Analysis and Optimization of Plant Layout using Relative Allocation of Facilities Technique

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1 Analysis and Optimization of Plant Layout using Relative Allocation of Facilities Technique Bobby John 1, Jubin James 1, R. Mahesh Rengaraj 2 1 Post Graduate Student, 2 Associate Professor, Department of Mechanical Engineering, SCMS School of Engineering and Technology, Kerala, India Abstract Factory layout involves the arrangement and selection of machines, material handling devices, material handling path, resulting in the reduction of cost and time involved in manufacturing a product. The facilities layout problem, which is an integral part of facilities design, aims to spatially locate the production units within a facility subject to some design criteria and area limitations, with one or multiple objectives. In this paper, a hybrid model that combines a facility allocation technique and a software analysis of the layout is done. Selecting the best block layout of the foundry section with the help of Computerized Relative Allocation of Facilities Technique (CRAFT). After selecting the best block layout detailed layout is constructed and this detailed layout is analyzed using ARENA. The installed utilization of the layout is checked. The utilization of the layout is increased by changing the position of the equipments or by introducing a new machine into the layout. With the advent of software which allowed the user to build models and move them around the screen and analysis can be done. Re-layout can also be done until satisfactory result is obtained. Keywords ARENA, Computerized Relative Allocation of Facilities Technique (CRAFT), Factory layout, simulation, utilization I. INTRODUCTION Layout problem aims to spatially locate interrelated units such as departments, machines, chips, etc., subject to some design criteria and area limitations, with one or multiple objectives. More specifically, the facilities layout problem, which is an integral part of facilities design, aims to locate the production units within a facility. Today, the layout problem is considered in a dynamic nature. There may be internal or external reasons why a layout would aspire to change. External reasons are effects from the environment the layout operates. These reasons are either hard or impossible to control, for which the layout must act either proactively or reactively. For example, a sudden change in the raw material procurement due to some unexpected government regulation on imported materials is most probably to result in a temporary change in product mix that the layout will be required to produce, although is not specifically designed to do so. 514 Computerized Relative Allocation of Facilities Technique (CRAFT) methodology was utilized in this case as part of the strategy to portrait the relationship between each department to generate improved layout alternatives. The future layout alternative will be evaluated using simulation software ARENA. The main objective of the thesis work is to apply multidisciplinary concepts; tools and technique to solve organizational problems and to evolve innovative theoretical frame work. In this work the present layout of the foundry section is improved using Computerized Relative Allocation of Facilities Technique (CRAFT). The model of the proposed improvement layouts will be modeled using ARENA. The models will be validated and verified. Experimentation of each layout proposal will be done using the simulation model. The results will be analyzed and compared with the existing layout II. SCOPE OF THE WORK Computerized Relative Allocation of facilities Technique (CRAFT) is used for the reallocation. Craft algorithm is developed by Armour and Buffa. It starts with an initial layout and improves the layout by interchanging the department pair wise so that the transportation cost is minimized. The algorithm continues until no further interchanges are possible to reduce the transportation cost A.CRAFT Requirements Initial layout Flow data Cost per unit distance Total number of departments Fixed departments No: of such departments Location of those departments Area of departments Several inputs like distance matrices, cost matrices and flow matrices are used. Area of each department is also required for the designing the new layout.

2 A. Data Collection III. METHODOLOGY Firstly data such as layout of the foundry is obtained from design section of the company. In the layout the area of different departments are measured. Cost of transporting the material from one department to other is also obtained. The distance between the departments is also required. B. Relationship Matrix Cost matrix (C ij ) is required to represent transportation cost per unit distances from Department i to Department j. The table 5.01 shows the example of the cost matrix From TABLE I EXAMPLE OF COST MATRIX To Flow matrix [f ij ] is also represented as above table. Flow matrix [f ij ] is required to represent the flow in terms of number of trips in agiven period of time from Department i to Department j. Centroids of all the departments in the initial layout are calculated by considering the left side of layout is assumed as Y axis and the bottom side of the layout is assumed as the X axis. The distances between the any two departments are represented by the rectilinear distance between the centroids of the two departments. d ij = X i -X j + Y i -Y j Where (Xi,Yi) and( Xj,Yj) are centroids of Departments i and j respectively. From the above data distance matrix [d ij ] is tabulated IV. FOUNDRY LAYOUT Present block layout of the foundry section is shown in figure. Figure 1 Present Layout 1- Induction furnace 2- Chemical laboratory 3- Sand drier 4- Sand plant 5- Shot blast 6- Foundry store 7- Compressor room 8- Shift room 9- Track for mold car 10- Molding machine 11- Knock out machine In this work first analyze the layout with the CRAFT technique and the best layout is selected by making required changes in the block layout. Various data regarding the layout should be collected. Data such as area of each department, cost of transporting one unit of material from one department to other, distances between the departments, etc. After finding out the best layout detailed layout is made and efficiency of the layout is checked using simulation soft ware ARENA. To improve the efficiency of layout position of the machines is altered or new machines are introduced into the layout. Again the layout is simulated changes are made until best efficiency is obtained V. APPLICATION OF CRAFT The CRAFT algorithm can be applied to the present layout. The layout has eleven departments. Cost matrix [c ij ] cell is formed. 515

3 TABLE II COST MATRIX [CIJ] From/ To The table III, cell values represent the flow in terms of trips in a given period of time from Department i to Department j TABLE III FLOW MATRIX [f ij] From/ To The area of each department is shown in the table. TABLE IV AREA OF DEPARTMENT Department Area(sq 1 units The centroids of each department are calculated from the initial layout, the left side of the layout is assumed as Y axis and bottom side of layout is assumed as the X axis. In this method the distance between any two department is represented by the rectilinear distance between the centroids of the two departments. d ij = ( Xi-Xj) + (Yi-Yj) Where (Xi, Yi) and (Xj, Yj) are the centroids of the departments i and j respectively. The distance matrix for the layout is constructed. The total cost for handling for the present layout is calculated using the formula Total cost = n i=1 i=j n f ij *d ij *c ij Where fij is the flow from department i to department j dij is the distance from department i to department j cij is the cost/unit of travel 516

4 By using the above equation the total cost of the present layout is found to be 3955 ie total cost = 3955 Now for the improvement of the layout various departmental interchanges are possible. The departmental interchanges that are possible are based on the Department having common border Department having equal area Pair wise interchanges are considered. For the present problem twelve interchanges are possible The summary of total cost of interchange due to pair wise interchange of centroids are given in the below table TABLE V HANDLING COST Pair of Department Cost 2 and and and and and and and and and and and and The interchange between 5 and 7 results into minimum cost of This cost is compared to the cost of present layout and only if the cost of the proposed layout is less than the present layout cost, the interchange is actually made. Here handling cost of new layout 3835 is less than the present layout cost of Interchange can be made between 5 and 7. The layout after making interchange is shown in figure Figure 2 Interchanged Layout Now the centroids of new layouts are are found out. Distance matrix and total cost for the new layout are found out. Total cost of the new layout is Compare the cost of new layout with the cost of present layout. It is found that it is lower than the previous layout. If the cost of the new layout is less than the cost of present layout, then treat the new layout as the present layout. Then applying the rule of common border or equal area all the possible pair wise interchanges are considered. For each possibility, centroids are interchanged and the resulting distance matrix and the total cost of handling are computed. The results are shown in table below TABLE VI HANDLING COST Pair of department Cost 2 and and and and and and and and and and and

5 The interchange between10and11 results into minimum cost of This cost is compared to the cost of present layout and only if the cost of the proposed layout is less than the present layout cost, the interchange is actually made. Here handling cost of new layout 3885 is less than the present layout cost of Interchange can be made between 10and11. The layout after making interchange is shown in figure The interchange 2 and 4 results into minimum cost 3905 This is compared with the present layout and it is found that it is higher than the total cost of the present layout. Since the cost is less than the cost of present layout, present layout is considered as the final layout. VI. ANALYSIS USING ARENA In the analysis part of this work is done using ARENA 10.0(student s version). For this the layout is modeled using the arena. Each module represents a process or a decision. And these modules are connected using connectors to represent the flow of material with in the layout. Then these modules are given sufficient data for conducting the analysis. These data are obtained by interrogating the personals and from the manuals kept in the company and taking the time using a stop watch. Figure3 Interchanged Layout New centroids and total cost of the new layout are found out Total cost of the new layout is Compare the cost of new layout with the cost of present layout and is found less than the previous layout having a total cost 3914 If the cost of the new layout is less than the cost of present layout, then treat the new layout as the present layout. Then applying the rule of common border or equal area all the possible pair wise interchanges are considered. For each possibility, centroids are interchanged and the resulting distance matrix and the total cost of handling are computed TABLE VII HANDLING COST Pair of department Cost 2 and and and and and and and and and VII. RESULTS AND DISCUSSION The production rate and the utilization of machines depend on how well the various machines; production facilities and employee s amenities are located in a plant. Only the properly laid out plant can ensure the smooth and rapid movement of material, from the raw material stage to the end product stage. By applying CRAFT algorithm the improved layout is formulated from the existing layout and these layouts are analyzed using the simulation software ARENA. The flow of materials in the foundry section is simulated. The results of the simulation of the initial layout and the improved layouts are compared. The results of the simulation of the existing layout is listed below 518

6 TABLE VIII RESULTS TABLE IX RESULTS Machines Instantaneous utilization (%) Machines Instantaneous utilization (%) Induction furnace Knock out machine Molding machine Sand drier Sand plant Shot blast Track Induction furnace Knock out machine Molding machine Sand drier Sand plant Shot blast Track The utilization of each machine is shown graphically Scheduled utilization of each machine in the new layout is shown graphically Figure 5 Results Figure 4 Results The new layout found by the craft technique is also simulated using ARENA and the results are plotted A. Comparison of the results The results of the simulation of the existing layout and the new layout are compared. In this thesis work, a hybrid model that combines a facility allocation technique and a software analysis of the layout is done. 519

7 UTILIZATION International Journal of Emerging Technology and Advanced Engineering The existing layout checked using Computerized Relative Allocation of Facilities Technique (CRAFT) and an improved new layout is proposed. Thereafter the both layout are simulated using a simulation software Arena. Results are plotted and the results of the initial layout and the new layout are compared and it is found that the utilization of the machines in the new layout is slightly increased. These results are tabulated and graphs are plotted. TABLE X COMPARISON OFRESULTS Machines Induction furnace Knock out machine Molding machine Instantaneo us utilization (%) existing layout Instanta neous utilizati on (%) new layout Sand drier Sand plant Shot blast Track SHEDULED UTILUZATION MACHINES Figure 6 Comparison Of Results INDUCTION FURNACE KNOCK OUT MACHINE MOLDING MACHINE SAND DRIER SAND PLANT SHOT BLAST TRACK VIII. CONCLUSION A well planned department provides the fundament for a profitable production. The production rate and the utilization of machines depend on how well the various machines; production facilities and employee s amenities are located in a plant In this thesis work, a hybrid model that combines a facility allocation technique and a software analysis of the layout is done. The existing layout checked using Computerized Relative Allocation of Facilities Technique (CRAFT) and an improved new layout is proposed. Thereafter the both layout are simulated using a simulation software Arena. Results are plotted and the results of the initial layout and the new layout are compared and it is found that the utilization of the machines in the new layout is slightly increased. Re-location of the machines is done such that the flow of the material is smoother. REFERENCES [1] Collaborative Factory Planning in Virtual Reality N. Menck, X. Yang, C. Weidig P. Winkes, C. Lauer, H. Hagen, B. Hamann, J.C. Aurich /Procedia CIRP 3 ( 2012 ) [2] The facility layout problem: recent and emerging trends and perspectives russell.d.meller and Kai-Yin Gau/ journal of manufacturing systems vol.15 /no 5/1996 [3] Software Evaluation Criteria for Rapid Factory Layout Planning, Design and Simulation N.Shariatzadeh, G. Sivard, D. Chen /Procedia CIRP 3 ( 2012 ) [4] The Use of Simulation in Facility Layout Design: A Practical Consulting Experience Emmanuel S. Eneyo Gertrude P. Pannirselvam/ Proceedings of the 1998 Winter Simulation Conference [5] Arena software tutorial ed. S. Andradóttir, K. J. Healy, D. H. Withers, and B. L. Nelson Proceedings of the 1997 Winter Simulation Conference. [6] Layout Design of a Furniture Production Line Using Formal Methods Pinto Wilsten J., Shayan E. Journal of Industrial and Systems Engineering Vol. 1, No. 1, pp 81-96Spring [7] A simulation based experimental design to analyze factors affecting production flow time Banu Y. Ekren, Arslan M. Ornek X/$ - see front matter _ 2007 Elsevier B.V. All rights reserved.doi: /j.simpat [8] Facility layout problems: A survey Amine Drira, Henri Pierreval, Sonia Hajri-Gabouj /$ see front matter # 2007 Elsevier Ltd. All rights reserved. doi: /j.arcontrol [9] Using WITNESS Simulation Software as a validation tool for an industrial plant layout Enrico Briano, Claudia Caballini, Roberto Mosca, Roberto Revetria. ISSN: XISBN: [10] Automated facilities layout: past, present and future Robin S. Liggett, 2000 Elsevier Science B.V. _. PII: S [11] Production and operation management R. Paneerselvamm, PHI 520