5t057-1620-2 Gear Processing Workflow

I. Blank Preparation

1. Forging Blank Production

• Hot Die Forging: Widely used for automotive gears, this process achieves high-precision blanks through plastic deformation at elevated temperatures, minimizing subsequent machining allowances.

• Cross Wedge Rolling Technology: Ideal for complex stepped shaft blanks, offering high precision, efficiency, and reduced machining allowances.

2. Normalizing Treatment

• Purpose: Refine grain structure, homogenize carbide distribution, eliminate internal stresses, and prepare the microstructure for subsequent cutting and heat treatment.

• Advantage: Isothermal normalizing ensures consistent product quality by avoiding issues like excessive hardness variation and uneven microstructure caused by uneven cooling in conventional normalizing.

II. Rough Machining Stage

1. Turning Operations

• Equipment: CNC lathes enable simultaneous machining of bore, end face, and outer diameter in a single setup.

• Precision Control: Ensures perpendicularity between the bore and end face while minimizing dimensional dispersion, providing a high-precision reference for subsequent gear processing.

2. Gear Cutting Operations

• Application: Suitable for internal gears or external gears with structural constraints.

• Characteristics: The shaping tool and workpiece engage in cylindrical gear meshing motion, with reciprocating motion as the main motion and circular motion as the feed motion.

• Principle: Generating method using a hob and workpiece in meshing motion to cut tooth profiles.

• Application: Widely used for external and cylindrical gears due to its cost-effectiveness.

• Hobbing:

• Shaping:

III. Finish Machining Stage

1. Gear Shaving

• Principle: A free-meshing shaving cutter removes fine chips from the gear surface through relative sliding motion, improving tooth surface accuracy.

• Advantage: High efficiency for mass production of non-hardened gears, enabling tooth profile and lead modifications.

2. Gear Grinding

• Principle: Generating grinding using worm, conical, or碟形 (disc-shaped) grinding wheels.

• Application: The only finish machining method for hardened gears, achieving high precision (IT5-6) and low surface roughness (Ra0.63–0.16 μm).

3. Gear Honing

• Principle: Non-defined cutting angles with a honing wheel meshing with the workpiece under pressure for precision finishing.

• Advantage: Cost-effective, producing smooth tooth surfaces with low noise. Low cutting speed (0.5–10 m/s) prevents thermal damage.

IV. Heat Treatment Stage

1. Quenching and Tempering

• Process: Quenching followed by high-temperature tempering to improve comprehensive mechanical properties.

• Material Example: 20CrMnTi steel achieves a surface hardness of HRC58–62 after quenching, with a core hardness of HRC30–45.

2. Surface Hardening Treatments

• Carburizing and Quenching: Enhances tooth surface hardness (HRC58–62) and wear resistance while maintaining core toughness.

• Induction Hardening: Rapidly heats the tooth surface to form a hardened layer, suitable for medium-carbon steel gears.

V. Post-Processing and Inspection

1. Tooth End Machining

• Operations: Chamfering, rounding, deburring to improve meshing performance and prevent edge chipping.

2. Final Inspection

• Parameters: Length, angle, tooth profile, lead, and pitch deviations.

• Methods: Gear measuring centers or specialized gauges ensure compliance with design requirements.

VI. Supplementary Special Processes

• Powder Metallurgy:

• Process: Metal powder pressed into molds → high-temperature sintering → finishing.

• Advantage: Suitable for mass production with high precision, low noise, and cost efficiency.

• Wire Electrical Discharge Machining (WEDM):

• Application: Machining straight-tooth gears, particularly for complex shapes or hard materials.