In the realm of mechanical engineering, gear manufacturing is a critical process requiring precision and specialized equipment. Among various machining methods, milling stands out for its versatility in producing gears, particularly for prototyping, custom jobs, or low-volume production. The primary milling machine employed for gear cutting is the universal milling machine, equipped with essential accessories like a dividing head and indexing mechanism. This configuration enables the accurate generation of gear teeth profiles across diverse gear types, including spur, helical, bevel, and worm gears.
(which milling machine is used to cut gears)
The universal milling machine’s adaptability stems from its ability to swivel the worktable and spindle in multiple planes, facilitating complex angular cuts. For gear cutting, a cutter mounted on an arbor is selected based on the gear’s module, pressure angle, and number of teeth. Crucially, the dividing head—attached to the worktable—rotates the gear blank incrementally between cuts via precise indexing. This ensures uniform tooth spacing (pitch). For spur gears, the blank is aligned parallel to the table; for helical gears, the table is tilted to match the helix angle, and the dividing head synchronizes rotation with table feed.
The process begins by securing the gear blank to the dividing head. The operator calculates indexing parameters (e.g., using a 40:1 ratio dividing head) to achieve the required number of teeth. Each tooth space is milled sequentially: after one cut, the dividing head indexes the blank to the next position. Form cutters (disc or end-mill types) replicate the gear tooth profile. While economical, this method has limitations—each cutter is module-specific, necessitating multiple cutters for different gears, and achieving high precision demands meticulous setup.
For high-volume production, dedicated gear-cutting machines like gear hobbing machines or gear shaping machines are preferred due to superior speed and accuracy. Hobbing employs a rotating hob tool that continuously engages the blank, generating teeth in a single pass. Shaping uses a reciprocating cutter. However, universal milling machines remain indispensable for bespoke or repair tasks where dedicated machinery is impractical.
(which milling machine is used to cut gears)
In summary, the universal milling machine, augmented with dividing and indexing tools, is the cornerstone of gear milling. Its flexibility in handling varied gear geometries makes it ideal for workshops prioritizing adaptability over volume. Engineers must ensure optimal cutter selection, rigid setup, and precise indexing to maintain gear quality, acknowledging that while milling is versatile, it is best suited for scenarios where advanced alternatives are unavailable or uneconomical.