Application of Petri nets towards improved utilization of machines in job shop manufacturing environments

2017 ◽  
Vol 28 (2) ◽  
pp. 169-188 ◽  
Author(s):  
Pravin S. Pachpor ◽  
R.L. Shrivastava ◽  
Dinesh Seth ◽  
Shaligram Pokharel
Keyword(s):  
Petri Nets ◽  
Material Handling ◽  
Job Shop ◽  
Work Force ◽  
General Purpose ◽  
The Body ◽  
Scheduling Problems ◽  
Job Shops ◽  
Content Type ◽  
Machine Utilization

Purpose The purpose of this paper is to demonstrate the use of Petri nets in a job shop setup for the improvement in the utilization of machines. Design/methodology/approach The study discusses concepts such as reachable state, token and matrix equations set, and demonstrates the improvements in machines’ utilization in a job shop. It makes use of algorithms to generate reachable markings to obtain utilization. The study not only describes the application of theory, but also extends the body of knowledge on Petri nets and job shops. Findings In this study, machines’ utilization has been studied in a job shop with six machines and eight products. The study finds that substantial utilization improvement in job shop set up can be obtained through the application of Petri nets. The study also exposes that Petri nets are mostly used for machines, jobs and tools scheduling problems, but its use in machines’ utilization is neglected. The framework and application presented here along with generalizable findings, is the first to report about machine utilization improvement in job shop manufacturing environment. Practical implications Job shops are characterized by high unit production cost, low investments, low volume and high variety, complex flows, flexible and skilled work force, general purpose machines, high material handling; resulting in poor utilization of machines. Therefore, the findings of this study can help in reducing such costs through better machine utilization. This can help in increasing the competitiveness of the companies. Originality/value The contribution of study lies in investigating and improving stage wise utilization in a job shop setup. It has never been reported before.

An integrated approach for line balancing and AGV scheduling towards smart assembly systems

2020 ◽  
Vol 40 (2) ◽  
pp. 219-234 ◽  
Author(s):  
Humyun Fuad Rahman ◽  
Mukund Nilakantan Janardhanan ◽  
Peter Nielsen
Keyword(s):  
Material Handling ◽  
Assembly Line ◽  
Computational Study ◽  
Automated Guided Vehicles ◽  
Robotic Assembly ◽  
Line Balancing ◽  
Assembly Systems ◽  
Scheduling Problems ◽  
Content Type ◽  
Smart Assembly

Purpose Optimizing material handling within the factory is one of the key problems of modern assembly line systems. The purpose of this paper is to focus on simultaneously balancing a robotic assembly line and the scheduling of material handling required for the operation of such a system, a topic that has received limited attention in academia. Manufacturing industries focus on full autonomy because of the rapid advancements in different elements of Industry 4.0 such as the internet of things, big data and cloud computing. In smart assembly systems, this autonomy aims at the integration of automated material handling equipment such as automated guided vehicles (AGVs) to robotic assembly line systems to ensure a reliable and flexible production system. Design/methodology/approach This paper tackles the problem of designing a balanced robotic assembly line and the scheduling of AGVs to feed materials to these lines such that the cycle time and total tardiness of the assembly system are minimized. Because of the combination of two well-known complex problems such as line balancing and material handling and a heuristic- and metaheuristic-based integrated decision approach is proposed. Findings A detailed computational study demonstrates how an integrated decision approach can serve as an efficient managerial tool in designing/redesigning assembly line systems and support automated transportation infrastructure. Originality/value This study is beneficial for production managers in understanding the main decisional steps involved in the designing/redesigning of smart assembly systems and providing guidelines in decision-making. Moreover, this study explores the material distribution scheduling problems in assembly systems, which is not yet comprehensively explored in the literature.

