实现实时控制图法的一种通用统计装置

控制图法在工厂企业的质量管理中得到广泛应用， 但是目前描绘控制图都需要人工输入测量数据， 整个过程还离不开人工干预， 这样不可避免地带来人为误差。本文提出并实现了一种集实时数据采集、数据通信、数据处理、数据存储和自动描绘控制图的通用装置。     

飞机装配过程质量数据深度分析与控制

飞机生产安装过程中,飞机装配是其中的重要环节。在飞机装配过程中,一定程度上存在装配过程质量数据系统性不足,数据利用效率有待提升的问题,针对这种问题,该文就飞机装配过程质量数据深度分析与数据控制的有效策略进行分析与探讨,以期提高装配质量数据的利用价值,发挥数据信息为支撑飞机装配质量优化起到的积极作用,有效提高飞机装配质量。     

实现实量控制图法的一种通用统计装置

控制图法在工厂企业的质量管理中得到广泛应用，但是目前描绘控制图都需要人工输入测量数据，整个过程还离不开人工干预，这样不可避免地带来人为误差。本文提出并实现了一种集实时数据采集、数据通信、数据处理、数据存储和自动描绘控制图的通用装置。     

转角控制与夹紧厚度和延伸率的关系

我们知道转角控制装配 ,又称超弹性装配 ,就是屈服点装配方法的一种。在装配过程中 ,首先确定一个转角起始扭矩 ,例如图 1中 ,是Ｍ 8,8.8级的螺栓 ,起始扭矩从 2 0Ｎｍ± 2Ｎｍ开始 ,然后再转 90°±10°。从图中曲线可以看出 ,螺栓材料到 36Ｎｍ已经屈服 ,也就是讲 ,从 2 0Ｎｍ开始 ,转 2 5°扭矩达到36Ｎｍ螺栓材料屈服 ,然后再继续转 6 5° ,装配机停止运转 ,整个装配过程结束。转角装配的优点是 :在装配过程的完成阶段 ,可以消除摩擦系数的影响 ,最有效的利用金属材料的强度特性 ,从而避免螺纹副的装配失效。图 1　转角控制的曲线图　　…     

发动机装配终检的质量控制研究

发动机整机装配后的终检工作是发动机装配检验工作的重要环节,终检质量直接影响发动机的装配质量和出厂质量。本文论述了发动机终检环节多余物控制等六项内容,给出了发动机终检时的质量控制要求。     

控制图在食品检验机构中应用

本文阐述了控制图的原理和绘制方法,利用食品中蛋白质检测的-X-R图来说明控制图在食品检测实验室中的应用,利用控制图可以判断系统效应和随机效应对食品检测过程的影响是否增大,与能力验证等其他质量控制手段相比,控制图具有方便易于操作的特点,食品检验机构可以及时发现检测过程中各阶段存在的波动情况并加以控制。     

控制图在扭矩扳子比对过程中的应用

通过建立控制图分析了扭矩扳子在比对过程中的质量控制结果。主要介绍了平均值-标准偏差控制图（xˉ-s图）的应用,以监视比对过程中数据的质量;根据控制图提供异常值的有关信息,采取相应纠正措施,使比对的测量过程处于统计控制状态。文章还从选择合适的控制图、测量频次的确定、绘制控制图的顺序、失控后的处置等方面分析讨论了实际操作中需要注意的问题,为计量人员开展扭矩扳子的测量工作提供参考。     

动态卡阻及主动柔顺装配策略研究

分析了基于轴孔装配的动态卡阻和楔紧现象,推导出一点和两点接触时,轴在孔中发生卡阻和楔紧状态的力学方程,给出动态卡阻图和避免卡阻和楔紧状态发生的力／力矩条件。通过研究主动柔顺装配过程,分析了影响装配的几个重要参数之间的相互关系,得出插轴入孔的主动柔顺运动空间。这些研究成果为机器人装配的主动柔顺控制研究奠定了一定的基础。     

一种保证预设质量和过程稳态的SPC方法

提出三种过程质量指数(PQI)的过程质量指数系统,基于过程质量指数的统计公差提供了一个过程质量要求和控制图设计之间的标准化界面.通过基于过程质量指数的统计公差带增加对x--R或x--s控制图中线的约束,建立一种保证预设质量和过程稳态的统计过程控制新方法.这不仅增强了控制图的功能,也为过程质量规划、统计公差和保证预设质量的SPC相关参数的并行设计提供了指导.     

