Integrated predictive maintenance strategy for manufacturing systems by combining quality control and mission reliability analysis

Predictive maintenance (PdM) is an effective means to eliminate potential failures, ensure stable equipment operation and improve the mission reliability of manufacturing systems and the quality of products, which is the premise of intelligent manufacturing. Therefore, an integrated PdM strategy considering product quality level and mission reliability state is proposed regarding the intelligent manufacturing philosophy of ‘prediction and manufacturing’. First, the key process variables are identified and integrated into the evaluation of the equipment degradation state. Second, the quality deviation index is defined to describe the quality of the product quantitatively according to the co-effect of manufacturing system component reliability and product quality in the quality–reliability chain. Third, to achieve changeable production task demands, mission reliability is defined to characterise the equipment production states comprehensively. The optimal integrated PdM strategy, which combines quality control and mission reliability analysis, is obtained by minimising the total cost. Finally, a case study on decision-making with the integrated PdM strategy for a cylinder head manufacturing system is presented to validate the effectiveness of the proposed method. The final results shows that proposed method achieves approximately 26.02 and 20.54% cost improvement over periodic preventive maintenance and conventional condition-based maintenance respectively.     

From color to chemometrics

In‐line and in‐situ process control for thin‐film properties during the production is an important factor to improve and stabilize the product quality. Furthermore machine set‐up times can be reduced significantly. ZEISS provides a variety of methods to fulfill this need. The article shows how a combination of different process capable methods — color, physical, and chemometric models — helps the operator to stabilize coating processes and control the final product quality with a single equipment.     

能源计量和建模技术的研究与应用

应用动态多参数在线能源计量技术对企业范围内各用能部门的实时能耗数据进行了准确、稳定、实时的采集和存储,形成了巨量的能源数据库。依据物质平衡和能量守恒原理,运用能耗基准因数法和e-p分析方法,建立了企业生产和能量转换过程的数学模型;评估和计算了设备和工序能耗、产品能值和单位能耗;建立了单位综合能耗模型。该模型成功地应用到北京某啤酒集团的能源计量系统中,通过设备和工序能耗的分析对比,指导工艺优化和节能空间的评估,对工艺和设备能耗进行合理预测。     

An option generation and selection methodology for process equipment selection

The option generation and selection (OGS) methodology forms part of a general approach for the design of agile chemical plants based on business, product and process knowledge, with support from information models. This paper describes an equipment OGS tool that encompasses the principles of combinatorial process and plant design. The main components of the methodology are: an equipment option generation model described as a set of objects, and the net relationships between them, and an equipment option selection model which consists of procedures for equipment selection. The two models are supported by databases containing information specific to each equipment type, the concept on which the equipment is based, and relationships with other equipment types. Robust, systematic and complete forms of these models can be used as the basis of an expert system for process equipment design, with equipment selected using these tools satisfying the requirements of both specific processes and families of processes (that contain common features, similar functional groups or similar raw material requirements for process operations). Application of the methodology also allows the evaluation of options for reconfiguring existing plant.     

基于FAHP的亲子健身器材可用性评价方法

目的 研究影响亲子健身器材可用性的设计因素,提高亲子健身器材的可用性。方法 运用层次分析法和模糊评价法相结合的模糊层次分析法,针对亲子健身器材的可用性进行综合评价。首先针对亲子健身器材初始方案运用层次分析法进行分析,建立可用性评价模型。其次构造判断矩阵,确定各个指标因素的权重值。然后结合模糊综合评价法,计算亲子健身器材可用性的分值,通过该分值评判出最终等级。结论 通过运用层次分析法,为亲子健身器材的改进提供指导,进一步提高了产品的美观性与可靠性。     

Methodology for Evaluating Manufacturability of Composite Materials

It is widely acknowledged that decisions made in the early design stages have a greater influence on the final product than those made in the later stages. In a conventional design process, composite products are designed without sufficient consideration being given to limitations of composite manufacturing process. Quite often some of composite designs cannot be produced with special performance requirement or cannot be produced at a reasonable cost. To resolve this drawback and achieve the competitive designs for composite product, an integrated knowledge framework that supports the quantitative manufacturability evaluation of composite design proposals was introduced. The essential concept of the composite manufacturability was defined through an in-depth analysis of composite manufacturing process. The evaluation flow was acquired according to the hierarchical indices. A stage-based quality assessment model for the composite multistage process was mainly studies. It relies on the consideration that the final quality of a composite product is mainly determined by some critical stages during a production cycle. Finally, the method is illustrated through a case focusing on the quality issue of void formation in autoclave process.     

