What is Gear Planing process?
Gear planing is a process of cutting gear teeth (especially for spur gear and helical gear) with the help of a rack type cutter.
The rack type cutter reciprocates forward and backward and the cutting action occurs on the gear blank.
The gear blank is made to roll relative to the rack cutter without slip.
For gear planing process, there are basically two process;
- Sunderland process
- Maag process
Both these processes work on the same principle but there is a difference in construction and working of the planing machines.
Let’s discuss both these gear planing process one by one.
#1) Sunderland process
First of all, you might want to know why it is named Sunderland? Actually, the name Sunderland came from the name of its inventor.
In this method, the gear blank is mounted such that its axis remains horizontal and the cutter slide is carried on a saddle that moves in a vertical direction. In this way the cutting takes place in this process.
The cutter reciprocates parallel to the axis of gear blank but it has a capacity to swivel in a vertical plane.
Hence, this method is used to cut spur gears as well as helical gears.
Along with the reciprocating movement of the cutter, it is also given feed towards the center of the gear blank.
As the rack is traversed at the tangent of the blank, it acts like a union on their respective pitch lines.
Because of the relative motion, the fresh part of the gear blank comes in contact with the rack and this generates the teeth on the blank with the size exactly as that of the teeth of rack cutter.
It is not possible to cut all the teeth in a single reciprocating motion, hence the machine is arranged such that it gets indexed automatically after the rolling motion has occurred for one or more pitches.
During the indexing process the rotation of the blank is stopped and the rack cutter is moved back to its initial position. This is done until the complete rotation of the blank.
The speed of reciprocating cutting can also be adjusted according to the type of blank material.
#2) Maag process
In Maag process, the gear blank is mounted on a machine table such that its axis is vertical.
The rack cutter is mounted on a slide and it slides vertically in a guide provided on a machine.
The cutter mounted on a slide can be set at any inclination in a vertical plane, and because of this the cutter can reciprocate in any desired direction.