Problem – Back to Back Sunroofs Slow Down Assembly Line
When an automotive manufacturer fits sunroofs, this is considered a high work content feature. If operators have to fit back to back sunroofs, this slows down the production line. This naturally reduces the throughput of the line and can thus impact further downstream operations. Sunroofs cannot therefore be scheduled back to back. Spacing out the Sunroof models ensures a smooth schedule and optimal throughput.
Numerous factors influence production schedules, variously referred to as constraints, rules, restrictions and so on. Some examples are: the capacity of a plant or supplier, the lifetime of a die, SKU based changeover times, the ideal batch size for a paint color. To ensure that the schedule is executable, all of these factors must be considered when creating it. Every factor that is ignored or violated has implications in terms of lost throughput, additional inventory, offline workforce, delayed deliveries, stability loss due to frequent rescheduling and more. Each has a cost impact.
Solution – Constraint Based Production Scheduling
When creating schedules, Eyelit Technologies considers all constraints and rules in a complete model. Constraints and rules may conflict with each other, so Eyelit Technologies allows the user to prioritize each factor, while recognizing that some factors just cannot be violated (often called “hard constraints”). The resulting Eyelit Technologies schedule will offer the best balance among these factors and save costs to the tune of $ millions.
Result – $4 Million Savings Per Year Per Plant
The legacy schedule showed multiple violations of this rule, resulting in an average annual loss of 435 vehicles due to reduced throughput. This was equivalent to roughly $300,000 annually. Eyelit Technologies schedule had no violations of this rule. This saved the entire $300,000 for the manufacturer – for this rule alone! The image below shows Sunroof orders spaced evenly across the sequence.
Significant cost savings accrued from just the sunroof spacing constraint. When all rules and constraints were considered, the annual cost savings for a single car plant was estimated at $4 million. All industries have such rules and constraints and can derive similar benefits from Eyelit Technologies scheduling.