基于3DP的快速模具制造技术在手轮制件上的应用

鉴于美国生产的能够用于直接浇注金属溶液的快速模具制造材料价格昂贵的问题,采用自配制快速成型材料,其主要成分为400目的石膏粉和200目的氧化铝粉的混合粉末,以手轮为研究对象,使用ZPrinter310快速成型机,成功打印成型出其模具零件,经烘干、固化处理后,浇注700℃左右的铝合金溶液,成功铸造出手轮.结果表明:采用自配制的400目石膏粉ZP102和200目氧化铝粉的混合粉末,不但能够成功成型出快速原型件、快速模具零件,还可实现浇注金属液成型出金属件的目的,同时自配置的打印原材料相比国外生产的同类材料的成本降低了一半.     

送粉式金属3D打印的技术现状及前景分析

送粉式金属3D打印,简称LDM,是通过送粉器将金属粉末输送到激光熔池,通过激光的辐射作用使粉末熔化和重新凝结,进而直接生产出金属制件.其具有产品成型尺寸大、加工迅速、可以实现复杂成分梯度打印等优点.而同时,又存在制件品质控制困难、制件外观粗糙等缺点.本文对送粉式金属3D打印的技术现状做了总结,并分析了其进一步的发展方向...     

基于RP的快速模具制造技术的应用研究

以美国Zcorp公司生产ZPrinter310系统为实验工具,使用石膏粉基的zp102为成型材料,利用快速成型技术中的三维打印技术,对三维实体模型进行切片分层处理,得到不同高度截面形状的数据信息,采用截面扫描,喷涂粘结剂,直接获得能够用于直接金属铸造的快速模具.以三通管为实验对象,讲述了整个工艺过程.结论表明,快速模具制造和直接金属铸造技术的结合,使产品的制造周期缩短、制造成本降低、铸件质量好等优点,体现了快速模具制造的优势,也为快速模具制造技术在金属制品的生产开辟了新的途径.     

基于RSM的三维打印参数对材料收缩率的影响

采用三维打印(three dimensional printing,3DP)成型的制件,经过干燥和后处理会在不同的方向上产生收缩现象,这严重影响成型制件的尺寸精度。将ZP310三维打印机作为试验平台,采用中心复合试验设计方法(central composite design,CCD)对打印参数进行实验方案设计.并用响应曲面法(response surface methodology,RSM)分析三维打印过程中饱和度和层厚对淀粉基混合粉末收缩率的影响,建立了三维打印成型过程中材料在X、Y、Z这3个方向上的收缩率与打印参数之间关系的数学模型。实验证明根据收缩率进行的误差补偿,降低了制件在不同方向上的尺寸误差。     

基于喷墨打印机的三维打印快速成型系统开发及实验研究

三维打印成型技术是目前快速成型领域最具生命力的技术之一,有广阔的应用前景。通过研究三维打印成型机理,针对目前在三维打印成型中广泛使用热气泡式喷嘴所存在的问题,提出了采用压电式喷嘴喷射成型材料和粘结材料的思想。讨论了基于压电式喷墨打印机的三维打印快速成型系统开发的关键技术和方法,根据这一思路开发了一套快速成型系统,并研究了粉末配方、铺粉方式、打印层厚、切片方向、等工艺参数。实验结果验证,所开发的快速成型系统制造的精细模型圆孔直径可达0.5mm,壁厚可达0.8mm,成型误差在±0.2mm以内。     

低温金属熔融沉积成型工艺研究

根据熔融沉积成型(FDM)工艺制造原型高效快速,原材料适应性广的特点,提出了以低温金属代替热塑性材料实现原型制造的方法,探究以低温金属为材料的熔融沉积成型工艺特点和各工艺参数对沉积成型质量的影响,并在此基础上开发了低温金属三维打印系统。实验以Sn99.3Cu0.7金属丝为材料,设计并实现了单层沉积和多层沉积实验。实验证明:通过优化低温金属三维打印系统运动参数,能够得到质量较好的单层金属线和三维金属模型,验证了低温金属熔融沉积成型工艺在PCB制版和金属三维成型方面应用的可行性,并根据实验结果提出了后续技术发展应重点解决的问题。     

