基于双闭环的直线容积式自校正灌装设备控制系统设计及应用

基于直线容积式灌装设备灌装精度不高的问题,研究了一种带称量反馈的直线容积式灌装设备,采用直线容积式进行灌装,容积缸采用高精度的伺服电机驱动,保证了容积缸准确的运动位移。容积式灌装同时将等量物料灌装到反馈秤里进行称量式校正,实时测量灌装误差并且自动校正,使得此种灌装生产线既有称量式灌装的高精度,又有直线容积式灌装的高速度,在实际应用中取得了较好的使用效果。     

金属用乳胶底漆耐蚀与焊接性能的评价试验

本文介绍了金属用乳胶底漆的耐蚀性以及在涂有乳胶底漆的钢板表面上直接进行焊接的可能性。文章列出了铁红苯丙乳胶底漆与日本的ASCA~#600乳胶底漆及C06—1醇酸铁红底漆所做一次对比试验的详细数据。     

涂料盐雾试样的勘误方法研究

在盐雾试验的基础上,对涂料试样提出了2种拓展考察的方法:残余附着力测试和划"×"处金属腐蚀状态勘验。在高氯化底漆+高氯化面漆、环氧底漆+高氯化面漆、环氧底漆+工程面漆和高氯化底漆+工程面漆等不同的涂料体系,通过试验得出了高氯化涂料具有突出的封闭阻挡性能,但涂层发脆。工程面漆与底漆粘附力较差,环氧底漆具有突出的基体附着力,与高氯化面漆配合,是性能优良的防腐涂料体系。     

自驱动润滑脂灌装装置的设计

目的研发一种高速节能的润滑脂灌装装置。方法 2个灌装头共用容积缸和进料管,活塞将容积缸分成2个腔对应2个灌装头,每个管路中设置有三通阀,三通阀连通容积缸、进料管和灌装头,在2个三通阀的控制下,靠进料管里物料自身的压力驱动活塞在容积缸内移动,从而实现2个灌装头交替灌装。结果自驱动交替灌装不需要提供灌装额外的驱动力,降低了生产成本,并且提高了灌装速度,保证了产品质量。结论自驱动润滑脂灌装装置真正实现了高速节能,而且结构简单,易于控制,在脂类等粘稠物质灌装领域具有很大的推广价值。     

盒中袋灌装阀阀口流场分析与结构优化

为了确定盒中袋灌装阀阀芯下降高度,对盒中袋灌装阀进行了流体流场分析计算。用Gambit软件网格前处理了灌装阀通道模型,基于标准k-ε湍流模型,对灌装阀进行了内部流场数值模拟。计算模拟了不同阀芯下降高度对内部速度压力云图的影响,分析了下降高度对灌装速率以及密封的影响。通过Fluent数值计算对灌装阀进行了流体分析,为灌装阀的优化设计提供了理论依据。     

家装攻略

选购乳胶漆应避免三大误区1.底漆不重要用户在选择乳胶漆时,重点往往放在面漆上,却忽视了底漆,或者为节约成本,干脆不用底漆。其实,使用底漆可以提高面漆的丰满度,提高面漆在普通批灰墙面的附着力,从而延长面漆的使用寿命;     

下开阀式塑料灌装阀

目的研发一种适合灌装腐蚀性溶液的灌装阀。方法打破金属灌装阀的传统设计理念,塑料灌装阀以高分子塑料为主体结构,利用塑料阀杆柔韧、抗拉的特点,当阀杆被向上拉起时,灌装阀关闭,同时阀杆下端的阀芯和导向阀体形成线性密封;当阀杆被推动下移时,灌装阀打开。另外灌装阀设置了弹簧,用于保障气路故障时灌装阀仍处于关闭状态,避免泄漏。结果塑料灌装阀不但能够抵抗强酸、强碱等液体的腐蚀,而且具有结构合理、安全可靠、成本低等优点。结论塑料灌装阀成功地解决了化工领域腐蚀性溶液灌装的难题。     

液位定量式灌装机的灌装精度概率模型与可靠度计算模型

描述了控制液位定量式灌装机的灌装时间与灌装精度的关系，推导出实际灌装时间的理论计算公式。针对实际存在的各种随机变量对灌装时间的影响，建立了灌装时间的概率模型，提出基于灌装时间随机误差的灌状精度以及灌装精度可靠度概念，并相应建立出灌装精度概率模型与灌装精度可靠度计算模型。     

