Production planning method, a storage medium and a production planning apparatus

A memory storing a computer-executable program code, a production plan being made by the program code in a production line for producing finished products from a raw material, a raw material-to-finished product production process being divided into a plurality of process steps, a plurality of equipments being arranged at the production line, and at least one of the equipments participating in at least two of the process steps, the program code comprising:

• means for causing a computer to, based on a stock number of works in respective process steps at a planning time, calculate the number of works processed in the respective process steps up to the planning time as current cumulated processed works of the respective process steps;
• means for causing the computer to calculate a target of a stock number of works in the respective process steps at a planned time following a passage of a plan period on the basis of a target production representing the number of finished products outputted up to the planned time and an average cycle time of production from the raw material to the finished products;
• means for causing the computer to, based on the target of the stock number of the works in the respective process steps, calculate target cumulated processed works of respective process steps at the planned time;
• and
• means for causing the computer to, based on the current cumulated processed works of the respective process steps at the planning time and the target cumulated processed works of the respective process step up to the planned time, calculate as a process step load of the respective process steps the number of works necessary to be processed at the respective process steps during a period from the planning time to the planned time;
• means for causing the computer to, based on the process step load of the respective process steps and a correspondence relation between the equipment and the process steps, calculate the number of work processed by the respective equipments during a period from the planning time to the planned time as an equipment load of the respective equipment;
• means for causing the computer to select equipments having equipment loads which exceed equipment processing capabilities;
• and
• means for causing the computer to reduce the process step load of the respective process steps based on an excess load of the selected equipment, wherein the further upstream the process steps, the greater a quantity of reduction of the process load so as to achieve target production.

A production planning apparatus for making a production plan in a production line for producing finished products from a raw material, a raw material-to-finished product production process being divided into a plurality of process steps, a plurality of equipments being arranged at the production line, and at least one of the equipments participating in at least two of the process steps, the apparatus comprising:

• means for calculating, based on a stock number of works in respective process steps at a planning time, the number of works processed in the respective process steps up to the planning time as current cumulated processed works of the respective process step;
• means for calculating a target of a stock number of works in the process steps at a planned time following a passage of a plan period on the basis of a target production representing the number of finished products outputted up to the planned time and an average cycle time of production from the raw material to the finished products;
• means for calculating, based on the target of the stock number of works in the respective process steps, target cumulated processed works of respective process steps at the planned time;
• and
• means for calculating, based on current cumulated processed works of the respective process steps at the planning time and the target cumulated processed works of the respective process steps at a planned time, the number of works necessary to be processed at the respective process steps during a period from the planning time to the planned time as a process step load of the respective process steps;
• means for calculating, based on the process step load of the respective process steps and a correspondence relation between the equipment and the process steps, the number of works processed by the respective equipments during a period from the planning time to the planned time as an equipment load of the respective equipment;
• means for selecting equipments having equipment loads which exceed equipment processing capabilities;
• and
• means for reducing the process step load of the respective process steps based on an excess load of the selected equipment, wherein in order to achieve target production, the further upstream the process steps, the greater a quantity of reduction of the process load.

A production planning method for making a production plan in a production line for producing finished products from a raw material through a plurality of process steps, the method comprising steps of:

• calculating the number of current cumulated processed works of each of the process steps on the basis of a stock number of works at each of the process steps, said number of current cumulated processed works of one process step being a total number of the stock numbers of works of said one process step and its upstream process steps;
• setting the number of target cumulated processed works of each of the process steps by adding a load to the number of current cumulated processed works of the corresponding one of the process steps;
• determining a process step at which the number of target cumulated processed works exceeds processing capability;
• reducing the number of target cumulated processed works of the determined process step;
• and
• reducing the number of target cumulated processed works of each of the process steps which are downstream from the determined process step, such that the number of target cumulated processed works of said each of the process steps does not exceed the number of target cumulated processed works of a preceding one of the process steps which is upstream from said each process step.