Gear hobbers are a type of gear machine that make teeth into a workpiece by cutting. Just like many other machines, there are vertical and horizontal types of gear hobbers. These machines are classified based on the largest gear that they can create. The Gear hobber works by rotating the shafts of two spindles that power the hob to cut into the material. These machines have drive motors and can typically create gears up to 10 feet. The hob that is mentioned is a cylindrical shape that has cutting teeth in a sort of spiral pattern. The teeth actually contain grooves that cut the material to form the gears. Some gear hobbers are available in certain sizes such as light, standard, medium, strong and heavy-duty. Heavy-duty being the best for cutting up to a diameter of 100 mm and light being the best for cutting diameters of up to 40 mm.
There are various materials gears can be created from such as wood, metal and plastic (plastic gears are mainly made by the process of injection molding or die casting). In addition to hobbing machines there are gear shaving machines, broaching machines, spline hobbing machines, spline milling machines, hard broaching machines, and bevel gear cutting machines.
What is hobbing? It is a very important process in gear manufacturing. It is the method of choice for the majority of helical and spur gears. The shape of the tooth in a gear are created by the combined motions of the cutting tool and material. Each revolution of the cutter will create one tooth in the gear. This means a 16-tooth gear means the hob rotated 16 times while the material (work piece) only rotated one time. Most hobs are called single-thread hobs, however, there are double and triple thread hobs for increased production. There are also custom hobs and general-purpose hobs depending on the type of gear to be produced. Hobbing is used to create several types of gears like spur gears, splines, sprockets, helical gears, involute gears, ratchets, and worm gears.
What is the difference between a spur gear and helical gear? Spur gears are more efficient and cost less than helical gears. Helical gears can hold larger loads than spur gears and are much more durable.
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