基于SPC的车间制造质量管理系统研究

本文针对某企业机械加工车间的生产特点和质量管理存在的问题和需求,将SPC技术与计算机信息技术相结合,分析和建立了车间质量控制流程及质量管理系统体系框架,开发了车间级的制造过程质量管理系统.采用控制图和过程能力分析对工序过程进行分析监控,实现了车间质量数据的分析处理和对产品质量的有效控制,提高了车间生产效率,降低了生产成本.     

关键重要零件质量控制技术

研究了加工关键、重要零件的质量控制问题.三坐标测量机将加工数据通过PCI总线传输给PC机,PC机对加工数据进行处理并形成质量控制图,利用神经网络技术对质量控制图进行模式识别和参数估计,并对国家标准的8种判异准则进行正确识别,对过程能力进行了分析研究,计算过程能力指数,最后在Matlab环境下编制了系统的GUI界面,在实际应用中取得良好效果.     

轴承锻造中的Minitab统计学分析

为了能够快速有效地对产品进行质量稳定性和过程能力分析,以锻造车间现场的轴承锻件锥度为例,采用Minitab软件对其数据进行统计,绘制控制图和过程能力图,通过因果图分析判定质量的稳定性和过程能力的有效性,并对存在的过程能力不足的问题提出了改进措施,使产品质量显著提高。     

基于物联网RFID技术的智能仓储系统的设计与实现

本文介绍了RFID技术的特点和基本应用,从业务和功能角度对智能仓储系统进行了数据流程分析,提出了基于物联网RFID技术的智能仓储系统的具体架构方案和功能模块,重点阐述了智能仓储系统的设计和实现过程,系统与企业ERP系统有效的结合,实现了产品全面的控制和管理,快速出入库和动态盘点,有效的利用仓库存储空间,提高仓库的仓储能力.     

基于“大数据”的冷轧板形分析与控制技术研究

为充分利用冷轧过程中的工艺数据,总结板形控制过程中的规律,文章借鉴了"大数据"的相关思想,对板形检测结果和大量工艺数据进行了分析,找到边部板形缺陷难以控制的原因在于冷连轧机现有板形控制手段能力不足,进而提出了能提高轧边部板形控制能力的辊形优化方法,并进行了工业试验,证明此方案的有效性。     

大型筒体对接过程多传感器在线检测方法

针对大型筒体和端框对接过程中精度难以精确控制,导致出现质量稳定性差、效率低等问题,提出了一种多传感器在线检测的方法,并开发了相应的在线检测装置。通过激光、CCD等传感器对对接关键特征进行数据在线采集,并进行数据分析和处理,从而实现零部件姿态分析。测量数据的分析处理是通过VC++平台开发的在线测量数据处理可视化软件系统实现的,该平台能够直观显示零部件姿态及调整数据。采用该方法,在大型筒体和端框对接过程中两者内圆径向误差调节精度有效控制在0.2mm以内,对接面间隙精度有效控制在0.1mm以内,结果证明,该方法能够有效检测控制对接过程中的相关精度,提高质量稳定性和效率。     

弧焊过程智能检测分析系统的建立与应用

为研究弧焊过程电弧的稳定性和熔滴过渡的控制，研制开发了一套弧焊过程电信号智能检测分析系统。该系统由硬件检测电路和相关软件组成，具有信号采集、波形显示、数据统计分析、曲线拟合及数据存储功能。该系统通过焊接电压和电弧电流的采样数据所进行的统计分析能够获得反映焊接过程的特征数据，并通过对这些数据的分析可对焊接过程的质量进行有效的评定。     

区域自动气象站小时雨量数据质量控制方法研究

提出了一种利用常规质量控制方法、空间水平一致性和雷达组合反射率强度与降水强度阈值判定的综合性质量控制方法,对对逐小时降水异常站点进行识别。通过个例分析表明:该分析方法可有效查找出小时降水数据中的异常数据,在提高质量控制、分析系统时效的基础上,缩短了雨量传感器故障发现时限,为降水过程中的设备维护提供了合理的数据证据,增强了装备保障的时效性。     