Mission reliability evaluation based on operational quality data for multistate manufacturing systems

Modern and intelligent manufacturing systems have a prominent multistate feature. However, previous studies of reliability analysis of multistate manufacturing systems mostly focused on the basic reliability of manufacturing systems but disregarded their operating characteristics, which has hindered the development of Prognostics and Health Management technique for intelligent manufacturing systems. Therefore, an evaluation approach of mission reliability for multistate manufacturing systems based on operational quality data is proposed in this paper. First, from the systematic viewpoint of the composition and operational principle of the manufacturing system, the relationship among production task execution state, production equipment degradation state, and produced product quality state is expounded, and the connotation of the mission reliability of multistate manufacturing systems is defined. Second, an extended state task network (ESTN) is presented to organise operational quality data by considering the quality state of work in process (WIP). Third, a fusion model of operational quality data for manufacturing systems is established with the aid of the ESTN, and an operational quality data-oriented evaluation method of mission reliability is been put forward. Finally, a case study of a manufacturing system for a cylinder head is conducted to verify the proposed approach.     

Material handling considerations in the FMS loading problem with full routing flexibility

This study exploits machining and routing flexibility to effectively deal with the material handling requirements resulting from a frequently changing demand mix in a manufacturing system where material handling is a bottleneck. For this purpose, the objective function of the operation and tool loading problem is selected as the minimisation of the total distance traveled by parts during their production. Versatile machines and the flexible process plans offer full routing flexibility that enable the same workpiece to be processed using alternative sequences of operations on alternative machines. Three mathematical programming (MP) models and a genetic algorithm (GA) are proposed to solve this problem. The proposed MP formulations include a mixed-integer nonlinear programming (MINLP) model and two mixed-integer programming (MIP) models, which offer different representations for the flexible process plans. The GA is integrated with linear programming for fitness evaluation and incorporates several adaptive strategies for diversification. The performances of these solution methods are tested through extensive numerical experiments. The MP models are evaluated on the basis of the exact solutions they yield as well as how they lend themselves for GA fitness evaluation. The GA–LP integration works successfully for this hard-to-solve problem.     

Structure dynamics control approach to supply chain planning and adaptation

Many of the existing methods and models of supply chain planning and control consider only one supply chain structure and assume it's more or less static in nature. In practice, supply chains have a multi-structural semantics and those multiple interrelated structures (organisational, functional, informational, financial, topological, technological, product, and energy structures) are dynamic and subject to many planned and disturbance-based changes. These changes are tackled by control activities which make planning an adaptive process. Although the supply chain optimal planning domain for static structures has been extensively investigated, the domain of planning and control of supply chains with structure dynamics merits more systematic and critical attention. In this study, an original form of supply chain representation as a dynamic system with changing multi-structural characteristics is developed. The structure dynamics control is a dynamic interpretation of the supply chain (re)synthesis process and aims at both advancing the supply chain (re)planning domain and enlarging the scope of the supply chain analysis domain that is currently rather limited. The developed approach is based on an optimal program control theory, active modelling objects, and structural–mathematical concept blended with mathematical programming. In this paper, we describe its basic features and exemplify possible applications and extensions regarding real planning and control problems faced by international supply chains in recent years.     

