Depending on the preferences of the manufacturer as well as the characteristics of the underlying manufacturing processes, either production leveling or sequence and quantity optimization approaches may be employed. In either case, the factory operations scheduling system must be able to handle the presence of alternative assembly lines for each product, maximum and minimum quantity per run constraints, supplier capacity constraints as well as other material supply related constraints and sequencing constraints that define which products are permitted to or prohibited from following each other on the assembly line in sequence. Needless to mention, the shift structure of each assembly line may be different from each other and may change from one day to another. All constraints may be hard or soft constraints.

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Regardless of whether production leveling or sequence and quantity optimization approaches are employed, after assembly line planning phase, required semi-finished parts and related operations can be scheduled on supporting workstations such as injection molding machines, if desired. The primary objective of scheduling operations on supporting workstations is to feed the assembly lines on-time possibly followed by the objectives of minimizing work-in- process inventory and/or satisfying some sort of efficiency related criteria.

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Due to the complex nature of the factory operations scheduling, sometimes it may be difficult to understand the implications of a given plan. NovaLab’s planning software, xS Planner, provides interactive raw material requirements plan view with the help of an embedded MRP module in addition to warnings related to various aspects of the plan such as late orders and a dashboard for KPIs.

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Other important planning problems for appliance manufacturing are capacity requirements planning and assembly line balancing which can provide significant improvements in assembly line performance.