German version

The success story of minibuses bearing the Mercedes star

Minibus GmbH is a true success story. Minibuses under the aegis of EvoBus have been part of the Mercedes-Benz portfolio since 1998. At the time, EvoBus began its activities in this segment with a participation in the minibus manufacturer Karl Koch GmbH in Mudersbach near Siegen. The business and industrial management of the new business unit became the responsibility of EvoBus.

Right from the start, the business unit made full use of the possibilities available within EvoBus. At the end of 2000 there were four production locations in Germany and France. There were also cooperative production arrangements in the UK, Italy and Spain. The Minibuses centre was formed as the business unit for this segment.

Mercedes-Benz Sprinter Travel 45

In 2004 the remaining Karl Koch shares were acquired, and Mercedes-Benz Minibus GmbH was founded with its headquarters in Dortmund. This is where minibus production had meanwhile been gradually expanded. At the end of 2005, all production in Germany was relocated to Dortmund. In the process the production area expanded to 5000 sq.m., and the number of employees increased to 160.

Continuous growth for the No. 1 position in Europe

Relocation of minibus production from Ligny (France) to Dortmund in mid-2008 was the deciding factor for expansion of the production area to over 7500 sq.m. This increased capacity to up to 1100 minibuses per year.

The number of production lines was increased, and for the first time continuous lines were used. Mercedes-Benz Minibus GmbH employed 250 personnel.

In subsequent years the constantly growing demand required a further expansion of the production and logistical capacity to the present level of around 12,000 sq.m. In line with this, the number of employees rose to the present level of around 330. Minibus GmbH is now able to produce up to 1300 vehicles per year on three bodyshell and four assembly lines. Mercedes-Benz is the western European market leader for minibuses over 3.5 t permissible gross vehicle weight.

The minibuses are now sold to more than 30 countries, the largest market continuing to be western Europe. Customers in Australia, South-East Asia and the Middle East are however also part of the regular customer base for Dortmund.

Minibuses with the three-pointed star – the same top quality as the large buses

Apart from individual product advantages, the success factors for Minibus GmbH include industrial production in Dortmund and the benefits of close links to the development and production of the Mercedes-Benz Sprinter as the base model.The specialists at Minibus GmbH are informed of any changes at an early stage. Modifications to the body and suspension system necessary for minibus production are coordinated right down to the last detail, as are additions to the vehicle weight.

Extensive driving tests verify the modifications. All procurement and production, as well as the complete order administration process, follow the stringent guidelines and processes of Mercedes-Benz. Guaranteed quality from a single source is one of the hallmarks of minibuses bearing the Mercedes star.

All industrial production processes and line assembly are subject to quality controls. Minibus production is governed by the same, high quality standards that apply to Mercedes-Benz Vans. An intensive final inspection provides independent quality assurance. Every minibus also undergoes an extensive test drive. A waterproofing test is also mandatory if modifications have been made to the roof.

Mercedes-Benz Minibus GmbH also provides after-sales backup for its customers and buses. Extensive documentation ensures the availability of replacement parts. Moreover, the minibuses are included in the unique, bus-specific service network of Omniplus. Used minibuses of proven quality are sold on a Europe-wide basis by the new used bus brand BusStore.

From sales, production and service to later recycling – the advantages of single-sourced minibuses bearing the three-pointed star are obvious.

Production: Flexible and professional

Interior conversions to panel vans, modifications to the bodyshell and installation of larger entries and rear-end extensions, custom bodies and even low-frame chassis of in-house design for the spectacular three-axle Sprinter City 77 – the minibus production is flexible and professional.

Bodyshell: disassembly precedes assembly

The plants in Düsseldorf (Sprinter panel van) and Ludwigsfelde (chassis) deliver the base vehicles for minibuses by truck. These are first disassembled before production commences: detachable parts such as bumpers, radiator grille, headlamps and tail lights, including the Mercedes star, are removed, as are the doors, cab seats, side windows and fuel tank. In the case of chassis this also includes the rear axle and propshaft.

Until reassembly all vehicle-specific parts are kept in pallet trucks in the logistical area, to be returned to production as and when they are needed. The cockpit remains in the vehicle, but is carefully covered over to ensure protection from damage and soiling.

Mercedes-Benz Sprinter Travel 55

Panel vans are frequently extended

Bodyshell production is on three lines. Typical bodyshell work for panel van conversions includes enlarged entries and large apertures for passenger doors. Reinforcement and cutting work for air conditioners, roof vents, skylights or destination displays is also carried out here, and wheel arches are lowered to provide more legroom in the passenger compartment.

The striking rear-end extensions of GFRP have an integrated tubular frame and are only mounted on the rear of the longest panel van version. These models also have window apertures enlarged towards the rear. The rear-end extensions reflect the styling features of the Sprinter, and are perfectly integrated into the overall design.

Models of ribbed construction: Cataphoretic immersion for perfect corrosion protection

For vehicles with a ribbed bodyshell structure, the body is completely prefabricated and delivered ready for assembly. As with the large buses from Mercedes-Benz, cataphoretic immersion priming dependably protects the structure against corrosion. Cab conversions for large passenger entries are carried out in the same way as for panel vans.

