分段沉积/雕铣成形的工艺规划研究

分段沉积/雕铣成形技术是快速原型结合传统加工方法的一种新的工艺,兼有快速原型的高柔性和传统加工的高精度.对分段沉积/雕铣成形技术中零件的分段、薄壁件的加工、尖角的加工、曲面的加工等一些特殊工艺进行合理的工艺规划,提出解决措施.     

选区电化学沉积快速成型轨迹规划

数控选区电化学沉积快速成型是将快速成型技术与电化学沉积技术相结合的一种新型快速成型方法。为保证数控选区电化学沉积快速成型的零件精度,提出了一种基于电化学沉积技术的快速成型工艺的路径生成算法。结合该成型工艺的特点,分析了快速成型领域常用的几种扫描方式,轨迹规划方案分为STL切片处理、轮廓偏置、轮廓填充、数控加工代码生成四个过程,提出了平行交错往复间隙填充法。实验表明该轨迹规划能够达到选区电化学沉积快速成型的要求,制造出高精度、高表明光洁度的零件。     

分段沉积/雕铣成形零件材料自动注射装置

根据分段沉积／雕铣成形工艺的特点。设计开发了适用于零件材料的自动注射装置。包括物料混合系统、物料输送系统和注射过程控制系统三个部分。该装置解决了高粘度树脂和低粘度固化剂在静态混合器内按比例的混合、注射轨迹和注射量的精确控制等核心技术问题。实现了物料注射过程的计算机控制。使用结果表明。该注射装置总体方案合理，主要参数控制精确，为分段沉积／雕铣成形新工艺的进一步研究奠定了良好的基础。     

基于Pro/E的GSFD6050数控雕铣机床身的参数化设计

在GSFD6050雕铣机床身结构的基础上,通过参数化设计技术实现GSFD6050数控雕铣机床身的快速变形设计;同时应用Pro/E软件,借助于参数化设计技术,实现GSFD6080雕铣机和GSFD5060雕铣机床身的快速设计。     

以刀具为核心的复杂形状产品雕铣加工优化方法

针对复杂形状产品的雕铣加工过程中由于形状复杂带来刀具运动过程复杂和小型刀具容易折断等因素,导致加工效率低、加工成本高、加工质量不易控制等系列问题,提出了一种以刀具为核心的复杂形状产品雕铣加工优化方法。首先,分析了复杂形状产品雕铣加工特点及刀具的特性,建立了复杂形状产品雕铣加工的刀具模型;在此基础上,建立了刀具确定状态下工艺参数优化模型;然后,提出了应用粒子群优化算法对刀具确定状态下工艺参数优化模型进行寻优求解的方案;最后,通过优化实例,验证了所提方法的可行性和实用性。上述方法已在生产实际中得到了应用,并展示了较好的应用前景。     

微小型立式五轴雕铣中心关键技术

本文阐述了一种微小型立式五轴雕铣中心的设计开发关键技术,包括机床总体布局、主要技术参数和特点、机床本体开发技术、RTCP检测技术和五轴加工后处理技术。微小型立式五轴雕铣中心的研制成功,有效解决了珠宝首饰的高精、高效、高稳定性加工难题,同时该产品填补了国内空白。     

带锯条铣齿切削量计算及工艺优化研究

针对带锯条铣齿加工常用的三段式加工工艺中切削量设计与精度要求不符的现象,综合考虑了成型铣刀刃口形状、空间运动形式以及锯齿形成的不同阶段,提出了以异形刃口离散的方法建立刃口切深与刃口作用长度关系模型。并在此基础上建立了带锯条成型铣刀单个刃口的切削量计算模型。以单圆弧过渡齿形为例,代入实际参数进行模拟计算,获得了带锯条铣齿加工过程中切削量以及刃口切削体积变化规律。结合带锯条实际加工对效率和精度的要求,提出了增加铣齿分段数量和控制吃刀量及切削体积的优化工艺方向。     

