2. GROUP MEMBERS
MUAAZ ALI BSME01113094
IRFAN ALI BSME01113098

3. MUAAZ ALI
INJECTION MOLDING
 BLOW MOLDING
 INJECTION BLOW MOLDING

4. INJECTION MOLDING
 Injection molding is one of the most commonly used
processing method for the plastic components
 It is defined as
“ A manufacturing process for forming objects, as of
plastic or metal, by heating the molding material to a
fluid state and injecting it into a mold “.

5. What does processing of plastic
means ?
 All the methods used for processing of plastics like
Injection molding, blow molding , thermoforming ,
extrusion e.t.c. , have a raw material i.e. plastic in some form
which is then heated , formed and cooled to get the desired
design and product.
 So , the term to memorize in all plastic processing methods
is HFC ( heating , forming , cooling )

6. INJECTION MOLDING (CONTINUED)
 It is used to process thin walled plastic parts for a
wide variety of shapes and products .
BASIC PRINCIPLE
Plastic material is melted in a heated chamber and
then injected in the mold , where it cools and
finally the finished plastic part is ejected out of the
cavity .

7. INJECTION MOLDING MACHINE
 The raw material in the form of powder/pellets is
introduced through hopper into the cylinder

8. Machine parts
 Hopper is a tapered container working with a hopping
motion to transfer grains into cylinder
 Inside the cylinder there is a piston /plunger which is used
to move the material from cylinder into the mold
 Heating arrangement is placed above and below the
cylinder .
 The mold is in two halves , it has a mold cavity and the
mold has two ejector pins.

9. Process
 As soon as the plastic is melted it will be pushed by the
piston into the sprue through which the material
would go into the mold cavity .
 The cavity will be filled by the pressure of the piston
and the mold should not be opened until the plastic
solidifies.
 When the plastic solidifies the ejector pins are
hydraulically moved backwards .

10. Stages of Injection molding
 Clamping : The two halves of mold are tightly closed before
the molten plastic is injected.
 Injection : Injection of raw material from hopper into
cylinder to the cavity is called the injection stage.
 Cooling : The material is cooled for at least 30-60 sec
 Ejection : The 2nd mold plate moves back by ejector pins
and the product is tapped out

11. IMPORTANT POINTS
 PRODUCTION RATE :
Production rate depends upon the clamping and de-clamping
time of the mold halves.
 INJECTION TIME:
The filling process should be optimal not too slow in order to
stop the production of cracks.
 SHOT VOLUME :
The amount of material that is injected into the mold is
referred to as shot volume
 PRESSURE and CYCLE TIME :
The pressure applied is in the range of 35-140 MPa while the
cycle completes in 2-60 sec

12. MATERIALS USED
 Acetate
 Acrylonitrile butadiene styrene (ABS)
 Cellulose acetate
 PVC ( poly vinyl chloride)
 Polycarbonate
 Polyesters
e.t.c.

13. ADVANTAGES
 Higher production rate
 Minimum wastage of material
 Complex geometry can easily be produced
DISADVANTAGES
• Tooling cost higher
• High setup cost
• Large undercuts can not be formed

14. APPLICATIONS
 It can be used to produce thin walled plastic products of
varying size and dimensions e.g.
 Medical devices such as surgical syringes
 Open container like buckets
 Plastic housings of different tools
 Daily use products such as tooth brushes

15. USED in PAKISTAN
 Faraz industries
Address: WH-3/2, sector 16-B , North Karachi , Karachi
 Siddique sons
Address: WH-2/7 ,Sector 16-B , North Karachi, Karachi

16. BLOW MOLDING
 “ It is a plastic processing technique which is used to
produce hollow plastic parts by inflating a heated
plastic until it fills a mold and forms the desired shape”
 The raw material used for processing in blow molding is
called parison
 Parison is a preform tube that is hollow and it has a hole
at one end

17. PROCEDURE
I. First the parison is obtained by means of extrusion or
injection molding process
II. Above the preform there is a blower and the preform is
positioned between two split halves of the mold.
III. The mold closes over the tube and the hot air is injected
from the blower into the hollow tube . The air expands the
tube against the sides of the mold
IV. After sufficient cooling , the mold opens to release the
product.

19. Important Process Parameters
 Cooling temperature of plastic material
 Air pressure required ( usually 2-4 Mpa)
 Cooling time
o Pressure is exerted both axially and radially , both
cavities are pressurized with a non-reactive gas such as
argon.

20. Types of Blow molding
 Extrusion blow molding
 Injection blow molding
 Stretch blow molding
 MAJOR DIFFERENCE:
All the types have one primary difference that is
making of parison by extrusion , injection and
stretching .

