零件编码与聚类分析

一、零件相似性与模糊分析 成组技术的出发点是按照产品零件的构成规律,利用零件中大量存在的相似性来组织产品零件的设计、加工与管理。因此,如何判别零件的相似性程度,如何按照零件的相似性来划分零件族,是推行成组技术中的一项极其重要的基础工作。 目前,常用两种方法来组织零件族。一种是利用零件分类编码系统制定特性矩阵或码域,用编码来识别零件相似性。采用这种方法,需要对产品零件信息进行全面的分析     

用图论法对机器零件进行聚类

一、前言 机器零件按照相似性进行聚类分组是企业中利用成组技术组织生产的重要环节与步骤。目前零件的聚类方法很多,均有其特点和利弊,本文提出的用图论法进行零件聚类曾经在指导学生的毕业论文中进行了尝试,证明这是一种简单而有效的方法。在聚类之前需首先进行零件编码,曾对200余零件进行了JLBM-1编码工作,根据零件组相似性的要求和一定的算法编制了计算机程序,将零件的原始数据输入计算机就可输出所需要的结果,然后绘制出最小支撑树的分组图,最后所得到的分组结果证明是令人满意的。     

基于结构相似性的轴类零件加工特征可拓关联方法

在现有轴类零件相似性检索方法的基础上,将轴类零件的信息模型划分为结构特征层和加工工艺层,并利用可拓基元方法进行形式化描述.提出从轴类零件结构和加工工艺两方面进行相似性检索的方法:首先基于结构矩阵表达方法,对轴类零件的结构特征进行相似性检索,从实例库中检索出2~5个相似实例,然后以可拓综合关联函数进行加工特征的相似度匹配,得出与新零件最相似的零件.通过实例验证,该方法具有可行性,并且可在检索过程中动态调整系数水平,具有检索适应性强的优点.     

零件特征信息统计、特征矩阵检索及排序的计算机程序

在我厂“纺机钣金零件分类编码系统”和“钣金零件的计算机辅助编码程序”的基础上,我们应用APPLE—Ⅱ型计算机及BASI-C语言编制了零件的编码排序、特征信息统计、光标显示式特征矩阵的建立及检索用的通用程序。并对3000多个零件信息进行处理,为我厂钣金件划分零件族,找出其几何特征和工艺特征分布规律,从产品设计到制造实施成组技术,提供了可靠的原始数据。实践证明是正确的。     

基于特征/零件族的工艺决策系统研究

在比较了几种工艺决策系统的基础上,根据企业制造资源个性和零件加工工艺的相似性特点,提出了基于零件特征/零件族的工艺决策系统模型.该系统以特征为最小表达单位,通过零件族将零件特征、特征工艺有机地整合,通过人机交互实现工艺规程的快速重生成,进而实现工艺的快速决策.本文建立了决策系统的系统模型,分析了各个模块的组成,给出了工艺决策系统的决策过程.     

微型计算机辅助成组技术——零件编码的检索统计和分组

用编码法划分零件组的实质是:用编码标识零件的结构特征,然后把编码相同或相近的零件分类归组,从而达到把零件结构相同或相近的零件分类归组。即:以数代形,以数归组,数同结构同,数近结构近.另一方面,零件的结构特征隐含着它的工艺信息,因而,针对零件组内的全部零件编制成组工艺和设计成组夹具,可大大减少工艺人员和设计人员不必要的重复性劳动,缩短生产周期.同时,使编制工艺标准化、统一化、规格化,节省工装夹具材料,降低生产费用。     

应用成组技术的机床模块化设计

本文利用成组技术的基本原理,在分析了机床部件结构及零件功能的相似性的基础上,采用分类编码的方法建立了机床模块化设计编码系统。     

成组技术讲座第六讲——应用成组技术的工艺设计

工艺设计是工艺部门经常性的工作,通过工艺设计编制的工艺文件是指导企业进行生产的依据,它联系着产品设计和产品制造的重要环节,因此它对工艺水平,产品制造周期,质量和成本有着十分重要的意义。 许多企业的现行工艺设计工作是以单个零件工艺规程编制和应用为基础的。这非但不能促进技术进步,难以提高企业的效益,而且存在不少问题。应用成组技术(以下简称GT)的工艺设计是以相类似的一组零件为考虑对象,是目前工艺设计合理化的一种新方法,它与传统的工艺设计方法有很大的区别。本文介绍一种以GT为基础的相似性工艺设计准备工作及方法,供参考     