熔融沉积快速成型工艺过程分析及应用

介绍熔融沉积快速成型技术的基本原理,分析成型工艺过程的技术特点。从机械系统和控制系统等主要组成部分论述了熔融沉积成型设备的整体构造。以一个深沟球轴承为研究案例,详细地论述了成型件的具体加工过程并在MEM320A快速成型机上加工出ABS材料的实物。最后,探讨了熔融沉积快速成型技术在产品设计、功能展示、样品制造和生物医学等领域的应用情况,同时展望了该技术在未来的发展前景。     

基于PC的高精度三维数控雕铣机

研发具有高表面加工质量的精细雕铣功能的高精度三维数控雕铣机,适用于三维空间曲面的形状、复杂多面相交及复杂零件二维、三维曲面的精确加工.     

ArtCAM在浮雕加工中的应用研究

以ArtCAM软件为平台,配合雕铣设备,研究了浮雕加工过程.利用ArtCAM软件将二维图片转换为三维浮雕,设置浮雕加工工艺并进行仿真加工,最终加工出浮雕产品.提出了利用ArtCAM 软件处理浮雕过程中的关键点,并给出了软件设置流程图和雕铣机操作流程图.实践表明,在浮雕加工中通过运用ArtCAM软件并配合合适的雕铣设备,能够降低生产成本、提高生产效率.为加工生产企业提供了必要的技术支持.     

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.     

Integrated simulation of the injection molding process with stereolithography molds

Functional parts are needed for design verification testing, field trials, customer evaluation, and production planning. By eliminating multiple steps, the creation of the injection mold directly by a rapid prototyping (RP) process holds the best promise of reducing the time and cost needed to mold low-volume quantities of parts. The potential of this integration of injection molding with RP has been demonstrated many times. What is missing is the fundamental understanding of how the modifications to the mold material and RP manufacturing process impact both the mold design and the injection molding process. In addition, numerical simulation techniques have now become helpful tools of mold designers and process engineers for traditional injection molding. But all current simulation packages for conventional injection molding are no longer applicable to this new type of injection molds, mainly because the property of the mold material changes greatly. In this paper, an integrated approach to accomplish a numerical simulation of injection molding into rapid-prototyped molds is established and a corresponding simulation system is developed. Comparisons with experimental results are employed for verification, which show that the present scheme is well suited to handle RP fabricated stereolithography (SL) molds.     

A unit sphere discretization and search approach to optimize building direction with minimized volumetric error for rapid prototyping

As a material-additive process, rapid prototyping (RP) has shown its capability in creating complex geometries that traditional material-removal processes cannot accomplish. However, its layer manufacturing nature still subjects itself to undesired staircase effects. It has been shown that staircase effects have relationship with the building orientation in RP processes. In order to minimize staircase effects, the building orientation has to be properly selected prior to the implementation of RP processes. This paper presents a method to select the optimal building direction in RP processes that leads to the minimized volumetric error. In order to explore the global directional space, a unit sphere is uniformly discretized first to represent the potential directions in a 3-dimensional (3-D) space. Following that, each facet comprising the STL geometric model is mapped onto the discretized unit sphere as a great circle individually, which represents the optimal directions for that facet. In order to find the globally optimal solution, both an exhaustive search and a genetic algorithm (GA)-based searching strategy are presented to identify the globally optimal direction for building the 3-D geometry. At the end of the paper, examples are presented to show the effectiveness of the method.     

基于RE和RP的前杯托盖试件制造

针对传统铜模制作前杯托盖试件时间长、费用大的问题,应用快速原型技术（RP）,并结合反求工程（RE）与CAD造型技术,得到前杯托盖塑件原型,并利用硅胶模真空注型技术,快速地将RP原型复制出前杯托盖试件,缩短了产品开发周期,降低了研发成本,带来很高的技术经济效益。     

