After completion of 1 or two teeth, the blank and gear rack for Machine Tool Industry china Cutter stop feeding and the cutter is withdrawn and indexed back again to its starting position, thus allowing a short rack cutter of a practical size to be used. Cutter is again fed back to depth and cycle is repeated. Quantity of teeth is managed by the machine gearing, and pitch and pressure angle by the rack cutter. This method is utilized for generation of external spur gears, being ideally suited for cutting large, dual helical gears. For producing helical tooth, the cutter slides are inclined at the gear tooth helix angle.
The hob is fed in to the gear blank to the correct depth and both are rotated together as though in mesh. One’s teeth of the hob cut in to the function piece in successive purchase and each in a slightly different placement. Each hob tooth cuts its profile based on the form of cutter , however the accumulation of these directly cuts produces a curved type of the gear teeth, therefore the name generating process. One rotation of the task completes the reducing upto certain depth upto which hob can be fed unless the apparatus has a wide face.
This methodis specially adopted to cutting large teeth which are difficult to cut by formed cutter, and to cut bevel-gear teeth. It isn’t widely used at the moment.
In gear planing process, the cutter contains accurate involute rack which reciprocates over the face of the blank and the blank rotates in the right relationship to the longitudinal movement of the cutter as if both roll jointly as a rack and pinion. At first the cutter is certainly fed into full tooth depth with cutter reciprocating and blank stationary. Involute shape is produced as the blank rotates and involute rack cutter feeds longitudinally.
In the other technique, both roughening and finishing cuts are taken with single pointed tools. The usage of the formed tool for finishing can be impracticable for the bigger pitches which are completed by an individual pointed tool. The number of cuts required is dependent upon how big is the tooth, quantity of share to be eliminated, and the kind of material.