Reusable unit process life cycle inventory for manufacturing: gas metal arc welding

The paper develops a unit process life cycle inventory (UPLCI) for gas metal arc welding (GMAW) process. UPLCI is a modeling approach that allows users to estimate the energy and materials flow of a unit process. A UPLCI model can be reused in different manufacturing settings where a wide range of machines and materials are used. GMAW is in the joining category of the taxonomy of manufacturing processes, and this work is part of the effort to build UPLCI models for all common manufacturing processes. Following UPLCI approach, the energy consumption is not limited to the energy needed to initiate and maintain the arc (i.e. active energy). Energy spent during idle and standby are also accounted. An example calculation is provided to demonstrate how the GMAW model can be used. It should be noted that the GMAW model can be linked to UPLCI models of other unit processes. This makes it possible to estimate the materials loss and energy use (thus environmental impacts) of a product made by a sequence of manufacturing processes.