Throughput Of Line Research Articles

An Adapted Variable Neighborhood Search based algorithm for the cyclic multi-hoist design and scheduling problem

This paper studies both the design and the cyclic scheduling of multi-hoist treatment surface facilities. Former research have always assumed that the design of the production line is already available with a fixed material handling fleet size. However, in this study, the number of hoists is considered as a decision variable of the problem. The latter is then bi-objective and called the Cyclic Hoist Design and Scheduling Problem (CHDSP). The optimization objective is to determine an optimal cyclic schedule for each possible number of hoists that minimizes the cycle time and thus maximizes the line throughput rate. The achieved results will contribute to building a decision support system that will enable to choose the required number of transportation resources for the production line regarding both aims of productivity maximization and cost savings. An original encoding approach is proposed that both assigns a number of hoists to the line and generates their move sequences, which are evaluated thanks to a mixed integer linear programming model. A rich and well-structured solving algorithm based on variable neighborhood search is developed and adapted to solve efficiently the whole problem. It is also improved by a backtrack procedure that further enhances the findings. Computational experiments are conducted on benchmark problems and demonstrate the high performance and effectiveness of the proposed algorithm that was, in most cases, even able to reach the optimal solutions.

A note on “Algorithms for the Calzedonia workload allocation problem”

Battarra et al. recently proposed a novel assembly line balancing problem with applications to the apparel industry, where the tasks are performed in a fixed order. To solve the problem, one has to assign workers and tasks to the workstations with the objective of maximising the throughput of the assembly line. In this paper, we provide dynamic programming formulations for the general problem and some special cases. We then use these formulations to develop an exact solution approach that optimally solves the instances in Battarra et al. within seconds.

Continuous Mixing Technology: Characterization of a Vertical Mixer Using Residence Time Distribution.

Continuous powder mixing technology (CMT) application during continuous direct compression has emerged as a leading technology used in the development and manufacture of solid oral dosage forms. The critical quality attributes of the final product are heavily dependent on the performance of the mixing step as the quality of mixing directly influences the drug product quality attributes. This study investigates the impact of blend material properties (bulk density, API particle size distribution) and process parameters (process throughput, hold up mass and impeller speed) on the mixing performance. Mixing of the blend was characterized using the Residence Time Distribution (RTD) of the process by trending the outlet stream of the mixer using a near-infrared (NIR) probe after the injection of a small mass of tracer at the inlet stream. The outcomes of this study show that the RTDs of the mixer with throughput ranging between 15 and 30kg/h; impeller speed ranging between 400 and 600rpm and hold up mass (HUM) ranging between 500 and 850g can be described by a series of two ideal Continuous Stirred Tank Reactors (CSTRs) with different volumes, and correspondingly, different mean residence times. It is also observed that the mixing is mainly occurring in the lower chamber of the CMT and the normalized RTDs of the mixer are similar across the range of process conditions and material attributes studied. The results also showed that the formulation blend with different API particle sizes and bulk properties, like bulk density and flowability, provide insignificant impact on the mixing performance. The CMT allows independent selection of target set points for HUM, impeller rotational speed and line throughput and it shows great robustness and flexibility for continuous blending in solid oral dose manufacturing.

Features of determining capacity on double-way lines when passing high-speed passenger trains

Development of proposals for adapting the existing methodology for calculating the available throughput to the operating conditions of the railways of Uzbekistan, taking into account the factors that ensure traffic safety when passing high-speed passenger trains. Methods: Grapho-analytical approaches and a comparative analysis method were used to determine the throughput of railway lines with mixed train traffic. Results: The main factors influencing the capacity of lines, advantages and disadvantages for each existing method for determining the capacity of railway lines are given. To assess the quality of transportation processes on railway lines, experimental train schedules were constructed. Based on the analysis of their indicators, a formula was proposed for calculating the throughput on double-track lines when passing high-speed passenger trains. Practical significance: The application of the proposed methodology improves the calculations of the performance indicators of sections with an unparalleled train schedule.

