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Gears in Motion: Decoding CNC Machining Methods for Precision

Gears are tooth-shaped mechanical structures used in many machines to transfer power and motion between the components. Although they look simple, these components have complex part geometries. This is why many gear fabrication methods have evolved over the years. CNC machining, additive manufacturing, powder metallurgy, and so on are a few popular methods among them. CNC machining has emerged as one of the popular gear fabrication methods in recent years due to several advantages offered by them. This post introduces you to some popular methods employed for CNC machining gears.

CNC Machining Gears - Motor & Gear Engineering

A Few Popular Methods of CNC Machining Gears

Gear fabrication is performed in three ways – gear generation, gear form cutting, and gear forming.  In this, gear form cutting is performed by employing the following CNC machining processes:  

  • Gear Hobbing: In this process, the gear is created, where the gear is blank and the hob is rotated at the same time by maintaining a fixed gear ratio between them. Here, the hob is the rotating cutter. The motion of the hob and the gear blank is maintained steady for effective results. The teeth of the cutter possess a helix angle. During the process, the hob is tilted to this angle to ensure the cutting edges remain square with the gear blank. This technique is employed for creating a wide range of gears, including spur gears, helical gears, worms, splines, and sprockets. It can also be used to create internal gears, for which the machine needs to have the ability to fit a particular head. 
  • Gear Grinding: This can be performed in two ways – form gear grinding and generating gear grinding. The gear is formed from a blank material through abrasion. The abrasion is produced by rubbing a surface against a metal piece at high speeds. This technique helps remove small pieces of metal at a time without changing the shape of the gear. In form gear grinding, a disc wheel is used to grind the sides of the gear. This process is guided by the involute which is attached to the wheel. In the generating gear grinding, the blank material follows the abrasive tool to create the splines.
  • Shaping: Gear shaping is frequently used to create spur gears, herringbone gears, and ratchet gears. This method is also considered a generating process by gear hobbing because the gear is shaped on the basis of the cutter mounted on the cutter spindle. The blank to be shaped is placed on the fixture or arbor on the work spindle. The workpiece is rotated at 360 degrees at the set infeed depth until the desired tolerances and shape are achieved.
  • Cutting/Milling: In gear milling, the material is removed and gear teeth are formed using a multi-toothed cutter. The desired gear’s tooth profile may match or differ from that of the gear milling cutter. The milling cutter is fed into the workpiece as it is rotating to produce the gear teeth. This approach is adaptable and works for both cutting spur and helical gears. The gear milling is a good choice for designing intricate gear designs. Helical and spur gear wheels are perfect examples of CNC milling machining for various applications, such as hob cutters and car transmissions.

If you are planning to outsource your CNC machining of gears, it is important to partner with an experienced manufacturer. Selecting the appropriate gear fabrication method requires careful consideration of factors such as material compatibility, production volume, lead time, tolerances, and cost-effectiveness. Motor & Gear Engineering specializes in CNC machining of gears. It regularly performs CNC gear grinding, hobbing, gear shaping, turning and milling, and precision gear cutting. The company regularly machines spur and helical gears, spline shafts, pinions, racks, worm and wheel spirals, and straight bevel gears. They regularly work with materials like steel, gray iron, aluminum, ductile iron, alloy steel, powdered metal, and so on. Contact them today to discuss your requirements for CNC machining of gears and expect the best assistance and services from their experts.