In this presentation design of extrusion die is has been described

1. Design of Extrusion Die
MOHD AMIR
13MEB122
A4MA-31
GG0768

2. Extrusion
Extrusion is a plastic deformation process in
which a block of billet is forced to flow by
compression through the die opening of a
smaller cross-sectional area.
Types of Extrusion
Direct Extrusion
Indirect Extrusion

3. Die Design
Die characteristic for rectangular cross section can
be extracted using the following
formula. Where
Q = KP
K = Fbd3/12nLd
Therefore Q = (Fbd3/12Ld) * P
b is the greater dimension of the cross-section
d is the least dimension of the cross-section
F is a non-dimensional factor (Flow coefficient).
Ld is the length of the Die.

4. Factors
1. Rheology :In very short processing times, the
polymer may behave as a solid, while in long
processing times the material may behave as
a fluid. This dual nature (fluid-solid) is
referred to as Viscoelastic behaviour.
2. Non-Newtonian Fluid Behaviour : A non-
Newtonian fluid is a one whose flow curve
(shear stress versus shear rate) is nonlinear
or does not pass through the origin.

5. Factors
4.Melt Behaviour :Change Of Viscosity ,Pressure ,
Temparature ,Flow Behaviour etc.
5. Density
a:Melt Density :The melt density of neat polymer
is an inherent property of the polymer and can
be altered by fillers. e.g. various polyethylene
with different solid densities have the same
melt density and the same compressibility. The
melt density of a polyethylene at ambient
pressure and 220 C is 0.7432 g/cm^3.

6. Factors
b . Bulk Density :bulk density is directly
proportional to the output rate per screw rpm
and that the higher the bulk density the higher
the output rate at a defined screw speed.
5. Flow Analysis
a . Drag Flow: caused by the relative motion of
one or more boundaries.
b .Pressure Flow :Flow caused by the presence
of pressure gradients. The flow rate is
determined by the pressure at the die inlet, often
referred to as die head pressure.

7. Equations for calculation
• Momentum Balance Equations
• Energy Balance Equations
• Mass Balance Equations

8. Power Law Model
“The power law model is one of the simplest
models for presenting the viscous-shear
behaviour of plastic melt. The law accurately
demonstrate the shear thinning region in the
viscosity versus strain rate curve”.
n = m(T)γn-1
m = consistency index
n = power law index

9. CORPORATE TRAINING AND PLANNING
APPLICATIONS OF EXTRUSION
1. Film: Blown film, Cast film, Co-extruded films, BOF.
Material Used: PP,PVC, LDPE, HDPE, PET, Nylon etc.
2. Pipe/tube
Material: HDPE, LDPE, LLDPE, PVC etc.
3. Sheet
Material: HDPE, ABS, HIPS, PC etc.
4. Monofilament
Material: PP, Nylon etc.
6. Box Strapping
Material: PP, HDPE etc.
7. Tape/Woven Sack
Material: PP, HDPE
8. Wire Coating/Covering
Primary/Secondary insulation
Material: LDPE, PVC (Primary insulation) Nylon (secondary insulation)
9. Profiles (Door and window)
Material: PVC

10. References
1.Richardson J.F, 2008. Non-Newtonian Flow
and Applied Rheology, 2nd ed. Pergamon
Press in 1960 .
2. Crawford, R., 1998. Plastic Engineering, 3rd
ed. Oxford: Butterworth – Heine-mann
3. Rauwendaal, C., 2001. Polymer Extrusion, 4th
ed. Carl Hanser Verlag, Munich 2001
4. Rosato D. V., 1998. Extruding Plastics,
Chapman and Hall