联合监控均值和方差的累积和控制图优化设计

为了提高监测均值和方差微小偏移的敏感度,围绕生产过程质量控制,建立同时监控均值和方差的累积和控制图.模型考虑均值和方差的变化,针对生产过程中的微小偏差,提出了一个新的累积和控制图,并给出了基于马尔可夫链理论的新控制图的平均链长计算方法.编程求解后对比文献中各控制图的平均链长数据以及更换变量数值改进控制图,通过计算变动比率得出新控制图的检测力度在不同偏移力度下都明显优于其他控制图方法.     

A forecast‐based monitoring methodology for process transitions

Nonconforming parts are often produced when a process moves from one level to another due to transition events. Control charting, when applied to a stable state process, is an effective monitoring tool to continuously check for process shifts or upsets. However, the presence of transition events can impede the normal performance of traditional control chart with increased false alarms. The presence of autocorrelation also requires modification to the control charting procedure. We present a methodology for characterizing the process transition which involves a tracking signal statistic, based on the forecast‐based exponentially weighted moving average (EWMA). This test will supplement the forecast‐based EWMA control charting as a means of detecting when the transition event is complete. Such a procedure facilitates smooth application of the appropriate control chart by knowing when the transition is over. The transition characterization methodology also carries benefits in cost and material savings. We use a color transition process in plastic extrusion to illustrate a transition event and demonstrate our proposed methodology. Simulation is employed to evaluate the performance of the methodology. Copyright © 2001 John Wiley & Sons, Ltd.     

基于负荷平衡的雷管填装流水线工序布局设计

在雷管填装流水线生产过程中,经常出现工序之间作业不平衡现象.由于雷管填装生产的特殊性,可采用工序同期化理论,确定流水线节拍,评测雷管填装生产线,进而改进工艺布局,提高了生产效率.     

Fast algorithm for assembling blocks of global equations in FE programs

A new method for assembling blocks of global equations in FE programs is presented. The method has been implemented in SAP IV, the well-known FE program. The new assembling process consists of two phases. First, for each pair of blocks, the numbers of active elements are determined in ascending order. Then, from the sequential file containing element matrices, active records only are read and processed, the non-active ones being skipped. The most important features of the new method as compared to the method previously used are the following: (i) it saves up to 2/3 of the CPU-time for assembling, (ii) the amount of data on an auxiliary file is negligible, (iii) it does not require any additional high speed storage, (iv) it can be directly applied in any FE program with blocks using the constant bandwidth row storage scheme, (v) after some modifications it can be applied also in FE programs with blocks using the skyline column storage scheme. The full source code in FORTRAN IV is given in Appendix II.     

基于元件组合优化的电控板装配作业分配

以电控板装配的手插件工序为研究对象,在作业标准化的基础上,结合生产工艺要求与元件特征属性,利用聚类分析方法对元件进行分类,确定其优先分配顺序,提出了一种基于元件组合优化的电控板装配作业分配方法,较好地解决了双手作业负荷与装配线平衡问题。以某企业A型电控板为例,通过上述方法确保各工位内部作业平衡,使线平衡率提高了22.13％,每小时产量提高了35.99％,从而验证了方法的有效性。     

Economic design of process adjustment for on-line control

A new control policy for process adjustment is proposed for an on-line control situation. The new procedure suggests minor and major adjustment intervals and is designed to overcome the problem of increasing variation of the process in which the traditional economic design of process adjustment is inadequate. Approximated solutions and algorithms are obtained for the process adjustment intervals. Simulated numerical examples and comparison with a traditional procedure show interesting results in which the new control policy can be applied advantageously and has many potential practical applications.     

