Machining Integrated Carbon Fiber and Metal Hybrid Bike Handlebars with 5-Axis CNC
The pursuit of aerodynamic and weight savings has led to the rise of one-piece carbon fiber handlebar and stem combinations .However ,the clamp areas for the shifters and stem faceplate are problematic—carbon fiber can be crushed by high clamp forces.The advanced solution is a hybrid preform:a carbon fiber bar with precisely located ,co-cured or bonded aluminum insert segments at the clamp zones ,which is then finish-machined as a single unit.This requires the capabilities of 5-axis CNC machining ,a core strength of DHT.
The Hybrid Preform: Best of Both Worlds
The part begins as a molded carbon fiber bar with partial aluminum cylinders or blocks co-cured at the shifter and steerer clamp locations. This preform is rough, with excess material on the metal inserts. The challenge is to machine the final clamp features—complex rounded shapes, grooves, and threaded holes—in the aluminum and seamlessly blend these machined surfaces into the contoured carbon bar, all in one setup.
5-Axis CNC: The Essential Enabler
A 3-axis machine cannot access the compound angles of a handlebar. 5-axis simultaneous machining is required:
Single Setup Accuracy
The hybrid preform is fixtured once. The 5-axis machine can rotate and tilt the part, allowing the cutting tool to approach every surface from the optimal angle. This guarantees that the machined features on multiple aluminum inserts are perfectly aligned with each other and with the carbon bar’s geometry.
Contoured Blending
The machine can follow the 3D contour of the carbon bar to machine a smooth, flush transition from the aluminum insert to the carbon surface, eliminating any steps or gaps that could create stress risers or an unappealing finish.
Machining the Carbon Sections
The same setup can be used to trim the ends of the carbon bar or machine other carbon features with extreme precision, ensuring everything is referenced to the same datums.
DHT’s Process for a Flawless Finish
Custom Soft-Jaw Fixturing
We mill custom fixturing that cradles the delicate carbon shape without crushing it, while securely locating the preform via the unmachined aluminum inserts.
Toolpath Strategy for Dissimilar Materials
We program separate toolpaths for aluminum (higher speeds/feeds) and carbon (abrasive, fiber-specific parameters), using different tools to optimize finish and tool life for each material.
Dust and Chip Management
A specialized vacuum system removes aluminum chips immediately to prevent them from scratching the carbon surface.
The result is a high-end, one-piece handlebar where the performance of carbon fiber is combined with the reliable, durable clamping of machined aluminum, all in a perfectly integrated component with flawless aesthetics and geometry. For brands at the forefront of cockpit design, this hybrid manufacturing approach, executed with DHT’s 5-axis precision, is the key to delivering next-level performance and integration.