液体物料的灌装技术

FillingTechniqueofLiquidProducts重力灌装法重力灌装法是灌装容器到预定的液位。来自贮液箱的液体流经一个弹簧充填阀,阀下容器打开,液体由于自重流入被密封的容器。容器内的空气经高出贮液箱液面的排气管排出。当容器内的液位上升到比排气管的下口略高时,灌装停止。同压力灌装和真空灌装一样,这种灌装方法不会有液体溢出,液体中渗气很少,灌装液位高度一致、灌装方法比较简单、易于掌握。它可以用于大规模的无菌灌装,灌装各种不含气的液体。重力真空灌装法这种灌装法和重力灌装法类似。事实上,它是一种在低真空下靠重力灌装的方…     

包装生产线智能灌装系统设计

目的 为提高灌装生产线的灌装精度和速度,设计一种包装生产线智能灌装控制系统.方法 阐述灌装生产线基本结构,包括输送、空瓶检测、灌装、质量检测、二次补灌、套盖以及成品输出等工位.以二次补灌为重点研究对象,设计一种基于小脑神经网络PID控制的微量灌装控制系统,可弥补常规PID控制的不足,同时采用卡尔曼滤波器消除操作过程干扰信号和噪声.通过实验验证所述控制系统的可行性和有效性.结果 分析了灌装特性,认为影响灌装精度的因素比较多且相互干扰.实验结果表明,所有样本的质量偏差均没有超过0.1 g,灌装过程中生产线运行稳定、快速、可靠.结论 所述微量灌装控制系统能够提高灌装精度、速度,可满足包装生产线高精度、高速度的要求.     

The production capacity of job shops with limited storage space

Suppose the number of jobs which can be stored in front of the machines in a job shop is limited. As a result, arriving jobs for which there is no space in the shop will form a shop queue. The production capacity or maximum departure rate of jobs from the shop will depend on the way in which jobs are selected from the shop queue for release to the machine queues. For a job shop with two identical machines and random routing of jobs a number of release rules are compared. It is shown that the production capacity is increased when the number of jobs in the shop is kept less than the available storage space. Among release rules independent'of job processing times and number of operations the optimum release rule is shown, using dynamic programming, to be the idle machine rule, i.e. only release a job to the shop when a machine would otherwise be idle.     

Learning and labour assignment in a dual resource constrained cellular shop

Recent studies have shown that in a cellular shop that benefits from learning due to repetitive processing, limitations attributable to routing flexibility can be more than offset. Moreover, the shop can respond more quickly to changes in demand than a job shop. This study examines the impact of labour assignments in a dual constrained cellular shop in which processing times decrease with operator task repetition. Results indicate that in the presence of operator learning, shop performance is significantly affected by the flexibility permitted in labour assignments. Moreover, the sensitivity of performance to labour assignments is significantly impacted by staffing levels and the magnitude of learning effects.     

Multi-agent hybrid shop floor control system

A manufacturing system is composed of many activities that can be monitored and controlled at different levels of abstraction. A shop floor can be considered an important level at which to develop a Computer Integrated Manufacturing system (CIM). However, a shop floor is the dynamic environment where unexpected events continuously occur, and impose changes to planned activities. To deal with this problem, the shop floor should adopt an appropriate control system that is responsible for the coordination and control of the manufacturing physical flow and information flow. In this paper, a hybrid control system is described with a shop floor activity methodology called Multi-Layered Task Initiation Diagram (MTD). The architecture of the control model identifies three levels; i.e. the shop floor controller (SFC), the intelligent agent controller (IAC) and the equipment controller (EC). The methodology behind the development of the control system is an intelligent multi-agent paradigm that enables the shop floor control system to be an independent, autonomous, and distributed system, and to achieve an adaptability to change the manufacturing environment.     

具有工序顺序柔性的车间调度问题研究综述

某些加工车间在生产过程中具有多种柔性,工序顺序柔性就是其中重要的一种。通过对具有工序顺序柔性的车间调度问题的优化求解,能够极大地提高生产效率,节约生产成本。本文对具有工序顺序柔性的车间调度问题的研究现状进行整理分析,主要包括混合车间调度问题(mixed shop scheduling problem, MSP)、分组车间调度问题(group shop scheduling problem, GSP)和部分车间调度问题(partial shop scheduling problem, PSP)。最后,指出了具有工序顺序柔性的车间调度问题的发展前景及发展方向。     

Managing worker flexibility and attrition in dual resource constrained job shops

Worker flexibility is an attractive option for enhancing manufacturing performance, since it provides several strategic advantages, and also allows the firm to buffer against uncertainty. In this paper, we investigate issues related to acquiring a flexible work-force in those dual resource constrained (DRC) job-shops that have high learning costs and the presence of worker attrition. Our results show that significant improvement in traditional shop related measures can be attained at even very high attrition rates by incrementally training each worker in one additional department. However, this improvement comes at the expense of productivity losses which shop managers may not be willing to accept. The nature of the tradeoffs that exist in acquiring this incremental worker flexibility are addressed. Two strategies for improving shop performance, based on incrementally training workers or reducing attrition rates, are also recommended for the DRC shop modelled in our study. Conditions under which either of these two strategies should be pursued by the shop managers are also identified.     