21. INJECTION BLOW MOLDING
 The injection blow molding is used for the production of
hollow objects in large quantities . The main applications are
bottles, jars and other containers.
 The process is divided into three sections
i) Injection
ii) Blowing
iii) Ejection

22. IRFAN ALI
 EXTRUSION BLOW MOLDING
 STRETCH BLOW MOLDING
 THERMOFORMING

23. EXTRUSION BLOW MOLDING
 In this process the blow molding machine is based on a standard
extruder barrel and screw assembly to plasticize the polymer.
 The polymer is heated inside the barrel , the molten polymer is
led through a right angle and through a die to emerge as a
hollow section.
 When the parison has moved enough length it is cut through by
a knife and fits inside the bottle mold .
 The bottle mold moves toward the jet where the air blows and
the product is obtained after cooling .

25. Stretch blow molding
 Stretch blow molding is also carried out by injection . Used
the production of high quality containers.
 This process is divided into four steps
 Injection : The material is injected as discussed before.
 Stretching : One conditioned to correct temperature , the
parison is stretched by the blow pin/stretch rod that stretches it
longitudinally .
 Blowing : Using two levels of air pressure , the preform is
blown circumferentially.
 Discharge : After a set time for cooling the molds open and the
product is removed .

26. ADVANTAGES
 Low tooling costs .
 Fast production rates .
 Ability to mold complex parts .
 Little scrap generated .
 Large hollow shape can be produced .
 Produced parts can be recycled .
DISADVANTAGES
• Limited to hollow parts .
• Thick parts cannot be manufactured.

27. Applications
 Different types of plastic products can be
manufactured by this process such as:
 Bottles in different shapes and sizes
 Jars and containers
 Fluid oil tanks
 Mugs
 Toys etc

28. THERMOFORMING
 “ Thermoforming is a plastic processing technique in
which the thermoplastic sheets are formed by applying
temperature and pressure inside the mold .”
 The raw material here is usually plastic sheet
 Different types of this process are
I. Vacuum forming
II. Pressure forming
III. Matched die forming

29. VACUUM FORMING
o The vacuum pressure is used to form the heated
thermoplastic sheet into the desired shape.
o Thermoplastic sheet is placed on the mold surface
and fixed with the help of clamping unit.
o The sheet is heated until it softens and there after ,
vacuum needs to be applied quickly.
o There is tank with nozzles that suck air and creates
vacuum in between sheet and mold.

31. Few important parameters
 How much heat is required ?
 Amount of vacuum needed .
 These parameters solely depends upon the type of
thermoforming and the thickness needed.
Video of vacuum forming

32. PRESSURE FORMING
 The forming process is closely related to the vacuum
forming .
 The air pressure required is much higher as compared
to the pressure required in the vacuum forming
 The preheated plastic sheet is placed on the mold
surface and then air pressure is applied quickly above
the sheet.
 The high pressure is developed in between the
softened sheet and pressure box
 Due to the high pressure, the preheated plastic sheet
can be deformed into the mold cavity in a fraction of
second (means high production rate).

33.  The formed sheet is held in the mold cavity for cooling
for few seconds
 The formed parts thereby solidifies and is ejected.

35. MATCHED DIE FORMING
 A matched die forming is also called mechanical
forming .
 Mold consists of two parts i.e. (i) die and (ii) punch
 Thermoplastic sheet is heated with the application of
heat until it softens
 Preheated sheet is placed into the die and through the
punch , pressure is applied on sheet
 Air between the die and sheet is evacuated by using
vacuum pump , and sheet conforms to the mold shape.
 Formed part is cooled and ejected from the mold.

36. Materials used
 ABS (Acrylonutrile butadiene styrene)
 Celloluse acetate
 LDPE (Low density polyethylene)
 HDPE (High density polyethylene)
 PVC etc

37. ADVANTAGES
 Design flexibility
 Rapid prototype development
 Low initial setup costs
 Low production cost
 Less thermal stresses
 Good dimensional stability
DISADVANTAGES
• Poor surface finish
• Parts may have non-uniform thickness
• All parts needs to be trimmed
• Limited materials can be made

38. Applications
 Thermoforming has many applications like
I. Food packaging
II. Automotive parts
III. Aircraft windscreens
IV. Vehicle doors

39. APPLICATIONS IN PAKISTAN
 Ideal Industry
Mailing Address: Plot # 109, Kerbath Soling, 1 km Off Main Bedian
Road, Lahore Pakistan.
Pabx: 92 42 35600211/12
Cell: 92 344 6001111
Fax: 92 42 35600209
Email: sales@idealindustriesm.pk