this is my prsentation of Plastic Process and Processing Parameter in manufacturing process. here discussed moulding process for plastic, plastic injection moulding, machine parts and procedure, material used to making mould and blow moulding process, thermoforming process, vacuum forming process, and application
3. INJECTION MOULDING PROCESS
FOR PLASTIC PROCESSING
It is a manufacturing technique for making parts
from thermoplastic and thermoset materials
In contrast to the extrusion (which makes
continuous parts of constant cross section),
injection molding make discrete parts (with
complex and variable cross section)
Molten plastic is injected at high pressure into a
mold, which is the inverse of the desired shape.
The mold is made from metal, usually either steel
or aluminium
Widely used for manufacturing a variety of parts,
from the smallest component to entire body panels
of cars
5. 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.
6. PROCEDURE
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 .
8. BLOW MOULDING PROCESS FOR
PLASTIC PROCESSING
“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
11. THERMOFORMING PROCESS FOR
PLASTIC PROCESSING
“ 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
12. VACCUME FORMIMG PROCESS
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.