An integrated approach to evaluating the production system in closed-loop supply chains

The increasing demands for environmental resource protection and sustainable development have been forcing enterprises to put sustainable supply chain management on their agendas in recent years. At the same time, intense global competition requires organisations to adopt practices that enable them to provide high-quality products and services. In this paper, we consider the problem of comprehensively evaluating the production system in closed-loop supply chains. We first propose an evaluation framework that consists of economic evaluation, product quality evaluation and ecological evaluation modules. Based on mathematical probability theory and the dynamic characteristics of reverse supply chain logistics, we then focus on the evolution dynamics in the quality evaluation dimension, where the concept of product quality, which builds on the reliability and the time-utility value of a product, is proposed. The basic production evaluation model is then extended to incorporate different sustainable procurement strategies, which take into consideration the trade-offs among cost, environment and quality. An outline and corresponding flow chart of corporate procurement strategy optimisation are provided which allow the proposed evaluation model to be implemented in computer-aided decision-making, further providing decision support for production system and supply chain management. Simulation and case studies are presented to promote a better understanding of the model approach and its managerial implications. Results also suggest that quality characteristics of components and sustainable procurement strategies are two important factors that determine the final production performance and should be paid special attention in closed-loop supply chain practice.     

INTEGRATING PRODUCT DESIGN AND MANUFACTURING: A GAME THEORETIC APPROACH

One approach for increasing the quality of a product and the efficiency of its realization is to pay attention to the integration of product design and manufacturing. An integrated product realization process must be able to accommodate sequential stages of activity along a product realization time-line, independent information flow between stages, and trade-offs between various activities and factors. In this paper, a decision-based approach that is consistent with such characteristics is explored. This approach is anchored in game theory and a decision construct, namely, the Compromise Decision Support Problem. The merging of these two elements provides a mathematical and systematic basis for coordinating product design and manufacturing. This approach is illustrated via an example, namely, the redesign of a common component platform for a family of absorber-evaporator modules for absorption refrigeration, in order to reduce their costs and production times. The focus is on the method rather than the results per se.     

Integrated production planning and quality control for linear production systems under uncertainties of cycle time and finished product quality

This work considers serial production systems with several process steps and a possible quality control at final step. It deals with the problem of optimising planned lead time when the real lead time for each process is stochastic and the finished product quality is uncertain unless it is inspected. Three analytical models are proposed aiming to minimise the expected total cost, which is composed of the inventory and backlogging costs for the finished product and quality costs associated with inspection and non-conformities. These models correspond to three quality control policies: (i) without quality control, (ii) with quality control but without taking into account the inspection duration when optimising the planned lead time and (iii) with quality control and with considering the inspection duration when optimising the planned lead time. Based on the results, it can be highlighted the economic advantage of integrating quality control at the early stage of supply and production planning decisions for some cost parameters conditions. The robustness of the proposed models is also analysed regarding the variance of the probability distributions of the lead times.     

融合生产信息的产品检验不确定度评定

为合理减小测量不确定度对产品合格判定的影响,研究融合生产信息的产品检验不确定度评定。建立融合加工信息和测量信息的贝叶斯信息融合模型,基于被测参数后验分布对测量结果及其不确定度进行重新估计,依据信息融合后的结果进行产品合格判定;提出利用质量控制信息计算贝叶斯先验参数的方法。仿真实验和实例分析结果表明,在产品检验不确定度评定中融入生产信息,可有效扩大产品检验合格区,合理减小合格判定的工作量。     

大数据环境下产品质量风险评估系统的研究与设计

产品质量风险评估已成为新形势下政府监管面临的重要课题之一。本文结合我国产品质量风险评估研究基础,以大数据技术为导向,结合神经网络、动力系统科学理论、数理统计等理论,运用指标树、K-means聚类分析、判别分析等方法,构建一种新的产品质量风险评估系统,以实现智能评估分析产品质量风险等级。     

鸡蛋包装生产工艺的生命周期评价

鸡蛋包装多为一次性使用且消耗量很大,其材料一般为纸浆模塑和PVC等.基于生命周期评价(LCA)方法,利用eFootprint软件及数据库,对采用两种不同材料生产的鸡蛋包装分别建模,对二者的环境影响进行评价.研究选取的功能单位是可容装30枚鸡蛋的单个蛋托,尺寸为长292 mm、宽245 mm、高35 mm;系统边界包含该蛋托加工过程的主要工序,如包装材料加工、压制成型、分切、出厂包装等工艺过程.研究结果表明,评价对象在全球变暖潜值(GWP)、水资源消耗(WU)和初级能源消耗(PED)等环境影响方面贡献值较大,纸浆模塑蛋托这三类环境影响分别为90 g,0.17 kg,1.3 MJ,PVC蛋托这三类环境影响分别为720 g,4.27 kg,9.84 MJ.根据评价结果可知,纸浆模塑蛋托比PVC蛋托对环境产生的影响更小,故应优先选择纸浆模塑蛋托.建议在保证产品质量的前提下,优先选择对环境影响小的材料以及助剂进行产品设计、生产,并通过选择更高克重的PVC材料、修改蛋托结构设计等方式,降低包装产品对环境的影响.     

