expandable polystyrene foam sheets (VLM-ST), has been developed to reduce building time by employing thick layers and to improve the surface finish of parts with a sloping surface. This paper describes the method to generate the unit shape layer (USL), the cutting path data of the four-axis hotwire cutter for the VLM-ST process. The USL is the basic unit of cutting and building in the VLM-ST process and it is also the basic unit of cutting path data of each layer. The USL includes data such as layer thickness, positional coordinates, side angles of each layer, and reference shape. The method to generate the USL is as follows: (1) the mid-slice of each layer is generated from the CAD model, (2) each mid-slice is converted into a simply-connected domain, (3) the rotation angle of the hotwire of the cutting system is calculated for each layer, and (4) the reference shape of each layer is generated for manual stacking. The procedure to generate the cutting path data of the linear hotwire cutter for VLM-ST was practically applied and verified for various three-dimensional shapes.     

快速原型直接模具在熔模铸造中的应用研究

针对单件小批量产品的熔模铸造,提出了快速原型方法直接烧结模具,并用该模具浇制低温合金熔模的方法.提供了较为详细的解决问题的步骤,并作了相应的分析和论证.此直接模具制造并浇制熔模的方案,简单易行,可使生产周期大大缩短,有利于产品迅速响应市场需求.     

基于RP技术的滴灌用灌水器滴头的快速定型

摒弃滴灌产品的传统制作模式，借助高新技术进行产品的快速研制定型。RP技术为此提供了新途径，由三维CAD模型在成型机上快速做出滴头原型，就可直接进行流量试验，经综合评价，便可实现滴头的快速定型。提出了基于RP和ANSYS软件的滴灌用滴头的双闭环研制方案。     

经济型快速成型技术的软件系统研究

提出了经济型快速成型系统的概念 ,研究开发了用于经济型快速成型技术的软件系统 ,并介绍了这一软件系统的开发过程和方法     

CS File – An Improved Interface Between CAD and Rapid Prototyping Systems

The STL file, which is de facto standard for the rapid prototyping industries, has too large a file size. This paper proposes an improved interface between CAD and rapid prototyping systems, i.e. a CS (compressed STL) file that has very low data storage redundancies and is completely compatible with the STL file. The CS file is about a quarter of the size of the original binary STL file, without any model information loss. This is very suitable for file transferring via the Internet. Removing coordinate data of duplicate vertices, bit-compression technology, and a comparison of the size and compressed performance of the STL and the CS are also discussed. ID="A1"Correspondance and offprint requests to: Dr Li-Chao Zhang, Rapid Prototyping Building, State Key Laboratory of Plastic Forming Simulation and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, PR China. E-mail: elegantteac@yahoo.com     

基于工业设计和先进制造技术的产品快速开发

提出一种将工业设计与逆向工程（RE）、CAX技术、快速成型和快速模具结合起来的集成开发模式。在该模式下,利用RE技术直接将工业设计获得的实物模型转换为数据模型。数据模型在CAD系统中进行处理,构造曲面模型或STL模型表面、再经过STL模型表面的偏置处理,利用RP和RT技术直接、快速的制作出样件或小批量成品,利用CAM系统还可以输出机械加工需要的数据代码。本文洋细介绍了该模式的组成部分、工作流程以及接口等关键技术,并以一个实例来说明该模式的正确性和高效性。     

基于Web的RP通用软件系统设计研究

针对单机RP软件系统的局限性,分析比较了C/S和B/S模式的优缺点,进行了C/S和B/S混合模式的RP通用软件系统的设计研究,介绍了系统体系结构并阐述了系统开发的关键技术。