Patent ID: 8301476

Claim:
A method of determining a possible lot size of units with respect to a fixed date for a chain of at least two process steps, each process step requiring a respective assigned resource, and consuming a respective time per unit for being performed by the respective assigned resource, where the process steps are sequentially dependent on each other, the method including: (a) determining, by a hardware computer for each resource, a respective time interval of availability during which the respective resource is continuously available, each time interval being limited by the fixed date, (b) calculating, by the hardware computer for each determined time interval of availability, a respective largest possible number of times the respective process step can be performed by the respective resource, (c) selecting, by the hardware computer, the lot size of units to the minimum of the largest possible numbers, and (d) identifying, in an iterable replacement step, a current bottleneck as the one of the resources corresponding to the minimum of the largest possible number, and if the corresponding interval of availability is limited by a break period, the time interval of availability is extended beyond the break period until the next limit, and wherein the calculation and selection steps (b) and (c) are repeated with the extended bottleneck time interval of availability as the corresponding time interval of availability to recalculate the lot size, wherein the recalculated lot size K Ri is [L max (R i )−· j (b jRie −b jRib /· k=1 . . . i t uRk )] with R i being the current bottlenecked resource, L max (R i ) being a time interval of availability for the current bottlenecked resource R i , b jRib , b jRie , defining the beginning and end of the j-th break for the current bottlenecked resource R i running from beginning time t uR1 through end time t uRk .