Incorporating tool design into a comprehensive life cycle cost framework using the case of injection molding

The performance of most manufacturing processes is highly determined by the tooling engineering, not only in regard to reliability and process cycle time, but also to material and energy consumption levels. Despite being acknowledged by the industry, the explicit quantification of the impact of tooling design decisions is still lacking mainly due to the “one-of-a-kind” nature of these tools. The proposed Comprehensive Life Cycle Cost (C-LCC) framework integrates the part and the tool life cycles and combines process-based models of all life cycle phases involved, mapping the dependencies and impacts between them. A case study regarding a plastic part produced by injection molding is presented, illustrating the C-LCC framework and exploring its advantages in supporting tooling design decisions. A special attention is devoted to tool reliability, expected downtime, energy and material consumption modeling. Results obtained in the case study show significant life cycle cost variations between mold design alternatives. This approach is especially useful when dealing with new technologies and tool features, as the modeling of the processes allows estimating their future costs and other impacts without major investments. Hence, it can be used to support more informed decisions in the tooling design phase, prior to the part production.