At its Regensburg plant, BMW’s jigs and fixtures department is currently using fusion deposition modelling (FDM) for the direct production of tools used in various manufacturing and testing processes. According to engineer Günter Schmid, the FDM process has proved an effective alternative to conventional metal-cutting manufacturing methods like milling, turning, and boring. Both he and fellow engineer, Ulrich Eidenschink, have also demonstrated its financial advantages. And for hand-held devices used on the assembly line, they have discovered that there are even greater advantages that arise from the design freedom that the technology offers.
Schmid and Eidenschink employ FDM to make ergonomically designed assembly aids that perform better than conventionally made tools. The FDM technique is used to enhance the ergonomics of hand-held assembly devices, improving productivity, worker comfort, ease-of-use, and process repeatability. The freedom that this design technique imparts has allowed the engineers to create lighter configurations with better balance. Indeed, Schmid insists that tool designs created in FDM often cannot be matched by alternative parts that have been machined or moulded.
In one example, BMW reduced the weight of a device by 72% with a sparse fill build technique. Replacing the solid core with internal ribs cut 1.3 kg from the device. “This may not seem like much,” says Schmid, “but when a worker uses the tool hundreds of times in a shift, it makes a big difference.”
Another advantage of rapid manufacturing is improved functionality. Since the additive process can easily produce organic shapes that sweep and flow, the tool designers can maximise performance while improving ergonomic and handling characteristics.
“The layered FDM manufacturing process is well suited to 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 they are 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 FDM’s 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 capitalise 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. They claim that FDM is taking on increasing importance as an alternative manufacturing method for components – particularly those made in small numbers.
FDM technology is marketed exclusively by Stratasys