A mean-shift pattern study on integration of SPC and APC for process monitoring

To detect a long-term mean shift of an autocorrelated process, traditional Process Control (SPC) techniques can be applied to monitor a process with Automatic Process Control (APC) or Engineering Process Control (EPC). In this paper, we investigate the relationships between the run-length performance, the mean-shift pattern, and the autocorrelation structure of the original process. For both monitoring the output and monitoring the control action of the APC-controlled process, we study how the mean-shift pattern affects the run-length distribution of the monitoring process. We compare the performance of the two monitoring approaches and make recommendations for various autocorrelated processes. We find that one can indicate the average run-length performance of an automatic-controlled process by examining the mean-shift pattern of the monitoring process.     

An Analysis of Four Spectral Control Charts

Control charts are used in manufacturing settings to monitor and detect changes in a process. Spectral control charts, based on the periodogram evaluated at the Fourier frequencies, have been designed to detect the onset of periodic behavior. In this article, two additional spectral charts formed using established periodogram tests are proposed. Comparisons of the average run lengths of the spectral charts based on these tests are made using Monte Carlo techniques. These comparisons evaluate how well the methods detect both simple and compound periodic behavior corresponding to both Fourier and non-Fourier frequencies. The charts are also compared using an industrial data set involving the widths of coating on silicon wafers. The analysis will illustrate both the strengths and weaknesses of each procedure and give suggestions as to appropriate usage.     

Stochastic assessment considering process variation for impact of welding shrinkage on cost of ship production

Since ship hull blocks are constructed by assembling numerous intermediate parts, relatively small changes in their dimensions can easily accumulate to cause serious reworking during the block erection stage, as well as deteriorate the productivity in ship production industry. One of the major dimensional accuracy control activities in shipbuilding is shrinkage margin design, by which an optimal length of excess edge is assigned to plates, in order to compensate for welding shrinkage and thus minimise reworking due to shrinkage. This paper presents a stochastic methodology for a quantitative assessment procedure of welding shrinkage on production cost in shipbuilding. This reworking cost evaluation procedure includes not only the prediction of a nominal shrinkage profile, but also a statistical cost estimation process for shrinkage variation. The formulation to predict total rework cost is suggested to be a combination of nominal shrinkage profile, process variation and quality loss functions for each rework region. Also, this approach investigates the relationship between the shrinkage margin and the predicted rework cost, in case of different process variations for a 15?m?×?15?m ship block model. It also presents an optimal shrinkage margin calculation procedure for ship designers in order to minimise the impact of dimensional variation due to welding shrinkage, on productivity.     

Single Variables Control Charts: an Overview

Control charts are widely used in industries to monitor a process for quality improvement. When dealing with variables data, we usually employ two control charts to monitor the process location and spread. We give an overview of the control charts proposed in the last decade or so in an effort to use only one chart to simultaneously monitor both process location and spread. Two approaches have been advocated for using one control chart for process monitoring. One approach plots two quality characteristics in the same chart while the other uses one plotting variable to represent the process location and spread. Copyright © 2006 John Wiley & Sons, Ltd.     

飞机装配工序的可视化建模及仿真

针对目前国内外飞机装配工序设计技术研究中存在问题,从新的角度提出基于产品预装配功能自动生成飞机装配工序的方法.通过分析飞机装配工序的组成及特点,建立其数字化模型;利用产品CAD系统中"装配设计"功能开展飞机交互预装配,并从中提取相关装配工序信息,自动生成装配工序;设计和开发算法,将产品装配工序转化为宏指令代码,运行此代码可实现飞机装配过程的动态仿真.结合某飞机垂直尾翼的总装,验证了方法的可行.