基于LOM技术的大型原型成形效率分析

如何提高加工效率一直是快速成形（RP）技术的一个重要课题，也是快速成形技术走向大型化的一个主要障碍。通过对几种典型的快速成形工艺的分析、比较，认为分层实体制造（LOM）工艺以面作为最小成形单位，具有最高的成形效率，是RP技术中较适合制造大型原型的工艺。以清华大学激光快速成形中心的SSM-1600成形系统为例，分析了成形大型原型时的工艺特点以及提高成形效率的一些途径。     

铸造成形过程研究与创新

在对成形系统分解与综合的基础上，提出了成形工艺创新的基本思路。通过对传统有模型砂型制造过程的分析，指出导致其柔性较低的主要原因是信息过程与物理过程相对独立。将离散／堆积成形原理与树脂砂工艺有机结合，提出了CAD模型直接驱动的铸型制造工艺，又称无模型铸型制造。     

动态分区并行扫描方法研究

如何制造大型原型零件是目前快速成形技术(RP)研究的热点之一。分层实体制造工艺(LOM)在直接制造大型原型方面具有独特的优势。造型周期长是制造大型原型的困难之一,针对LOM工艺提出了动态分区并行扫描成形的方法。分析和试验结果表明,采用该方法可以有效提高成形效率,是实现直接制造大型原型的可行途径之一。     

快速成形技术的发展

21世纪将是以知识经济和信息社会为特征的时代,制造业面临信息社会中瞬息万变的市场对小批量多品种产品要求的严峻挑战。在制造业日趋国际化的状况下,缩短产品开发周期、减少开发新产品投资风险,成为企业赖以生存的关键。快速成形技术(RP)自80年代问世以来,在成形系统、材料方面有了长足的进步,同时推动了快速制模(RT)和快速制造(RM)的发展,如今快速成形/快速制模/快速制造技术已经成为企业提高竞争力的一种先进手段。     

快速成形材料及应用

快速成形技术(RP技术)是一种用材料逐层或逐点堆积出制件的制造方法,目前比较成熟的有LOM、SLS、SLA、FDM等技术,比较引人注目的还有新出现的金属板材快速成形和快速制模。 RP系统由于其成形工艺的特殊性对其材料有     

发动机排气管的铸型数控切削快速制造

铸型的数控切削技术是以水玻璃砂为成型材料,利用特种铸型数控切削机床、由三维CAD模型驱动、采用铣刀层层铣削,直接获得水玻璃砂铸型或铸造模具的一种快速制造技术.该工艺加工的铸型会出现、凹坑、裂纹、崩角、坍塌、精度低等缺陷,通过改变砂坯制造工艺、铸型切削参数、刀具的选择、最终得到无缺陷和精度高的发动机排气管铸型.     

基于快速原型的金属成型技术发展现状研究

直接用三维CAD模型驱动制造金属零件、模具是快速原型技术研究的热点之一。本文阐述了RP金属成型技术的主要工艺方法,通过对目前主要基于RP工艺的金属成型工艺研究现状的综述,提出直接制造金属型是RP技术今后发展的一个重要方向。     

快速成型砂心工艺

当今铸造行业采用快速成型工艺进行砂心制造取得了良好效果。 砂型铸造是长期发展的传统工艺之一,现在正大大得益于快速成型(RP)新技术。由于有了新型树脂粘结砂和激光熔炼快速成型技术的结合,制造砂心成了特别令人难忘的应用领域。 目前可以只用原工艺几分之一的时间完成特别复杂的砂心铸造。RP技术应用于砂心铸件的特点之一是在不同的专业公司之间建立起紧密的合作关系,每个专业公司都可以拿自己的专长帮助用户。     

直接金属沉积成形工艺的RP软件研究

直接金属沉积（DMD）快速成形是快速制造的一种新工艺，其原理与传统的快速成形工艺（如分层实体制造SSM，熔融挤压成形MEM，立体光刻SLA等）相同。所介绍的直接金属沉积成形工艺是在CAD模型直接驱动下，由高功率激光熔化同轴输送的金属粉末，层层扫描熔化堆积，直接形成致密的金属零件，该直接金属成形系统包括数控系统，激光系统，同轴送粉系统，RP数据处理软件系统，控制软件系统等，重点针对高功率激光同轴送粉的真空金属沉积成形工艺，研究相应的控制软件开发和数据处理软件的改进。     

快速成形技术研究现状及其应用前景

简单阐释了快速成形(Rapid Prototyping)的工作原理及典型工艺,综述了这一先进制造技术的研究状况,重点介绍了RP技术在工业、军事、建筑、医学等领域的应用,展示了目前国内外研究的最新成果.     

Plaster casting process for prototyping of die casting based on rapid tooling

Rapid prototyping (RP) combined with a gravity casting process can provide a suitable substitute with steel tool die casting for prototyping metal casting. Due to differences between die casting and gravity casting, there are several drawbacks in RP simulated die casting. This paper is concerned with the development of a new plaster die casting process that combines pressurization and vibration for prototyping of die castings, and with a plaster die casting machine that has a structure similar to that of a die casting machine. The machine utilizes an oil cylinder for pressurization and a magnetic actuator for vibration. A rapid prototyped pattern is made by the laminated object manufacturing (LOM) process to prepare a plaster mold. In the process, a plunger in the developed machine simultaneously pressurizes and vibrates the molten metal to fill the plaster mold completely and to facilitate the creation of nuclei in the molten metal, respectively. The developed machine has produced a prototype of an end clutch cover with remarkable improvement in mechanical properties.     

