plastic moulding a topic with some less knowledges but surely help out the masters as well as unger graduates in their assignments no need to modify just go through it and take some innovative ideas and some will be making some more better ones but for those who are in a hurry and want to minimise their time or wants to save their time its a copmlete package just go through it

3. CONTENTS

4. INTRODUCTION
• Plastics are one of the polymeric materials and have extremely large
molecules.
• Consumer and industrial products made of polymers include food
and beverage containers, packaging, housewares, foams, toys etc.
• Polymers are formed by polymerization process.
• Polymerization processes are of complex nature and of two types
1) Condensation Polymerization 2) AdditionPolymerization
• Plastics ( polymers) are of two types :
Thermoplastics – Acetals, acrylics, polystyrene, polypropyleneetc.
Thermosetting plastic – Alkyds, aminos, epoxies, phenolicsetc.

5.  Plastic is material consisting of any of a wide range of synthetic or semi-
synthetic organic compounds that are malleable and so can be molded into solid
objects.
 Plastic moulding is the process of shaping plastic using a rigid frame or
mould.
 The technique allows for the creation of objects of all shapes and sizes with
huge design flexibility for both simple and highly complex designs.
 A popular manufacturing option, plastic moulding techniques are responsible
for many car parts, containers, signs and other high volume items.
 The underlying concept of plastic moulding is placing liquid polymer into a
hollow mould so that the polymer can take its shape, often with various ranges of
pressure and heat required.
 There are different plastic moulding techniques available to accomplish this
including rotational moulding, injection moulding, blow moulding, shell
moulding and compression moulding to name just a few.
 Each technique has its benefits and is best suited for the creation of specific
items.

7. 1 • Compression
Moulding
2 • Injection
Mouldings
3 • Blow
Moulding
4 • Shell
Moulding
5 • Extrusion
Moulding
6 • Vacuum
Moulding
7 • Calendarin
g
8 • Rotational
Moulding
9 • Transfer
Moulding
Plastic Moulding Methods

8. • It is a high pressure moldingoperation used for thermosettingplastics.
• Charge of thermosettingresin is placedin the die cavityof a matched mold.
• The moldis closed by bringing the two halvestogether.
• Pressureis exerted to squeeze the resin.
• Whileunder pressure the materialis heated,whichcauses it tocure and to harden.
• Whenthe materialwill becomehard, the mold is opened and the partis removed.
• Helmets,automobilebody panels etc.are someexamplesof compression moldedparts.
• Alsocalled as compressionpress
• Opening between base and compressionassembly
called as daylightopening.
• Slide rod guidesthe movementof compression assembly.

9. Working Principle:-
 The charge of plastic material is
place in the lower half of a
heated mould cavity.
 The mold cavity is closed with
upper movable half mold &
pressure is applied.
 The pressure is applied along
with heat to compress the
material, which also increases
the polymerization process.
 The mould cavity is then
openedand the final product
is take out.

10. • Polymeris heated to highly plastic state and forcedto flow underhigh
pressure into mold cavity,where itsolidifies.
• Molded part called ‘molding’ is removedfromcavity.
• Production cycle time is typically in range of 10 to 30sec.
• Part size range from 50 g to 25 kg and economical forlarge production quantities
only.
• Doors of refrigerator, buckets, automobile parts etc. aresome
examples of injection molding.

11. Working Principle:-
1. First, we auto loader the plastic material into the barrel, which is
surround by heating elements melting the plastic.
2. In the barrel which is assembled with servo motor screw. The plastic
melt will flow up the screw and under the heating condition get tight
and move forward to the screw head.
3. At the same time, due to the plastic reacting force, the screw will step
back. So at the screw head, it formed a plastic melt saving space to
finish its plasticizing process. Also under the injection hydraulic
cylinder force, the screws will injection the plasticizing melt into the
plastic mould through the nozzle. The plastic melt will remain in the
mould cavity through the holding pressure, cooling, process, and then
formed into solid shape ejected out of the mould.

12. • Plastic forming process suitable for manufacture of bottles and other simple
hollowparts.
• Three simple steps of blow molding
- Melting the resin
- Forming a preform tube
- Blowing the preform tube
• Melting and forming can be done either in an extruder or in an injection
moldingmachine.
• Cycle of blow molding are very short.
• Economically used for parts ranging from few ml to over 450 l involume
• Two types of blow molding processes are used
1) Extrusion blow molding
2) Injection blow molding

13. Working Principle:-
It is a process of shaping thermoplastic material into one piece,
hollow articles by means of heat & air pressure.
A hot thermoplastic tube known as parison is injected in mould
cavity. High pressure air in parison& it can be blow out to
acquired shape of die.
Then such shape cooling against mould wall, after product is
cooled the mould is opened & part is ejected.

14.  It is also known as shell mould casting.
 It is an expandable mold casting process that uses a
resin covered sand to form the mould.
 As compared to sand casting, this is process has better
dimension accuracy, a higher productivity rate & lower
labour requirement.

15. • AlsocalledasRotomolding.
• Usesrotationofamoldinaheatedchambertoformthepart.
• Ideallysuitedtotheformationofverylarge,seamlessandstressfreehollow parts.
• MoldingProcess
1) Loading
2) Heating
3) Cooling
4) Unloading

16. WorkingPrinciple:-
 This process employs the simultaneous rotation of thin walled mould about two axis, which is perpendicular to
each other. After being charged with plastic material the mould are heated externally while rotating, due to
particles melton the inner surface of mould.
 Successively layers are deposited until all material are uniformly distributed &
fused, then mould cooledby air or spraying water while still rotating.

17. Nylon Very strong, nylon can be machined and will take a fine thread. It is also slippery and can be used to
make washers, spacers and bushes.
Nylon was originally developed as a textile but is available in many forms with vastly different
properties.
Acrylic Comes in a range of thicknesses, colours and can be opaque or transparent. There are two type of
acrylic extruded which is cheaper and very "plastic" and cast which machines better but is harder and
less flexible. Acrylics are available in a range of colours and can be opaque, translucent or
transparent. They are available in sheet, rod, and tube for use in injection moulding, extrusion and
vacuum forming.
PVC and
uPVC
Stiff, hard,tough lightweight plastic. uPVC is stabilised for outside use ans is uded for plastic
windows and plastic pipes. Plasticised PVC is used for flexible applications such as insulating -
cables.
Polythene This plastic has a range of uses from food packaging to gas pipes. The plastics can be injection
moulded or extruded and is available in two forms. High-density polyethylene (HDPE) is a hard
rigid plastic.Alow-density grade ( LDPE )is tough and flexible.
Polypropylen
e
Polypropylene is a tough, cheap plastic, it has a slightly waxy feel. It can be bent repeatedly without
breaking. Used for Medical equipment such as syringes, stacking chairs (chairshell is polypropylene),
suitcases with integral hinges,
Polycarbonate Used for making eye protection, machine guards and riot shields. It is not as hard as acrylic and can be
cut easily but it will absorb impacts.
Bakelite A thermosetting plastic. Dark brown. Used as a composite reinforced with paper or cloth. Usedto
make circuit boards and heat proof insulated parts in the electronicsindustry.
Epoxy resin A two part mix which can be used as a glue (ARALDITE) or be reinforced with carbon fibre to
produce a very strong and light composite materials which is used in aerospace and Formula 1
Melamine A thermoset very tough and heat resistant. White but can be produced in a full range ofcolours.