Comparison of Several Processing Techniques for Hardened mf farmtrac Gear Surfaces
Gear Hobbing
Principle: The gear tooth profile is cut through the relative rolling motion between the hob and the gear blank.
Characteristics:
Advantages: High production efficiency, suitable for mass production; gear hobbing accuracy can reach Grade 7 when the hobbing machine has good rigidity and high precision.
Disadvantages: Relatively low tooth profile accuracy and unstable processing precision; high cost for large-module gears.
Application Scenarios: Widely used in the automotive industry and large industrial gearbox manufacturing, but limited by the outer contour of the workpiece being processed.
Gear Grinding
Principle: Precision grinding of the gear surface using grinding tools to improve gear accuracy and surface roughness.
Types:
Form Grinding: Suitable for batch production of Grade 5-6 precision gears, with high production efficiency, especially for gears with large modules, few teeth, wide widths, and various modified tooth profiles.
Generating Grinding: Includes single-tooth indexing generating grinding and continuous generating grinding. Single-tooth indexing generating grinding includes disc grinding, conical grinding, and large-plane grinding; continuous generating grinding mainly refers to worm grinding.
Characteristics:
Advantages: High grinding accuracy and excellent surface quality; worm grinding offers the highest efficiency, suitable for processing Grade 5-6 precision gears with a tooth pitch > 8 mm or diameter > 600 mm.
Disadvantages: Swiss MAAG grinding machines using disc grinding offer high precision but often take several hours to grind one gear, resulting in high costs; conical grinding machines have a long transmission chain, affecting processing accuracy and stability; large-plane grinding machines have low processing efficiency.
Application Scenarios: Gear processing with extremely high precision requirements, such as in the aerospace and high-precision machine tool industries.
Gear Shaping
Principle: Cutting is performed on a gear shaping machine using a gear shaper cutter in a specific meshing relationship with the gear blank.
Characteristics:
Advantages: Capable of processing gears of various shapes, especially suitable for internal gears and multi-link gears; precision shaping of hardened gears enables efficient processing of straight external gears, internal gears, double-link (triple-link) gears, or gears with shoulders, with low cost and high efficiency.
Disadvantages: Lower production efficiency compared to gear hobbing.
Application Scenarios: Situations requiring the processing of internal gears or multi-link gears, as well as hardened gear processing with high cost considerations.
Gear Shaving
Principle: Removing a small amount of material from the gear surface through the relative sliding motion between the shaving cutter and the gear to improve gear accuracy and surface quality.
Characteristics:
Advantages: High production efficiency, strong tool durability, high tooth profile accuracy, and relatively low surface roughness of the processed gear; good mandatory tooth alignment correction capability, with strong stability of the processed parts after shaving.
Disadvantages: Primarily suitable for the finishing of unhardened gears, with limited processing capability for hardened gears. However, domestic technology can now shave Grade 7 precision gears with medium-hard tooth surfaces of around 48 HRC.
Application Scenarios: Gear processing with certain requirements for precision and surface quality, but with relatively low tooth surface hardness.
Gear Honing
Principle: Final precision machining of hardened gears using an amorphous cutting angle.
Characteristics:
Advantages: High cost-effectiveness, enabling the processed gears to have a smooth surface with low noise; low cutting speed avoids damage to the gear processing caused by cutting heat.
Disadvantages: It is difficult to improve honing accuracy to Grade 6.
Application Scenarios: Hardened gear processing with high requirements for surface quality and noise.
