Brake Caliper Casting and CNC Machining Manufacturing Guide
Caliper Types
Automotive brake caliper manufacturing uses gray iron G3500 for fixed calipers and A356 aluminum for floating calipers. Piston bore H8 with Ra 0.4 finish. Seal groove ±0.05mm. Guide pin bores for floating caliper alignment.
Weight: iron calipers heavy (performance/SUV), aluminum light (passenger car). Bleeder screw port with 60° cone seat.
| Type | Material | Weight | Vehicle |
|---|---|---|---|
| Fixed Caliper | G3500 iron | Heavy | Performance/SUV |
| Floating | A356 aluminum | Light | Passenger car |
| Integrated EPB | A356 alum | Light | Electric park brake |
| Monoblock | G3500 | Heavy | Racing |
Cast and Heat Treatment
Sand casting for iron, gravity/low-pressure for aluminum. T6 for aluminum: solution 540°C 8h, age 175°C 6h. X-ray for porosity, Zyglo for cracks. A356 with Sr modification achieves T6 tensile 275 MPa.
Iron G3500 as-cast 250 HB with pearlitic structure. Aluminum T6 achieves 275 MPa tensile strength with 5% elongation.
| Process | Iron G3500 | A356 Alum |
|---|---|---|
| Casting | Sand mold | Gravity/LPDC |
| Heat Treat | None | T6 540+175°C |
| Tensile | 250 MPa | 275 MPa |
| Hardness | 250 HB | 95 HB |
CNC and Testing
Bore: H8 tolerance, Ra 0.4, 0.01mm roundness. Seal groove ±0.05mm. 100% leak test at operating pressure. Burst: 4x operating. Sliding force test for floating calipers. CMM dimensional inspection.
Bleeder thread form verification. Guide pin bore alignment for floating calipers. Mounting face flatness check.
