Desktop Factory: Production from a Construction Kit
A visit to Legoland shows that everything can be easily assembled with small building bricks. A similar path is now also being pursued in production by Bosch and its subsidiary BoschRexroth: Entire production lines can be assembled anew with small production modules ('the bricks'). This saves on production floorspace, is more flexible in planning and operation, and lower-risk in the face of fluctuating quantities and uncertain business developments.
Flexibility in production is everything: Start of production is getting closer. A customer would like to see some last-minute changes to the product taken into consideration. An inspection process for quality assurance is still to be swiftly incorporated. The quantity is increased. In short: Production engineers are in a constant state of stress. But now they can breathe a little sigh of relief: Researchers and design engineers at Bosch have, under the name of Desktop Factory (DTF), devised and brought onto the market through the subsidiary BoschRexroth a production concept which takes production flexibility to the peak of performance with a modular assembly system.
The name Desktop Factory says it all: The assembly processes actually take place on the dimensions of a desk. And even smaller still: The typical process surface area for interconnection, laser welding, joining, pressing in, inspection, and testing of parts and components is a classic DIN A4 sheet. Ahead of this the researchers position a transportation system from module to module, and after this the material feed. "In total one module measures not more than 22 times 66 centimeters," explains Volker Henrichs from Bosch Research in Schwieberdingen. A project team of assembly experts from the plants and from Research devised the concept, which around two years ago was transferred to the Linear Motion and Assembly Technologies Division at Rexroth.
The project was assigned high priority in application research. Each production module, whether it be for joining, assembly or welding, should be structured as simply as possible, tailored perfectly to a single production step, and slotted precisely -- just like Lego bricks -- into a production line of similar modules.
Short conversion times, reusable process modules
Since the completion of the research projects two years ago and the successful transfer of the DTF concept to the Bosch subsidiary Rexroth, researcher Henrichs has taken on the role of a consultant: With all his acquired know-how he is the point of contact for the production engineers at Bosch and analyzes with them "whether" and "how" DTF can be used in their production tasks.
The boundary conditions for "production on a desk" are clearly defined: The component should not measure more than ten centimeters (Henrichs: "Everything that fits into one hand."), cycle times are above three seconds and with so-called "one piece flow" always a complete component "growing" on the line sets off on its journey. Within these stipulations DTF delivers amazing results, as Henrichs can report from initial successes: In a concrete DTF application 90 days of line stoppage could be avoided through conversions and adaptations compared with conventional assembly lines. This increases productivity. "For a plant this becomes a clear site advantage," says Henrichs. In this application case the engineers even reduced the conversion costs to under one tenth. The overall length of the assembly line could be reduced from 60 to 15 meters.
The DTF process steps include assembly, laser welding, joining, pressing in "and very special inspection and test programs," explains Henrichs. If specifications for the product change or a customer wants additional inspection and test processes, the individual modules can be easily exchanged or rearranged. If the quantities are to increase, the engineers increase the output simply by multiplying modules with time-critical processes. Such conversion measures are not only shorter, but also cheaper because the modules are reusable. "A conversion used to mean that many machine parts were segregated and scrapped," says Henrichs. Today the removed modules can be reused: As defined process modules they are ready to be called for reuse.
Process-module construction kit is available throughout the company
At Bosch the DTF innovation pays off twofold. On the one hand, the company has acquired its own process construction kit of standard production modules. This kit contains modules for pressing in, joining, metering, sticking, laser welding and labeling, and palletizing. From this construction kit available exclusively to Bosch, production engineers can put together their lines, whereby simple modules come from suppliers and modules with key technologies are created in-house.
On the other hand, Rexroth also offers the DTF basic construction kit (not including the processes with the Bosch core know-how) on the market and uses the opportunity to generate new sales and to achieve for Bosch economies of scale on the cost side.