零件分组的新探索

本文采用零件编码与生产流程法相结合的原则,提出一种计算机辅助形成零件机床组和划分成组生产单元的方法。经过某油泵油咀厂和某矿机厂近九百种零件的实际分组,表明这种方法可以克服单独应用编码法或者生产流程法的不足,以可以大大提高分组的精确性,经济性。并可以随时识别新零件,大大提高分组的灵活性和柔性。     

MODROC法在零件分组和单元设计中的应用

一、引言 成组技术是利用零件之间固有的结构工艺相似性,通过归并成组,从而使生产合理化的一种现代制造哲理。所谓归并成组,便是零件分组。因此,划分相似零件组尤其是划分工艺相似零件组是成组技术中的一个核心问题。而生产单元是实施成组技术的一种有效的生产组织形式。     

基于实例推理的钢产品包装工艺检索

为充分利用前人的经验以及有效地提高钢产品包装工艺规划的速度,提出了一种基于实例推理的钢产品包装工艺检索方法。基于钢产品包装工艺实例库,提出了2 层次的实例检索,第1 层采用层次编码来检索出相同包装代码下的包装工艺实例集;在第2 层检索中计算钢产品包装零件类型、材质特征以及几何尺寸的相似度,来逐步过滤掉不符合要求的实例,从而获得工艺最相似的包装工艺。通过具体的实例验证了该方法的有效性。     

销钉类零件的机加工工艺规程的自动生成研究

本文介绍一个面向销钉类零件的基于特征的参数化CAPP系统．利用成组技术将销钉分类编码,设计主样件的工艺规程模板．根据零件编码选择工件类别,输入零件的设计尺寸和公差,设定每种加工方法的加工余量,就可以计算出各道工序的尺寸,自动生成工序图．根据企业标准,各工序尺寸的公差实现自动分配,并由系统校验余量公差,最终生成完整的机械加工工艺规程．     

Formation of independent flow-line cells based on operation requirements and machine capabilities

In this paper we study the generalized grouping problem of cellular manufacturing. We propose an operation-sequence-based method for forming flow-line manufacturing cells. Process planning in the form of selection of the machine for each operation is included in the problem formulation. Input requirements include the set of operation requirements for each part type, and operation capabilities for all available machine types. The objective is to find the minimum-cost set of flow-line cells that is capable of producing the desired part mix. A similarity coefficient based on the longest common operation subsequence between part types is defined and used to group parts into independent, flow-line families. An algorithm is developed for finding a composite operation supersequence for each family. Given machine options for each operation in this sequence, the optimal machine sequence and capacity for each cell is then found by solving a shortest path problem on an augmented graph. The method is shown to be efficient and computational results are reported.     

Automated retrieval and ranking of similar parts in agile manufacturing

The environment considered is an agile enterprise where manufacturing partners share product related data to come up with new, customized, and high quality products at minimal leadtimes. Given this context, this paper addresses the problem of identifying existing parts that are similar, in one or many characteristics, to a new part at the design stage. The proposed method is based on the principles of group technology (GT), and on the definition of the neighborhood of similarity of critical design attributes. A two-step procedure is proposed: (1) a search procedure, which acquires and processes the designer's search intent to retrieve similar parts; and (2) a sorting procedure, which ranks these parts in order of their similarity to the candidate part. Both procedures are based on GT codes, while the second can employ more detailed critical design information. This information is assumed available in the product databases of distributed partners, and can be generated via an existing GT design processor. The approach employs a systematic procedure to combine independent similarity indexes to a unique measure for sorting. A software system using object-oriented technology has been developed to implement the procedure.     

