基于免疫遗传算法的工程图自动调优技术

针对目前三维模型参数化变型后,工程图自动生成方法中出现的视图布局不合理、比例失调、标注混乱等问题,及现有调图技术的局限性,论文提出采用免疫遗传算法对工程图进行优化调整。实现了基于模板参数化驱动后工程图的自动更新与视图布局、视图比例及其各种标注位置等的优化调整。实验证明该方法可以实现智能化快速出图,保证设计的准确性,提高设计效率和质量。     

机械产品虚拟装配智能导航技术的研究

通过对机械产品虚拟装配过程中装配关系的分析,在理解与识别设计者的装配操作和意图基础上,对共线约束和共面约束的智能导航进行了深入研究,实现了机械产品虚拟装配的智能导航.该方法有助于在虚拟装配环境下快速准确地进行零部件虚拟装配,提高产品设计效率.     

二维装配图零部件序号标注智能布局方法

主流CAD软件在由三维模型生成二维工程图时,因没有充分考虑布局等因素,自带的零部件序号自动标注功能无法实现智能有序布局,导致标注结果不符合相关标准.针对该情况,在研究工程图零部件序号标注特点基础上,建立待标注零部件序号子集的数学模型,并利用算法实现子集的规划、均匀排列等功能,进而实现零部件序号标注的智能布局.经过在CATIA平台上的验证,该方法具有较强的自适应性与稳定性,零部件序号的智能标注功能良好.     

面向虚拟装配系统的模型数据库构建

针对虚拟装配系统中三维模型数据量大的特点,提出在采用关系数据库表达层次模型的基础上,基于Oracle数据库的LOB(大的二进制对象)来实现三维模型及装配信息的存储与读取功能。应用VC++构建了虚拟装配系统软件平台,实现了三维模型文件在虚拟装配系统中的显示与管理。     

基于UG的内燃机活塞机构虚拟装配和运动仿真

为改变二维设计的不足和适应现代化的需要,借助UG强大的建模和装配技术,分析了内燃机活塞机构中各构件的三维建模过程及构件之间的虚拟装配过程;通过UG的仿真技术,对内燃机活塞机构设计过程中的连杆创建、运动创建、驱动定义等环节进行了分析.实践证明,利用UG进行虚拟装配和运动仿真,可以缩短产品的研发周期,提高生产效率.     

液压集成块优化设计系统中装配图的智能化生成技术研究与实现

研究了液压集成块优化设计系统中的二维装配图自动生成技术.结合具体实例,从投影变换理论入手,对三维向二维投影和装配图自动标注技术进行了深入的探讨,总结了装配图标注的引线规则和有效算法.所做工作对液压集成块自动化设计具有一定意义.     

一种基于虚拟技术的机械产品设计工作室系统

分析了虚拟现实技术和真实感图形学在三维机械CAD中的应用,在对机械产品造型特征分析的基础上,提出了一种基于虚拟技术的机械产品设计工作室系统,利用基于图像的照明方式和图形处理器的加速功能,实现了实时渲染。为产品设计人员提供了交互式实时操作产品模型、虚拟漫游装配场景和立体显示等功能。对提高设计人员和用户的交流效率,优化设计质量有较重要的作用。     

立式袋装机三维数字模型生成二维工程图的实现

探讨利用Solid Edge软件对立式袋装机设计过程中,三维参数化模型自动生成的工程图时的视图布局较差,尺寸标注不整洁,线条繁杂等缺点,研究了如何根据国家标准,设置工程图模板、零件图与剖视图生成与调整方法、以及部件图明细表的自动生成与调整方法.从而使立式袋装机三维参数化模型快速生成符合国家标准的二维工程图.     

