this is a slide which gives information regarding methods of formation of thermoplasics,

1. THERMOPLASTICS
MADE BY – ROHIT SINGH
S . E MECHANICAL(2013-2017)
ARMY INSTITUTE OF TECHNOLOGY

2. THERMOPLASTICS
A thermoplastic, also called a thermosoftening
plastic is a polymer which becomes pliable or
moldable above a specific temperature and returns
to a solid state upon cooling.
METHODS OF MOULDING

3. INJECTION MOULDING PROCESS
 Injection moulding is the process in which a polymer
is heated to a highly plastic state and forced to flow
under high pressure in mould cavity , where it
solidifies.

4.  Granulated material is fed from hooper
 Temp. – 150 to 300 degree c
 Pressure-100 Mpa to 150 Mpa
 Moulding die is water cooled
 Two principal units—
1.Plastic injection unit
-melt and homogenize the polymer
-inject the liquid plastic into mould cavity
2.Clamping unit
-hold two halves
-to keep the mould closed during injection

5. PLUNGER TYPE INJECTION MOULD

6. SCREW TYPE INJECTION MOULD

7. ADVANTAGES and application s OF INJECTION
MOULDING
 Advantages:-
 Faster process.
 Higher speed (Used for mass production)
 Complicated shape with high accuracy.
 Material wastage is low.
 Applications:-
 Cups, Chairs, Toys, Container, Knobs,
Automobile parts, Air conditional parts,
Eletrical fitting.

8. BLOW MOULDING
 It is a moulding process in which air pressure
is used to inflate soft plastic into a mould
cavity.
 Blow moulding performed in two steps:
1). Fabrication of starting tube of molten plastic
which is called as parison.
2). Inflation of the tube to the required
foundation.
 Pressure :- 400 – 800 kPa.

9. APPLICATIONS

10. THERMOFORMING
 It is a series of processes for forming thermo
plastic sheet or film over a mould. With the
application of heat and pressure.
 Used in packaging of consumer product and
to fabricate large parts like bath tubs , internal
door liners etc.
 Two methods of Thermoforming
1. Vacuum Forming
2. Pressure Forming

12. VACUUM FORMING
 Plastic sheet thickness-0.125 to 3.2 mm
 Temperature- 55 to 90 degree c

13. PRESSURE FORMING


14. ADVANTAGES OF THERMOFORMING
 Initial setup cost is low.
 Intricate shapes are easily formed.
 Production cost is low.
 Less thermal stress during process.
 Holes less than equal to 0.5mm.
 Cost of tooling is low.
 Aluminium moulds are used.
 Example:- Jelly containers, luggage
belts,Refrigerator inner pannels

15. THERMOFOFMING PRODUCTS