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6.0 POLYMER PROCESSING

SUMMARY

In this chapter we studied that:
1. polymers can be shaped by a variety of processes, including extrusion, molding,

casting, and thermoforming, as well as by some of the processes used in metalworking;
2. injection molding is a process in which a polymer is heated to a highly plastic state and
forced to flow under high pressure into a mold cavity;
3. in plastic extrusion, a polymer melt is compressed using screw to flow through a die

orifice and thus the continuous length of the plastic assumes a cross-sectional shape
that is approximately the same as that of the orifice;
4. compression molding started when pressure is applied by a hydraulic press to the two
halves of the mold which puts the material and the mold under a compressive load;

5. same as compression moulding, transfer molding consists of melting the plastic resin in
a separate chamber and then injecting it into a closed mold;
6. the blown moulding process consists of extruding the molten plastic through a circular
die to form a thin walled tube before internal air pressure expands the tube.

REFERENCES
1. S. Kalpakjian, S.R. Schmid, Manufacturing Engineering and Technology 5th edition,
Prentice Hall, 2005.
2. Steve F.Krar Technology of Machine Tools, Mc Graw Hill.

BPLK 164 DME 1083