Mechanical Technology July 2015

⎪ Special report ⎪

From the first W121 Mercedes-Benz 190 built at the Mercedes Benz South Africa’s (MBSA’s) East London plant on January 31, 1958, to the fourth generation W205 C-Class – 2015 World Car of the Year – South Africa’s premium automotive manufacturer has now produced its millionth car. MechTech visits the multi-award winning manufacturing plant. Mercedes-Benz: from one to one million

O n May 28, 2015 at its East London plant, having pro- duced its one-millionth Mer- cedes-Benz passenger car, a white right-hand drive C200 Mercedes- Benz C-Class, MBSA added a milestone to its journey as an automotive manu- facturer of premium brand vehicles. The millionth vehicle was produced following a complete overhaul of the manufacturing plant – a R5-billion investment between 2011 and 2015 mooted to be the largest single-project investment in the automotive industry in recent history – to accommodate mostly export demand for the new W205 C-Class. The first Mercedes-Benz passenger car, a W121 Nap Vista Blue Mercedes- Benz 190, came off the line of the then Car Distributors Assembly (CDA) plant in East London more than 57 years ago. CDA, the company that would become Mercedes-Benz South Africa, opened

Mercedes-Benz South Africa CEO and executive director for manufacturing, Arno van der Merwe, poses alongside the millionth Mercedes Benz to be manufactured at the company’s East London plant. MBSA’s new paint shop for the W205

P ainting of completed car bodies manufactured in the body shop is a vital step in ensuring product quality for the finished vehicle. The quality of the applied coating is directly responsible for long-term corrosion protection and vehicle life. The paint shop is, therefore, a tightly controlled area that must remain dust free and under humidity control. Following manufacture, the built bodies with mating doors are transported to the paint shop on conveyors. Each body has it own transponder with unique informa- tion about the finished car’s specifications, including its future colour. At the paint shop, bodies are transferred onto skids, which first guide them though the pre-treatment process. Pre-treatment: Each vehicle body is washed to remove small particles, grit and obvious debris. Then the whole body is immersed and degreased in a chemical

solvent bath before being rinsed with de- ionised water. They then enter a chemical dip tank, where the entire body is sub- merged so that all crevices can receive chemical treatment. The whole structure is then electro-coat- ed. This is an electrolysis-based process, also called e-coating or electrophoretic lac- quering, and provides a chemically-bonded primer layer onto the entire car body. The electro-coated car bodies then enter a bak- ing oven to cure the e-primed layer. This completes the pre-treatment process. Sealing and masking: Prior to painting, areas that will later have adhesives applied are masked off. The line of bodies is then conveyed down to the sealant deck, where all exposed seams have sealant applied to guard against water ingress and corrosion. The underside of the body is sealed using robot applicators, while at critical points, sealant is applied and spread manually

by operators. The paint line then passes through a sealer curing oven.

Painting: Each vehicle receives three coats of paint, starting with an inspection stage where any visible defects are removed. The bodies are moved through an automatic cleaning station to remove any small dust particles. Primer paint is then applied to act as fill- ing and smoothing agents. The interiors are manually spray-painted, while all exterior

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Mechanical Technology — July 2015