Clemson has been a strategic partner with BMW since 2008, running a two-year-long project in which students in the Automotive Engineering program work to design, develop, program, prototype, and produce an innovative vehicle. For this latest version of the project, known as Deep Orange, the PhD students on the team worked on the BMW X3 in order to create a cost-efficient, low-volume manufacturing plan. The intention was that any new manufacturing plan created could not negatively affect the production processes currently in place.
The students approached the project by conducting basic market analysis in order to understand the consumer for whom they were designing. The BMW X3 is a vehicle that attempts to combine the utility of a pickup, through elements such as ample cargo space, while still meeting the requirements of higher fuel efficiency in a compact vehicle.
The students created a design that included a sliding roof that allows the trunk compartment to be transformed into an open-bed providing for a more truck-like hauling experience. In addition, other modifications were made to ensure the flexibility and functionality of the vehicle’s transformation from closed trunk to open-bed. All of this was designed to fit within the framework of the already existing BMW X3 but did require that modifications be made to the tailgate, roof, panels, side frames, guide rail, and windows. No small task indeed.
When the team approached the design of these modified parts, they had automatically defaulted to traditional metal stamping as the means for their creation. However, they soon began to search around for other options after getting a quote on the price and the timeline that the metal shop needed in order to create the parts. The program director of Deep Orange, Bill Sowerby, characterized the students discovery of the reality of metal stamping:
“Even with the excellent relationships we have with manufacturing suppliers, it didn’t make sense to steel stamp these large parts. Once the students realized traditional manufacturing was out of the question, they had to go back and rethink how to design and build the prototype.”
It was after hitting a wall that a student finally spoke up and suggested the team investigate the possibilities present through additive manufacturing. After that, everything just seemed to fall into place. After researching the options, the team decided to use Fused Deposition Modeling to produce the necessary parts. They chose this because the process allows for the creation of large objects by bonding smaller plastic pieces together using the same thermoplastic with which they were created, basically erasing the seam.
They created the files for the parts and sent them off to Stratasys Direct Manufacturing to get a quote and a timeline that they could compare to the alternative, steel stamping. To their great delight, the parts quote came back reduced by 75% and the timeline was shortened by 3 – 4 months. The team’s project manager, Ashish Dubey, described the pressures and solutions the team experienced:
“My team and I were facing the challenge of getting the parts built in the shortest possible time within the budget constraints. In addition to that, we were dealing with extremely tight dimensional tolerances and even a few millimeters of deviation from the CAD models would have resulted in [misalignment] of the parts or would leave us with big gaps…During our research we came across the FDM process; we chose FDM because the cost and time to make all the parts was drastically lower than the conventional sheet metal forming processes. The final parts were as good as it can get in terms of geometric dimensioning and tolerances. Overall, it was great working with the Stratasys Direct Manufacturing team and at the end of the day we got a chance to learn about a new technology which could very well be the future of low volume production parts.”
As in many industries, more and more people are beginning to realize the potential that additive manufacturing holds for the re-imagination of traditional manufacturing. The learning curve occurs as people and companies recognize that 3D printing does require consideration of a unique set of factors and adjustments need to be made to the design process itself to accommodate those. Senior project engineer at Stratasys Direct Manufacturing explained:
“FDM is a very different process than steel stamping so the redesign was important. I helped the Clemson students determine the best orientation and placement for the bonding joint to ensure we would accurately build and weld the parts together to meet dimensional accuracy. With thicker walls, we also knew there would be some slight stair stepping on the surface of the parts which is inherent with the layering process. This was new to the Clemson team and we reassured them that the layer lines could be removed with secondary operations.”
In all, Stratasys built 14 parts using ABS-M30 using the Stratasys 900mc 3D Production System. The finishing department there sanded the parts in preparation for the application of primer and paint and hot air welded the smaller segments into their larger finished form. The students and Stratasys weren’t the only ones pleased with the results. Rich Morris, Vice President of Assembly at BMW stated:
“The ability to integrate more low-volume models without incurring capital-intensive retooling costs and efficiency losses will be key to success in the future as we strive to respond to changes in market needs faster and with more flexibility. The students working on this phase of the project did an excellent job of keeping costs down while finding optimal integration opportunities.”
Let’s hear your thoughts on this intriguing use of 3D printing as a cost and time saver. Discuss in the 3D Printed BMW Prototype forum thread on 3DPB.com. Be sure to check out the time lapse video below of the students building this partially 3D printed proptoype vehicle for BMW: