OEM&Lieferant Ausgabe 2/2021

91 Products and Markets Pre-treatment of multi-metal car bodies with a high aluminum throughput By Joerg Zumkley, Global Communications Coatings, BASF and Jessica Giordano, Communications EMEA & SA, Chemetall GmbH The ongoing drive to reduce vehicle weight is seeing an increasing percentage of aluminumbeing used in car bodies. An ambitious goal in the context of this lightweighting challenge: a targeted share of 80% aluminum throughput in a phosphating pre-treatment plant. The Surface Treatment global business unit of BASF’s Coatings division, operating under the Chemetall brand, has mastered this task together with Porsche. Lightweight materials such as aluminum play an ever-greater role in modern vehicle manufacturing. Lower weight not only has a positive effect on driving dynamic pa- rameters, it also reduces fuel consumption. Porsche was quick to recognize the benefits of a higher percentage of aluminum in car bodies and has been utilizing this material for many years. A higher share of aluminum in the car body requires an increasingly complex paint pre-treatment, as aluminum places very different demands on corro- sion pre-treatment compared to steel or galvanized steel. With its Gardo®Flex tech- nology, Chemetall introduced a process at Porsche that affords maximum quality while at the same time reduces costs thanks to its multi-metal capability and shorter process- ing times. Optimized pre-treatment of multi-metal car bodies The Gardo®Flex technology makes it pos- sible to apply a continuous, homogeneous phosphate layer on all metal substrates of a car body and therefore also to pre- treat modern multi-metal car bodies with 80% aluminum content. This is achieved by optimally combining modern activation and phosphating technologies. As a result, coating formation on the metal substrate is accelerated in the phosphating bath and pickling loss is reduced. Significantly less sludge forms which in turn has a positive effect on maintenance and disposal costs. Also, the consumption of fluoride additives can be reduced by up to 40%. The deposi- tion of an even phosphate coating on alu- minum substrates can smoothen out minor irregularities from previous process steps and thereby promotes an even deposition of the electrocoat. Also, activation bath cooling, as required by other technologies, is no longer necessary. As a result, and de- pending on the individual configuration of the plant, a higher throughput speed and thus a larger number of parts treated per shift or a reduced bath temperature can be achieved. New pre-treatment for the new 911 series With the market launch of the latest 911 series in 2018, this car body pre-treatment technology was introduced at Porsche for the new multi-metal mix car bodies featur- ing 80% aluminum content. By shifting to an immersion pre-treatment of the parts, a further improved coating of the car body interiors along with energy savings of up to 20% was achieved as compared to the pre- viously used method. Another benefit is that fewer incrustations form in the treatment tunnel and on the skids of the phosphating step, leading to significantly reduced main- tenance work, on-time production process- es as well as minimized plant downtimes. Overall, more than 80 million vehicles treat- ed with the Gardo®Flex technology are currently on the roads worldwide. Also, in the future, Chemetall’s customers can rely on the fact that the company is continu- ously developing new, innovative technol- ogies to guarantee an optimally protecting pre-treatment. Image: © Porsche Chemetall www.chemetall.com BASF Coatings www.basf-coatings.com Share With its Gardo®Flex technology, Chemetall introduced a process at Porsche that affords maximum quality.