WorkNC helps to shorten lead times in the Bentley Motors Styling Studio

Bentley Motors has been dedicated to the design, engineering and crafting of the world’s most respected high performance cars since 1919. Owned by the Volkswagen Group since 1998, the company’s Crewe headquarters have received massive investment, with a new and successful racing programme and the design and launch of the new Continental range.

<< The WorkNC calculation times are really fast, it only takes 15 minutes to create a day’s worth of machining. >>
Kevin Baker, Design Model Manager for Bentley Motors

Bentley’s Styling Studio plays a crucial role in the pace of development for its new cars, and it selected WorkNC to machine internal and external clay styling models as part of the transition from manual methods. Kevin Baker, Design Model Manager for Bentley Motors, said, “We have four ITP machines with CMM and machining capability which have the capacity to machine both sides of four full sized vehicles simultaneously. We chose WorkNC for its ease of use and flexibility.”

During the development phase of a new vehicle, two or three third scale models may be cut through WorkNC from imported IGES CAD data. Designers will refine these by hand until they are satisfied with the aesthetics. The models are then reviewed so that a choice can be made for the manufacture of a full sized car and, ultimately, to achieve styling release. Cloud scanning of the chosen design records the finished shape which can then be imported into WorkNC as an STL file for remanufacture, or into the company’s CAD systems, allowing the true shape of the vehicle to be captured. STL files of half the vehicle can be around 75Mb, while IGES files for the full vehicle can be 80Mb. Kevin Baker added, “Once the model is loaded, manipulation in WorkNC is very fast, making it easy to rotate pan and zoom the large amount of data we import.”

For components such as road wheels, lamps and fascias the company also has a fifth ITP machine programmed by WorkNC. This can machine harder materials such as model board, enabling prototypes and prototype tooling to be manufactured to prove out the design.

When building a model, the Styling Studio starts with a base shape in foam, which is undercut, using WorkNC, by about 30mm. Clay is then built up to above the finished surface level and, once this has set, a grid cut is performed with a 50 to 100mm stepover to ensure sufficient material has been added. The next roughing pass with a 12mm ball cutter and 8mm stepover uses WorkNC’s Planar Finishing cycle and leaves 5mm of material on. Finally, the finishing toolpath, again using Planar Finishing uses a 10mm ball cutter with 2mm stepover. At each stage, users can quickly and simply modify or restrict the cutter trajectory with WorkNC’s graphical toolpath editing. Kevin Baker said, “The WorkNC calculation times are really fast, for one side of a complete car it only takes about 15 minutes to create a day’s worth of machining.”

Using digital methods has some very significant advantages for Bentley as it can carry out more design iterations within a shorter time. Prior to using WorkNC and the ITP machines, shaping a full sized model would take four to six people three weeks. The same task can now be completed by one person in one week. Additionally, shaped pockets can be reliably machined into the finished and painted model, ready to accept prototype fittings such as lamps and door handles. Finally, the symmetry of the car is guaranteed by using the same model data to cut both sides of the vehicle, reducing the time to balance surfaces by half. Kevin Baker added, “Four modellers in the Styling Studio use the two WorkNC seats. Its ease of use makes their tasks much simpler and they have absolute confidence in the results it produces.”

Model production times have been greatly reduced at Bentley. Furthermore, using the new techniques has introduced a more structured approach to vehicle development, making it easier to interpret CAD images by comparing them with a physical model, which in turn reduces the number of design iterations. Kevin Baker concluded, “WorkNC is a very important element in this new process, helping us to reduce timescales and optimize our designs.”