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FlexSim versus Excel for factory layout optimization

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FlexSim versus Excel for factory layout optimization

  1. 1. A Comparison of Discrete Event Simulation and Excel Spreadsheets Methods for Optimizing Factory Layout and Operations urvival of any manufacturing industry in today’s competitive market depends upon the ability of the industry to satisfy customer demand, with the use of a minimum number of resources in the least possible time. Hence to obtain competitive edge, companies must extract every drop of value from their resources, to derive maximum value. They must also have a deep analytical understanding of all aspects of manufacturing operations and be able to visualize different scenarios possible; from impact of variations in product demand, capacity consumption to machine breakdowns to draw optimum conclusions. To this end, it is essential to have the right software tool to accomplish this task. The most commonly used tool used today in analyzing manufacturing operations and manufacturing layouts are traditional Excel spreadsheets. This is because Excel is a low cost solution that is available in almost all computer desktops and laptops in a typical factory, and therefore has become the default tool when a requirement occurs to analyze manufacturing operations or a new factory design layout for efficiency. Excel however, is very limited in its ability to accurately assess and capture the many elements at play in a manufacturing system. This is because; manufacturing processes are inherently discrete event processes. This means that the operation of a system takes place as a discrete sequence of events, with each event causing a change in the state of the system. For instance, a machine undergoes several changes in state during the manufacturing process, going from processing to idle, to a possible breakdown or maintenance state, to setup and to a possible state of repair. All these changes happen during different periods of time. Excel, as a primarily mathematical spreadsheet tool, lacks the fundamental requirement of being able to track time or changes in state over a time interval. S Figure 1: Excel Sheet representation of a Factory Process Commercial Consultancy Services pg. 1 Head office: 3B Alps Estate, First Block, 460 / 1 Kaikodanahalli, Sarjapur Road, Bangalore 560 035, India Tel: +91 98864 78720 email: mano@ccsstrategy.com www.flexSim.com
  2. 2. Because, Excel cannot track changes in state behavior of various entities like machines process and set up times, varying customer demand , shift timings, operators and material handling equipment travel distances and speeds, maintenance schedules etc, it is limited in its ability to provide a proper analysis of a factory, where every aspect of the manufacturing operation changes with time. As a result, the Excel user makes gross assumptions to simplify calculations, resulting in large errors in estimation of results. Excel also carries with it the disadvantage of not being able to visualize the dynamic nature of the manufacturing system or its behavior in real time. Real manufacturing systems are highly complex in nature, with multiple requirements, such as routing logic, processing priorities, task sequences, shift timings, and more. Capturing these hundreds of nuanced complexities adds yet another dimension of difficulty to an Excel user, for it is not designed specifically for such a purpose. Thus no amount of formula manipulation in an Excel spreadsheet can assess a factory performance in terms of factory throughput, need for additional resources, such as operators or machine, areas where the production line is having a bottleneck etc. With all these clear disadvantages in using Excel, what then can we turn to? The answer lies in discrete event simulation or DES software. This type of software is specifically designed to simulate manufacturing processes with great ease and accuracy. The great advantage of DES software over traditional spreadsheets is their ability to capture change in state over a period of time. Furthermore, DES software technology in recent times has made great strides in user-friendliness enabling a user to use it with a minimum amount of training. Since, DES software is designed for simulation of manufacturing layouts and processes, all the aforementioned shortcomings of Excel are overcome. A DES software user can easily add machines, CAD image files of the factory layout, material handling equipment like cranes, forklifts, conveyors, elevator and workers etc, that animate in real time with mathematical precision based on their respective speeds and acceleration in all 3 dimensions to ensure the analysis of the factory performance produces highly accurate results. Furthermore, the DES user can also specify the path of travel and traffic rules that need to be followed by these materials handling equipment to ensure safety during factory operations. These features put DES software heads and shoulders above any spreadsheet. And since manufacturing processes are determined largely in part by many Figure 2: A Factory Floor Plan can be imported in FlexSim Commercial Consultancy Services pg. 2 Head office: 3B Alps Estate, First Block, 460 / 1 Kaikodanahalli, Sarjapur Road, Bangalore 560 035, India Tel: +91 98864 78720 email: mano@ccsstrategy.com www.flexSim.com
  3. 3. unknown, random factors known only through statistical distribution, discrete event software takes this into consideration and enables the ability to represent even these random events and situations. The premier discrete event simulation software on the market today is FlexSim. FlexSim boasts all the advantages of traditional discrete simulation software, and more. Using FlexSim, one can model almost any manufacturing process with tremendous accuracy and ease. It has the ability to capture the movement of operators and material handling machinery in 3 dimensions i.e. in x, y and z directions, taking into consideration distance, speed, acceleration and deceleration. FlexSim utilizes simple drag and drop technology, enabling users to use pre made objects in the FlexSim library, such as queues, processors, operators, conveyors, cranes, and more. This enables users to build complex manufacturing models with little or no programming. However, if factory operations are of a complex nature, a user can program in FlexSim using C++ or the proprietary Flexscript language to deal with any difficult or unique situation that needs addressing. FlexSim also contains libraries of all statistical distributions, to ensure an even higher level of accuracy. The results obtained can be of 99% or more accuracy. Figure 3: A Working Model of a Factory Floor in FlexSim FlexSim even boasts the ability to add custom objects, a tremendously useful capability, as all manufacturing plants either use unique machines, or obtain and employ new ones. This allows the user to configure machines to a very exact specification, each with custom properties, and thus an entirely new custom library can be created. A simulation model is always tested under different conditions or scenarios to see what impact each variation has on factory operations. A typical situation can be the impact on the factory performance by modifying the size of a given WIP area or adding a new machine. In FlexSim, there is a built-in module known as the 'Experimenter', allowing users to test any desired scenarios easily, without making changes to the simulation Commercial Consultancy Services pg. 3 Head office: 3B Alps Estate, First Block, 460 / 1 Kaikodanahalli, Sarjapur Road, Bangalore 560 035, India Tel: +91 98864 78720 email: mano@ccsstrategy.com www.flexSim.com
  4. 4. model. In addition, a user can create a custom GUI, wherein a user can input data directly into the model to determine the performance of the system for different values of input. Figure 4: A Working Factory Layout Using Discrete Event Simulation Software Reporting the results of a simulation model is of utmost importance, because this enables the user to decide the future course of action needed to improve factory performance and to make optimum decisions. For reports, FlexSim has a wide range of capabilities, such as create Excel based reports, real time dashboard graphs, or integration with an external reporting application. In today’s market environment, where competition is harsh, it is very important to optimize manufacturing operations via a virtual 3d analysis of the factory layout before building the factory or executing the factory orders on the floor. Thus FlexSim simulation software saves significant amounts of money to the organization and provides a big return on investment. Commercial Consultancy Services pg. 4 Head office: 3B Alps Estate, First Block, 460 / 1 Kaikodanahalli, Sarjapur Road, Bangalore 560 035, India Tel: +91 98864 78720 email: mano@ccsstrategy.com www.flexSim.com