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.
In 1949 the former aircraft engine plant began producing parts for motorcycles (being assembled at the Munich plant at that time). Over a period of years motorcycle production was transfered from Munich to Berlin with the fi rst complete machine being produced at the plant in 1967.
- 1949 – Production of machine tools and motorcycle components at BMW Maschinenfabrik Spandau
- 1967 – Start of motorcycle assembly – fi rst model BMW R 60/2
- 1969 – Start of engine assembly – transfer of motorcycle production to Berlin concluded
- 1984 – Inauguration of new assembly hall and machine shop with SOP of K-Series
- 1993 – Expansion of assembly facilities and machining operations for production of new generation of Boxer motorcycles
- 2001 – One millionth motorcycle produced at Berlin
- 2009 – 40th anniversary of production at Berlin
AMS: How many models are currently produced at Berlin?
Franz-Xaver Burgmeier: We produce 19 different models here. These are both volume and niche models. We are starting production on a new model (based on the S1000RR) in September, but it will be very low volume to begin with and then we ramp up production in the spring of next year
AMS: How many lines do you have for engine and bike assembly?
F-XB: There are seven lines for motorcycle assembly at present, but we will be adding an eighth line in 2013 for full production of our E-Mobilty electric scooter that was used at the London Olympics. We have four engine lines.
AMS: Which of these lines are dedicated and which ones mixed?
F-XB: We currently produce all versions of the aircooled generation boxer models on line T1, but this will be switched in the future to a mono-line for the new generation (water-cooled) of boxer models. The lines are mixed according to the model, so the S1000RR and K1600 models are produced together, scooters variants on another line and twin cylinder bikes on another. There are up to five different models on one line.
AMS: Did you have to introduce any new machining/ assembly processes for the six-cylinder and new water-cooled boxer engines?
F-XB:We had to introduce a new cold test process for both engines. The crankshafts for the six-cylinder required very high tolerance machining, down to 2μm. This level of accuracy required us to invest in new machining centres and a climate controlled testing room to ensure accuracy of measurement.
AMS: Why did you introduce new cold testing for these engines?
F-XB: It is a much faster test procedure and allows us to identify any problems much sooner. The loop for any corrective action is only two metres along the line and there is no additional handing required so the whole process is now much faster. Investment in new production systems is an on-going process; we invest around €30 million per year just on production, excluding buildings.
AMS: What is the current lead-time on production planning?
F-XB:At present it’s nine days. Most of our production is built to order, so the customer can make changes to their order up to nine days before we start building the bike. After this the specification is fixed. The average time from start of production to the finished bike is around 6 to 12 hours, depending on the model and specification.
AMS: How do you track and monitor a given motorcycle through the production process?
F-XB: We use IPSL, international production system software. The bike is checked 20 times during the production process to ensure it’s following the order specification. We have a ‘history book’ for each bike produced, which records every stage of its assembly. We use both bar codes and RFID systems for tracking and tracing; it depends on the application as to which method we use.
AMS: It was interesting to see that certain operations are performed by the car division; notably the aluminium fuel tank pressing and forming for the S1000RR and crankcase machining on the six-cylinder engine. What percentage of this type of operation is outsourced?
F-XB: We weld the fuel tanks here at Berlin as well as the aluminium frames. We also produce some of the steel frames. About 80% of the components are outsourced.
AMS: Berlin is an historical site so I understand there are restrictions on making changes to certain building at the plant. Also you are situated in a built-up area, so do you have any plans to expand the facility?
F-XB: We have been fortunate enough to acquire a site next to here, which covers about 40,000m2. As yet it has not been decided what purpose it will have.
AMS: You mentioned a new line for producing the electric scooters. Are there any particular challenges in manufacturing this type of vehicle?
F-XB: It is not as easy due to the high voltages involved with the EV batteries, so we have to address safety issues for the workers. But it is a less complicated process than with a normal bike. The battery is also the chassis and it is much quicker to test the motor and systems.
AMS: Will you use a similar assembly process to that of the motorcycle?
F-XB: The initial volume will be low so it will be more of a ‘hand-built’ approach to production, but as the volume grows we will develop the process.
AMS: What areas of production are looking to improve efficiencies?
F-XB: This is a daily business for us; we look at every area of production to see how we can improve the efficiency. For example over the last six years we have reduced our energy consumption across the plant by 20% and we are targeting a further 20% reduction over the next six to seven years.