Data-Enabled Real-Time Modeling for Production Systems with Variable Cycle Time

Cycle time is one of the essential parameters that could lead to a significant improvement on the productivity of a manufacturing system. In the traditional manufacturing systems, cycle time for each station is recommended by the vendor and determined based on production line design and through repeated experiments and simulations. Once determined, the cycle time is typically unchangeable during the production operation. Nowadays, the development of smart manufacturing enables a flexible production operation, and the cycle time of each machine can be made changeable to quickly respond to market demand fluctuation and to further improve the system efficiency. To evaluate the performance of a serial production line with variable cycle time, a novel data-enabled manufacturing system model is developed, in which sensor data inputs are allowed and cycle times are modeled as input variables. In addition, an opportunity window concept, which has been studied in the previous study and has been treated as a real-time system status measurement, is extended to the variable cycle time scenario. Numerical case studies are presented to validate the fidelity of the data-enabled model and demonstrate the influence of variable cycle time of individual machines on the production line throughput and the opportunity windows.

Establishing Line Throughput with Regard to the Operation of Longer Trains

The paper deals with the issue of capacity of railway infrastructure in connection with the operation of freight trains with a length of up to 740 m. First, the facts in the field of the arrangement of railway infrastructure elements that may have a potential impact on capacity will be listed. Subsequently, there will be proposed indicators that can be used for detection of possible changes in capacity, due to the operation of trains with a length of 740 m. In the last phase, several simulation scenarios will be realized in the OpenTrack program. In these scenarios 740 m long trains will be deployed on the selected routes of the model timetable. The simulation results will eventually be evaluated using previously proposed indicators.

Optimization of Dispensing Parameter to Speed up the Die Attach Throughput

Driven by the company vision to become a high-volume manufacturing (HVM), increasing throughput in the manufacturing line is critical to meeting market demands. The ever-growing demand for integrated circuits in part requires additional capital investment to purchase new equipment such as die bonders to support the new requirement. Making the best of existing resources is often the most common approach to deal with this challenge. Defining the correct method and making the most of the secondary parameters necessary to increase the bonding speed by means of a creative analysis that made this article interesting. The objective of this project is to boost productivity by maximizing UPH to improve the epoxy writing process at Attach, which is a bottleneck area. Optimization of the dispensing sequence and the dispensing direction to improve and speed up the epoxy dispensing process unit per hour.

Efficiency of implementation of interval traffic regulation by the "virtual coupling” system on the section of the railway line in the framework of the "digital railway” project

In order to remain competitive in the world market, to maximize the needs for transportation with increasing volumes of work, to ensure the availability and quality of services provided on railway transport in the field of organizing the transportation process, it is necessary to use modern digital approaches. The article provides an assessment of the existing technology for organizing the driving of connected trains using the example of the operation of the Mariinsk - Krasnoyarsk-Vostochny section of the Krasnoyarsk railway. With the development of technology for driving connected trains, it has become possible to connect trains by means of a virtual coupling, which does not imply physical coupling of trains using an automatic coupling device, while the trains are in a constant, equidistant, position from each other. To analyze the efficiency of organizing the driving of double trains in the "Virtual Coupling" mode, the authors of the article built train schedules with an interval for double trains of four minutes, and in the future with an interval of two minutes. The calculation of the main indicators of the train schedule and the line capacity has been made. The calculation revealed that with the introduction of the technology of interval regulation according to the "Virtual Coupling" system, the required throughput of the railway line increases by 19.05% relative to the existing traffic schedule with the use of double trains. The use of trains with "Virtual Coupling" on the Mariinsk - Krasnoyarsk-Vostochny section is preferable, since their use reduces losses in the traction network, power consumption and other parameters of the traction network, and the voltage at the locomotive current collectors is significantly higher than when using connected trains. The economic effect from the use of this technology for organizing the work of the Mariinsk-Krasnoyarsk Vostochny section will amount to 894.14 thousand rubles per year.

