Disc rotors, also known as brake discs or brake rotors, are a crucial component in the braking system of vehicles equipped with disc brakes. The primary purpose of disc rotors is to work in conjunction with brake pads to generate the friction necessary for slowing down or stopping a vehicle. Here are the key purposes of disc rotors in a vehicle's braking system:

1. **Friction Surface:** Disc rotors provide a flat and smooth surface where brake pads can make contact. When the brake pedal is pressed, hydraulic pressure is applied to the brake calipers, causing the brake pads to squeeze against the rotating disc rotor. This contact generates friction, converting the kinetic energy of the moving vehicle into heat.

2. **Heat Dissipation:** As the brake pads clamp down on the disc rotor, the friction generated produces a significant amount of heat. The disc rotor's design includes features such as vanes or fins that help dissipate this heat efficiently. Proper heat dissipation is crucial to prevent brake fade, maintain braking performance, and extend the life of brake components.

3. **Braking Force Transmission:** The disc rotor serves as a platform for the brake pads to create the necessary braking force. The friction between the brake pads and the rotating disc rotor is what ultimately slows down or stops the vehicle.

4. **Compatibility with Calipers:** Disc rotors are designed to work in conjunction with brake calipers, which house the brake pads. When the caliper squeezes the brake pads onto the disc rotor, the resulting friction generates the force required to decelerate the vehicle.

5. **Compatibility with Anti-lock Braking System (ABS):** Disc rotors play a role in ABS-equipped braking systems. ABS uses sensors to detect wheel lockup during braking. The design of the disc rotor, along with the responsiveness of the brake system, helps facilitate the modulation of brake pressure by the ABS system, preventing skidding and improving vehicle control during emergency braking situations.

6. **Durability and Material Selection:** Disc rotors are typically made from durable materials such as cast iron or composite materials. The choice of materials ensures that the disc rotor can withstand the intense heat generated during braking without warping or deteriorating over time.

Regular inspection and maintenance of disc rotors are essential to ensure their proper functioning and to address any signs of wear or damage. Over time, disc rotors may wear down, become scored, or develop grooves, requiring replacement to maintain effective braking performance and overall vehicle safety.