DC MACHINE-Motoring and generation, Armature circuit equation
Extrusion process presentation JJJJ.pptx
1. Classification of Extrusion
Prepared by:-
Team 3
Supervised by:-
Dr. Ahmed Kassem
Eng. Abdelmegeed El-sayed
1
Manufacturing Technology (A) (M 1271) – Fall 22
12/19/2023
2. Classification of Extrusion
Ahmed Abdelmoneiom Abdelsadek
Ahmed Abdelazeem Abdelfatah
Ahmed Magdy El-Desouqy
Ahmed Abdalla Mohamed
Ahmed Adel Mahmoud
Team 3 members
2
Manufacturing Technology (A) (M 1271) – Fall 22
12/19/2023
3. Hot Extrusion
• involves prior heating of the billet to a
temperature above recrystallization temperature.
• For metals and alloys that do not have sufficient
ductility at room temperature
• This reduces strength and increases ductility of
the metal.
• It keeps the material from work hardening.
• Increase ram speed and reduce ram force.
• High maintenance required.
3
Manufacturing Technology (A) (M 1271) – Fall 22
12/19/2023
4. Hot Extrusion
• Cooling of the billet as it contacts the
container walls is a problem, and
isothermal extrusion is sometimes used
to overcome this problem
• Surface oxides on product may be
undesirable when good surface finish is
important.
• Dummy blocks slightly smaller in
diameter than the container.
• Glass is often used as a lubricant
4
Manufacturing Technology (A) (M 1271) – Fall 22
12/19/2023
5. Cold Extrusion
• Cold Extrusion is a process done at room
temperature or a slightly warm
temperature (less than recrystallization
temperature). It is also known as cold
pressing.
• Soft Metals like copper , tin , titanium ,
aluminum alloys can be extruded
through the cold extrusion process.
• They are generally used to produce
discrete parts
5
Manufacturing Technology (A) (M 1271) – Fall 22
12/19/2023
6. Cold Extrusion
Advantages:
• Work hardening leads to
improved properties, as long as
frictional heat does not cause
recrystallization.
• Good dimensional tolerances.
• Less energy required (no
preheating)
• High production rate and
relatively low cost
Disadvantages:
• Higher stresses on tooling and
dies (Especially with steel
workpieces)
• The punches are critical
component; they must have
sufficient strength, toughness,
and resistance to wear and
fatigue
6
Manufacturing Technology (A) (M 1271) – Fall 22
12/19/2023
7. Direct Extrusion
• It is also called “Forward Extrusion”.
Advantages:
• Can be used for both hot and cold extrusion
• Simple tooling compared to other extrusion
process
Disadvantages:
• The relative motion between billet and
container wall develops high friction.
• a small portion of the billet called “butt end”
cannot be pushed through the die opening.
7
Manufacturing Technology (A) (M 1271) – Fall 22
12/19/2023
8. Indirect Extrusion
It is also called “backward extrusion and
reverse extrusion”.
Advantages:
• The ram force is lower than in direct extrusion
because there is no friction at the container
walls.
• It can produce hollow (tubular) cross sections.
Limitations:
• Lower rigidity of the hollow ram.
• difficulty in supporting the extruded product as
it exit the die (length limitations)
• support of ram becomes a problem as work
length increases.
8
Manufacturing Technology (A) (M 1271) – Fall 22
12/19/2023
9. Impact Extrusion
• The punch is made to strike the slug at high speed
by impact load.
• It is useful to produce short lengths of hollow
shapes like collapsible tooth paste tubes and thin
walled cans.
• It is usually a cold working process, but the high
speed of deformation develops heating.
Limitations :
• The forces acting on the punch and die are
extremely high, tooling must have sufficient
impact resistance, fatigue resistance and strength
9
Manufacturing Technology (A) (M 1271) – Fall 22
12/19/2023
11. Hydrostatic Extrusion
• Friction problem can be addressed by surrounding the
billet with fluid inside the container.
• there is no friction inside the container and the friction
at the die opening is reduced.
• Extruded product has good surface finish and
dimensional accuracy.
• Brittle materials can be successfully extruded with this
process.
• Ductile metals can also be hydrostatically extruded,
and high reduction ratios are possible.
• It can be carried out at room temperature or at
elevated temperatures , therefore, special fluids and
procedures must be used in this case.
11
Manufacturing Technology (A) (M 1271) – Fall 22
12/19/2023
12. Plastic Extrusion
Types of plastic Extrusion :
1. Tubing Extrusion.
2. Blow Film Extrusion.
3. Sheet Film Extrusion.
4. Over Jacket Extrusion.
12
Manufacturing Technology (A) (M 1271) – Fall 22
12/19/2023