The Sprinter City 77 is a special case: this three-axle model with space for up to 40 passengers has its own low-frame chassis. It is produced as a complete ribbed structure including the mountings for the independent rear suspension before being joined to the Sprinter tractor unit.

In the next stage the crew install the rear end, roof and GFRP side panels of vehicles with a ribbed body structure. These parts are bonded in place with adhesives. Apertures are then cut for roof vents and air conditioning units as with panel vans.

Paintwork: Carefully applied individual colours

All new and modified body surfaces are painted – in the case of panel vans with a rear-end extension e.g. the extension and the directly adjacent areas, but not the tractor unit. Parts added as modifications to the original body, e.g. entries, are also painted. Window apertures in the body are carefully masked by the personnel before painting. They also prime and paint the seams and structural ribs.

As the next stage, the body is cleaned and degreased before being treated with filling compounds and ground smooth. After further cleaning it is primed, and a filler coat is applied. Only then is the cover coat applied. Metallic paints are always given an additional coat of clear varnish, and a clear coat is also available with non-metallic paints on customer request. The painted body is then polished to a high sheen. There is an almost unlimited choice of individual paint finishes: In addition to over one hundred listed paint designs, Mercedes-Benz is able to cater for almost any colour request, including the detachable parts. These are separately painted by hand, with a high-quality surface finish. Multi-coloured paint finishes are a day-to-day occurrence in minibus production, as are customer-specific vehicle decals.

For perfect corrosion protection, the painted buses are then transferred to vacuum pressure cabins. This is where the cavity sealing is applied, and the underbody protection completed and sealed with a layer of wax.

Assembly: Customer-specific buses on four lines

Installing the interiors of the minibuses is particularly labour-intensive. Including pre-assembly operations, around 100 personnel are engaged in this. Production is on four lines, depending on model series and the work required.

Preassembly work is carried out in the same production shop, in parallel with installation. This is where the flooring is cut to shape by machine, windows are delivered on a vehicle-specific basis, instrument panels are prepared for additional, bus-specific controls and the vehicle electrics are prepared with an individual wiring harness. Ceilings, luggage shelves, air conditioning ducts and panelling are pre-assembled. Not least, the personnel carry out modifications to the powertrain, prepare the doors, grab rails and partition walls, and make the seats available. Delivery to the relevant assembly station covers short distances, using pallet trucks on a lateral supply basis.

Extensive procedures covering eight work cycles

The assembly process for each bus consists of eight cycles, each with extensive working procedures. It begins with adhesive bonding of the flooring in the required decor, and installation of the windows and roof vents. This is followed by installation of the electrics and a high-level station. This is where underbody work is carried out on the chassis, e.g. modifications to the powertrain, installation of the retarder, rear axle, fuel tank and exhaust system. This above all involves installation of the components and parts that were initially removed when the panel van or chassis was first delivered.

Back on level ground, work continues with the interior panelling including luggage shelves and air conditioning ducts, convector heaters and doors, plus their power supply. The interior fittings are completed during the last two cycles. The main items are the seats, grab rails, partition walls and curtains. Service fluids are checked and the batteries are installed.

Finish: Meticulous checks before an extended test drive

The finishing and final inspection stations await the new minibus after assembly. If included, the destination display is defined and programmed at this point.

Each individual bus is subsequently subjected to rigorous checks. This even extends to verifying the distances between seats for approval purposes. Not least, the personnel verify the quality reports from every assembly station. Even then, the process is not yet at an end: every minibus is sent on an extensive test drive. This takes place on public roads and takes around half an hour. A waterproofing test is also mandatory if modifications have been made to the roof. Only then is the bus given a final inspection and acceptance. The new bus is delivered either to the customer or to the relevant sales office. Depending on the model and level of equipment, between ten and 35 days will have passed since production commenced.

Intensive quality checks even after delivery

Quality is the watchword in production. As in all the company's plants, the global product audit system GPAS is used as the assessment principle. In this process, quality is precisely measured using comparable key figures. All production processes are subject to quality controls which are independent of production.

The quality of minibuses from Dortmund unreservedly meets the level of their larger siblings bearing the Mercedes star. This is also confirmed by the customers. Six weeks after delivery, customers are asked to give a satisfaction rating by an external service provider. The results are relayed to Dortmund for intensive evaluation.

Highly trained and qualified personnel

The preconditions for first-class quality not only include a precise production process with intensive checks and tested, high-quality parts, but above all also highly motivated and well-trained personnel. Only specialist personnel are employed in minibus production.

This is why Mercedes-Benz Minibus GmbH has an above-average commitment to the training of young people: around ten percent of the production workforce are trainees. Dortmund carries out training in five professional areas: body and vehicle assembly, automotive mechatronics, paintwork, warehouse logistics and administration.

Completion of this training does not bring learning to an end at Mercedes-Benz, however: the further training requirements of every single employee are assessed during annual interviews, and a training schedule is prepared on this basis. This ensures that the knowledge and capabilities of all employees are always up-to-date. The aim is after all to further consolidate the leading position of Mercedes-Benz minibuses in western Europe.

Mercedes-Benz Sprinter Travel 65

Photos and text:
Daimler AG