Core Machining Indicators	Precision Parameters	Technical Value
Dimensional Accuracy	Main journal diameter tolerance ±0.001 mm Connecting rod journal roundness ≤0.0005 mm Journal step concentricity ≤0.002 mm	Ensures precise fit with bearings and connecting rods, reducing operational clearance and wear
Surface Quality	Journal surface roughness Ra 0.05 μm Fillet transition R0.5–2 mm (burr-free)	Reduces stress concentration, improves fatigue strength, and extends crankshaft service life
Material Adaptation	42CrMo quenched & tempered steel / Ductile iron QT700 / Aerospace-grade titanium alloy	Meets the needs of different power equipment, balancing high strength, lightweight design and corrosion resistance
Dynamic Balance Performance	Dynamic balance grade G1.0 (rotational speed ≤8000 r/min) Unbalance ≤0.5 g·mm	Avoids vibration during high-speed rotation, reducing equipment noise and energy consumption
Machining Process	5-axis CNC turning-milling compound machining, one-time clamping forming Main journal high-frequency quenching (hardness HRC 58–62)	Reduces clamping errors, enhances journal wear resistance, and adapts to long-term high-load operation

Quality Inspection Standards and Compliance Requirements

1. Dimensional Inspection: Use Coordinate Measuring Machine (CMM) for 100% inspection of key dimensions, with detection accuracy up to 0.0001 mm to ensure parameters meet standards
2. Defect Detection: Through magnetic particle inspection or penetration testing, check for internal cracks, pores and other defects to prevent unqualified products from flowing downstream
3. Batch Control: 100% inspection of first article, 3 pieces sampled for inspection every 50 pieces in batch production, defect rate controlled below 0.1%, qualification rate ≥99.9%
4. Compliance Certification: Compliant with ISO 9001 quality management system, aero-grade crankshafts can provide AS9100 certification-related test reports