scholarly journals Bottlenecks in serial production lines: A system-theoretic approach

1996 ◽  
Vol 2 (3) ◽  
pp. 233-276 ◽  
Author(s):  
C.-T. Kuo ◽  
J.-T. Lim ◽  
S. M. Meerkov

In this work, a new definition of production systems bottlenecks is formulated and analyzed. Specifically, a machine is defined as the bottleneck if the sensitivity of the system's performance index to this machine's production rate in isolation is the largest. Although appealing from the systems point of view, this definition suffers a deficiency due to the fact that the sensitivities involved cannot be either measured on-line or efficiently calculated off-line. To avoid this, the paper develops a method based on indirect but real-time data. From this point of view, the main result of the work is as follows: The bottleneck machine in a serial production line can be identified by analyzing relationships between the so-called manufacturing blockage and manufacturing starvation of each machine. This leads to a simple rule for bottleneck identification. The rule requires neither the calculation of the production rate sensitivities nor the production rate itself. When the probabilities of manufacturing blockages and starvations are not available from on-line measurements, the paper presents their analytical estimates which, under certain conditions, can be used for bottleneck identification. Finally, a case study at an automotive component plant is described.

Author(s):  
Yang Li ◽  
Qing Chang ◽  
Michael P. Brundage ◽  
Guoxian Xiao ◽  
Stephan Biller

Standalone throughput (SAT) of a single station is one of the most widely used performance indexes in industry due to its clear definition, ease of evaluation and the ability to provide a guidance for continuous improvement in production systems. A complex multistage manufacturing system is typically segmented into several subsystems for efficient local management. It is important to evaluate performance of each subsystem to improve overall system productivity. However, the definition of standalone throughput of a production subsystem is not as clear as for a single station in current literatures or in practice, not to say an effective evaluation method. This paper deals with the standalone throughput of a serial production line segment. The definition and implication of standalone throughput of a line segment is discussed. A data driven method is developed based on online production data and is proved analytically under a practical assumption. In addition, the method is verified through simulation case studies to be an accurate and fast estimation of the standalone throughput of a production line segment.


2001 ◽  
Vol 7 (6) ◽  
pp. 543-578 ◽  
Author(s):  
S.-Y. Chiang ◽  
C.-T. Kuo ◽  
S. M. Meerkov

The bottleneck of a production line is a machine that impedes the system performance in the strongest manner. In production lines with the so-called Markovian model of machine reliability, bottlenecks with respect to the downtime, uptime, and the cycle time of the machines can be introduced. The two former have been addressed in recent publications [1] and [2]. The latter is investigated in this paper. Specifically, using a novel aggregation procedure for performance analysis of production lines with Markovian machines having different cycle time, we develop a method for c-bottleneck identification and apply it in a case study to a camshaft production line at an automotive engine plant.


2019 ◽  
Vol 69 (4) ◽  
pp. 7-32
Author(s):  
Arkadiusz Woźniak

AbstractMaintaining a stable carbon dioxide content below the established CTQ1 requirements in the process of obtaining breathing gas for hyperbaric oxygen conditions is essential for the safety of underwater work. This article discusses the subject of validation of a selected measuring system for on-line control of the breathing gas production process and describes the application of multidimensional sensory systems to control critical parameters of the production process in production systems intended for intensive use away from supply facilities. In this case, the on-line contamination measurement option should be considered2. Monitoring of the analysed process from the point of view of its ability to minimise its variability should be oriented towards measuring the input or process values in such a way as to prevent the occurrence of potential defects already at the production stage. The assessment of the CCS - Carbon Dioxide Control System3 selected for testing, designed to control the carbon dioxide content, was performed in DUWT PNA4 for the DGKN - 120 complex compressed air supply system5. The system evaluation was conducted using MSA6 procedures and methods of SPC7.


MRS Bulletin ◽  
1989 ◽  
Vol 14 (6) ◽  
pp. 24-27 ◽  
Author(s):  
Diran Apelian

The main concept of intelligent materials processing systems is to have online control during processing. Successful implementation of on-line control of materials processing from the total manufacturing point of view involves full integration of design, procurement, control of incoming components, manufacture, assembly, handling, packaging, and distribution.There are three primary concerns if on-line control of materials processing is to be successful:1. Definitive understanding of the process. Process models need to be developed which will bring forth an understanding of the processing variables.2. Sensors that can interrogate the processes in a manner that allows for process control. Sensing is needed throughout the processing steps so that one can determine and measure various indices and the significant parameters … as borne out by physical and mathematical modeling.3. Armed with the above, process controls are established to compare the on-line feedback obtained from sensors with the process models. When deviations are observed, measures are taken to change the processing variables so that the operation will yield a “quality” product. Intrinsic to process control is a clear definition of the properties required at the end of individual steps and the relation of the intermediate properties to those specified for the material when the total processing is completed. In fact, only in the light of a definition of the properties and the processes is it possible to define the parameters that can be monitored for on-line control.


2006 ◽  
Vol 2006 ◽  
pp. 1-24 ◽  
Author(s):  
A. B. Hu ◽  
S. M. Meerkov

Lean buffering is the smallest buffer capacity necessary to ensure the desired production rate of a manufacturing system. In this paper, analytical methods for selecting lean buffering in serial production lines are developed under the assumption that the machines obey the Bernoulli reliability model. Both closed-form expressions and recursive approaches are investigated. The cases of identical and nonidentical machines are analyzed. Results obtained can be useful for production line designers and production managers to maintain the required production rate with the smallest possible inventories.


2020 ◽  
Vol 8 ◽  
pp. 1-16
Author(s):  
Natalia López-Cortés

Lexical ambiguity takes place when a word has more than one meaning. This phenomenon could therefore lead to multiple difficulties in the processing of information; however, speakers deal almost effortlessly with ambiguous units on a daily basis. In order to understand how ambiguous items are processed by speakers, a clear synchronic definition of homonymy and polysemy is needed. In this paper a methodology to gather subjective information about ambiguous words and the relation within their meanings is proposed. Based on this methodology, a corpus of Spanish stimuli is being developed: this corpus consists of words classified as monosemic, homonymous and polysemous via the subjective interpretation of Spanish speakers. This corpus could be used to conduct experimental tasks to determine the behaviour in on-line processing of items with more than one meaning, in order to later design appropriate methods of approaching this complex phenomenon from the point of view of Psycholinguistics.


Author(s):  
Celia Helena de Pelegrini Della Méa ◽  
Clides Aliande Loreto Pereira

Considerando a pertinência de práticas orais no ambiente escolar e entendendo que o oral é um saber de referência que necessita legitimidade, elabora-se esta pesquisa que se define como uma tentativa de conferir ao oral um procedimento de avaliação da aprendizagem comparável à do texto escrito. Com esta proposição se elege o gênero entrevista radiofônica que, como um objeto de ensino e aprendizagem, consiste em “fazer falar”, ou seja, um entrevistador (aluno) busca informações sobre um problema ou questão em um entrevistado (expert) e isso, na concepção de Dolz e Schnewuly (2004), servirá para comunicar/informar a terceiros. Seguindo essa noção se busca estabelecer e entender critérios para avaliação de atividades com esse gênero oral em ambientes de ensino. Para isso, aplicou-se um formulário on-line a vinte alunos do Ensino Fundamental II, da Escola de Ensino Fundamental João XXIII – São Sepé/RS, com 12 critérios previamente estabelecidos, no intuito de entender o ponto de vista de alunos sobre esse gênero. Como resultados se teve a definição de quatro possíveis critérios apontados como muito relevantes pelos participantes, a saber: 1) Observância de papéis sociais de cada participante; 2) Planejamento prévio da interação comunicativa; 3) Capacidade de incitar/promover a fala do outro; 4) Respeito às trocas de turno. Palavras-chave: Oralidade. Ensino. Avaliação. AbstractConsidering the pertinence of oral practices at the school environment, and understanding that the oral one is a reference knowledge which needs legitimacy,  this research was elaborated, that defines itself as an attempt to confer to the oral practice an evaluation procedure of the learning comparable to that of the written text. With this proposition, it was chosen the radiophonic interview genre which, as a teaching and learning object, consists of “talking”, that is, an interviewer (student) will seek information on an issue or question from an interviewee (expert) and this, in Schnewuly and Dolz’s (2004) conception, will serve to communicate/inform third parties. Following this notion, it was sought  to establish and understand criteria for the evaluation of activities with this oral genre in teaching environments. For this purpose, an online form was applied to twenty students from the Elementary School II-  João XXIII Elementary School - São Sepé/RS, with twelve previously established criteria, in order to understand the students’ point of view about this genre. As results, there was the definition of four criteria pointed out as very relevant by the participants: 1) Observance of the social roles of each participant; 2) Prior planning of the communicative interaction; 3) Ability to encourage/promote the speech of the other; 4) Respect for shift alternation. Keywords: Orality. Teaching. Evaluation.


2006 ◽  
Vol 2006 ◽  
pp. 1-30 ◽  
Author(s):  
Shu-Yin Chiang

This paper develops the procedure for the analysis of the production systems with quality control devices. The evaluation of the production system requires an expression for the system performance measures as functions of the machine and buffer parameters. This paper presents a method for evaluating these functions and illustrates their practical utility using a case study at a production plant.


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