Life cycle inventory of the automotive paint processes

JCT CoatingsTech, June, 2008 by Lindita Prendi, Edwin K.L. Tam

As an assembly line process, pretreatment is comprised of 13 substages. Each substage of pretreating the BIW has a significant impact on the quality and quantity of the final product, and also potential effects on the environment.

METHODOLOGY

Industry Partnership

The research in this project was conducted over a two-year period through a partnership between the University of Windsor and a North American-based vehicle manufacturer. Subsidiary partnerships were also initiated with two of the partnered vehicle manufacturer's supplier organizations: a paint supplier and an energy provider.

ISO Compliance

The research complied with relevant LCI protocols (i.e., ISO 14041) by referencing the LCI protocol developed for the NREL LCI Database project in the "U.S. LCI Database Project Research Protocol" (1) and by referencing a standardized LCI data collection sheet. (1) Consistent with these LCI protocols, the research followed several key activities, including;

(1) LCI goal definition

(2) LCI scope definition

(3) Data source identification

(4) Process flow mapping

(5) Functional unit development

LCI GOAL DEFINITION--The primary goal of the research project was to develop a representative LCI dataset on the automotive paint process for inclusion in NREL's public LCI database. In addition to contributing to the NREL database, the LCI dataset was expected to lead to future Design for the Environment (DfE) opportunities at the partnered OEM, such as manufacturing process improvements and an improved materials selection process.

LCI SCOPE DEFINITION--The U.S. LCI Database Project (1) requires that datasets populating the database represent their respective industries. Although there are process variations among the many paint shops in North American-based assembly facilities (e.g., differing technology levels dependent on age of plant and recent paint shop upgrades), the paint processes and facilities were selected to represent the majority of the North American-based assembly facilities.

The paint process was then scoped down to several sub-modules for feasibility, including the pretreatment process presented in this article. Two additional paint processes scoped for LCI were e-coat and topcoat. These three paint processes represent the bulk of the environmental impact associated with the automotive paint process.

The environmental impact parameters scoped for the automotive paint pretreatment process LCI include materials use, energy use, and pollutant emissions. These are shown in Figure 2. The LCI employed several simplifying assumptions:

[FIGURE 2 OMITTED]

* The assembly plant used in this study manufactures two vehicle models that share a common vehicle platform design, allowing for model-specific data to be aggregated and reported as a single representative vehicle model.

* Environmental impacts and related parameters used (e.g., production volumes) measured, calculated, and estimated data from both public and internal sources.

* The LCI analysis was restricted to primary processes within the facility. For example, the mass of the material input is considered, but environmental impacts incurred during manufacturing and transportation of the material to the automotive facility are excluded. Essentially, the LCI represents only the "gate-to-gate" analysis scenario.