Analyzing Production Schedules
More powerful, low cost computing systems and software development tools that allow creation of fast, easy-to-maintain software have driven the cost of sophisticated software down with no compromise in performance. Formanufacturing, the most visible example of enhanced price/performance software is finite capacity scheduling (FCS) systems. As with any tool, the real value in understanding what the results have to say. Introduction In a relatively short period of time, the combination of the acceptance of the Windows operating system, cheap and powerful PCs, and highly visual and rapid software development tools suchas C++ and Visual Basic have made technology once reserved for the Fortune 1000 now accessible to all manufacturing tiers. This phenomenon was first felt on the factory floor, driving the cost down on SCADA systems. The next systems impacted were the MRPII and ERP systems. As these information management systems matured, the middle layers of the factory had to be addressed to achieve completeintegration of the enterprise information network. We now see in the post-Y2K world that the sophisticated modeling and analysis functions are being offered at commodity prices, with no sacrifice in their sophistication or usability. One area of tremendous breakthrough is finite capacity scheduling (FCS). So What is FCS Exactly? Finite capacity scheduling emerged as a response to the limitations ofinfinite capacity scheduling that is common to all MRPII systems. The basic problem in MRPII is that the production plans lack realism since they are produced under the assumption that all resources have an infinite capacity to perform work. As any production manager knows, the real world does not work this way, and many of the problems of resource underutilization, excessive inventories andwork-in-progress, and job lateness relate back to the inaccuracy of the production plan. FCS itself is not a new idea, and for many years versions of FCS emerged to enhance the accuracy of the production plan to better manage inventory, resources, and customer satisfaction. The first systems were simple, involving the measure of the primary resource to do work, and either scheduling forward from thecurrent date for new orders (single constraint finite forward scheduling FFS). Multiple constraints were later added to provide more accurate modeling of the production resources. About the same time backwards and bi-directional scheduling began to appear in some packages. Then the explosion of different production philosophies appeared to challenge the American ideas of MRP and massmanufacturing, notably just-in-time and theory of constraints. Variations of FCS systems emerged, some committed to supporting one of the three competing philosophies. This forced the innovative FCS companies to face the reality that to remain flexible, the new FCS systems would need two basic improvements: 1. Model any production philosophy and 2. Extend the model with rules that capture the nuances of thecompetitive model of the client as it related to scheduling. To achieve these goals, the new FCS systems had to support job-based, resource-based, and event-based modeling. By applying any one or a combination of these three views of the production floor, a FCS model can produce the accuracy that adds value to the business goals of the enterprise. The Value of FCS The value of FCS comes from theaccuracy not obtainable in tradition infinite capacity planning. With this accuracy, raw material levels can be in sync with demand from the production floor, customer service levels improve since throughput is predictable and due dates are more reliable,
Please purchase PDFcamp Printer on http://www.verypdf.com/ to remove this watermark.