激光熔融金属快速成型技术

正快速成型(Rapid Prototyping),又称增材制造(Additive Manufacturing)和3D打印(3D Printing)。其主要工艺流程是直接根据三维CAD模型转化成标准的STL数据格式,分层后层层叠加制作成实体模型或最终产品,无须编程或模具。从快速成型(RP)整个行业来说,商业化始于1987年左右,第一台SLA技术面市,从而各类塑料、树脂和粉末成型技术相继出现,如后来的     

基于快速原型的金属粉浆无压浇注成型与烧结

通过快速成型技术与硅橡胶软模技术首先制得试样的硅橡胶模具,然后将由铁粉与树脂粘结剂混合而成的粉浆浇注进硅橡胶模具中翻制试样的型坯,再对型坯进行烧结制取内部孔隙均匀的金属骨架状型坯。在试验对比的基础上,探讨了金属粉浆无压浇注成型与烧结工艺中树脂粘结剂的选用、金属粉的选用、粉浆浇注与烧结等问题。结果表明:199聚脂树脂较适合作为该工艺的粘结剂,同时双组分混合铁粉较单一铁粉更有利于形成孔隙均匀的骨架状型坯的烧结成型。     

金属3 DP法三维打印水基黏结剂体系的研究

为了拓展3DP法三维打印技术的应用,介绍了金属3DP法两种常用的黏结方式,并选择水基黏结剂体系用于不锈钢粉末的3DP打印试验,研究了所采用的聚乙烯醇(PVA)和淀粉两种黏性粉末以及所喷射溶液的有关特性。结果表明,加热到约240℃时,PVA开始分解,加热到约280℃时,淀粉开始分解,加热到约600℃时,两者都基本分解完成。黏性粉末烧损后极少量的残留物中只含C、H和O三种元素。不锈钢粉末中添加10 wt%PVA和2 wt%淀粉得到的混合粉末具有较好的流动性,能够得到平整光滑的铺粉表面。以80 vol%水与20 vol%乙醇为溶剂添加少量聚乙烯吡咯烷酮配制得到的喷射溶液,其黏度和表面张力均在3DP技术适用溶液的参考值范围内,得到的打印层无翘曲变形。最后采用该水基黏结剂体系得到了质量较好的打印坯。     

快速原型及模具网络化数字制造的工程应用

研究新产品快速开发、装配及功能试验的方法,金属直接成型的数字化新工艺及如何实施快速原型与模具数字集成制造的技术。在此基础上,介绍典型工程应用的成功案例。     

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。     

3D打印砂模的结构优化设计方法研究

砂模3D打印是一种快速发展的砂模智能制造技术,能够对任意复杂形体进行几何造型。在实际应用中,砂模造型设计仍沿用传统设计思想,尚未充分发挥3D打印所带来的技术优势。由于传统砂模几何形体中存在冗余结构,直接影响打印效率,因此有必要结合3D打印技术优势对砂模结构进行设计优化,以提高生产效率、节约生产成本。在新工艺环境下,本文建立了一种砂模结构优化设计方法及其设计流程;以砂模壁厚作为优化参数,依据力学性能要求,建立了砂模结构优化设计模型;最终基于某厂铸造试验件进行了范例设计与仿真校核。优化设计后的试验件砂模在满足力学性能要求的前提下,体积优化率达到42.6%,有效提升3D打印砂模的生产效率与经济性。     

An investigation into the rapid prototyping of moulds for expanded polystyrene foam

Expanded polystyrene foam, a packaging material, is traditionally injection-moulded by classical moulding techniques. However, the design and fabrication of these moulds is both intricate and time-consuming. In today's manufacturing environment of short time-to-market, the luxury of producing a mould for, often, a first-off article for client approval, is virtually untenable. Rapid prototyping technologies appear to offer an alternative method of fabrication which promises to drastically reduce the time for mould fabrication. When rapid prototyping of the mould is combined with microwave curing of the polystyrene, as an alternative source of energy to traditional steam heating, the benefit of considerably short throughput times can be expected. This paper describes the computer-integrated design and fabrication of both the mould and foam product, and discusses the main issues associated with rapid prototyping the mould, viz. accuracy of the prototype mould and the suitability of acrylic resin used in stereolithography apparatus for fabricating the mould, as well as the parameters for moulding expanded polystyrene using microwave energy. Initial results suggest that both the stereolithography process, and the acrylic resin used to build the stereolithographic model, can be used for rapid prototyping expanded foam products and their associated mould.     