过程能力分析在压缩机密封圈加工质量控制中的应用

为了保证大批量零件加工的产品质量合格率满足客户的要求,通过Ppk （过程性能指数）计算来评估初始加工过程能力,结果表明初始工序的过程能力不足。经因果分析,采取了相应的整改措施。落实改进措施后,在稳定状态下,取样所加工的统计数据,运用MINITAB软件,绘制了控制图、过程能力图,并进行了过程能力指数Cp ,Cpk （短期）与过程性能指数Pp ,Ppk （长期）计算和分析。最后根据客户反馈的质量数据确定了加工过程的工序能力水平与状态,使其工序能力满足客户的要求。     

尾透静叶环设计制造的问题及解决

以硝酸尾透静叶环逆向设计及加工制造的过程为研究对象,以数据分析、试验的方式对静叶环加工制造过程中的质量问题进行了分析,得出了合理的安装间隙,静叶环焊接变形得到了有效控制。     

基于模糊物元的小批量生产典型工序能力分析

社会科技的进步和市场竞争的白热化,以及以顾客为中心的市场导向,都使得多品种、小批量生产成为了目前制造业的主流趋势,然而由于加工数据的缺乏,多品种、小批量生产过程的质量控制和分析却成为了一个棘手的问题。为了破解这个难题,提出一种基于模糊物元的小批量生产“典型工序”能力分析方法。采用模糊物元分析的方法,将一个工序看作是一个模糊物元,根据工序能力影响因素构造出工序相似条件并判定出与原始工序相似的工序,利用这些工序组成一个新的含有大批量样本数据特征的“典型工序”;针对构建出的“典型工序”进行工序能力分析,判断出该“典型工序”的工序能力水平并进行相应控制;最后用实例验证了该方法的正确性和可行性。     

Fuzzy process capability plots for families of one-sided specification limits

Process capability indices (PCIs) have been popularly used in the manufacturing industry for measuring process potential and performance. When our data are imprecise, classical PCIs are improper. In this paper, a graphical approach has been presented for monitoring whether or not our process is capable by using the process capability plots for two families of the one-sided PCIs based on fuzzy data. The presented methodology takes into consideration the certain degree of imprecision on the sample data and leads to the three-decision rule that has been presented on the process capability plot. Also, the advantages of this method in comparison to the fuzzy hypothesis test have been discussed. Two real examples have been presented to demonstrate this approach.     

质量成本与西格玛能力之关系模型探讨

通过对6σ波动和概率分布的研究，给出了工序能力指数计算的详细方法，进而通过对质量成本、工序能力指数和西格玛水平的系统分析，首次建立了质量成本与西格玛水平之间的联系，拓展了质量成本分析控制的领域和层次，给企业领导阶层提供了决策依据。     

Effective process design and robust manufacturing for hydroformed parts

A general trend and one of the important strategies in the automotive industry is reducing the lead time of a new car development. In order to obtain this goal the efficient use of simulation software is needed to effectively design a hydroformed part. The stages of the design chain are integrated in one simulation tool. The outcome of this feasibility analysis is a virtual prototype saying that it is possible to produce the part. In fact one process point has been defined whereas when going into production a process window must be know to guarantee a stable production process. In order to achieve this latter we are suggesting a process performance analysis. Based on multiple simulations the influence and sensitivity various process parameters on the forming process can be identified. Besides combining the analysis with statistical process control evaluation the process capability (Cpk-values) can be defined. This design chain analysis will be applied on a hydroformed part. The process performance analysis is the identification of the process window and process capability in advance, so before any tool has been milled. This will be demonstrated on a second hydroformed part.     

