A gear is a part of a machine that has cut teeth and is used with other parts of machines to make the machine function. Gear cutting is a specialized machining process. There are different methods of gear cutting like hobbing, broaching, milling, and grinding. These gears are made from different metals like iron, steel, brass, etc. The gears to be produced must be durable and should have high quality as it is essential for the working of machines.
- Gear hob cutters: Gear hobbing is the most preferred method of gear manufacturing for producing helical or spur gears. It is a flexible generating process that gives the smooth teeth shape to gear with the help of a cutting tool. These tools are known as gear hob cutters. A hob is a cylindrical surface that works with the gear blank to cuts the teeth. The quality of these tools is essential for giving the right type of finish and cuts to the gear. They maintain the accuracy of the teeth. These are the multi-tooth cutting tools that help in generating teeth on the gears. The gear hob cutter price varies with its quality. The hob cutters have many straight flutes at its boundary that are parallel to its axis.
- Gear hobbing process: The process of gear hobbing includes rotation of hob at an appropriate speed. The gear blank keeps on rotating simultaneously. The speed of the gear blank accompanies the speed of the tool or hob cutter. The motion of both tool and blank is maintained accurately and steadily. They both keep on rotating till the cutters reach the required depth of the blank. Then the cutter revolves till the teeth are fully made on the gear blank. Several teeth are cut on a progressive basis. In the whole process, three things need to be maintained properly, i.e. index movement, angle, and speed. The gear hobbing cutters are tilted at a particular angle to give proper shape to the gears.
- Types of hobbing process: There are different types of hobbing process based on the direction of the hob feeding for cutting the gear like axial feed hobbing, radial feed hobbing, or tangential feed hobbing. There can be two different techniques for performing such a process i.e. climb hobbing and conventional hobbing.
- Gear hobbing machines: In these machines, gears are produced by cutting, grinding, or by the combination of both cutting and grinding. These machines are fully automatic and are also known as hobbers. They are available in different sizes and models. These machines are differentiated based on the pitch diameter they can produce.
The hobbing method is an elementary process that is preferably used because of productivity and accuracy. It can be used for both high and low volume production of external cylindrical gears. It is also a fast and cheap method as compared to other processes of gear cutting. As the process is continuous and the same cutter can be used to cut gears having the same module.