<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.     

基于快速成型技术的电机壳体金属模具制造

分析了快速成形(RapidPrototypingRP)技术的离散堆积成形原理,并采用非线性有限元算法对凝固过程中铸件的尺寸精度进行数值模拟,且详细给出了直接制模铸造工艺机理及流程,对解决当前我国模具制造业中成本高、周期长、性能差等问题具有一定的现实意义。     

快速成型技术在熔模精密铸造中的应用

快速成型技术是具有高柔性的先进制造技术,无需任何专用工具,由零件的CAD模型直接完成零件或零件原型的成型制造。将快速成型技术与铸造技术结合起来,采用快速成型技术制造铸型或铸模,可极大提高铸造的柔性和生产效率,满足新品试制和小批量生产的需求,这也是快速成型技术的一个主要发展方向。本文通过几种快速成型模在熔模精密铸造中的实际应用和试验得出,采用SLA法制作的蜂窝结构快速成型模在尺寸波动方面满足精铸需要,并能实现铸件的快速制造。     

一种用于快速成形设备的“跳跃”式铺粉装置

快速成形技术是一种多学科交叉的系统工程技术,在以粉末作为成形原料的快速成形技术中,铺粉装置是其成形设备中的关键部件之一。现有的铺粉装置存在粉末约束难、易堆积,粉末利用率低,结构复杂且难以调整等缺点,借鉴原有的铺粉装置,利用轨道变化使刮片在工作行程中实现＂跳跃＂动作并增加可调侧翼形成新的＂跳跃＂式铺粉装置,通过实验验证可以有效的改善上述问题。     

Process chain development for the rapid prototyping of microstructured polymer, ceramic and metal parts: composite flow behaviour optimisation, replication via reaction moulding and thermal postprocessing

Different variants of reaction moulding techniques exploiting the rapid light-induced photopolymerisation of reactive resins are widely used in microsystem technologies for the fabrication of plastic components or for rapid prototyping (RP) purposes. In this paper, the further development of micro reaction moulding with respect to a rapid prototyping of ceramic and metal parts will be described. As in powder injection moulding, the process sequence binder–filler–formulation, replication, debinding and sintering has to be passed. The mould filling and, hence, the accurate reproduction of surface details depend strongly on the composite’s viscosity, which is a function of the filler load. Especially, an improved process control of the composite formation prior to moulding and the thermal debinding is crucial for the realisation of microstructured ceramic or metal parts. The development of the whole process chain and some examples will be presented. This paper was originally presented at the International Conference on Multi-Material Micro Manufacture (4M), Karlsruhe, Germany, 29 June 2005 to 1st July 2005, and is extended for publication in this journal.     

Re-triangulation in STL meshes for rapid prototyping and manufacture

The main objective of this research is to identify ways to simplify the STL meshes, while simultaneously maintaining the accuracy of the STL file. It demonstrates a technique to simplify large and complex STL triangular meshes and to optimise STL shape for rapid prototyping and manufacture. STL mesh re-triangulation can be separated into two processes, i.e., mesh deletion and mesh rearrangement. In the mesh deletion process, two kinds of weighted-value ratio algorithms can be chosen for determining the suitable value of STL mesh deletion. A genetic algorithm that incorporated fitness functions was used for the optimisation of the rearranged STL meshes. Two case studies of STL mesh reconstruction, which examine the effects of the algorithms, are presented. These studies show that optimisation of the shape of the STL file reduces its size, resulting in a reduction of the fabrication time and improvement of the rapid prototyping process.     

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.