The effectiveness of implementation grid energy storage in power supply systems

The most important indicator of the reliability of the power system is the quality of the supplied electricity. The quality of power supply depends on many parameters, the maintenance of which at a given level (voltage, frequency deviation) is carried out using various devices. One of these devices is grid energy storages, allowing you to even out schedules of daily, weekly, seasonal and annual electrical loads. Energy storage devices can also act as an uninterrupted power supply for substations and electrical grids, provide increased dynamic and static stability, and increase the transmission line throughput. However, the use of energy storage to eliminate irregularities in the schedule of generating capacities is not a traditional way. When using energy storage devices, the most important task is to determine their total capacity and energy intensity, as well as the location of the storage devices in the energy system and the economic feasibility of these measures. The criterion for the placement of storage devices is to reduce energy losses when using grid energy storages. In the course of the research, graphic and analytical dependencies of the distribution grid loads were obtained before and after the placement of grid energy storages, depending on the average daily active load.

Simulation metamodeling approach to complex design of garment assembly lines.

The today's competitive advantage of ready-made garment industry depends on the ability to improve the efficiency and effectiveness of resource utilization. Ready-made garment industry has long historically adopted fewer technological and process advancement as compared to automotive, electronics and semiconductor industries. Simulation modeling of garment assembly line has attracted a number of researchers as one way for insightful analysis of the system behaviour and improving its performance. However, most of simulation studies have considered ill-defined experimental design which cannot fully explore the assembly line design alternatives and does not uncover the interaction effects of the input variables. Simulation metamodeling is an approach to assembly line design which has recently been of interest to researchers. However, its application in garment assembly line design has never been well explored. In this paper, simulation metamodeling of trouser assembly line with 72 operations was demonstrated. The linear regression metamodel technique with resolution-V design was used. The effects of five factors: bundle size, job release policy, task assignment pattern, machine number and helper number on throughput of the trouser assembly line were studied. An increase of the production throughput by 28.63% was achieved for the best factors' setting of the metamodel.

A dynamic scheduling mechanism of part feeding for mixed-model assembly lines based on the modified neural network and knowledge base

Inspired by the manufacturing costs proportion of part feeding in automotive mixed-model assembly lines (MMALs) being up to 20–35%, this paper takes the dynamic scheduling of part feeding for automotive MMALs as a crucial and complex problem. Therefore, a dynamic scheduling mechanism basing on the knowledge base (KB) and fruit fly optimization algorithm (FOA) with variable step sizes and logistic chaos (VSCFOA)-enhanced general regression neural network (VSCFOA-GRNN) is proposed to tackle the real-time part feeding scheduling problem of tow trains under the dynamic manufacturing system. A mathematical model is developed to illustrate the problem, where the throughput of the assembly line and the material delivery distance are determined as components of the objective function. Subsequently, samples of the MMAL are generated by the plant simulation software and used to train the VSCFOA-GRNN model off-line. Afterward, the trained model and KB are adopted in the real-time scheduling process to determine the optimal scheduling rule combination. Finally, the effectiveness, feasibility and accuracy of the novel scheduling mechanism are validated by computational results, especially in dynamic scheduling processes. It can cope well with changes in the dynamic environment, thus effectively realizing the higher productivity of assembly lines and better system performance.

Economic load intervals for selecting 10 kV cable cross-sections for agricultural consumers

District electric networks for agricultural purposes are characterized by a constant increase in loads. In these conditions, it is important to choose the correct parameters of power lines and, first of all, the cross-sections of overhead lines (overhead lines) and cable lines. There are technical possibilities to increase the capacity of overhead power lines, which can be carried out in the following ways: voltage regulation; reactive power compensation; replacement of existing wires with wires of a larger cross-section; load unbundling; transfer of the network to an increased voltage. Increasing the capacity of cable transmission lines by all of these methods is not possible due to their design features. Thus, due to the difficulties of increasing the capacity of cable lines and dynamically developing networks, the problem of choosing the optimal cable cross-section for lines with an ever-increasing load is becoming more acute. Currently, agricultural distribution electric networks have a constant increase in load. In these conditions, the correct choice of the parameters of cable lines and the residential cable line is of great importance. Due to the complexity of increasing the throughput of cable lines and dynamic networks, problems arise with the choice of optimal paths for wires and residential cables for agricultural lines.

