Manufacturing Facility Layout Research Articles

Optimizing Cellular Manufacturing Facility Layout Design through Digital Twin Simulation: A Case Study

Cellular manufacturing is a lean manufacturing approach that involves grouping machines, processes, and workstations into self-contained cells to reduce material handling, waiting times, and inventory. The layout design of cellular manufacturing facilities has a significant impact on their efficiency, productivity, and throughput. However, traditional trial-and-error methods for facility layout design can be time-consuming, costly, and risky. Digital twin simulation offers a powerful alternative by allowing designers to create virtual models of the facility and test different layout configurations before physically implementing them. Our study shows that digital twin simulation can help identify the optimal layout design that maximizes productivity, minimizes waste, and ensures the smooth flow of materials and products. Additionally, it enables us to evaluate the impact of changes in the production system on the facility's performance, helping decision-makers make informed decisions. Overall, this paper highlights the potential of digital twin simulations as a powerful tool for optimizing cellular manufacturing facility layout design and improving operational performance.

The facility layout instances of the generalised travelling salesman problem

In this paper, we provide new insight into the problem of designing loop flow-patterns and input-output (I/O) stations in a facility layout to minimise the summation of loaded and empty trip distances. The loop covering at least one contourline of each workcenter in a manufacturing facility layout is an instance of the generalised travelling salesman problem (GTSP). The shortest length solution to this GTSP provides a promising heuristic scheme to minimise the total loaded and empty flow in vehicle-based material handling. The sequence of the I/O stations alongside the loop also plays a significant role in determining the volume of the loaded and empty flow. The larger the set of candidate locations for I/O stations, the higher the flexibility in sequencing the stations. On this foundation, we define a new objective function of maximal-node-covering for our instance of the GTSP. By combining the characteristics of the shortest and the maximal-node-covering loops, a set of complementary heuristics are developed to design a loop and locate the I/O stations to minimise the total loaded and empty flow.

Group Technology for Optimizing Manufacturing Facility Layout

In recent years, the process of cellular manufacturing and group technology have received a lot of attention and popularity in many developed countries. By applying Group Technology (GT), many benefits of flow-line production can be attained in a batch production system. GT improves material handling significantly by reducing material flow time, distance, and setup times. In this paper, an earnest investigative attempt was made to provide valuable information regarding the use of Group Technology by applying to a real world jobshop system. The proposed GT model has the flexibility of choosing the number of cells required, which is very useful in examining different manufacturing cell configurations; or in case the workshop or factory prefers a certain number of work cells. The GT model results were found satisfactory and superior to other techniques in some cases.

Research on Cell Manufacturing Facility Layout Problem Based on Improved NSGA-II

Research on Cell Manufacturing Facility Layout Problem Based on Improved NSGA-II

Covering and connectivity constraints in loop-based formulation of material flow network design in facility layout

The shortest loop covering at least one edge of each workcenter in a manufacturing facility layout is an instance of the generalized traveling salesman problem. The optimal solution to this problem is a promising design for non-vehicle-based material handling, typical of most types of conveyors and power-and-free systems, where the length of the path is the main driver of the total investment costs. The loop formulation is usually embedded within a larger problem of the concurrent design of the loop and the input/output stations for vehicle-based material handling typical of automatically guided vehicles and autonomous delivery robots. In these systems, it is not the length, but the total flow of the loaded and empty vehicles that drives the objective function. It has been shown that the shortest loop provides an effective heuristic scheme to achieve prosperous and robust solutions for the concurrent design of the loop and input/output stations. We review and compare covering constraints formulations, provide new insight into connectivity constraints, improve the model formulation and its solution procedure, and report computational results.

Designing manufacturing facility layouts to mitigate congestion

When workflow congestion is prevalent, minimizing total expected material handling time is more appropriate than minimizing a distance-based objective in manufacturing facility layout design. This article presents a model labeled the Full Assignment Problem with Congestion (FAPC), which simultaneously optimizes the layout and flow routing. FAPC is a generalization of the Quadratic Assignment Problem (QAP), a classic problem for the location of a set of indivisible economic activities. A branch-and-price algorithm is proposed and a computational study is performed to verify its effectiveness as a solution methodology for the FAPC. A numerical study confirms the benefits of simultaneous consideration of layout and routing when confronted with workflow congestion. A detailed simulation for a case problem is presented to verify the overall benefits of incorporating congestion in layout/routing. A critique of FAPC with two alternative models is also provided. Three conclusions are offered from this work. First, a combination of re-layout and re-routing is a more powerful way to mitigate the impact of workflow congestion rather than using just the re-layout or just the re-routing options. Second, it is important to model workflow congestion in a manufacturing facility—that is, ignoring it can result in a significantly poor design. Third, the QAP layout is dominated by the FAPC layout for situations of medium workflow intensity.