A new approach for performance assessment of parallel and non-bottleneck machines in a dynamic job shop environment

2019 ◽  
Vol 13 (4) ◽  
pp. 787-803
Author(s):  
Maurizio Faccio ◽  
Mojtaba Nedaei ◽  
Francesco Pilati
Keyword(s):  
Completion Time ◽  
Job Shop ◽  
Primary Objective ◽  
Design Parameters ◽  
Job Shops ◽  
Objective Functions ◽  
New Approach ◽  
Content Type ◽  
Decision Variables ◽  
Dynamic Job Shop

Purpose The current study aims to propose a new analytical approach by considering energy consumption (EC), maximum tardiness and completion time as the primary objective functions to assess the performance of parallel, non-bottleneck and multitasking machines operating in dynamic job shops. Design/methodology/approach An analytical and iterative method is presented to optimize a novel dynamic job shop under technical constraints. The machine’s performance is analyzed by considering the setup energy. An optimization model from initial processing until scheduling and planning is proposed, and data sets consisting of design parameters are fed into the model. Findings Significant variations of EC and tardiness are observed. The minimum EC was calculated to be 141.5 hp.s when the defined decision variables were constantly increasing. Analysis of the optimum completion time has shown that among all studied methods, first come first served (FCFS), earliest due date (EDD) and shortest processing time (SPT) have resulted in the least completion time with a value of 20 s. Originality/value Considerable amount of energy can be dissipated when parallel, non-bottleneck and multitasking machines operate in lower-power modes. Additionally, in a dynamic job shop, adjusting the trend and arrangement of decision variables plays a crucial role in enhancing the system’s reliability. Such issues have never caught the attention of scientists for addressing the aforementioned problems. Therefore, with these underlying goals, this paper presents a new approach for evaluating and optimizing the system’s performance, considering different objective functions and technical constraints.

Design and control of food job-shop processing systems

2017 ◽  
Vol 28 (3) ◽  
pp. 782-797 ◽  
Author(s):  
Stefano Penazzi ◽  
Riccardo Accorsi ◽  
Emilio Ferrari ◽  
Riccardo Manzini ◽  
Simon Dunstall
Keyword(s):  
Food Processing ◽  
Job Shop ◽  
Discrete Event ◽  
Cost Optimization ◽  
Job Shops ◽  
Content Type ◽  
Processing Equipment ◽  
Catering Industry ◽  
High Flexibility ◽  
Capacity Constrained

Purpose The food processing industry is growing with retail and catering supply chains. With the rising complexity of food products and the need to address food customization expectations, food processing systems are progressively shifting from production line to job-shops that are characterized by high flexibility and high complexity. A food job-shop system processes multiple items (i.e. raw ingredients, toppings, dressings) according to their working cycles in a typical resource and capacity constrained environment. Given the complexity of such systems, there are divergent goals of process cost optimization and of food quality and safety preservation. These goals deserve integration at both an operational and a strategic decisional perspective. The twofold purpose of this paper is to design a simulation model for food job-shop processing and to build understanding of the extant relationships between food flows and processing equipment through a real case study from the catering industry. Design/methodology/approach The authors designed a simulation tool enabling the analysis of food job-shop processing systems. A methodology based on discrete event simulation is developed to study the dynamics and behaviour of the processing systems according to an event-driven approach. The proposed conceptual model builds upon a comprehensive set of variables and key performance indicators (KPIs) that describe and measure the dynamics of the food job-shop according to a multi-disciplinary perspective. Findings This simulation identifies the job-shop bottlenecks and investigates the utilization of the working centres and product queuing through the system. This approach helps to characterize how costs are allocated in a flow-driven approach and identifies the trade-off between investments in equipment and operative costs. Originality/value The primary purpose of the proposed model relies on the definition of standard resources and operating patterns that can meet the behaviour of a wide variety of food processing equipment and tasks, thereby addressing the complexity of a food job-shop. The proposed methodology enables the integration of strategic and operative decisions between several company departments. The KPIs enable identification of the benchmark system, tracking the system performance via multi-scenario what-if simulations, and suggesting improvements through short-term (e.g. tasks scheduling, dispatching rules), mid-term (e.g. recipes review), or long-term (e.g. re-layout, working centres number) levers.

scholarly journals On Neighborhood Structures and Repair Techniques for Blocking Job Shop Scheduling Problems

Algorithms ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 242 ◽  
Author(s):  
Julia Lange ◽  
Frank Werner
Keyword(s):  
Simulated Annealing Algorithm ◽  
Job Shop ◽  
Job Shop Scheduling ◽  
Heuristic Method ◽  
General Purpose ◽  
Future Research ◽  
Scheduling Problems ◽  
Shop Scheduling ◽  
Feasible Solutions ◽  
The One

