Customer Case: Precision Machining of 20MNCR5 Gears and Car Shafts Using PCBN Inserts

Challenge of Machining 20MNCR5 Steel

The customer was facing significant challenges in machining 20MNCR5 due to its high hardness (58-62 HRC) after carburizing. This material is tough to machine, particularly under conditions requiring strict dimensional tolerances and surface finish standards. Additionally, in operations involving intermittent cutting or high friction, the performance and stability of the cutting tools were highly demanded. The customer required a solution that could effectively handle continuous cutting, light interrupted cutting, and finish machining under high hardness conditions without compromising tool life or part quality.

Solution for Machining 20MNCR5 Steel

To address these challenges, the customer chose Moresuperhard PCBN Inserts for their gear and car shaft machining processes. The specific tool setups and cutting conditions were as follows:

1. Gear Machining

• Material: 20MNCR5
• Hardness: 58-60 HRC
• Tool: CBN Inserts – 4 Blades CNGA 120408
• Operation: Facing machining, continuous cut, and light interrupted cut
• Cutting Parameters:
  • AP (Depth of Cut): 0.1mm
  • f (Feed Rate): 0.07

2. Car Shaft Machining

• Material: 20MNCR5
• Hardness: 62 HRC (after carburizing)
• Tool: CBN Inserts – 4 Blades CNGA 120412
• Operation: Finish machining and light interrupted cut
• Cutting Parameters:
  • AP (Depth of Cut): 0.4mm
  • S (Spindle Speed): 1400 rpm
  • f (Feed Rate): 0.14

Results

The introduction of Moresuperhard PCBN Inserts led to substantial improvements in the machining process:

• Enhanced Tool Life: The wear resistance of the PCBN inserts allowed for longer tool life, reducing the frequency of tool changes and lowering overall production costs.
• Improved Surface Finish: Both gears and car shafts achieved superior surface finishes, meeting the stringent quality requirements for automotive and industrial applications.
• Higher Productivity: The tools performed reliably under continuous cutting and light interrupted cutting conditions, increasing the machining efficiency and reducing cycle times.
• Consistent Precision: Despite the challenging hardness range of 20MNCR5, the tools maintained excellent dimensional accuracy, improving part qualification rates and reducing scrap rates.

Conclusion

Moresuperhard’s PCBN inserts provided a tailored solution for machining 20MNCR5, a difficult-to-machine material. The customer achieved optimal performance under continuous and interrupted cutting conditions, improving both the precision and efficiency of their production process. These results highlight the value of Moresuperhard’s PCBN tools, which are designed for the toughest machining challenges in high-speed, high-friction environments, particularly in the automotive and industrial transmission industries.