scholarly journals Using Computer Simulation Method to Improve Throughput of Production Systems by Buffers and Workers Allocation

2015 ◽  
Vol 6 (4) ◽  
pp. 60-69 ◽  
Author(s):  
Sławomir Kłos ◽  
Peter Trebuna

Abstract This paper proposes the application of computer simulation methods to support decision making regarding intermediate buffer allocations in a series-parallel production line. The simulation model of the production system is based on a real example of a manufacturing company working in the automotive industry. Simulation experiments were conducted for different allocations of buffer capacities and different numbers of employees. The production system consists of three technological operations with intermediate buffers between each operation. The technological operations are carried out using machines and every machine can be operated by one worker. Multi-work in the production system is available (one operator operates several machines). On the basis of the simulation experiments, the relationship between system throughput, buffer allocation and the number of employees is analyzed. Increasing the buffer capacity results in an increase in the average product lifespan. Therefore, in the article a new index is proposed that includes the throughput of the manufacturing system and product life span. Simulation experiments were performed for different configurations of technological operations.

2011 ◽  
Vol 299-300 ◽  
pp. 1279-1282
Author(s):  
Xiu Chunb Wu ◽  
Kun Li ◽  
Bo Wang ◽  
Xue Shenc Su

Computer simulation method is used to study the relations of airbag effect and occupant position. By changing the position of 50% dummy model to achieve the purpose of changing the position between airbag and occupant, three kinds of simulation test are made, and the simulation results are analyzed and compared. It is shown that between the belted occupant and airbag exists such a position or distance, at which the injury to occupant is the smallest when the traffic accident happens.


BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6752-6765
Author(s):  
Roman Bambura ◽  
Erika Sujová ◽  
Helena Čierna

Computer simulation methods are currently used to simulate production processes and optimize production systems. Computer simulation is one of the most effective tools for implementation of Industry 4.0 principles in industrial practice. This research focused on the optimization of production processes in furniture production using simulation, which is an innovative method of production optimization for furniture manufacturers. The aim of this research was to improve the production system of Slovak furniture manufacturing enterprise by creating a discrete event simulation model of production based on the analysis of its current state. Improvement indicators are specific parameters of the production system, which primarily include material flow, productivity, and workload utilization. First, with the use of Tecnomatix Plant Simulation software and the collected real production data, the original production system processes were simulated and analyzed. Second, the incorporation of more powerful devices was proposed to improve the production line. Third, the proposed improvements were simulated and analyzed. The result of this research was a statistical comparison of the parameters of the current production line and the proposed production improvements.


2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Jing Huang ◽  
Qing Chang ◽  
Jorge Arinez

Abstract In production systems, the buffer capacities have usually been assumed to be fixed during normal operations. Inspired by the observations from the real industrial operations, a novel concept of Adaptive Buffer Space (ABS) is proposed in this paper. The ABS is a type of equipment, such as movable racks or mobile robots with racks, which can be used to provide extra storage space for a production line to temporarily increase certain buffers’ capacities in a real-time fashion. A good strategy to assign and reassign the ABS can significantly improve real-time production throughput. In order to model the production systems with changing buffer capacities, a data-driven model is developed to incorporate the impact of buffer capacity variation in system dynamics. Based on the model, a real-time ABS assignment strategy is developed by analyzing real-time buffer levels and machine status. The strategy is demonstrated to be effective in improving the system throughput. An approximate dynamic programming algorithm, referred to as ABS-ADP, is developed to obtain the optimal ABS assignment policy based on the strategy. Traditional ADP algorithms often initialize the state values with zeros or random numbers. In this paper, a knowledge-guided value function initialization method is proposed in ABS-ADP algorithm to expedite the convergence, which saves up to 80% computation time in the case study.


2007 ◽  
Vol 124-126 ◽  
pp. 1613-1616
Author(s):  
Xiao Ning Zhang ◽  
Qing Wang

This paper presents a simulation method on shielding effectiveness(SE). The method is completely general and able to optimize shielding materials. We found a sandwich structure that it can efficiently shield plane wave, using this simulation method. The relationship of film thickness and its skin depth was investigated in this study. Two-dimensional curves and three-dimensional graphs were calculated by tri-layer SE formulas. A sandwich structure, which is 3μm iron-brass-iron films, is capable of excellent shielding properties: the SE is between -73dB and -100dB in the frequency range of 1MHz~10MHz. Another sandwich structure with 12μm thickness of brass-iron-brass films can offer -680dB shielding attenuation. Simulation experiments indicate that sandwich films with diamagnetic and ferromagnetic layers have outstanding contribution on SE.


2017 ◽  
Vol 8 (3) ◽  
pp. 40-49 ◽  
Author(s):  
Sławomir Kłos ◽  
Peter Trebuna

AbstractThis paper proposes the application of computer simulation methods in order to analyse the availability of resources, buffers and the impact of the allocation of workers on the throughput andwork-in-progressof a manufacturing system. The simulation model of the production system is based on an existing example of a manufacturing company in the automotive industry. The manufacturing system includes both machining and assembly operations. Simulation experiments were conductedvis-à-visthe availability of the different manufacturing resources, the various allocations of buffer capacities and the number of employees. The production system consists of three manufacturing cells –each cell including two CNC machines– and two assembly stations. The parts produced by the manufacturing cells are stored in buffers and transferred to the assembly stations. Workers are allocated to the manufacturing cells and assembly stations, but the number of workers may be less than number of workplaces and are thus termed ‘multi-workstations’. Using computer simulation methods, the impact of the availability of resources, the number of employees and of the allocation of buffer capacity on the throughput andwork-in-progressof the manufacturing system is analysed. The results of the research are used to improve the effectiveness of manufacturing systems using a decision support system and the proper control of resources. Literature analysis shows that the study of the impact of buffer capacities, availability of resources and the number of employees on assembly manufacturing system performance have not been carried out so far.


