Crankshaft
Precision CNC crankshafts and custom eccentric shafts are critical transmission components for internal combustion engines, industrial compressors, and high-performance power equipment. Manufactured using multi-axis CNC mill-turn machining, precision journal grinding, and strict dynamic balancing, our crankshafts deliver exceptional fatigue resistance, minimal vibration, and reliable torque transmission under extreme mechanical loads.
| Core Machining Indicators | Precision Parameters | Technical Value |
|---|---|---|
| Dimensional & Geometric Accuracy | Main journal diameter tolerance: ±0.002 mm Connecting rod journal roundness: ≤0.001 mm Journal step concentricity: ≤0.002 mm | Ensures precise fit with bearings and connecting rods, minimizing operational clearance, friction, and premature wear. |
| Surface Quality & Finish | Journal surface roughness: Ra 0.05 µm Fillet radius transition: R0.5–2 mm (burr-free micro-polishing) | Eliminates stress concentration points, significantly increases fatigue limit, and extends crankshaft service life. |
| Material Adaptation | 42CrMo (4140) quenched & tempered steel / Ductile Iron QT700 / Titanium alloy | Versatile material choices to balance ultra-high fatigue strength, lightweight structural requirements, and corrosion resistance. |
| Dynamic Balance Performance | Dynamic balance grade: ISO G2.5 / G1.0 (rotational speed ≤8,000 RPM) Residual unbalance: ≤0.5 g·mm | Suppresses high-speed rotational vibration, reducing operational noise and wear on bearing housings. |
| Machining Process & Hardening | Multi-axis CNC mill-turn machining with single-setup clamping Main journal induction/high-frequency quenching (Hardness: HRC 58–62) | Minimizes re-clamping errors, enhances journal surface wear resistance, and withstands long-term heavy-duty operation. |
Quality Inspection Standards and Compliance Requirements
- Dimensional Inspection: 100% CMM (Coordinate Measuring Machine) verification on critical journal dimensions and geometric tolerances, with repeatability precision up to 0.001 mm.
- Non-Destructive Testing (NDT): Magnetic Particle Inspection (MPI) and Penetrant Testing (PT) for surface flaw detection; Ultrasonic Testing (UT) available for internal crack and void inspection.
- Batch Quality Control: First-article inspection (FAI) mandatory; 3-piece sampling per 50 units during serial production. Target PPM yield ≥ 99.9% with defect rates kept below 0.1%.
- Compliance & Certification: Certified under ISO 9001 quality management system. Aero-grade and high-performance components can be delivered with AS9100-compliant material & inspection reports.
Materials & Specialized Heat Treatments
Forged & Billet Alloy Steel (4340 / 42CrMo / 40CrNiMo)
Standard choice for high-torque racing, marine, and industrial engine crankshafts requiring high fatigue strength.
Ductile Cast Iron (QT700-2 / QT800-2)
Cost-effective solution for general compressors, agricultural machinery, and commercial pumps with excellent vibration damping.
Stainless Steel & Titanium Alloys (17-4PH / Ti-6Al-4V)
Ideal for lightweight, corrosion-resistant UAV mini-engines and medical pump drive shafts.
Heat & Surface Treatments
Gas Nitriding, High-Frequency Induction Hardening (HRC 58–62), QPQ (Quench-Polish-Quench), Micro-Polishing, and Shot Peening for enhanced fatigue life.
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