CBN Inserts Machining Solution for Gray Cast Iron Brake Discs

Brake discs are mostly made of gray cast iron, with major grades including FC250 and FC300. Tool selection is crucial when mass-producing these workpieces.

Traditional gray cast iron brake disc machining relies on carbide or ceramic tools, but these shortcomings are particularly evident when used in mass production lines:

      1. Low cutting efficiency and poor surface finish.

       2. Short lifespan and frequent inserts replacement slow down the production line.

       3. Poor precision stability and high rework costs.

Addressing the limitations of traditional machining technologies, SCBN TOOLS continuously researches and develops breakthroughs, launching new brake disc solutions and leveraging its technological strength to efficiently solve problems for customers. Solid PCBN inserts (SBN850): enable integrated roughing and finishing.

 1. Roughing: High-Parameter “Violent Stock Removal” and Doubles Efficiency

Roughing brake discs requires rapid removal of 25-35mm thick stock. Conventional tools are afraid of wear and tear, so they are reluctant to increase speeds. CBN tools, however, can directly utilize “high cutting parameters”: Cutting speeds are increased to 350-550m/min (2.5-3 times that of carbide), with feed rates reaching 0.35-0.6mm/r. This reduces roughing time per piece from the traditional 9-12 minutes to 3-5 minutes, increasing efficiency by over 60%.

Longer-than-conventional tool life: High-quality solid CBN inserts can continuously process 1,000-1,500 brake discs before requiring a tool change, reducing tool change frequency by 10-15 times and perfectly adapting to the “non-stop” production rhythm of the assembly line.

      2. Semi-finishing: Wiper + Roughing and Finishing in One, Single-Pass Processing without Rework

 Semi-finishing requires a balance between dimensional accuracy (tolerance ≤ 0.02mm) and surface quality (Ra1.6-Ra3.2). Conventional tools require multiple passes, while CBN tools, with their integrated roughing and finishing cutter body and dedicated wiper, achieve a single-pass finish.

 The wiper of CBN inserts specifically designed for brake discs utilizes a “short straight line + slightly rounded transition”structure. Its length precisely matches the width of the brake disc’s machining surface (typically 80-120mm). This allows for direct smoothing of feed marks during cutting, maintaining a stable surface roughness within Ra1.8 without the need for additional grinding.

         SCBN TOOLS SBN850 CBN inserts are ideal for brake disc machining. With their long life, high precision, and excellent cost-effectiveness, this grade perfectly meets the needs for efficient machining of gray cast iron brake discs, providing manufacturers with a solution that combines performance and cost advantages.