Manufacturing System Modeling and Performance Analysis of Mineral Water Production Line using ARENA Simulation

Today’s scenario all manufacturing organizations are moving rapidly to adopt new process modeling, performance analysis through simulation, in order to design a new costeffective system. Organizations made several changes in their manufacturing systems to increase profit and to sustain their significance in global markets. Simulation modeling is a well accepted technique for improving process performance. In this study, the mineral water company operates the production line with less throughput, long cycle times, frequent machine failures and insufficient utilization of its resources. A simulation model is developed for the successful bottling and packaging of the production line by using Arena simulation software. The model is developed for AMWSC packaging process for returnable glass bottle Production Line. This model eliminates the bottlenecks in production line and provides optimal performance. By applying Effective Preventive Maintenance Strategy, the production line throughput is increased from 21.12% to 54.03% and the cycle time is reduced by 33.33%.

On the process of interaction of technical stations and hauls when passing train flows

The issues of traffic intensification on railway lines are always of high relevance. The throughput and carrying capacity of the railway line is determined by calculation on the basis of analytical dependencies, however, as in previous periods of the development of railway transport, currently, certain directions experience serious difficulties in passing train flows. At the same time, accepted calculated indicators of the throughput capacity of such lines do not allow to objectively determine the causes of difficulties in passing train flows and to develop the necessary solutions to overcome them. Railway infrastructure can be divided into several enlarged elements: sections, inlet and outlet necks of technical stations, pick-up and drop-off parks. This article does not consider power supply devices, locomotive facilities, performance of which changes less dynamically. Based on the research and experience in organizing the passage of train flows on one of the busiest railway lines of the TransBaikal Railway, the authors attempted to identify the main factors affecting the throughput and carrying capacity of freight-intensive directions, as well as to justify the need for integrated approaches in analyzing the throughput of a railway line with the interconnection of its main constituent elements and the definition of limiting. The article discusses in dynamics the interaction and mutual influence of the indicators of the main elements of the railway lines, as well as the analytical dependencies that allow to interlink the indicators that determine the throughput of individual elements of the railway line during their interaction. The results of analytical calculations are consistent with statistical indicators of the operation of railway lines in real operating conditions. With this in mind, significant dependencies between stages and technical stations were determined.

A New Cobot Deployment Strategy in Manual Assembly Stations: Countering the Impact of Absenteeism

Abstract This paper discusses a new strategy for deploying cobots in assembly lines having manual stations. The paper first presents the contribution of absenteeism to the temporary appearance of bottleneck stations and the resulted lost throughput. It then delineates some barriers and obstacles of cobots’ deployment in these stations. Finally, it discusses the advantages of employing a cobot-specialist for a defined segment of the assembly line. The suggested role of the cobot-specialist is to quickly find ways in which a cobot will alleviate the work of a temporary workers filling positions of absentees. Such replacement workers are in their early stages of their learning curve, and are considerably slow, with high chances of becoming a bottleneck. A bottleneck station dictates the pace of the whole line and reducing its cycle-time, increases the throughput of the whole line. Thus, the suggested approach prevents throughput losses due to absenteeism. Having a line-segment specialist that is familiar with the various stations in his/her segment ensures both having some pre-prepared schemes of cobot deployment for each station, and the ability of rapid installation of the cobot. Moreover, replacement workers typically are too busy to deal with the cobot’s installation or operation. The approach is validated using ARENA simulation scenarios for various line segments.

Buffer allocation, equipment selection and line balancing optimisation in unreliable production lines

This paper presents an integrated optimisation model to simultaneously solve buffer allocation, equipment selection and line balancing problems in unreliable production line systems. The considered unreliable serial production line consists of m workstations and m − 1 intermediate buffers. The objective is to maximise the system throughput level. A decomposition method is used to estimate the production line throughput. The decision variables in the formulated optimal design problem are buffer levels, types of equipment and the sets of tasks assigned to the workstations. An efficient algorithm, based on the nonlinear threshold accepting algorithm (NLTA) is proposed to solve this problem. The efficiency of the proposed approach is compared to existing algorithms and first tested on a simple assembly line balancing type-2 problem (SALB-2). Here the objective is to minimise the cycle time with a fixed number of workstations. In the second numerical experiment, the integrated model is solved using the NLTA, and its performance is compared to that of the great deluge algorithm (GDA) through several numerical examples. [Received: 9 June 2018; Revised: 15 September 2018; Revised: 18 April 2019; Accepted: 2 August 2019]

