The document discusses various gear manufacturing processes including extrusion, stamping, sintering, injection molding, cold drawing, and forging. Extrusion involves drawing material through a die to give it a constant cross-sectional shape, and can be used to make small gears from materials like aluminum and copper alloys. Stamping uses sheet metal and dies to form low-precision gears in large quantities for applications like toys and clocks. Sintering compacts metal powder in dies, then sinters the compact to form small gears while injection molding makes nonmetallic gears from plastics like nylon for uses where lubrication is not needed.

1. GANDHINAGAR INSTITUTE
OF
TECHNOLOGY
ACTIVE LEARNING ASSIGNMENT
ON
“Gear Manufacturing Processes”
PRODUCTION TECHNOLOGY [2161909]
MECHANICAL 6 (D3)
PREPARED BY:-
UPADHYAY AYUSH
(150123119053)
GUIDED BY:-
Prof. CHINTAN BARELWALA

2.  Content
 Extrusion Process
 Stamping Process
 Sintering Process
 Injection Molding Process
 Cold Drawing Process
 Forging Process

3. It is a manufacturing process where material is drawn through
a die, giving the material a new cross-sectional shape that is usually
constant throughout the lengths of the material. Dies with multiple
openings can extrude several strands simultaneously, as well as
create hollow cross-sections by using a pin (mandrel) in the die.
Extrusion

4.  Extrusion process is used to form teeth on long rods, which are
then cut into usable lengths and machined for bores and keyways
etc. Nonferrous materials such as aluminum and copper alloys are
commonly extruded rather than steels. Results in good surface
finish with clean edges and pore free dense structure with higher
strength
 Small sized gear can also be made by extrusion process. There is
saving in material & machining time.
 This method can produce any shape of tooth & it is suitable for
high volume production. Gears produced by extrusion find
application in watches, clocks, type writers etc.

5.  Sheet metal can be stamped with tooth shapes to form low
precision gears at low cost in high quantities. Surface finish
and accuracy are poor.
Stamping
Precision Stamping
 The dies are made of higher precision with close tolerances.
The stamped gears will not have burrs.
Application
 Toy gears, hand operated machine gears, slow speed
mechanism gears
 Clock gears, watch gears etc.
Application

6.  After stamping, the gears are shaved; they give best finish &
accuracy.
 The materials which can be stamped are: low, medium & high
carbon steels, stainless steel.
 This method is suitable for large volume production.
Stamped Gear

7.  The metal powder is pressed in dies to convert into tooth shape,
after which the product is sintered. After sintering, the gear may
be coined to increase density & surface finish. This method is
usually used only for small gears.
Sintering Process

8. Blended Powder Compacted Rigid Tooling
( Powder compacted rigidly)
Pre-sinter
Repress or Coining Re-sinter Gear
Sintering Process

9.  High quality gears can be made by powder metallurgy
method.
 Gears made by powder metallurgy method find application in
toys, instruments, small motor drives etc.
Advantages
 Accuracy similar to die cast gears
 Material properties can be tailor made
 Typically suited for small size gears
 Economical for large lot size only
 Secondary machining is not required
Applications

10. Injection Molding
 Injection molding is used to make nonmetallic gears in
various thermoplastics such as nylon. These are low precision
gears in small sizes but have the advantages of low cost and
the ability to be run without lubricant at light loads.
Applications
 Injection molded gears are used in cameras, projectors, wind
shield wipers, speedometer, lawn sprinklers, washing
machine
 The materials for injection molding components are Nylon,
cellulose acetate, polystyrene, polyimide, phenolics.
Materials

11.  Cold drawing forms teeth on steel rods by drawing them through
hardened dies. The cold working increases strength and reduces ductility.
The rods are then cut into usable lengths and machined for bores and
keyways, etc.
Cold Drawing

12.  The steps in forging process are represented in fig and the
forged gears are shown in fig.
Forging