28 Service Omnibus 3·<strong>2010</strong> Costs in focus Capital servicing, workshop repairs, fuel consumption, fleet management: bus operators have to calculate life-cycle costs just as closely as the actual price of acquiring a vehicle. <strong>Mercedes</strong>-<strong>Benz</strong> helps to keep life-cycle costs down.
THERE ARE unavoidable costs. Such as fleet maintenance. Fuel consumption as well as workshop repairs and servicing are major cost factors. But it is the life-cycle costs which ultimately determine just how economical a vehicle is. <strong>Mercedes</strong>-<strong>Benz</strong> takes all life-cycle cost factors into account, as a closer look at bus production operations at the Evobus plant in Mannheim reveals: a sophisticated quality management concept assures high standards of manufacturing. In conjunction with innovative engine technology, this is vital in keeping life-cycle costs to a minimum. Buses are genuinely hand-crafted products “The challenge of bus and coach production is to combine state-of-the-art mass production with the ability to deliver highly individualised ve hicles,” states Jürgen Birkmeyer, quality engineer with EvoBus GmbH in Mannheim. “Quality control and assembly processes must be carefully coordinated and be consistently applied to all vehicle types,” Birkmeyer goes on. Whether a coach or scheduled service bus, a low-floor model or articulated bus – the quality management concept must cover them all. It also has to incorporate all the different drive systems (diesel, natural gas, fuel cell, hybrid), as well as custom outfitting options. Buses are manufactured to order, with each one being fitted out to the customer’s specification. This poses major challenges to the craft skills employed in the assembly process, which must be effectively monitored and controlled by the quality procedures. One fundamental method employed in achieving this is the concept of “quality gates”. In practice, this means that quality control is implemented throughout the various stages of the production process, and not just at the end. The vehicles must pass through virtual “gates” at pre-determined intervals in their production. All assembly staff share responsibility for quality in their respective work segments. This practice of self-monitoring is the first quality control stage, or loop, involving checks by the operatives themselves. At the second – the quali ty gate – a “gate-keeper” checks the result of the production stage which has just been completed to ensure all required work has been done to the correct standards. At the end of the production line the buses are checked once again by Quality Assurance in a third quality control loop, based on defined function groups (running gear, electrics, etc.). This stage also incorporates dynamic testing, whereby the buses are put through their paces under real conditions. The interaction of the individual quality control loops assures the high quality of the vehicles. Quality Assurance also conducts random audits of individual vehicles. This involves subjecting the finished bus to intensive scrutiny. This check focuses on the question: “How would the customer judge the vehicle?” The Quality Assurance function performs other inproduction roles (including assuring the quality of purchased parts for example) as part of the overall concept. Quality is a key consideration right from the start of development of a new bus. Quality Assurance staff are involved in the Simultaneous Engineering process for all new models, from the concept phase through to production maturity. Complete vehicles and components are subjected to intensive testing based on mod- Omnibus 3·<strong>2010</strong> Service 29 Every bus that rolls off the production line has undergone a whole series of tests. The staff assigned to carry out that vital stage of post-production must be specially trained and qualified. A team of 100 is responsible for testing at the Mannheim plant. Because quality saves customers money. elling and prototyping. The object is to ensure that the standards of quality required to meet customers’ operational needs are fully attained. In the case of a new model start-up, all the workstations planned for the production line are simulated in real production operations, with each process being repeatedly run through and optimised. This results in standardised assembly processes which deliver consistently high product quality in subsequent production. Special induction The high demands placed on the bus assembly personnel make it necessary for them to undergo special induction procedures in addition to their thorough training. New employees are integrated onto the line by means of a mentoring concept. This involves experienced colleagues teaching them the job in a direct, hands-on way, so all staff staff develop the necessary skills and knowledge to handle the work practices within their particular assembly group. Any errors are caught by the group’s quality gate and returned for rectification. This is beneficial to the indi vidual employees, who undergo continuous improvement, and also optimises the production process as a whole, based on the idea: mistakes can happen; if something goes wrong, it goes wrong – and is put right – here, not when the bus is being used by the customer. Customers can then be assured that the high quality standards of <strong>Mercedes</strong>-<strong>Benz</strong> buses will minimise the need for workshop repairs. Though of course, if they are needed at any time, they too will be carried out based on the same stringent quality control procedures. t www.mercedes-benz.com Photos: Martin Heying
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