Volta Bikes builds about ten bikes a day, and every bike needs one crate of parts. Run the factory with just-in-time or just-in-case stock, then hit it with a supplier delay, a demand surge or a model change. Both systems face exactly the same days, so the scoreboard is a fair test.
Press Play to start the month. Try a disruption once both systems have settled.
Just-in-time (JIT) means stock arrives just as it is needed, so the business holds little or no buffer. Each time a bin of parts is used, a kanban card signals the supplier to send exactly that amount. JIT is a key part of lean production, made famous by Toyota.
Just-in-case (JIC) means holding buffer stock so production can continue if deliveries are late or demand jumps. Stock is reordered in large batches when it falls to a reorder level.