The job shop scheduling problem with blocking constraints and total tardiness minimization represents a challenging combinatorial optimization problem of high relevance in production planning and logistics. Since general-purpose solution approaches struggle with finding even feasible solutions, a permutation-based heuristic method is proposed here, and the applicability of basic scheduling-tailored mechanisms is discussed. The problem is tackled by a local search framework, which relies on interchange- and shift-based operators. Redundancy and feasibility issues require advanced transformation and repairing schemes. An analysis of the embedded neighborhoods shows beneficial modes of implementation on the one hand and structural difficulties caused by the blocking constraints on the other hand. The applied simulated annealing algorithm generates good solutions for a wide set of benchmark instances. The computational results especially highlight the capability of the permutation-based method in constructing feasible schedules of valuable quality for instances of critical size and support future research on hybrid solution techniques.

Workshop Layout Optimization Based on Genetic Algorithm

2012 ◽  
Vol 591-593 ◽  
pp. 169-173 ◽  
Author(s):  
Long Qiao ◽  
Hong Bin Yu ◽  
Jian Jun Sun
Keyword(s):  
Genetic Algorithm ◽  
Genetic Algorithms ◽  
Objective Function ◽  
Material Handling ◽  
Job Shop ◽  
Job Shops ◽  
Transfer Time ◽  
Set Up ◽  
Material Handling Costs ◽  
First Time

To shorten the transfer time of workpiece in job shop, it is necessary to optimize the equipment arrangement of job shops based on the technological process of workpiece. The objective function only considers the material handling costs, but it ignores the geometry of the workshop area utilization and so on factors. We propose and take an objective function that considers material handling costs and utilization proposed at the same time. And we set up an optimization model of facility layout is proposed and genetic algorithms is used to solve this mode1. The author brings forward the concept of carry quadrature for the first time. It is good to use this concept for the workshop in which many kinds of workpiece are produced. The result of optimal design is consonant with the desire of actual manufacture.

Evaluation of postural-assist exoskeleton for manual material handling

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Omobolanle Ogunseiju ◽  
Johnson Olayiwola ◽  
Abiola Akanmu ◽  
Oluwole Alfred Olatunji
Keyword(s):  
Range Of Motion ◽  
Material Handling ◽  
The Body ◽  
Task Completion ◽  
New Order ◽  
Body Parts ◽  
Severe Problem ◽  
Content Type ◽  
Work Related ◽  
Manual Material Handling

PurposeWork-related musculoskeletal disorders constitute a severe problem in the construction industry. Workers' lower backs are often affected by heavy or repetitive lifting and prolonged awkward postures. Exoskeletal interventions are effective for tasks involving manual lifting and repetitive movements. This study aims to examine the potential of a postural-assist exoskeleton (a passive exoskeleton) for manual material handling tasks.Design/methodology/approachFrom an experimental observation of participants, the effects of postural-assist exoskeleton on tasks and workers were measured. Associated benefits of the exoskeleton were assessed through task performance, range of motion and discomfort.FindingsFindings suggest that the exoskeleton influenced discomfort significantly, however range of motion decreased with lifting tasks. The reduced back flexion and increased hip flexion were also indicatives of the participants' responsiveness to the feedback from the exoskeleton. In addition, task completion time increased by 20%, and participants' back pain did not reduce.Research limitations/implicationsThe work tasks were performed in a controlled laboratory environment and only wearable inertia measurement units (IMUs) were used to assess the risk exposures of the body parts.Practical implicationsThis study opens a practical pathway to human-exoskeleton integration, artificial regeneration or enablement of impaired workforce and a window toward a new order of productivity scaling. Results from this study provide preliminary insights to designers and innovators on the influence of postural assist exoskeleton on construction work. Project stakeholders can be informed of the suitability of the postural assist exoskeletons for manual material handling tasks.Originality/valueLittle has been reported on the benefits and impact of exoskeletons on tasks' physical demands and construction workers' performance. This study adds value to the existing literature, in particular by providing insights into the effectiveness and consequences of the postural-assist exoskeleton for manual material handling tasks.

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