The value of the shortest loop covering all work centers in a manufacturing facility layout

In this study we develop mathematical models to design circular material flow systems. We first develop a tight formulation to find the shortest loop covering all work centers within a manufacturing facility layout. The shortest loop is an attractive solution for most types of conveyors and power-and-free systems, where the length of the flow path is the major driver of the total cost. We develop a primal as well as a dual graph formulation and discuss their one-to-one correspondence in node-edge as well as in connectivity constraints. Our solution times outperform other optimization models available for the facility layout shortest loop design problem. We then approach trip-based material handling, such as automated guided vehicle systems, where the total loaded and empty trip distance is the major driver of the total cost. The problem in these systems evolves into concurrent design of the loop, pickup and dropoff station, and the empty vehicle dispatching policies. On the foundation of the shortest loop model, we propose a decomposition heuristic for design of trip-based flow systems. Computational results indicate that the heuristic provides high quality and robust solutions.

Some comments on Malakooti et al. ‘Integrated group technology, cell formation, process planning, and production planning with application to the emergency room’

In this technical note, we suggest an alternative to the cellular layout for the emergency room problem discussed in Malakooti et al. (Malakooti, B., Malakooti, N.R. and Yang, Z., Integrated group technology, cell formation, process planning, and production planning with application to the emergency room. Int. J. Prod. Res., 2004, 42(9), 1769–1786). The alternative layout—hybrid flowshop layout—belongs to a class of hybrid cellular layouts that can be designed using the integrated suite of algorithms available in the production flow analysis and simplification toolkit (PFAST) software (Irani, S.A., Zhang, H., Zhou, J., Huang, H., Tennati, K.U. and Subramanian, S., Production flow analysis and simplification toolkit (PFAST). Int. J. Prod. Res., 2000, 38(8), 1855–1874). These layouts are intermediate between the traditional layout extremes—process layout and cellular layout—for a high-variety low-volume (HVLV) manufacturing facility. Our results indicate that the hybrid flowshop layout is superior to the cellular layout since it eliminates/reduces the duplication of procedures1, backtrack flows between non-adjacent procedures and by-pass flows between procedures. 1 A ‘procedure’ and a ‘patient’ in the emergency room layout problem are analogous to ‘machines (or work centres)’ and ‘parts (or products)’, respectively, in a typical manufacturing facility layout problem.

Solving unequal area facility layout problems using genetic algorithm

This paper presents an approach for solving multi-row, unequal area, manufacturing facility layout problems using genetic algorithm. The existing approach for solving problems of unequal area facility layout in manufacturing environments can provide optimal solutions with limitations like single design criterion, manual revision and approximated shape. Also, practical factors like cost involved in additional travel during facilities breakdown and floor space utilisation are not considered. The proposed model minimises the cost associated with material handling during normal and breakdown periods with due consideration of compactness of the layout. The reliability of the facilities are accounted for the calculation of additional material transfer between the facilities during a breakdown period. A novel placement procedure which is capable of changing the orientation of facilities is used to place the facilities in the given building area. The mathematical formulation, the details of solution and its methodology are presented with a case study.

Integrating design and production planning considerations in multi-bay manufacturing facility layout

This paper develops a new mathematical model that integrates layout design and production planning to prescribe efficient multi-bay manufacturing facilities. The model addresses the need to distribute department replicas throughout the facility and extends the use of product and process requirements as problem parameters in order to increase process routing flexibility. In addition, the model allows for the consideration of practical material handling and production features such as alternate process routings, product flow production patterns, and department replica capacities. Computational results demonstrate that the run time required to solve our test problems is quite acceptable given the long-term nature of facility layout decisions. Moreover, comparative results indicate that department replication can reduce material movement significantly while maintaining the existing production capacity.

Fuzzy decision support system for manufacturing facilities layout planning

Manufacturing facility layout problem is an unstructured decision-making problem due to natural vagueness associated with the inputs to the models. Arbitrary numerical ratings are assigned for relationship chart to determine facility selection routine. This paper presents a distinct decision support system based on multifactor fuzzy inference system (FIS) for the development of facility layout with fixed pickup/drop-off points. The algorithm searches several candidate points with different orientation of incoming machine blocks in order to minimize flow cost, dead space and area required for the development of layout. The proposed methodology is coded in C + language and implemented in a Pentium III, 550-MHz machine. The experimental results with a test problem are illustrated with encouraging result with its advanced soft computational effectiveness.

Virtual facility layout design using virtual reality techniques

Manufacturing facility layout design has long been recognized as one of the most critical and difficult design tasks in manufacturing industries. Traditional layout methods can not fully solve this complex spatial layout problem. Virtual reality (VR) is a new form of human-computer interaction, which has the potential to support a range of engineering applications. This paper discusses the reasons why manufacturing facility layout design is considered to be an appropriate new area of VR utilization. A VR-based layout design framework is proposed. The virtual environment construction issues are discussed. An example of the immersive VR application of facility layout is examined.

The multi-bay manufacturing facility layout problem

The multi-bay manufacturing facility layout problem is concerned with determining the most efficient layout in a facility that is defined by parallel bays, where the bays are connected at one or both ends by an inter-bay material handling system. This problem arises in a wide-variety of manufacturing contexts; e.g. heavy manufacturing and the semiconductor industry. The solution methodology is a two-stage procedure: (1) assigning departments to the bays and then (2) determining the layout of each bay. We present our procedure, which is based on mixed-integer programming and dynamic programming, to determine the optimal overall layout under the assumption of one inter-bay material handling system and a linear ordering of departments within the bays. Finally, we illustrate the procedure by solving four example problems. The runtimes to solve these problems highlight the feasibility of using our procedure as a design tool.