Rapid Prototyping Applications in Medicine. Part 1: NURBS-Based Volume Modelling

Rapid prototyping (RP) technology has extended traditional manufacturing applications in areas other than product engineering. Using RP to fabricate custom implants and prostheses for surgical planning and education is now an important area of research. Although, in theory, RP is capable of producing objects of any complexity, designing freeform shapes is difficult using current CAD systems. These CAD systems are geared toward the design of parts manufactured by traditional methods; they do not help designers exploit the extended opportunities offered by RP technology. Medical data cannot be input into these CAD systems directly for further modification and manipulation. The purpose of this project is to explore a new approach for modelling and prototyping biomedical objects. The work extends from volume modelling to RP and medicine. In this paper, Part 1 of two papers, a new approach to modelling complex objects, NURBS-based volume modelling, is proposed. A NURBS representation of volumes is developed to represent not only the surface boundary but also the interior of a 3D object. NURBS-based volume modelling inherits advantages from both NURBS modelling and voxel-based modelling. The key idea of the NURBS-based volume modelling is to exploit the flexibility of NURBS modelling and use the voxelised NURBS volumes as components for constructing complex objects. Part 2 deals mainly with issues of interfacing volume models to RP systems. A new approach to generate STL files through volume modelling and iso-surface extraction is proposed. This approach guarantees the validity of the final STL file inherently. Software development and case studies are also given.     

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).     

Rapid Prototyping Applications in Medicine. Part 2: STL File Generation and Case Studies

Rapid prototyping (RP) technology has extended traditional manufacturing applications in areas other than product engineering. Using RP to fabricate custom implants and prosthesis for surgical planning and education is now an important area of research. Although, in theory, RP is capable of producing objects of any complexity, designing freeform shapes is difficult using current CAD systems. These CAD systems are geared toward the design of parts manufactured by traditional methods; they do not help designers exploit the expanded opportunities offered by RP technology. Medical data cannot be input into these CAD systems directly for further modification and manipulation. The purpose of this project is to explore a new approach for modelling and prototyping biomedical objects. The work extends from volume modelling to RP and medicine. In Part 1 of two papers, a new approach to modelling complex objects, NURBS-based volume modelling, is proposed. A NURBS representation of volumes is developed to represent not only the surface boundary but also the interior of a 3D object. NURBS-based volume modelling inherits advantages from both NURBS modelling and voxel-based modelling. The key idea of the NURBS-based volume modelling is to exploit the flexibility of NURBS modelling and use the voxelised NURBS volumes as components for constructing complex objects. This paper, Part 2, deals mainly with issues of interfacing volume models to RP systems. A new approach to generate STL files through volume modelling and iso-surface extraction is proposed. This approach guarantees the validity of the final STL file inherently. Software development and case studies are also given.     

快速成型技术工艺特点及影响精度的因素

快速成型是一种基于离散堆积成型思想的数字化成形技术,可以在无需任何模具、刀具和工装的情况下,直接从CAD数据,快速制造出具有任意复杂形状的实体部件。介绍了快速成型领域四种典型的成型技术及其加工原理,阐述了其加工过程中所具备的快速性和高度柔性等现代化制造特点。比较了典型快速成型工艺的适用领域、加工成本和技术参数,找出影响成品精度的工艺及设备方面因素。分析各种成型技术在成形精度、表面质量、材料成本等方面的优点和缺点。     

<Emphasis Type="Italic">Rapid Moulding Using Epoxy Tooling Resin</Emphasis>

Rapid prototyping (RP) is fast becoming a standard tool in today’s product design and manufacturing environment. Significant benefits in terms of lead time and cost savings have been reported with the use of RP technology. However, these benefits can be derived only during the design and planning stages of a new product where RP parts are produced in small quantities for design evaluation, form fitting, and marketing analysis. The high cost of raw material stock used in current RP systems makes them economically unsuitable even for small-batch production during the product evaluation and manufacturing stages. Further to this, the difference between the mechanical and physical properties of RP and traditional manufacturing materials limits the functionality of RP end products. Rapid tooling (RT) technology has opened up new cost-effective solutions for small-batch production. In this paper, a technique using a rapid soft-tooling approach, namely, aluminium filled epoxy resin tooling for injection mould preparation is successfully explored. An aluminium filled epoxy resin mould is evaluated and the characteristics of the injection-moulded end products are presented.