Carbon Fiber or Aluminium for a Structural Part

The Property That Actually Matters

Most structural parts are not limited by strength. They are limited by deflection - the part is strong enough but bends too much, so the machine loses accuracy or the camera loses stability.

Carbon fiber has high tensile strength, low weight, high chemical resistance, high temperature tolerance and low thermal expansion. It is the combination of low weight with high stiffness that makes it desirable in aerospace, civil engineering, military and competition sports equipment manufacturing.

Question One: Does Weight Cost You Anything

On a drone, weight costs flight time directly. Compared with traditional materials, carbon fiber parts reduce weight by about 40 per cent, which largely increases the duration of flight.

On a robot arm, weight costs cycle time through inertia. On a static bracket bolted to a wall, weight costs nothing at all - and there aluminium usually wins on price.

Question Two: Is the Load Directional

Metal is isotropic: the same properties in every direction, whether you need them or not. Composite is not. Unlike metal tubing, carbon fiber tubing is designed with layers of fibres oriented at different angles to provide properties designed for a specific application.

If the load is predominantly in one direction, that is an argument for composite. If the load comes from everywhere, some of the advantage is lost.

Question Three: What About Heat and Interfaces

Aluminium conducts heat. If the part is a heat path, that is not negotiable, and a housing may need to stay metal even in an otherwise composite assembly.

Interfaces matter too. Threads, bearing seats and sealing faces are usually easier in metal. A common answer is a hybrid: high strength structural parts made from carbon fiber composite combined with traditional metal materials, which is exactly how many bicycle, sports equipment and drone parts are built.

A Practical Way to Decide

Quote both. CarbonWizer machines aluminium prototypes from solid and moulds composite parts in the same facility, so a housing can be priced in both materials before the decision is made rather than after.