2015 ◽  
Vol 21 (1) ◽  
pp. 70-88 ◽  
Author(s):  
Binghai Zhou ◽  
Jiadi Yu ◽  
Jianyi Shao ◽  
Damien Trentesaux

Purpose – The purpose of this paper is to develop a bottleneck-based opportunistic maintenance (OM) model for the series production systems with the integration of the imperfect effect into maintenance activities. Design/methodology/approach – On the analysis of availability and maintenance cost, preventive maintenance (PM) models subjected to imperfect maintenance for different equipment types are built. And then, a cost-saving function of OM is established to find out an optimal OM strategy, depending on whether the front-bottleneck machines adopt OM strategy or not. A numerical example is given to show how the proposed bottleneck-based OM model proceeded. Findings – The simulation results indicate that the proposed model is better than the methods to maintain the machines separately and the policy to maintain all machines when bottleneck machine reaches its reliability threshold. Furthermore, the relationship between OM strategy and corresponding parameters is identified through sensitivity analysis. Practical implications – In practical situations, the bottleneck machine always determines the throughput of the whole series production system. Whenever a PM activity is carried out on the bottleneck machine, there will be an opportunity to maintenance other machines. Under such circumstances, findings of this paper can be utilized for the determination of optimal OM policy with the objective of minimizing total maintenance cost of the system. Originality/value – This paper presents a bottleneck-based OM optimization model with the integration of the imperfect effect as a new method to schedule maintenance activities for a series production system with buffers. Furthermore, to the best of the knowledge, this paper presents the first attempt to considering the bottleneck constraint on system capacity and diverse types of machines as a means to minimize the maintenance cost and ensure the system throughput.


Author(s):  
Rafal Shakir Salloom ◽  
Prof. Dr. Manal Jabbar Sorour

The world is moving towards greening business in general and production systems in particular. At the same time, economic units seek to enhance their productivity and find any variables that can contribute to improving their elements. Economic units should not ignore the green dimension of cost management techniques because of its role in containing the green dimension of the production system and the product. However the few researches dealt with the subject of the green kaizen showed its role in reducing costs and improving the environment. Those researches did not address its contribution to raising the level of productivity. Productivity is an important indicator of economic units that expresses their level of success and progress, and they need new dimensions such as the green dimension to raise their levels. Here the research shows that Green Kaizen works to reduce the amount of waste, reduce costs, and improve the environmental aspects of the production system, which enhances the system's input of materials and energies and increases good output. The research aims to present the theoretical dimensions of the variables, link them in an analytical method, and explain the relationship between them. The research provides an opportunity for future research to apply green kaizen in many industrial or service fields and to use other tools to support continuous environmental improvements.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Eishi Chiba

The standard manufacturing system for Flat Panel Displays (FPDs) consists of a number of pieces of equipment in series. Each piece of equipment usually has a number of buffers to prevent collision between glass substrates. However, in reality, very few of these buffers seem to be used. This means that redundant buffers exist. In order to reduce cost and space necessary for manufacturing, the number of buffers should be minimized with consideration of possible collisions. In this paper, we focus on an in-line system in which each piece of equipment can have any number of buffers. In this in-line system, we present a computer simulation method for the computation of the probability of a collision occurring. Based on this method, we try to find a buffer allocation that achieves the smallest total number of buffers under an arbitrarily specified collision probability. We also implement our proposed method and present some computational results.


Author(s):  
David J. Lobina

Recursion, or the capacity of ‘self-reference’, has played a central role within mathematical approaches to understanding the nature of computation, from the general recursive functions of Alonzo Church to the partial recursive functions of Stephen C. Kleene and the production systems of Emil Post. Recursion has also played a significant role in the analysis and running of certain computational processes within computer science (viz., those with self-calls and deferred operations). Yet the relationship between the mathematical and computer versions of recursion is subtle and intricate. A recursively specified algorithm, for example, may well proceed iteratively if time and space constraints permit; but the nature of specific data structures—viz., recursive data structures—will also return a recursive solution as the most optimal process. In other words, the correspondence between recursive structures and recursive processes is not automatic; it needs to be demonstrated on a case-by-case basis.


2021 ◽  
Vol 13 (6) ◽  
Author(s):  
Tabea J. Koch ◽  
Patrick Schmidt

AbstractBirch tar is the oldest manmade adhesive dating back to the European Middle Palaeolithic. Its study is of importance for understanding the cognitive capacities and technical skills of Neanderthals and the aceramic production systems employed in the European Palaeolithic and Mesolithic. Several methods may have been used to make birch tar, the most common proposition being dry distillation in oxygen-depleted atmospheres. One of the major impediments for our understanding of the conditions employed to make Neanderthal birch tar, and ultimately the technique used, is that it remains unknown at which temperatures exactly birch tar forms. The relationship between heating duration and tar formation is also unknown. To address these questions, we conduct a laboratory heating experiment, using sealed glass tubes and an electric furnace. We found that birch tar is only produced at a narrow temperature interval (350 °C and 400 °C). Heating times longer than 15 min have no effect on the quantity of tar produced. These findings, notwithstanding previous propositions of necessarily long heating times and larger tolerances for temperature, have important implications for our understanding of the investment in time needed for Palaeolithic birch tar making.


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