Brake pads are installed on the wheels of a car. Disc brakes apply pressure to the brake caliper via a hydraulic system, creating brake pads that rotate with the wheel. This achieves braking friction. To ensure braking comfort, brake pads should be stable, noiseless, and vibration-free. Brake pads require high thickness uniformity and have specific requirements for surface runout, parallelism, and surface roughness.
Current Manufacturing Technology: Brake pads come in many types, are thin-walled, and are formed from a sand core. Different types of brake pads vary in disc diameter, disc thickness, and the gap between the two discs, as well as the thickness and height of the disc hub. Single-layer brake pads have a relatively simple structure. The weight of the casting is typically 6-18 kg.
Brake pads have screw mounting holes on their convex surfaces for connection to the car wheel. Double-sided discs have two friction surfaces. When the car brakes, the braking surfaces of the brake pads engage with the friction pads to generate braking torque. To ensure braking comfort, brake pads require high thickness uniformity, minimal runout of the brake surface end faces, parallelism of the brake surface end faces, and a low surface roughness.
Brake pads can be categorized by their structure into single-sided discs, double-sided discs, high-performance discs, and bearing discs. The brake pad blank is a casting. Machining requires the inner and outer diameters and end faces of the brake pad, drilling holes on the convex surface to connect threaded holes, and chamfering. High-performance brake pads also require drilling holes on the brake surface and hammering of some brake pad blocks. The brake pad machining environment is harsh, dusty, and involves a large amount of cutting. It requires machine tools with good protection and lubrication functions. The machine tool needs to maintain machining accuracy for extended periods under high torque. It requires machine tools with good rigidity and precision holding force.
The brake pad blank is a casting. End face turning, external turning, internal turning, and drilling must be completed. For finishing, two brake pad blocks are machined simultaneously using two turning tools to ensure the parallelism of the two brake surfaces. Typically, it consists of two turning sequences and one drilling sequence. The turning sequence is performed on two lathes. One lathe is equipped with a double-tool with a locking mold, and the drilling sequence is completed on a vertical machining center. The above process meets the requirements for machining accuracy and surface roughness; however, according to the brake pad brand's requirements, some discs need to be ground on a grinding machine.
Technical Requirements: The outer contours of the castings are all machined, and after finishing, there should be no shrinkage, porosity, sand holes, or other casting defects. The metallographic structure is medium-sized lamellar and graphitic, with a uniform structure and low section sensitivity. Most domestic manufacturers use clay sand wet molds, manual template molds, and grease sand cores. Some manufacturers or individual casting varieties use resin-coated sand hot box technology, while some manufacturers produce automotive brake pads on a molding line.