An improved tolerance charting technique using an analysis of setup capability

The tolerance charting method enables the calculation of working tolerances in machining process planning. The method has been used as a basic tool for analysing process plans for many decades. Process capability in tolerance charting is modelled using the tolerances of the working dimensions. The literature shows that machining process capability can be analysed from the point of view of surface position errors. During setups, it is possible to perform decomposition into two surface position tolerances: a datum surface position tolerance and a machining surface position tolerance. This type of analysis has the advantage of producing simplified tolerance chains. This paper provides an adaptation of the tolerance charting technique that uses a capability model based on datum and machining surface position tolerance. The results show an improvement in the working tolerance stackup that reduces the capability required for productive resources. As a result, reductions in manufacturing costs can be achieved. The proposal is valid for manual or computer-assisted techniques.     

The study of cost-tolerance model by incorporating process capability index into product lifecycle cost

To reduce the cost of manufacturing systems, many studies of cost minimization have been performed. Since tolerance design significantly affects the manufacturers’ cost, the optimization of cost-tolerance allocation will be an important issue for reducing these costs. Costs incurred in a product life-cycle include manufacturing cost and quality loss. However, most cost-tolerance optimization models frequently ignore the concept of quality loss and may not lead to an accurate analysis of the tolerance. Until now, process capability analysis has been the tool used to evaluate the adequacy of a production tool in meeting a quality target. Hence, the concept of process capability analysis should be included into the cost-tolerance optimization model. In this study, a flexible cost-tolerance optimization model will be constructed by integrating the process capability index into the product life-cycle cost function. The constructed cost-tolerance optimization model simultaneously considers the manufacturing cost of the components, the process capability of the manufacturing operations, and the quality loss of products. The decision-maker can apply the proposed cost-tolerance optimization model to determine a reasonable tolerance with minimum total cost including consideration of the process capability .     

On the process capability of the solid free-form fabrication: a case study of scaffold moulds for tissue engineering

This study applies the methodology and procedure of process capability to investigate a solid free-form fabrication technique as a manufacturing method to produce scaffold moulds for tissue engineering. The process capability Cpk and process performance Ppk of scaffold mould manufacture using a solid free-form fabrication technique has been analysed with respect to the dimension deviations. A solid free-form fabrication machine T66 was used to fabricate scaffold moulds in this study and is able to create features that ranged from 200 microm to 1000 microm. The analysis showed that the printing process under the normal cooling conditions of the printing chamber was in statistical control but gave low process capability indices, indicating that the process was 'inadequate' for production of 'dimension-consistent' scaffold moulds. The study demonstrates that, by lowering the temperature of the cooling conditions, the capability Cpk of the printing process can be improved (about threefold) sufficiently to ensure the consistent production of scaffold moulds with dimension characteristics within their specification limits.     

Process capability analysis for a multi-process product

In this paper, we propose a flow path to evaluate the process capability of an entire product composed of multiple process characteristics. There are six steps in the flow path. Whether process data comply with a normal distribution or a non-normal distribution, the flow path can be applied. Based on C_pu, C_pl, and C_pn, the research aims to develop a multi-process capability analysis chart (MPCAC) model to evaluate process capability in a normal distribution. Similarly, the research aims to define non-normal multi-process capability analysis chart (NMPCAC) to evaluate process capability in a non-normal distribution based on N_pu, N_pl, and N_pn.     

A process capability index for simple linear profile

In some cases, the quality of a process or a product is characterized by a linear regression model which is also called a linear profile. Process capability index is an important concept in statistical quality control and measures the ability of a process to manufacture products that meet certain specifications. There has been little attempt to study the process capability in linear profiles. In this paper, two methods are proposed for measuring the process capability in simple linear profiles. The first method uses the percentage of nonconforming parts produced at each level of the independent variable to introduce a process capability index. The second method is a multivariate process capability approach where a vector of three components is introduced. The components of the vector assess the process dispersion, its centrality, and its location within the upper and the lower specification limits. In comparison to the only existing method, numerical analysis based on simulation studies indicates that the suggested process capability measurements perform more accurately in evaluating the capability of a process generating a simple linear profile. When the error term variance is 1 and the actual percentage of nonconformities is 0.11 %, the proposed method estimates 0.11 % nonconforming percentage and a capability index of 1.06. While the existing method results in 0.27 % nonconforming percentage and a capability index of 0.9, the existing method underestimates the process capability.