BMW has applied a high level of automation to motorcycle production at its Berlin plant
Motorcycles are as much part of BMW’s manufacturing heritage as cars, and both divisions share production processes and developments. Motorcycle production typically allows or requires less automation, but just as in four-wheel manufacturing, flexibility, efficiency and productivity are key and the Berlin plant has optimised its production processes with high-tech automated systems.
The plant’s 60 CNC machining centres process the main engine elements, such as engine cases, cylinder heads, crankshafts and connecting rods. The new six-cylinder engine case is the exception; machining on this is carried out at another BMW facility. The parts are finished to very high tolerances, as head of assembly Franz-Xaver Burgmeier expalins overleaf, and to ensure the levels of accuracy are met the company has installed a climate controlled, cleanroom that uses Zeiss 3D measuring systems to monitor quality. The machine shop also features a valve seat insertion machine and titanium cutting tools.
A highly concentrated cooling lubricant is combined with water (which makes up most of the coolant volume) to form an emulsion for the machining processes. BMW says this specialised process gives the lubricant a service life of over five years.
Frame elements, fuel tanks and chassis components are also produced here. Utilising other BMW resources the fuel tank sections are cut and formed at the company’s Eisenach pressing facility. At Berlin these pieces are then placed on a turntable jig and welded using a 10-axis automated welding system.
The frame production at Berlin also uses high-tech automated systems. For example, the K-Series bikes use a large-volume aluminium frame, which is made up of nine different sections. Two linked machining centres cut and process the aluminium frame and cast parts using a dry process that requires no coolant. The parts are transported between machining operations on free-moving work piece carriers that are controlled using transponders. A 10-axis laser cutting system prepares the ends of the individual frame tubes prior to welding. These computer controlled machining centres, are designed to offer maximum flexibility and high precision. The steel tubular frame for the R1200 GS model is also welded by robots, but the rear section is a complex structure, consisting of 80 individual parts, so some manual finishing is required.
Again computer management systems control the assembly and testing process. A conveyor line takes 70 work-piece carriers to 150 engine technicians working in two shifts who build up to 450 engines per day. The technicians are supported by 21 automatic workstations. It takes around 90 minutes to assemble a Boxer engine and around 160 minutes to assemble an in-line six-cylinder engine. The work piece carriers feature transponders that provide assembly information for each engine. Engine testing uses a combined cold-running and gearbox tester that checks engine torque, noise emissions and conducts pressure tests. BMW has developed new production tooling for specific applications. An example of this is assembly of the valve-train on the K-series engines. The double overhead cam, 16-valve units require a complex assembly and set-up process so the company has developed special tooling for setting valve timing and clearances. Further automation includes the application of sealants.
While the whole plant typifies BMW’s high-tech approach to production the paintshop presents an interesting contrast. Five computer-controlled robots apply 30 shades of waterbased paint to several thousand motorcycle components a day, and these will encompass more than 70 different configurations and designs. In contrast to this, a steady human hand is still needed. A team of expert painting specialists applies the traditional trim lines as well as tape applications to the tanks and side panels.
BMW says this is one of its most advanced paint facilities using hydro-technology to reduce its environmental impact.
Although most of the assembly is a manual operation, the process employs a high level of automation in the delivery and monitoring of components. The motorcycles are fixed on mounting hooks, moving on a flexible conveyor system through a 500-meter-long assembly line. To offer the best ergonomic solution the hooks swivel through 180° and adjust automatically to the optimal working height at the assembly stations. All order-related data as well as fastening torques and default settings are conveyed automatically to the particular assembly station. Depending on the model it requires between 220 to 360 minutes for the 2,000 parts and components to be assembled into a complete and customerready BMW motorcycle. Cascade (Control Application Sequences for Coding and Diagnostics Execution) is an electronic system that is used to check all the essential functions of the motorcycle in a programmed order.
Dynamic testing is the final stage. A team of nine specialists ‘ride’ each motorcycle 100km on the dynamometers. Here the bikes are taken up to speeds of 120km/h while the brakes, ABS, gearbox and suspension are all given a final test. Like the paintshop this part of the process uses both automation (electronic monitoring and display of performance parameters) and the expertise and intuition of the specialists.