Introducing new parts into existing cellular manufacturing systems based on a novel similarity coefficient

Over the last three decades, designing cellular manufacturing systems (CMS) still centres on assigning machines to machine cells and parts to part families. This task ends after assigning these part families to the appropriate machine cells. In the past, testing CMS was evaluated according to the efficiency of clustering, but actual testing of CMS after installation is still unexplored. Introducing one or more new parts (products) into CMS without any changes in the installation of the cells during processing of the current parts is a new concept to be considered and evaluated. Transferring these systems from traditional ideologues to advanced ideologues (agile systems) is highly desired. This concept can be considered as part (product) flexibility in CMS. To address this concept, a new similarity coefficient between the new part and the existing manufacturing cell will be created. New productivity and flexibility measurements in CMS will also be suggested. A new strategy for accepting a new part into CMS will be proposed based on machine utilization and flexibility in the cells, cell utilization and flexibility in the system, product flexibility (system flexibility), and similarity of this part with existing manufacturing cells. A complete analytical example will be presented.     

基于模糊聚类分析的家具零件成组研究

合理的零件分组是成组技术实施的关键因素之一,对山东省德州市某板式衣柜厂典型产品进行零件成组案例研究,通过生产流程分析,建立零件相似矩阵,利用传递闭包法求出等价矩阵,从而实现理性化的零件成组分类,进而通过Matlab的编程实现复杂零件系统的成组。结果表明：随着分组阈值的不断增加,分组数量随之增加,零件平均相似度也随分组阈值的不断增加而增加, 企业生产规模与选择的分组阈值、零件分组数量成反向关系,企业规模越小,分组数量应较小,从而实现组内零件较大批量的生产加工。     

基于成组技术的夹具快速配置研究

提出了基于成组技术的夹具快速配置系统体系结构,研究贯穿了零件分类编码、夹具设计需求和夹具元件库的建立等方面.采用基于成组技术的方法开发了夹具快速配置系统,支持企业对夹具快速设计.     

Improved approach to quality function deployment based on Pythagorean fuzzy sets and application to assembly robot design evaluation

Quality function deployment (QFD) is an effective method that helps companies analyze customer requirements (CRs). These CRs are then turned into product or service characteristics, which are translated to other attributes. With the QFD method, companies could design or improve the quality of products or services close to CRs. To increase the effectiveness of QFD, we propose an improved method based on Pythagorean fuzzy sets (PFSs). We apply an extended method to obtain the group consensus evaluation matrix. We then use a combined weight determining method to integrate former weights to objective weights derived from the evaluation matrix. To determine the exact score of each PFS in the evaluation matrix, we develop an improved score function. Lastly, we apply the proposed method to a case study on assembly robot design evaluation.     

Design of delayed reconfigurable manufacturing system based on part family grouping and machine selection

To improve the convertibility of reconfigurable manufacturing system (RMS), the concept of delayed reconfigurable manufacturing system (D-RMS) was proposed. RMS and D-RMS are both constructed around part family. However, D-RMS may suffer from ultra-long system problem with unacceptable idle machines using generic RMS part families. Besides, considering the complex basic system structure of D-RMS, machine selection of D-RMS should be addressed, including dedicated machine, flexible machine, and reconfigurable machine. Therefore, a system design method for D-RMS based on part family grouping and machine selection is proposed. Firstly, a part family grouping method is proposed for D-RMS that groups the parts with more former common operations into the same part family. The concept of longest relative position common operation subsequence (LPCS) is proposed. The similarity coefficient among the parts is calculated based on LPCS. The reciprocal value of the operation position of LPCS is adopted as the characteristic value. The average linkage clustering (ALC) algorithm is used to cluster the parts. Secondly, a machine selection method is proposed to complete the system design of D-RMS, including machine selection rules and the dividing point decision model. Finally, a case study is given to implement and verify the proposed system design method for D-RMS. The results show that the proposed system design method is effective, which can group parts with more former common operations into the same part family and select appropriate machine types.     

基于多触点定位和状态校验的虚拟装配技术

目的提供一种具有通用性的虚拟装配零部件设计方法,能够实现多位置、多旋转状态判定的装配方式与灵活的装配序列规划。方法首先使用多个定位触点进行碰撞检测来确定零件的位置和旋转状态,然后使用二进制整数作为零件状态码表达零件间的装配依赖关系,最后通过二进制运算表达式的校验算法限制零件状态码的取值决定零件是否可以装配,从而达到装配序列的约束规划。结果在装配方式上使得所有零件具有通用的设计方案,针对特殊零件只需要设置特殊定位触点,在装配序列规划上实现了多种灵活的装配顺序设计,装配逻辑关系表达更加清晰。结论通过多触点定位和状态校验可以实现具有很好通用性和扩展性的虚拟装配技术。