Product design and process design device

A product design and process design device comprising:

• a storage device that stores:
• design specification information containing a tolerance of at least one dimensional variation of an assembled product,
• part dimension error information on plural part dimensional errors of plural parts of the product, related to the design specification information,
• assembly facility error information on plural assembly facility errors of plural facilities that assemble the product,
• assembly tolerance information containing at least one relational expression for the assembled product among the design specification information, the part dimension error information, and the assembly facility error information,
• part manufacturing cost information on plural costs with respect to the part dimension error information, and
• facility investment cost information on plural costs with respect to the assembly facility error information;
• and
• a processor programmed to:
• generate plural proposed tolerance distributions that are different combinations with respect to the plural part dimension errors and plural assembly facility errors and which satisfy the design specification information using the assembly tolerance information, and
• calculate respective part manufacturing costs for each of the plural proposed tolerance distributions based on part manufacturing cost information,
• calculate facility investment costs based on the plural assembly facility errors for each of the proposed tolerance distributions based on the facility investment cost information,
• calculate, as an evaluation index, total production costs respectively comprising sums of the part manufacturing costs and the facility investment costs for each of the plural proposed tolerance distributions, and
• determine a proposed tolerance distribution from the plural proposed tolerance distributions according to the evaluation index, and
• output the optimum proposed tolerance distribution which specifies a combination of the part dimension errors and one of the assembly facility errors which satisfy the design specification information for the assembled product, and
• wherein the processor is further programmed to:
• accept, as input, existing and new pieces of assembly line information for the plural facilities, the assembly line information containing assembly facility information, and
• use the assembly facility errors included in the proposed tolerance distributions and the assembly facility information to calculate the facility investment costs and determine an assembly line configuration for assembling the product,
• wherein the assembly line configured is used to assemble the product in at least one of the plural facilities.