快速模具技术在摩托车齿轮箱盖制造中的应用

介绍了将快速模具技术应用于摩托车齿轮箱盖零件制造的过程,研究了纸基砂型铸造模具制作的技术方案和实施步骤,并对其中的一些技术关键进行了深入的探讨.结果表明,利用快速模具技术可以取代传统的木模制作工艺,此技术具有制作周期短、成本低、尺寸精度高的特点,适用于产品开发过程中小批量样件的快速制造.     

新的激光快速成形方法及应用

针对目前主要激光快速成形方法的优缺点,提出一种基于三维实体边界分割的激光快速成形新方法.该方法将叠层实体制造(LOM)法主要进行激光二维轮廓线扫描和选择性激光烧结(SLS)法能够加工多种覆膜粉末材料的优点有机结合,能够克服SLS法加工效率低,成形件致密度、硬度、精度和表面粗糙度等性能较低的缺点.利用自主开发的快速成形系统,采用热像仪测温与Ansys模拟激光能量输入模型相结合的方法对工艺参数进行确定,对基于三维实体边界分割激光快速成形方法进行应用研究,实现三维实体的快速成形及金属零件的快速铸造,并通过无模具快速铸造的手段获得金属齿轮铸件.     

Rapid prototyping and tooling techniques: a review of applications for rapid investment casting

Investment casting (IC) has benefited numerous industries as an economical means for mass producing quality near net shape metal parts with high geometric complexity and acceptable tolerances. The economic benefits of IC are limited to mass production. The high costs and long lead-time associated with the development of hard tooling for wax pattern moulding renders IC uneconomical for low-volume production. The outstanding manufacturing capabilities of rapid prototyping (RP) and rapid tooling (RT) technologies (RP&T) are exploited to provide cost-effective solutions for low-volume IC runs. RP parts substitute traditional wax patterns for IC or serve as production moulds for wax injection moulding. This paper reviews the application and potential application of state-of-the-art RP&T techniques in IC. The techniques are examined by introducing their concepts, strengths and weaknesses. Related research carried out worldwide by different organisations and academic institutions are discussed.     

Rapid Sheet Metal Manufacturing. Part 2: Direct Rapid Tooling

The traditional methods adopted for tool design and production in the sheet metal forming industry usually carry a high cost and long lead time resulting in cost justification problems for short production runs. Rapid tooling (RT) technology is capable of justifying the cost of tooling suitable for short production runs or design evaluation purposes. In Part 1 of this work, a new process termed rapid sheet metal manufacturing (RSMM) for the production of soft tooling suitable for prototyping, tool development, and short production runs was introduced. In addition, an indirect RT method employing rapid prototyping (RP), rapid soft tooling, and casting for the fabrication of non-ferrous tools was presented. The current work, Part 2, presents an alternative technique for RSMM whereby metal forming tools are fabricated directly from the RP system via selective laser sintering (SLS).     

<Emphasis Type="Bold">Laser Sintering of Silica Sand – Mechanism and Application to Sand Casting Mould</Emphasis>

Silica sand is commonly used in the foundry industry. With a high melting point of 160°C, the silica sand is normally sintered in a high-temperature furnace. However, silica with contents of calcium, aluminium, magnesium, and chlorine, etc. can form low-melting point eutectics. Therefore, a relatively low-power laser can be used to sinter the silica sand directly. The investigation of the mechanism and process for direct laser sintering of the silica sand, without any binder, is presented in this paper. Combined with rapid prototyping (RP) technology, the laser sintering of the silica sand can be used to directly fabricate a sand casting mould, called a rapid sand casting mould. By avoiding the time-consuming process of fabricating a pattern, the rapid sand casting mould process has the potential of further reducing the lead time for producing a casting product. Some important issues, such as the lead time of producing a sand mould, its accuracy, and surface finish, etc., are discussed.     

基于快速原型骨替代物的个体定制化制造

为解决普通人工骨替代物的形状匹配问题，提出了应用快速原型技术结合传统制造工艺实现，人工骨替代物的个体定制化制造方法，其优势在于它能为患者提供形状准确的定制化的骨替代物，其中传统工艺选择熔模铸造或粉末冶金，论述了将这些传统工艺运用于骨替代物的制造中所引起的一系列问题和解决办法，对其中的光固化造型＋熔模铸造方法进行了深入研究，运用该方法制造的人工骨替代物已成功投入临床应用。     

汽车发动机缸体铸造技术分析

随着当今社会经济与科学技术的协同发展,汽车制造行业的发展也十分迅速.而在汽车制造中,发动机缸体是一个关键部分.为实现发动机制造及其应用质量的良好保障,本文特对其发动机缸体的铸造技术进行分析.希望通过本次的分析,可以为汽车发动机缸体加工及其后续应用效果的保障提供科学参考,以此来促进汽车生产制造质量的进一步提升.     

矿铸件材料在装备制造业中的应用

结合矿铸件材料属性,与铸铁、钢进行对比,介绍该材料在制造设备应用中的各种优势,列举了矿物铸件产品的应用实例,探讨了矿铸件的加工方法及相关技术.     

Plaster casting process for prototyping of die casting based on rapid tooling

Rapid prototyping (RP) combined with a gravity casting process can provide a suitable substitute with steel tool die casting for prototyping metal casting. Due to differences between die casting and gravity casting, there are several drawbacks in RP simulated die casting. This paper is concerned with the development of a new plaster die casting process that combines pressurization and vibration for prototyping of die castings, and with a plaster die casting machine that has a structure similar to that of a die casting machine. The machine utilizes an oil cylinder for pressurization and a magnetic actuator for vibration. A rapid prototyped pattern is made by the laminated object manufacturing (LOM) process to prepare a plaster mold. In the process, a plunger in the developed machine simultaneously pressurizes and vibrates the molten metal to fill the plaster mold completely and to facilitate the creation of nuclei in the molten metal, respectively. The developed machine has produced a prototype of an end clutch cover with remarkable improvement in mechanical properties.