基于UG二次开发的PMI信息快速标注研究

随着技术的快速发展,MBD(Model Based Definition)技术逐渐应用到汽车航天等制造领域。MBD技术的核心思想是用一个集成的CAD三维模型来完整的表达产品定义信息,将三维模型作为信息传递的唯一载体。而三维标注技术就是将产品信息和三维模型关联起来的关键环节。针对目前三维标注存在的问题及缺陷,本文提出一种全新的PMI信息快速标注路线。在MBD技术的基础上,制定模型要素的PMI信息明细表,并对CAD模型中的要素进行定义;以UG11.0为开发平台、利用C/C++编程语言实现了CAD三维模型PMI信息的快速标注。     

由三维参数化模型生成工程图的自动调整技术

针对由三维参数化模型自动生成的工程图中视图布局较差,比例不合理,尺寸标注不整洁,线条繁杂,注释错误等缺点,根据企业给定的工程图模板及相应标准,研究了工程图模板创建与保存方法、三维模型驱动后工程图视图布局、比例、特征尺寸、焊接符号、零件序号的调整方法,以及部件图明细表的自动生成与调整方法.     

超高速轮转式贴标机的关键技术

目的研制一台合格率高、可靠性好的超高速轮转式贴标机。方法采用机械动力学基本理论,对贴标定位方式、压标方式、漏贴检测与剔除等关键技术进行改进。结果样机运行速度达到了60 000瓶/h,贴标合格率为99.5%。该机型实现了在PET瓶上用机械方法进行双标及三标的定位贴标,提高了定位贴标的精度,降低了机器成本,避免了光电定位的不稳定性。实现了更加可靠的自动剔除功能,解决了高速流水线上执行机构剔除时间不够的问题。实现了在PET瓶的瓶盖与瓶身之间折角面贴标的功能,提高了贴标效果,避免了标签倾斜。结论该样机达到各项设计指标。     

Integrated Virtual Assembly Environment and its application in ship piping layout

Complex pipe layout plays an important role in ship building. Pipes prefabricating and assembling often depends on testing and rebuilding in outfitting. This leads to more workload, high cost and longer manufacturing cycles. In this paper, a new virtual assembly system called Integrated Virtual Assembly Environment (IVAE) is introduced, in which the ship outfitting can be simulated and process planning can be completed. With the help of assembly constraints management, collision detection and response, assembly sequence and paths planning, users can assemble the parts interactively in a virtual outfitting environment, just as in an actual cabin. As well as for virtual ship outfitting, IVAE can also be used in general product development. As a typical case, the pipe layout in the engine room of a 5000?M³ hydraulic dredge from Hudong-Zhonghua Shipbuilding (Group) Co., Ltd is given to test virtual ship outfitting in IVAE.     

Assembly systems layout design model for delayed products differentiation

Frequently changing customers’ needs and market pressures motivate manufacturers to offer a wide variety of their products. Poor demand prediction and increased manufacturing complexities and managerial burdens are just a few symptoms of products variety proliferation. Applying a postponement strategy is an effective method for mitigating the complexities arising due to increased products variety and customisation. Delayed product differentiation (DPD) is a prerequisite for applying form postponement strategies, where the unique features that distinguish each product are added at the final stages of production. This paper introduces an innovative design methodology to derive and represent an assembly line schematic layout for delayed products differentiation. The proposed methodology incorporates product commonality analysis and feasible assembly sequences to synthesise the assembly line layout in a single integrated logical design framework, without pre-defining either the number or the positions of differentiation points along the line. Products commonality analysis is performed using cladistics techniques commonly used for biological classification. The classical cladistics was modified to take into consideration the precedence constraints, which are required to ensure the feasibility of assembly sequences. Real product variants are used to validate the proposed DPD assembly line layout design methodology and demonstrate its merits.     

包装机械设计中的一种新方法——虚拟设计技术

虚拟设计技术在包装机械开发中的应用，主要体现在三维造型设计、虚拟装配、虚拟运动仿真、分析优化等方面。许多产品有了一种基型以后，只要改变一下造型，就可推出几种甚至几十种适合不同顾客需求的变型新品种，这类工作占有较大的比例，其次是结构设计，涉及产品的可装配性、可制造性和功能指标等问题。包装机械开发，大量的工作是造型设计。     

A methodology to reduce variability during vacuum infusion with optimized design of distribution media

