3. Introduction
Plastic processing techniques?
The processing stages of plastics are Heating, Forming and
Cooling in continuous or repeated cycle.
The manufacturing process of plastics products depend on
shape of final product and types plastic material being used
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4. Plastics
It is a organic polymer of high molecular mass which can
be easily molded.
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5. Types of Processing Techniques
1.Processing Techniques for Thermosets-
Thermosets can be processed in two steps first it can be
melted and then poured into the mold to make desired shape.
Examples- casting, resins transfer molding etc.
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6. 2.Processing Techniques forThermoplastics
Thermoplastics can be processed by heating up to the
glass transition temperature and formed into the shape
with the application of pressure.
Examples - thermoforming process , extrusion process,
blow molding, compression molding etc.
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7. Casting
Materials Used-
The thermosets (such as polyesters,urethanes,phinolics
and epoxy) and thermoplastics(as nylons) can be used
with powdered stone for colouration.
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8. Advantages
Low initial investment
cost
Flexible parts can be
made
Dimensional stability
High production rate
Disadvantages
This is more labour
intensive than resin
transfer molding
Complex shape can't be
produced
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9. Applications of Casting
Toys, garage kits , sheets either individual parts or
entire model of objects like trains, aircrafts, boats, ships
etc.
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10. Thermoforming
Thermoforming is a plastic processing technique in
which the thermoplastic plastic sheet are formed with the
application of heat and pressure in a mold.
There are different types of thermoforming process-
• Vacuum forming
• Pressure forming
• Matched die forming
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11. Materials Used
Low density polyethylene
(LDPE)
Polyvinyl Chloride (PVC)
High density polyethylene
(HDPE)
Polystyrene
Acrylonitrile butadiene
styrene (ABS)
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15. Advantages
Design flexibility
Low initial step cost
Low production cost
Good Dimensional
stability
Disadvantages
Poor surface finish
Parts may have non
uniform wall thickness
Very thick plastic sheet
can not be used
Limited materials can be
used
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17. Extrusion Processing Techniques
It is a high volume manufacturing process
Materials Used- polyethylene, polypropylene, nylons,
PVC, ABS etc.
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18. Types of Extrusion process
There are different types of Extrusion process-
Sheetfilm Extrusion
Blow film Extrusion
Co- Extrusion
Extrusion coating etc.
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24. Advantages
High production volume
Relatively low cost with
respect to other molding
process
Design flexibility
Short lead time
Continues part can be
produced
Disadvantages
Limited complexity of
part
Uniform cross section
can be only form
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