September 1997, Volume 3, No. 9 Selecting Finite Capacity Planning Software

By Dick Kuiper Determining if your manufacturing facility really needs or wants finite capacity scheduling (FCS) requires more thought than most people first assume. If you don't really need automated detail scheduling assistance, the investment in time and money may be wasted. Plants that react to demand peaks by simply working overtime may find FCS to be a nuisance when it keeps trying to automatically schedule work into the next time period. But, if your long-term survival in the business world hinges on optimum scheduling of your constraining production resources on the shop floor, the payback is almost guaranteed. Once you have determined the "why," you're ready to tackle the tough questions - the "what" and "how." First and foremost, you must consider the interaction between your FCS function and your existing ERP/MRP system which handles scheduling at the higher level. The optimal solution is, of course, to have an ERP system with its own FCS module that meets the company's needs. Since the more common occurrence is to purchase an FCS package from another software vendor, however, the interfacing of the two is paramount. With no solid integration of ERP and FCS, one immediately steps into the abyss of "islands of automation," and as time goes on the gap between high-level planning and detailed plant scheduling will grow wider and wider. Ensuring the ERP and FCS can be integrated in harmony is the first requirement of software selection. After the high-level issues have been resolved, or at least used to determine the system framework, the company must define and prioritize the details of which functions the FCS system will perform. Here are several of the functionality issues that must be addressed: What is to be scheduled? Not everything needs to be scheduled through the FCS module in most cases. Any resource components that can be scheduled adequately at the higher levels (ERP/MRP) need not be handled by FCS. Where hour-by-hour schedule manipulation is a reality and/or critical bottleneck resources are involved, FCS provides a solid solution. In this context, the three chief components of labor time, machine time and material availability should be considered separately. Must secondary items be included? In addition to the three primary components, many environments call for other items to be included in scheduling algorithms. For maintenance intensive work centers, periodic maintenance requirements must be factored into the schedule. For quality intensive operations, inspection and testing activities may well be an integral scheduling component. Where do rework activities fit into the scheduling picture? What about tooling and fixtures - should they be scheduled by the system? What about job set-up and tear-down - are these scheduled separately? In some situations, storage space may even be a constraint that must be factored into detailed scheduling. Must product variability be factored in? Determining the extent to which the products themselves impact detailed scheduling helps to define the complexion of the FCS. If products can be categorized into families with like characteristics, an FCS that supports part family grouping can be a benefit. Is rules-based product sequencing needed to achieve efficiency? Examples: small-to-large sequencing where size is important, light-to-dark sequencing where color is important. Is rules-based scheduling for other complex product relationships needed? How does plant floor organization affect the picture? The way the plant is organized has a significant effect on how the FCS must be structured. Discrete, batch repetitive and continuous flow operations all have divergent scheduling needs. The use of work cells rather than or in addition to traditional work centers has an impact on scheduling methodologies. Integrated multi-plant operations or the subcontracting of production operations add greatly to the scheduling complexity. Other issues that may arise include: line loading and balancing, dynamic control of buffer inventory at constraint bottlenecks, automatic alternate routing or material substitution suggestions when bottlenecks or breakdowns occur, and incorporation of automated data collection for a feedback loop. What are the customer-related issues? Although FCS is predominantly an internal tool, customer requirements should bear heavily on functionality decisions. Is delivery date prioritization factored into the equation? Are customer order "ship with" and "ship together" instructions taken into consideration? Is there support for system-assisted expediting without need to regenerate a plan? If the company operates in a job shop environment, must FCS track status and costs by customer job? Reporting and operational requirements? How interactive must the system be? Does it use a "workbench approach" that facilitates user-friendly interactive rescheduling and what-if analysis? Does it offer interactive, real-time warning of over-commitment of equipment, personnel or materials? Does it provide bottleneck analysis? Does it depict results in graphical form for rapid problem identification? Is there a need for expert system intelligence that builds on past history of results? In summary, finite capacity scheduling comes in many different flavors, and one must look beyond simply measuring inputs versus capacity when choosing an FCS software package. The right choice for you will: integrate with your high-level planning system, schedule all the component types you need scheduled at the detail level, fit your product line makeup, meet your customer scheduling demands, support your plant floor organizational setup, and handle the reporting requirements that best suit your business style. Dick Kuiper is vice president of Expert Buying Systems Inc., and can be contacted at (702) 363-4046. This is part of an ongoing series of articles on the selection and implementation of manufacturing applications software. We will be dealing with projects, teams, methodologies, vendors, RFPs, requirements/needs, justification, training, attitudes, platforms, technology, reengineering, vertical software, and best-of-breed decisions. If there are any areas of particular concern to you or your company, please call Dick Kuiper and we'll try to cover it in a later article.

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