Direct Digital Manufacturing at BMW
In the jigs and fixtures department at BMW
AG, Regensberg, a Fortus system is used
to manufacture assembly tools. This tool is
used to affix the rear name badge.
Produced with direct digital manufacturing,
this tool is used to attach bumper supports.
Rapid prototyping has become a standard practice in product development. At the BMW AG
plant in Regensburg, Germany, FDM (fused deposition modeling) continues to be an important
component in vehicle design prototyping. But moving beyond prototyping, BMW is extending
the application of FDM to other areas and functions, including direct digital manufacturing.
The plant’s department of jigs and fixtures uses a Stratasys 3D Production System to build
hand-tools for automobile assembly and testing. According to engineer Günter Schmid, “BMW
has determined that the FDM process can be an alternative to the conventional metal-cutting
manufacturing methods like milling, turning, and boring.” Schmid and fellow engineer, Ulrich
Eidenschink, have shown that financial advantages include cost reductions in engineering
documentation, warehousing, and manufacturing.
For hand-held devices used on the assembly line, engineers have discovered that
there are even greater advantages that arise from the design freedom that FDM
offers. Capitalizing on the elimination of constraints, Schmid and Eidenschink
employ FDM to make ergonomically designed assembly aids that perform better
than conventionally made tools.
To improve productivity, worker comfort, ease-of-use, and process repeatability,
the plant uses FDM to enhance the ergonomics of its hand-held assembly devices.
The freedom of design allows engineers to create configurations that improve
handling, reduce weight, and improve balance. According to Schmid, “The tool
designs we create often cannot be matched by machined or molded parts.” In
one example, BMW reduced the weight of a device by 72 percent with a sparsefill
build technique. Replacing the solid core with internal ribs cut 1.3 kg (2.9 lbs)
from the device. “This may not seem like much, but when a worker uses the tool
hundreds of times in a shift, it makes a big difference,” says Schmid.
Another advantage of direct digital manufacturing is improved functionality.
Since the additive process can easily produce organic shapes that sweep and
flow, the tool designers can maximize performance while improving handling
characteristics. “The layered FDM manufacturing process is well suited for the
production of complex bodies that, when using conventional metal-cutting
processes, would be very difficult and costly to produce,” says Eidenschink.
An example is a tool created for attaching bumper supports, which features a
convoluted tube that bends around obstructions and places fixturing magnets
exactly where needed.
The jigs and fixtures department has developed a simple flow chart to determine
when FDM is a fitting option. The criteria are temperature, chemical exposure,
precision, and mechanical load. With Stratasys ABS material, which the engineers
find comparable to polyamide (PA 6), many tools for vehicle assembly satisfy the
criteria. For those that do, designers can create devices that capitalize on all the
advantages of the additive process.
Both Schmid and Eidenschink believe that no enterprise can afford to do without
rapid prototyping for product development. Yet, they see so much more possibility.
“FDM is taking on increasing importance as an alternative manufacturing method
for components made in small numbers,” says Schmid.