光固化快速成型技术及其应用

一、快速成型技术简介 随着科学技术的发展和社会需求的多样化,产品的竞争愈来愈激烈,更新的周期也越来越短,因而要求设计者不但能根据市场的要求尽快设计出新产品,而且能在尽可能短的时间内制造出原型,从而进行必要的性能测试,同时在征求用户意见的基础上作出相应的修改,最后形成能投放市场的定型产品。用传统的方法制作原型,成本高、周期长,已不能适应日新月异的市场变化。近年来,出现了一种新的制造技术——快速成型技术(Rapid Prototyping,简称RP),它的出现为此问题的解决找到了答案。     

经济型光固化快速成型系统——CPS250

快速成型(RP—Rapid Prototyping)技术是80年代后期发展起来的一种新型制造技术,它集CAD/CAM、激光技术、材料科学、计算机和数控技术于一体,被认为是近20年来制造领域的一次重大突破。RP技术以其高度柔性、适宜成型复杂零件的优势正得到越来越广泛的应用。目前商品化的快速成型机价格均很昂贵,致使成型零件的成本比较高。本文提出一种用紫外灯作光源的光纤扫描快速成型方案,它可以有效降低成本,是一种新的三维打印机。     

光固化立体成型技术及其最新发展

论述光固化立体成型的工艺原理,系统组成和影响原型精度的各种因素及其改善途径,介绍了光固化立体成型的发展现状与应用前景。     

一种新的光固化快速成型工艺的研究

零件的变形是光固化快速成型中经常遇到的问题,它不但影响成型零件的尺寸精度,还会引起结构整体变形、翘曲或层间开裂,更有甚者使得成型过程无法继续进行。此外,变形也是快速成型制造中普遍存在的问题,即使在LOM法中也存在着     

快速成型与快速模具制造技术

介绍了快速成型制造技术（ＲＰ＆Ｍ）的基本原理和主要方法以及常用的基于ＲＰ＆Ｍ的快速模具（ＲＴ）制造技术及其工艺流程,以及快速成型与快速模具制造技术的研究进展,分析了迅速增长的快速成型与快速模具制造技术市场及经济效益。     

光固化快速成型工艺过程分析及应用

光固化快速成型作为先进的制造技术的一部分,具有重要的应用价值。首先介绍了光固化快速成型工艺的基本原理,分析其存在的优点与缺点。论述了光固化快速成型设备的主要组成部分,如光学装置、容器系统、光敏材料、涂敷机构和控制系统等。以一个非标准圆柱齿轮为例,详细论述具体的加工过程并在SCPS350B成型机上加工出实物。探讨光固化成型技术在产品设计、模具制造、精密铸造、生物医学等方面的应用,展望该技术在未来的发展前景。     

立体光固化快速成型技术的应用及发展

立体光固化快速成型技术(SLA)是一门发展迅速的高新快速成形制造技术,他具有其他的快速成形技术无法比拟的优点,拥有广泛的应用市场.文中根据国内外最新的研究资料,对立体光固化快速成型技术的工作原理、具体的工艺形式,以及其优点及应用进行了较为详实的介绍和论述.     

光固化零件的变形理论研究

光固化零件的变形是光固化成型工艺中必须解决的关键问题之一。论文主要研究了光固化零件的层内应力—应变分布 ,在推导出相关理论公式的基础上 ,指出减小零件变形的有效措施 :采用对称方式扫描固化可以消除拉弯耦合效应 ;采用正交扫描方式可以消除拉剪耦合效应及弯扭耦合效应 ;减小层厚可减少耦合效应。     

半导体激光器在光固化快速成型中的应用

半导体激光器以其独特的性能及优点获得了飞速发展和广泛应用.回顾了半导体激光器的原理、结构、进展和产品,提出了半导体激光器可作为光固化快速成型新型光源,并列举其优点,使光固化快速成型设备变为一种桌面式三维打印系统的设想成为现实.     

光固化快速成形技术中的精度研究

结合激光快速成形ＬＰＳ－６００Ａ系统论述光固化法快速成形技术中的精度概念，分析影响度的各种因素及改善制件精度的途径，讨论原型制件精度的评价标准问题。     

基于Voronoi图的快速成型扫描路径生成算法研究

提出一种平面多连通区域的算法 ,该算法对波前传播算法进行了扩展 ,能适用于平面多连通区域。用 VC++实现了平面多连通区域的 Voronoi图算法 ,并应用于立体光固化法快速成型中的扫描路径规划     

基于快速原型技术的产品创新流程再造

指出了基于快速原型技术产品创新过程中的信息流动是以数字信息为主,从而为创造信息化流程提供了良好的基础条件,并在分析传统职能部门型组织弊端的基础上,讨论了基于快速原型技术产品创新流程的三种常见基本组织形式,分析了其基本功能并对其本质特性进行了详细的研究.     

