Advanced Robotic Radiative Process Control for Automotive Coatings

Abstract

In modern automotive manufacturing, coating, drying and curing processes provide essential protection for car bodies besides decorative functions. However, current coating and curing processes largely involve the use of convection bake-ovens and contribute immensely to the energy consumption and greenhouse gas emissions. For example, according to a recent study (Siewert, 2008), the total energy consumption per car manufactured averages about 3 MW-hr, of which 1.0-1.4 MW-hr (33-46%) happens in the painting/coating booth. Likewise, of the nearly 1.1 tons of CO2 emissions per car manufactured, 0.4 tons (37%) of CO2 emissions arise in the painting booths (Prendi et al., 2008). Assuming even the lowest industrial energy costs and considering the total annual global sales of nearly 70 million cars, estimated energy costs of painting booth operations alone run into trillions of dollars, not to mention the emission of tens of millions of tons of CO2 into the atmosphere. The energy and environmental issues involved in current automotive coating/paint curing processes may be alleviated by recent radiation-based methods which use either ultraviolet (UV) or infrared (IR) radiation to activate/initiate the curing or drying processes (Hagood et al., 2008) (Vgot, 2007). Compared to convection bake-ovens (Fig. 1a), these radiation-based methods use less energy, give improved productivity, and produce less air pollutions, such as CO2, volatile organic compounds (VOCs), etc. As an example, a case study reported in (U.S. Department of Energy, 2003) showed that the replacement of the convection oven by a new IR oven allowed a metal finishing plant to increase its production by 50% and reduce natural gas consumption by 25% annually. Another study showed that the implementation