维修管理模式对制造企业质量控制影响的实证研究

可靠的设备预防维修水平和卓越的产品质量保证能力是保障产品过程质量的关键,现有多数研究集中在质量管理模式与企业绩效的关系分析。在对过程质量控制、设备维修管理评述的基础上,探讨了设备维修管理模式与维修绩效及过程质量控制绩效间的关系。以国内制造企业的连续生产方式为研究对象,运用结构方程模型剖析了RCM、TPM、设备采购管理与和设备维修绩效、过程质量控制绩效的路径关系,发现基础维修管理活动对维修绩效有间接影响,RCM、TPM对设备维修绩效有显著影响,路径系数分别为0.346、0.717,设备维修绩效对过程质量控制绩效的影响显著,路径系数为0922。证明制造企业为提升产品质量,需要完善其设备预防维修系统。     

Process cycle optimization in press forming of paperboard

Three‐dimensional forming of paperboard is commonly done by a press forming process, which has been widely researched. However, the process cycle of the press forming of paperboard trays has not yet been completely optimized due to limited adjustability and unsophisticated mechanical structure of commonly used forming equipment. The object of this study is to optimize the force curve of stroke to improve product quality without compromising the production rate using LUT Adjustable Packaging Line prototype for practical evaluation of formability and multibody dynamics software MSC Adams for simulation. Several process parameters were investigated with different process cycles to study their effect on the quality of the formed products. With optimized male mould speed, acceleration and speed of the blank could be reduced, which led to significantly reduced rupturing tendency without compromising the production speed. It was also found that a constant blank holding force should be used to achieve acceptable tray quality, although this results in a significantly increased surface pressure applied to the formed substrate. It was also discovered that a novel male mould attachment, which included a pressing force adjustment system that utilized a spring set with an adjustable preload, made it possible to control the force distribution between different forming tools during the dwelling phase of the process cycle in an improved way. Utilization of the method used in this paper leads to a better tray quality without compromising the production efficiency. Furthermore, this can increase the number of possible package applications for sustainable materials, such as paperboard.     

基于Witness的看板生产系统仿真与参数优化研究

以看板生产系统基本理论为基础,某发动机总装车间为实证案例,应用Witness物流仿真软件对该车间看板生产系统进行仿真与优化,实现在短时间内预见实施效果,对系统绩效如设备利用率、订单处理效率等做出评价。结果表明,实施看板系统后,订单得到及时响应,提高了客户满意度,设备平均利用率和生产效率显著提高,产品产量达到目标产量。最后对看板生产系统的隐性参数进行优化,为不同企业根据实际生产情况实施看板生产系统参数选取提供依据     

Variability modelling and balancing of stochastic assembly lines

In a production flow line with stochastic environment, variability affects the system performance. These stochastic nature of real-world processes have been classified in three types: arrival, service and departure process variability. So far, only service process – or task time – variation has been considered in assembly line (AL) balancing studies. In this study, both service and flow process variations are modelled along with AL balancing problem. The best task assignment to stations is sought to achieve the maximal production. A novel approach which consists of queueing networks and constraint programming (CP) has been developed. Initially, the theoretical base for the usage of queueing models in the evaluation of AL performance has been established. In this context, a diffusion approximation is utilised to evaluate the performance of the line and to model the variability relations between the work stations. Subsequently, CP approach is employed to obtain the optimal task assignments to the stations. To assess the effectiveness of the proposed procedure, the results are compared to simulation. Results show that, the procedure is an effective solution method to measure the performance of stochastic ALs and achieve the optimal balance.