生物假体模型的快速成型制作技术

介绍了几种用于赝复体制作的快速成型方法,提出采用选区激光烧结成型快速制造医学假体,在人造五官医学假体特别是整容术赝复体的设计及制造方面,具有良好的应用前景,并采用选区激光烧结蜡粉得到赝复体原型蜡模,用于赝复体的快速制作。     

快速原型技术现状与发展趋势研究

该文简要介绍了快速原型技术的原理、快速原型技术的特点,阐述了国内外现状及发展趋势。     

影响激光快速成型精度的因素及对策

成型精度是快速成型技术在工业应用中的关键问题之一，但目前高的成型精度往往难以保证。本文研究了立体光造型（StereolithgraPhy）过程中影响成型精度的主要因素和解决办法，并提出了智能快速成型的概念。     

A New Slicing Procedure for Rapid Prototyping Systems

The current slicing rule of most rapid prototyping (RP) systems cannot ensure unilateral tolerances on the whole prototype and often results in problems of overcut and undercut on the same part. This drawback leads to unsatisfactory precision of the part in post processing. In order to reduce the above problems, a new slicing method is proposed in this paper. Based on the geometry information in a stereolithography (STL) file, an algorithm is developed. The appropriate slicing rule is selected according to the inner product of the normal vector and working direction of the part, together with the function of the part to be manufactured. The STL file is cut into 2D sections and an accurate contour is calculated. After the slicing computation, an appropriate working path is produced. The rules proposed in this paper have been verified. This work contributes to the improvement of slicing rules in existing RP systems, especially in systems using uniform thickness slicing. It also improves manufacturing efficiency and working tolerances.     

PART BUILDING ORIENTATION OPTIMIZATION METHOD IN STEREOLITHOGRAPHY

Aiming at the part quality and building time problems in stereolithography (SL) caused by unreasonable building orientation, a part building orientation decision method in SL rapid prototyping (RP) is carried out. Bringing into fall consideration of the deformation, stair-stepping effect, overcure effect and building time related to the part fabrication orientation, and using evaluation function method, a multi-objective optimization model for the building orientation is defined. According to the difference in the angles between normal vectors of triangular facets in standard triangulation language (STL) model and z axis, the expressions of deformation area, stair-stepping area, overcure area are established. According to the characteristics in SL process, part building time is divided into four sections, that is, hatching scanning time, outline scanning time, support building time and layer waiting time. Expressions of each building time section are given. Considering the features of this optimization model, genetic algorithm (GA) is used to derive the optimization objective, related software is developed and optimization results are tested through experiments. Application shows that this method can effectively solve the quality and efficiency troubles caused by unreasonable part building orientation, an automatic orientation-determining program is developed and verified through test.     

Rapid Prototyping and Tooling of Custom-Made Tracheobronchial Stents

Rapid prototyping (RP) and rapid tooling (RT) techniques can be applied to the field of medicine primarily because of their ability to produce customised profiles and geometries in relatively short lead times. In this paper, the process by which these techniques can be applied for the production of customised tracheobronchial stents for the purpose of maintaining patency in an occluded respiratory tract is described. A comparison of RP systems was carried out to establish the preferred RP method to produce the master model. The vacuum casting RT process was then used to produce the stent.     

Dual Material Rapid Prototyping Techniques for the Development of Biomedical Devices. Part 1: Space Creation

Polymeric drug delivery devices play an important role in drug administration. However, the current polymeric drug delivery device fabrication methods lack precision. This impairs the quality of the devices, resulting in a decrease in the efficiency and effectiveness of drug delivery. The concept of building parts layer by layer out of powdered raw materials makes selective laser sintering (SLS) a suitable process for fabricating polymeric matrix drug delivery devices. The current SLS process is not capable of processing two or more materials separately. This work explores the possibilities of SLS per-forming a dual material operation by developing two process models. These two processes can then be integrated to form a dual or expanded multimaterial fabrication technique and act as a foundation for future work in multimaterial applications such as polymeric drug delivery device fabrication. Accord-ingly, two papers are presented. In this paper, Part 1, the focus is on the first process, which is a "space" creation technique in which a "space" is created by varying the density of a first representative material using heat during sintering. Three methods – one based on a vacuum and a place method, and the other two based on two variations of a laser compacting method – were tested. Results have shown that by varying the laser power during sintering, it is possible to create channels in which a second material can be deposited.     

Dual Material Rapid Prototyping Techniques for the Development of Biomedical Devices. Part 2: Secondary Powder Deposition

Polymeric drug delivery devices play an important role in drug administration. However, the current polymeric drug delivery device fabrication methods lack precision. This impairs the quality of the devices, resulting in a decrease in the efficiency and effectiveness of drug delivery. The concept of building parts layer by layer out of powdered raw materials makes selective laser sintering (SLS) a suitable process for fabricating polymeric matrix drug delivery devices. The current SLS process is not capable of processing two or more materials separately. This work explores the possibilities of using SLS to perform a dual material operation by developing two process models. The two processes can then be integrated to form a dual or multimaterial fabrication technique and act as a foundation for future work in multimaterial applications such as polymeric drug delivery device fabrication. Accordingly, two papers are presented. In this paper, Part 2, the emphasis is on a secondary powder deposition method, which is an electrostatic technique based on electrography. Developed toner on the photoconductor is scraped off using mechanical shearing and is deposited using an electrostatic force by electroplating. Results have shown that by reducing the distance between the photoconductor and surface of deposition, the resolution of the printout can be refined. Other important factors include the efficiency of powder removal from the photoconductor, printing speed, and the traversing speed during deposition.