A model to examine the effect of loading conditions on scheduling rules in a job shop environment

Although a great deal of research has been carried out in the field of job scheduling this has generally been directed towards examining the benefits of particular rules and presenting improved algorithms. This paper examines how real job shop problems can be modelled and available scheduling rules examined for particular capacity loading conditions. A model of a medium-size production job shop is developed and it is shown that, for their particular shop layout and job mix, the performance and ranking of particular rules with respect to certain criteria, change with shop conditions. The model developed can easily be applied to a wide range of job shop situations and once performance charts have been produced for those scheduling rules available, they can be used to aid the existing scheduling system whether manual or computer based.     

On the beat of the drum: improving the flow shop performance of the Drum–Buffer–Rope scheduling mechanism

One of the main elements of the theory of constraints is its Drum–Buffer–Rope (DBR) scheduling (or release) mechanism that controls the release of jobs to the system. Jobs are not released directly to the shop floor – they are withheld in a backlog and released in accordance with the output rate of the bottleneck (i.e. the drum). The sequence in which jobs are considered for release from the backlog is determined by the schedule of the drum, which also determines in which order jobs are processed or dispatched on the shop floor. In the DBR literature, the focus is on the urgency of jobs and the same procedure is used both for backlog sequencing and dispatching. In this study, we explore the potential of using different combinations of rules for sequencing and dispatching to improve DBR performance. Based on controlled simulation experiments in a pure and general flow shop we demonstrate that, although the original procedure works well in a pure flow shop, it becomes dysfunctional in a general flow shop where job routings vary. Performance can be significantly enhanced by switching from a focus on urgency to a focus on the shortest bottleneck processing time during periods of high load.     

An active tool-tracking system for increased productivity

Keeping track of tools is essential for smooth running of any production unit. Being one of the critical resources for production, non-availability of tools can affect productivity of any manufacturing shop floor seriously. In this paper, a novel tool-tracking system, which can be used to monitor the movements of tools in a shop floor to prevent tool loss and tool hoarding, is described. The system uses miniature transmitters embedded in the tools together with a number of receiver stations located strategically around the shop floor. Each tool intermittently transmits a coded signal so that it may be identified as well as located. Simulation studies show that the system is effective particularly in situations where the productivity would have been low because of high tool losses.     

Workshop scheduling using practical (inaccurate) data Part 1: The performance of heuristic scheduling rules in a dynamic job shop environment using a rolling time horizon approach

This paper is a report on a simulation study to investigate the performance of a number of scheduling rules on the basis of a rolling time horizon approach for a dynamic job shop environment. The performance measure considered is an economic objective which includes the main costs involved in a scheduling decision. The first purpose of the study was to find the best scheduling rule and the second to investigate the effects of the rescheduling interval on performance and examine whether there is a policy that can always improve performance. The simulation study, which is part of a larger project on practical workshop scheduling, has been carried out under widely varying conditions in terms of due date tightness, shop load level, and shop load balance level. The results show that a recently developed scheduling rule, SPT-C/R, is the most appropriate scheduling rule in minimizing overall cost and that the relationship between performance and rescheduling interval can be shown.     

Adaptive scheduling of batch servers in flow shops

Batch servicing is a common way of benefiting from economies of scale in manufacturing operations. Good examples of production systems that allow for batch processing are ovens found in the aircraft industry and in semiconductor manufacturing. In this paper we study the issue of dynamic scheduling of such systems within the context of multi-stage flow shops. So far, a great deal of research has concentrated on the development of control strategies, which only address the batch stage. This paper proposes an integral scheduling approach that also includes succeeding stages. In this way, we aim for shop optimization, instead of optimizing performance for a single stage. Our so-called look-ahead strategy adapts its scheduling decision to shop status, which includes information on a limited number of near-future arrivals. In particular, we study a two-stage flow shop, in which the batch stage is succeeded by a serial stage. The serial stage may be realized by a single machine or by parallel machines. Through an extensive simulation study it is demonstrated how shop performance can be improved by the proposed strategy relative to existing strategies.