Determining a possible lot size

An apparatus capable 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 apparatus including

• (a) determining means that, for each resource, determine 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 means that, for each determined time interval of availability, calculate a respective largest possible number of times the respective process step can be performed by the respective resource, and
• (c) selecting means that selects the lot size of units to the minimum of the largest possible numbers, wherein the determining, calculating, and selecting means comprise hardware processors;
• (d) replacement means that, after the selection means selects the lot size of units, performs an iterable replacement step to identify a current bottleneck resource as the one of the resources corresponding to the minimum of the largest possible number, and extends the time interval of availability beyond the break period until the next limit of the corresponding interval of availability is limited by a break period;
• and
• (e) iteration means that addresses the calculating means and the selecting means to repeat the calculation and selection (b) and (c) 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 KRi is [Lmax(Ri)−·j(bjRie−bjRib/·k=1 . . . ituRk)] with Ri being the current bottlenecked resource, Lmax(Ri) being a time interval of availability for the current bottlenecked resource Ri, bjRib, bjRie, defining the beginning and end of the j-th break for the current bottlenecked resource Ri running from beginning time tuR1 through end time tuRk.

A computer readable medium having program code stored therein that when executed by a processor cause the processor to:

• determine a possible lot size of units with respect to a fixed date for a chain of at least two sequentially dependent process steps, each process step requiring a respective assigned resource by:
• (a) determining, 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, 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, and
• (c) selecting the lot size of units as 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 correspond 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 KRi is [Lmax(Ri)−·j(bjRie−bjRib/·k=1 . . . ituRk)] with Ri being the current bottlenecked resource, Lmax(Ri) being a time interval of availability for the current bottlenecked resource Ri, bjRib, bjRie, defining the beginning and end break of the j-th break for the current bottlenecked resource Ri running from beginning time tuR1 through end time tuRk.