Development of Optimization Sensitivity Equation by Multiple Linear Regression and Correlation Analysis

Gas pipeline pressure-flow problem are affected by varieties of factors notably frictional pressure drop and other pressure drops components. These problems inevitably result in the reduction of the operating efficiency of gas pipelines by virtue of reduction in the line throughput and increased pressure drop along the line. It has been established that increased pressure drop will ultimately lead to increased pump power as well as higher cost of design, construction and operations of gas pipelines. These prevailing factors prompts the need to ascertain the stability and reliability of the optimal flow results. The develop sensitivity model prediction was hinged around ∆L/L (%) being zero. It invariably confirmed that the results of optimal flow capacity are more sensitive to changes in upstream and downstream pressures. It was least sensitive to pressure gradients. The governing conditions being that changes in pipe diameter, ∆D/D (%) and flow capacity, ∆Q/Q (%) were in the order of 5%.

Development of Optimization Sensitivity Equation by Multiple Linear Regression and Correlation Analysis

Gas pipeline pressure-flow problem are affected by varieties of factors notably frictional pressure drop and other pressure drops components. These problems inevitably result in the reduction of the operating efficiency of gas pipelines by virtue of reduction in the line throughput and increased pressure drop along the line. It has been established that increased pressure drop will ultimately lead to increased pump power as well as higher cost of design, construction and operations of gas pipelines. These prevailing factors prompts the need to ascertain the stability and reliability of the optimal flow results. The develop sensitivity model prediction was hinged around ?L/L (%) being zero. It invariably confirmed that the results of optimal flow capacity are more sensitive to changes in upstream and downstream pressures. It was least sensitive to pressure gradients. The governing conditions being that changes in pipe diameter, ?D/D (%) and flow capacity, ?Q/Q (%) were in the order of 5%.

Spare parts or buffer? How to design a transfer line with unreliable machines

In this paper, we study the design of a transfer line consisting of two unreliable machines in series and an interstage buffer. In addition to the buffer capacity, the system planner can decide on the inventory levels for spare parts in order to reduce the time to repair failed machines. Our work aims to find cost-efficient combinations of buffer capacity and spare parts inventory. We formulate discrete-time Markov chains for two different situations in order to analyse the trade-off between buffer capacity, spare parts inventory and throughput. By means of numerical examples, we illustrate that the effect of a spare part on the efficiency of a transfer line is much greater than the effect of additional buffer places. We conclude that it is necessary to optimize buffer capacity and spare parts inventory levels simultaneously. For systems with identical critical components, our results show that not only is there a pooling effect of safety stocks but also between the buffer places and spare parts inventory levels. We conclude that planners who select a standardised component for the system design and optimize spare parts levels as well as buffer capacity can significantly reduce costs or increase the throughput of a transfer line.

Product Segmentation and Sustainability in Customized Assembly with Respect to the Basic Elements of Industry 4.0

Sustainable manufacturing is not just about manufacturing, but also products and services. In the area of custom production processes, there may also be circumstances of organizational management where compliance with labor productivity and the due-date principle is problematic. Similar products with different operating times cause the throughput of assembly lines to slow down, increase number of works in progress (WIP), and increase productivity waste. It is possible to reduce this impact through various productivity-enhancing methods and innovations. This paper presents an innovative approach to product segmentation in the assembly phase of custom manufacturing, and a proposal for a new segmentation procedure that will allow significantly better integration of products into existing assembly processes without negatively impacting the company’s production indicators. The scientific problem was defined on the basis that extending existing segmentation by the third dimension of operating times allows products in MTO (made to order) environments to be divided into families with approximately equal operating times. This will increase assembly efficiency in existing medium to large companies without large investments in the development and adaptation of assembly process products. The contributions of this work relate mainly to simple adaptations to existing processes in medium-sized businesses. The proposed solution respects the basic elements of Industry 4.0.