Seemann Composites Resin Infusion Molding Process (SCRIMP) is a widely used version of Vacuum Assisted Resin Transfer Molding (VARTM) in which a highly permeable layer (distribution media) is placed on top of the dry preform to distribute the resin with very low flow resistance to reduce the filling and hence the manufacturing time. The flow patterns during filling may vary from part to part due to the variability associated with the material, part geometry, and layup of the assembly, which may result in race-tracking channels. The process is considered as reliable and robust only if the resin completely saturates the preform despite changing filling patterns caused by flow disturbances.The resin flow pattern can be manipulated with a tailored distribution media layout as it does impact the flow patterns significantly. The continuous distribution media layout over the entire part surface works well for very simple geometries with no to little potential for race-tracking along the edges. In this study we address complex cases, which require placement of an insert within the assembly, which will introduce race-tracking along its edges, and hence uniform placement of distribution media over the entire top surface will fail to yield a void free part. We introduce a methodology using a predictive tool to design an optimal shape of distribution media, which accounts for the flow variability introduced due to race-tracking along the edges of the inserts. This iterative approach quickly converges to provide the placement of distribution media on selective areas of the preform surface that ensures complete filling of the preform despite the variability. This approach has been validated with an experimental example and will help mitigate risk involved in manufacturing complex composites components with Liquid Molding.     

Homogeneous detection of single rolling circle replication products

We describe a simple and straightforward approach for homogeneous and isothermal detection of individual rolling circle replication (RCR) products, which represent individual padlock probe circularization events. The RCR products constitute tens of kilobases long single-stranded tandem repeated copies of the probe sequence, and in solution, they fold into micrometer-sized random coils. The method is based on the local enrichment of fluorescence-labeled probes that hybridize to the coiled RCR products compared to the concentration of free probes in solution. We present a detailed characterization of the fluorescence-labeled products using a highly sensitive and fast microscopy setup. At a 10(4)-fold excess of free label, we were able to detect and follow individual RCR products at a signal-to-background noise ratio of 27. This high signal-to-background noise ratio leaves room for analysis in a simple detection device at higher speeds or at lower labeling ratios.     

AUTOMATED PROCESS PLANNING FOR PRINTED CIRCUIT CARD ASSEMBLY

Printed circuit card assemblies form the core of a vast array of contemporary manufactured products. The technologies for assembling printed circuit cards require a hierarchy of complex decisions for grouping card types and processes, staging components at assembly machines, arranging feeders, and sequencing placement operations. This paper is motivated by the largely unmet needs of industrial process planners for computer aids. Our objective is to develop a framework for the printed circuit card assembly process planning problem and to assess the current state of the research on appropriate models and solution methods. We first provide an overview of the essential elements of printed circuit card terminology, assembly technologies, and assembly system operations. Then we propose a decision hierarchy, survey the published literature, and identify needs for future research.     

Optimal coordinate sensor placements for estimating mean and variance components of variation sources

In-process optical coordinate measuring machines offer the potential to diagnose the sources of the variations that are responsible for product quality defects. Such a sensor system can thus help manufacturers to improve product quality and reduce process downtime. The effective use of sensor data in the diagnosis of the sources of variations depends on the optimal design of the sensor system, which is often also called the problem of sensor placement. This paper addresses coordinate sensor placement for the diagnosis of dimensional variation sources in assembly processes. Sensitivity indices for the detection of the process mean and variance components are defined as the design criteria and are derived in terms of process layout and sensor deployment information. Exchange algorithms, originally developed for optimal experimental design, are revised and then used to maximize the detection sensitivity. A sort-and-cut procedure is proposed, which is able to significantly improve the algorithm efficiency of the current exchange routine. The resulting optimal sensor layout and its implications are illustrated in the specific context of a panel assembly process.     

Assembly system facility design

This paper addresses the design of an assembly system facility consisting of multiple assembly lines of different shapes. In such a design problem there are two conflicting objectives: (i) to minimize the overall area of the facility; and (ii) to maximize the efficiency of the material handling transportation system. We first address the optimization problem of objective (ii) when replacing objective (i) with a constraint on the facility area. We propose a mixed-integer linear program to determine the layout of a facility with given dimensions and with given assembly line areas and shapes (that cannot be changed due to technological considerations). In the layout model, the physical placement of each line within the facility is a decision variable. The objective function of the layout model is to minimize the distances traveled by material flow. Our performance analysis provides an indication of the maximal problem size that can be solved in a reasonable amount of time and we examine the effect of the problem parameters on the solution run time. This layout model is then incorporated into an efficiency frontier approach for facility design to address both objectives. Examples are presented to illustrate the use of the proposed facility design model.