What is Gear Shaping? (Working, Advantages & Disadvantages)

Gear shaping: Gear shaping is a technique for creating teeth on the gear by using a gear shape cutter.

In gear shaping operation, the gear shape cutter is used which possess cutting edges on the gear.

The gear shape cutter as well as the workpiece (gear blank) rotates as if they are actually meshing with each other.

Due to the rotation of gear shape cutter, the cutting action takes place on the workpiece by a series of incremental cuts. And finally the desired tooth profile is obtained.

Well, this was just a short explanation. But further I have explained the entire gear shaping technique with diagrams, advantages, disadvantages as well as applications.

So let’s dive right into it!

Gear shaping operation

Gear shaping

Gear shaping is a faster method of gear manufacturing.

In gear shaping operation, the gear shaped cutter having cutting edges is used which has a clearance on the tooth face and sides.

This gear shape cutter has a hole in the centre which is required to mount it on a spindle of the machine.

Gear shaping operation

As shown in the above diagram, the cutter is mounted on a vertical axis and it moves up and down.

Apart from the up-down reciprocating movement, the rotation of the cutter and workpiece also takes place during this movement (see above image).

The relative speed of cutter and the workpiece is the same because the cutter and workpiece will have the same size and the same number of teeths.

There are change gears attached with the gear shaper which helps in achieving the same rotation speed for cutter and workpiece.

Thus the rotational movement and liner movement (up to down) of the spindle generates teeth on the workpiece.

But besides this, the feed is also given to the workpiece or cutter to achieve the cutting of the teeth.

The rotary gear shaper cutting involves various motions that are mentioned below.

Gear shaping

The cutting of heat tooth takes place either in an upward stroke or downward stroke of the cutter.

During the return stroke, either the cutter is withdrawn from the table or the table is withdrawn from the cutter. 

This is done to prevent the rubbing of cutting edges to prevent its wear as well as to protect the damage of tooth profile of workpiece.

By using gear shapers, the straight tooth as well as helical tooth can be cut on a gear blank.

In order to cut the helical tooth, the tool and the gear blank should be rotated in an oscillating rotational motion.

Gear shaping using rack cutter

Gear shaping also uses rack type cutters or rack shaped cutters.

In this method, the rack type cutter reciprocates in the horizontal and vertical direction and the workpiece (gear blank) meshes with it, which forms a rotational motion.

During this the cutting action takes place on the workpiece.

The main disadvantage of using a rack type cutter is that once the full length of the rack is used, the cutting operation is required to be stopped to bring the workpiece back to the position. (This is mostly done when cutting larger gears with more teeth.)

Having said that, let’s now discuss the advantages and disadvantages of gear shaping.

Advantages of gear shaping

The advantages of gear shaping are mentioned below.

  • Gear shaping is a fast gear cutting technique and it is suitable for medium as well as large size production of gears.
  • The chips of uniform size are cut by the gear shape cutter. Hence this method shows high dimensional accuracy.
  • Sour gear, helical gear, cluster gears, splines, and many other gears can be cut by gear shaper.
  • The main advantage of this method is that only one gear shape cutter can be used to cut all the spur gears of the same module (irrespective of the number of teeth on gear).

Disadvantages of gear shaping

The disadvantages of gear shaping are mentioned below.

  • It is difficult to cut gears having wider flanks, because the length of the cut is shorter.
  • Different helical guides are required to cut helical gears with different helical angles.
  • By this method, only one gear can be cut at a time.

Applications of gear shaping

Gears manufactured by gear shaping are used in areas like;

  • Automobiles
  • Machine tools
  • Instruments
  • Machinery
  • Clocks
  • And many other equipment.

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