Question

Internal gear cutting operation can be performed by
1. Milling
2. Shaping with rack cutter
3. Shaping with pinion cutter
4. Hobbing

Answer 1

Correct Answer - Option 3 : Shaping with pinion cutter

Explanation:

• Gear shaping is a generating process. The cutter used is virtually a gear provided with cutting edges. The tool is rotated at the required velocity ratio relative to the gear to be manufactured and anyone manufactured gear tooth space is formed by one complete cutter tooth. This method can be used to produce cluster gears, internal gears, racks, etc with ease, which may not have the possibility to be manufactured in gear hobbing.
• Gear Hobbing is a continuous generating process in which the tooth flanks of the constantly moving workpiece are formed by equally spaced cutting edges of the hob. The main advantage of this process is its versatility to produce a variety of gears including Spur, Helical, Worm Wheels, Serrations, Splines, etc. The main advantage of the method is the higher production rate of the gears due to continuously indexing.
• Gear Milling is one of the initial and best-known and metal removal processes for making gears. This method requires the usage of a milling machine. This method is right now used only for the manufacture of gears requiring very little dimensional accuracy.
• Gear forming: In gear form cutting, the cutting edge of the cutting tool has a shape identical to the shape of the space between the gear teeth. Two machining operations, milling and broaching can be employed to form cut gear teeth.

Points to remember:

• Internal gears are manufactured by the shaping process with a pinion cutter.
• Hobbing, milling, and shaping with a rack cutter is mainly used for external gears.